神冬4.00Mta选煤厂初步设计【含CAD图纸+文档】
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目录 第一部分1 概 述11.1选煤厂类型、厂型及厂址11.2工作制度11.3矿区及厂址概况11.4原料煤矿井概况11.5选煤工艺11.6产品品种及用途11.7供水、供电11.7.1水源11.7.2电源21.7.3交通运输21.8主要经济技术指标22 工艺部分42.1煤质资料分析及可选性研42.1.1煤质资料的审查及分析42.1.2两矿原煤可选性研究及分组分级讨论172.2选煤工艺的初定和技术经济比较302.2.1 初步选定的方案分析302.2.2 方案的预测312.2.3、方案的技术经济比较342.3 选定流程的介绍及流程计算372.3.1 辅助工艺的确定372.3.2设计工艺流程的整体描述及工艺流程图402.4流程计算412.4.1 数质量流程计算422.4.2 介质流程计算422.5 设备选型及计算572.5.1 选型与计算的原则和规定572.5.2 主要设备选型与计算582.6选煤工艺布置672.6.1 总平面布置672.6.2 原煤受煤、配煤672.6.3 主厂房672.6.4 产品仓692.6.5 煤泥压滤车间692.7 生产技术检查692.7.1检查的内容与项目692.7.2 技术检查取样设置712.7.3 检查室713 建筑物和构筑物713.1 概述713.1 气象级地震资料723.3 建筑物及构筑物设计723.3.1 建筑设计723.3.2 结构设计724 给水排水724.1给水水源724.2用水量和水压734.3给水系统734.4排水735 生产辅助设施735.1机电修理车间735.2介质制备车间745.3压缩空气供应746 电 气756.1供配电756.1.1 电源及供电方式756.1.2 供配电系统756.1.3照明756.1.4防雷756.2集中控制与自动化766.2.1控制系统766.2.2 控制原则766.3通讯调度767 铁路运输767.1本厂区各铁路专用线的技术条件767.2股道设置768 采暖通风与药剂库778.1 概述778.2 采暖778.3 室外供热管道778.4 通风除尘778.5 药剂库789 工业场地总平面789.1 原始资料789.2 总平面布置789.2.1 布置原则789.2.2 场地功能区分789.2.3 总平面布置789.2.4辅助车间的布置799.2.5行政、生活福利设施的布置799.2.6运输799.2.7场地利用系数及绿化7910 技术经济7910.1 劳动定员7910.2选煤成本8110.2.1 产品销售收入8110.2.2 计算方法及依据8210.2.3分离后成本8210.2.4 技术经济评价与指标8311 环境保护8411.1 主要污染源及其控制措施8411.2厂区绿化8412 劳动安全8512.1预防自然灾害的措施8512.2防火措施8512.3防机械伤害和人身安全措施8512.4防触电伤害措施8512.5安全救护85 第二部分1 概算编制说明851.1 工程概况及投资范围851.2 编制依据及取费标准861.2.1编制依据861.2.2 概算指标861.2.3 价格861.2.4 取费标准861.2.5 基本预备费861.2.6 概算总投资862 概算结果汇总86 第三部分浅析褐煤应用技术99 第四部分1 英文原文1022 中文译文121致 谢1351 概 述1.1选煤厂类型、厂型及厂址神冬选煤厂以入凉水井矿和榆阳矿的原煤为主,比例为7:3,是一座矿区型选煤厂,设计入洗能力为4.00Mt/a。该选煤厂拟建于神木凉水井矿区内。1.2工作制度选煤厂实际生产时间为每年330天,每天16小时,两班生产,一班检修。1.3矿区及厂址概况凉水井矿位于神木县锦界镇,西距榆林市85公里,东距神木县城25公里,省道204、榆神高速公路、神延铁路紧邻工业广场,交通条件便利,地理位置优越。1.4原料煤矿井概况凉水井矿井井田面积68.08平方公里,地质储量6.65亿吨,可采储量4.07亿吨,地质构造简单,煤层赋存稳定,属低灰、低硫、低磷、高发热量的电力和汽化用煤。榆阳矿与本矿煤质相似。1.5选煤工艺神冬选煤厂以入凉水井矿和榆阳矿的原煤为主,比例为7:3,据原始煤质资料及用户的要求灰分级别,此时原煤可选性属易选。经过五种入洗工艺的方案比较,本选煤厂采用斜轮重介选有压两产品重介选粗煤泥分选直接浮选联合工艺。具体工艺为:原煤经过13mm分级筛分,筛上进入斜轮重介选,筛下进入有压两产品重介旋流器进行分选,10.25mm粗煤泥采用螺旋分选,-0.25mm采用机械搅拌式浮选机浮选。斜轮分选出块精煤和块矸石,分别经过固定筛和脱介筛后成为产品,末精经过弧形筛和脱介筛在经过离心脱水成为产品,末矸经过弧形筛和脱介筛成为最终产品;粗精煤泥经震动弧形筛煤泥离心机脱水后成为产品;浮选精煤经快开压滤脱水成最终产品;浮尾和粗尾煤泥经浓缩机浓缩后在快开脱水成为煤泥。块精煤上仓后经200mm分级,筛上破碎到200mm一下,筛下和破碎后精煤经100mm分级,最终出200mm100mm精煤,100mm13mm精煤;末精和粗精及浮精混到一起成末精煤;块矸和末矸分别单独进仓;尾煤泥经晾晒后成最终产品。1.6产品品种及用途神冬选煤厂选后产品分为大块精煤、中块精煤、末精煤、矸石、煤泥;中块精煤和末精产品主要用于动力发电,;矸石主要用于附近的矸石砖厂;大块精煤和煤泥地销。1.7供水、供电1.7.1水源生活及消防用水取自厂外生活及消防给水管网,其水量、水质、水压都能满足生活用水要求;生产用水可取自处理后的矿井井下来水,也可来自水源井,水量、水质都能满足生产用水要求。1.7.2电源厂区设有变电所,电源引至10kVA高压电网,和矿井属同一级别。经厂区变电所将其变成动力用电、生活用电等级后供厂区生产、生活使用,因而电源有可靠保证。1.7.3交通运输省道204、榆神高速公路、神延铁路紧邻工业广场,交通条件便利。1.8主要经济技术指标主要技术经济指标见表1.8-1。表1.8-1 技术经济指标表序号指标名称单位指 标备注1选煤厂类型矿区型2处理能力(1)年处理能力万t400.00 (2)日处理能力t12121.21 (3)小时处理能力t757.58 3设计工作制度(1)年工作天数d330(2)日工作小时h164原煤质量牌号不粘煤灰分21.47 5原煤的可选性易选序号指标名称单位指 标备注6选煤方法重介-浮选联合工艺7选后产品质量(灰分/水分)(1)块精煤7.52/14.7(2)末精煤7.32/13.8(3)矸石84.93/24.0(4)煤泥76.77/28.68选后产品产率(1)块精煤47.05 (2)末精煤34.28 (3)矸石13.29 (4)煤泥5.38 9选后产品年产量(1)块精煤万t188.18 (2)末精煤万t92.48 (3)矸石万t53.17 (4)煤泥万t21.54 10全厂在籍人数人196其中:生产工人17311劳动生产率(1)全员效率t/工70.00 (2)生产工效率t/工75.60 12吨煤用水量(1)清水m3/t0.21 (2)循环水m3/t1.41 13吨煤电耗kw.h7.50 14重介系统吨煤介耗Kg/t1.22 15建设项目静态总投资万元25508.26 其中:土建工程万元19073.80 设备购置万元2823.69 安装工程万元3171.43 其他费用万元1295.97 工程预备费万元1443.86 16吨原煤基建投资元83.82 17吨原煤加工费元26.42 18选后产品单位成本(1)块精煤元/t414.74 (2)末精煤元/t362.90 (3)矸石元/t2.59 (4)煤泥元/t10.37 19年平均税后利润万元/年79764.96 20静态投资回收期年0.32 序号指标名称单位指 标备注6选煤方法重介-浮选联合工艺7选后产品质量(灰分/水分)(1)块精煤7.52/14.7(2)末精煤7.32/13.8(3)矸石84.93/24.0(4)煤泥76.77/28.68选后产品产率(1)块精煤47.05 (2)末精煤34.28 (3)矸石13.29 (4)煤泥5.38 9选后产品年产量(1)块精煤万t188.18 (2)末精煤万t92.48 (3)矸石万t53.17 (4)煤泥万t21.54 10全厂在籍人数人196其中:生产工人17311劳动生产率(1)全员效率t/工70.00 (2)生产工效率t/工75.60 12吨煤用水量(1)清水m3/t0.21 (2)循环水m3/t1.41 13吨煤电耗kw.h7.50 14重介系统吨煤介耗Kg/t1.22 15建设项目静态总投资万元25508.26 其中:土建工程万元19073.80 设备购置万元2823.69 安装工程万元3171.43 其他费用万元1295.97 工程预备费万元1443.86 16吨原煤基建投资元83.82 17吨原煤加工费元26.42 18选后产品单位成本(1)块精煤元/t414.74 (2)末精煤元/t362.90 (3)矸石元/t2.59 (4)煤泥元/t10.37 19年平均税后利润万元/年79764.96 20静态投资回收期年0.32 2 工艺部分2.1煤质资料分析及可选性研煤质分析可谓选煤设计的重中之重,进行透彻的煤质分析,准确把握原煤特性,设计出适于原煤实际特性的工艺流程,可为选煤厂创造更大的经济效益,同时为社会也做出了贡献。否则,设计的选煤厂无法正常生产,不能实现既定的生产技术指标,产品不能满足用户要求,对设计方与投资方都会造成巨大损失。为了进一步了解煤的内在性质,以制定合理的选煤工艺流程,下面将原煤资料进行如下分析。2.1.1煤质资料的审查及分析一、资料可靠性分析对原煤资料的分析,首先要特别重视煤质资料的代表性。用不具代表性或代表性差的筛分、浮沉资料提供设计,是对设计的误导,后果是严重的。因此,对煤质资料的代表性问题应该引起高度重视。现将原煤资料可靠性分析如下:1、原煤矿样分别是:凉水井矿采样地点:凉水井煤矿4-2煤层,榆阳矿采样地点:陕西中能煤田有限公司榆阳煤矿,没有用相邻矿井和其他地质资料作代资料,故该矿样具有高度的代表性。2、该矿样是经过采样、试验、制样、化验、计算等工序完成的,各工序都可能产生误差。如果误差超过一定限度,不仅影响资料的准确性和可靠性,甚至判定该资料不能使用,所以筛分、浮沉试验都要按国家标准GB/T477-1998煤炭筛分试验方法、GB478-87煤炭浮沉试验方法和行业标准MT-93煤粉筛分试验方法、MT57-93煤粉浮沉试验方法进行审查。(1)、试验过程中试样重量损失的审查:对筛分或浮沉试验资料,试验前后煤样的重量的差值比不得超过2%。即 =(煤样总质量毛煤质量)/煤样总质量;对于凉水井矿:1=(10541.31506.4)/10541.3=0.33%2%,小于规定的重量损失百分数,资料可用;对于榆阳矿:1=(10562.410552.7)/10562.4=0.09%2%,小于规定的重量损失百分数,资料可用;(2)、试验结果的灰分差值:筛分试验前总样灰分与试验后各粒级产物灰分的加权平均值的差值,以及浮沉试验前煤样灰分与试验后各密度级产物灰分的加权平均值的差值,按其灰分不同、粒度不同有不同的规定。(3)、筛分试验的审查:对于筛分试验,煤样灰分20%,相对差值不超过10%;煤样灰分20%,绝对差值不超过2%。2=(筛分试验前总样灰分试验后各粒级产物灰分的加权平均值)/筛分试验前总样灰分;对于凉水井矿:2=22.4221.34=1.08%2%,小于规定的重量损失百分数,资料可用;对于榆阳矿:2=20.80-21.77=0.97%2%,小于规定的重量损失百分数,资料可用;(4)、浮沉资料的审查:对于浮沉资料,粒度大于或等于25mm时,煤样灰分20%,相对差值不超过10%;煤样灰分20%,绝对差值不超过2%;最大粒度小于25mm时,煤样灰分 50 合计4156.6 39.56 15.05 0.20 5040煤653.0 6.22 7.66 21.72 0.25 22.890 4035煤366.2 3.49 7.28 20.00 0.19 23.500 3530煤374.9 3.57 6.65 19.41 0.00 23.940 3025煤384.6 3.66 7.16 15.24 0.34 25.540 2513煤995.5 9.48 6.74 25.11 0.19 20.960 136煤909.7 8.66 7.35 23.89 0.17 21.980 63煤838.8 7.98 8.08 24.89 0.18 21.330 30.5煤1260.0 11.99 6.75 30.54 0.21 20.140 0.50煤567.1 5.40 6.43 36.96 0.36 17.580 50 0 合 计6349.8 60.44 25.46 0.21 原 煤 总 计10506.4 100.00 6.95 21.34 0.21 原 煤 总 计10107.0 (除50mm级矸石和硫铁矿)通过对大样资料的分析,从表2.1-2 中可以看出:a、从表2.1-1中可以知道其硫分和灰分,根据选煤工艺设计与管理P40表3-1可知,此煤灰分为21.34%,属于中灰分特低硫分煤。b、矸石含量3.80%,根据选煤工艺设计与管理P42表3-5可知,属于中矸,因此不宜手选,初步判定可能用机械排矸。c、原煤主导粒级80-50mm,占原煤总样的14.78%。各粒级灰分随粒度的减小呈上升趋势,且各粒级含量相差不大,说明煤质较硬。d、原煤灰分随粒度级的变化较明显,说明矸石易碎。(3)、凉水井矿原煤的泥化试验表2.1-3 凉水井矿原煤泥化验报告表项 目第一次试验重复试验平均值产率+500m82.60 82.56 82.58 %-500m+10m13.27 13.31 13.29 -10m0.03 0.03 0.03 泥化比,%13.30 13.34 13.32 试样水分(Mt), %4.14.14.1注:泥化比即是小于500m筛下物的百分数根据MT/T1075-2008 煤伴生矿物泥化评定标准 可知属于中高程度泥化,故在煤泥水处理环节应多加考虑。1、 榆阳矿原煤筛分资料分析(1)、榆阳矿原煤的工业分析表2.1-4 榆阳矿原煤工业分析报告表采样地点:陕西中能煤田有限公司榆阳煤矿 项目 煤样MadAdVdafSt,adQgr,adGR.I.胶 质 层(%)(%)(%)(%)(MJ/kg)X(mm)Y(mm)原 煤4.50 0.00 0.00 1.83 -0.172 浮煤(-1.4)5.09 0.00 0.00 1.26 1360.0 6.0 由给定的原始资料易知,凉水井矿的原煤牌号为不粘煤,可作动力用煤。(2)、榆阳矿原煤的筛分试验表2.1-5 榆阳矿原煤筛分试验报告表筛分前煤样总重量: 10562.4 kg 最大粒度:282315174 mm 粒 级 (mm)产物名称产 率质 量质 量占全样筛上累计MadAdSt,adQgr,ad(kg)(%)(%)(%)(%)(%)(MJ/kg)100手选煤116.4 1.10 3.71 13.60 2.64 26.438 矸 石244.4 2.32 0.67 94.20 0.59 0.383 小计360.8 3.42 68.20 1.25 10050手选煤292.5 2.77 3.69 12.31 2.08 26.874 矸 石271.7 2.57 0.91 90.39 0.51 0.629 小计564.2 5.35 49.91 1.32 50 合计925.0 8.77 57.05 1.30 5025煤913.9 8.66 2.33 30.74 2.27 20.891 2513煤1343.6 12.73 3.20 24.63 1.94 22.855 136煤1784.2 16.91 2.47 20.31 2.18 25.301 63煤2312.0 21.91 3.92 13.77 1.88 27.205 30.5煤2356.9 22.33 4.94 13.29 1.77 26.647 0.50煤917.1 8.69 2.12 17.89 2.09 25.623 50 0 合 计9627.7 91.23 18.38 1.97 原 煤 总 计10552.7 100.00 3.36 21.77 1.91 原 煤 总 计10036.6 (除50mm级矸石和硫铁矿)通过对大样资料的分析,从表2.1-5 中可以看出:a、从表2.1-5中可以知道其硫分和灰分,根据选煤工艺设计与管理P40表3-1可知,此煤灰分为21.77%,属于中灰分中硫分煤。b、矸石含量4.89%,根据选煤工艺设计与管理P42表3-5可知,属于中矸,因此不宜手选,初步判定可能用机械排矸。c、原煤主导粒级3-0.5mm,占原煤总样的22.33%。各粒级灰分随粒度的减小呈下降趋势,且各粒级含量相差不大,说明煤质较脆易碎。d、原煤灰分随粒度级的变化较明显,说明矸石易碎。(3)、榆阳矿原煤的泥化试验表2.1-6 榆阳矿原煤筛分试验报告表项 目第一次试验重复试验平均值产率+500m95.48 95.44 95.46 %-500m+10m2.81 2.85 2.83 -10m0.01 0.01 0.01 泥化比,%2.82 2.86 2.84 试样水分(Mt), %1.71.71.7注:泥化比即是小于500m筛下物的百分数根据MT/T1075-2008 煤伴生矿物泥化评定标准 可知属于中程度泥化。3、凉水井矿原煤浮沉资料分析根据前面所述的原煤浮沉资料的审查,该资料准确可信,对指导设计有很大的作用,下面将该矿的浮沉资料分析如下:由2.1-7可知:(1)由50-0.5mm级可以看出,该矿的主导密度级为-1.3kg/L,占该矿样的50-0.5mm级的42.57%,占该矿全样的21.29%。1.3-1.4kg/L密度级的含量较多占本矿样的14.44%。1.4-2.0kg/L密度级的含量少,+2.0kg/L密度级的含量增多,综上可以发现,该煤样的密度分布是“两头多中间少”,可以粗略的判断出,该煤样在灰分要求不低的情况下可选性较好。在具体的灰分要求下,用0.1邻近密度物含量法来判定煤的可选性。(2)12%,故没有用重力分选方法获得低灰精煤的可能;2.0 g/cm3密度级的灰分Ad=86.58%,故矸石很纯,在生产中可以得到高灰产品。(3)原煤中2.0 g/cm3的产率为9.05%,灰分为86.58%,因此矸石含量较多,初步考虑需进行机械排矸。(4)随着粒度级的降低,低密度级(1.301.40 g/cm3)和中间密度级(1.40-1.80 g/cm3)含量无明显变化趋势,说明该煤硬度中等。随着粒度的降低,高密度级(+2.00 g/cm3)含量降低,但灰分无明显变化,说明矸石硬度中等。表2.1-7 凉水井矿原煤自然级浮沉试验报告表4、榆阳矿自然级浮沉资料试验分析2.1-8 榆阳矿自然级浮沉试验报告表由表2.1-8可知:(1)由50-0.5mm级可以看出,该矿的主导密度级为-1.3kg/L,占该矿样的50-0.5mm级的52.68%,占该矿全样的42.53%。1.3-1.4kg/L密度级的含量较多占本矿样的14.4417.19%。1.4-2.0kg/L密度级的含量少,+2.0kg/L密度级的含量增多,综上可以发现,该煤样的密度分布是“两头多中间少”,可以粗略的判断出,该煤样在灰分要求不低的情况下可选性较好。在具体的灰分要求下,用0.1邻近密度物含量法来判定煤的可选性。(2)12%,故没有用重力分选方法获得低灰精煤的可能;2.0 g/cm3密度级的灰分Ad=82.39%,故矸石很纯,在生产中可以得到高灰产品。(3)原煤中2.0 g/cm3的产率为10.95%,灰分为82.39%,因此矸石含量较多,初步考虑需进行机械排矸。(4)随着粒度级的降低,低密度级(1.301.40 g/cm3)含量增加,中间密度级(1.40-1.80 g/cm3)含量无明显变化趋势,说明该煤硬度差。随着粒度的降低,高密度级(+2.00 g/cm3)含量基本不变,灰分无明显变化,说明矸石较硬。5、凉水井矿、榆阳矿破碎级500.5mm浮沉试验报告分析该两煤样分别来源于两矿的筛分大样资料的破碎煤样的浮沉试验,由表2.1-9可知,破碎后得到很好解离,-1.40g/cm3占本级83.12%,但是由于原煤是动力用煤是否破碎还需后续讨论;由2.1-10可知表中数据分析可知,低密度级(1.301.40 g/cm3)和高密度级(+2.00 g/cm3)含量多,中间密度级(1.40-1.80g/cm3)含量少;高密度级灰分有所提升,说明得到一定解离,但是中间密度级含量特别少,高密度级含量占 57.83%,同时由于牌号,不能确定是否破碎。6、凉水井矿、榆阳矿煤粉筛分试验报告分析两矿煤泥浮沉资料2.1-11、2.1-12、2.1-13、2.1-14可以看到:(1)煤泥各粒级的分布很不均匀,0.500-0.125mm级的含量占一半以上;且粗粒煤灰分低于细粒煤的灰分。 粒 级质量/g占本级占全样Ad/%( mm )产率/%产率/%0.5000.2505050.00 2.70 34.92 0.2500.1253535.00 1.89 36.46 0.1250.0751010.00 0.54 42.75 0.0750.04533.00 0.16 48.54 0.04522.00 0.11 50.30 总 计100100.00 5.40 36.96 (2)煤泥各粒级的灰分变化幅度较大,再一次说明矸石泥化。这对于煤泥水处理系统很不利。(3)煤泥灰分处于中等水平,其可选性有筛分表可预测为易选或中等可选,是否分选还需进一步讨论。表2.1-11 凉水井矿自然级煤粉筛分试验报告表2.1-9 凉水井破碎级500.5mm浮沉试验报告表表2.1-10 榆阳矿破碎级500.5mm浮沉试验报告 表2.1-12 凉水井矿破碎级煤粉筛分试验报告粒 级质量/g占本级占全样Ad/%( mm )产率/%产率/%0.5000.2503333.00 0.23 17.56 0.2500.1254040.00 0.28 20.26 0.1250.0752222.00 0.16 30.24 0.0750.04533.00 0.02 35.66 0.04522.00 0.01 37.23 总 计100100.00 0.71 22.36 表2.1-13 榆阳矿自然级煤粉筛分试验报告粒 级质量/g占本级占全样Ad/%( mm )产率/%产率/%0.5000.2503232.00 2.78 15.88 0.2500.1253232.00 2.78 16.11 0.1250.0752020.00 1.74 18.84 0.0750.04588.00 0.70 22.21 0.04588.00 0.70 26.33 总 计100100.00 8.69 17.89 表2.1-14 榆阳矿破碎级煤粉筛分试验报告粒 级质量/g占本级占全样Ad/%( mm )产率/%产率/%0.5000.2502828.00 0.04 30.04 0.2500.1252929.00 0.04 33.24 0.1250.0752727.00 0.04 34.81 0.0750.04599.00 0.01 39.36 0.04577.00 0.01 41.48 总 计100100.00 0.15 33.90 7、凉水井矿、榆阳矿煤粉筛分试验报告分析由两矿煤泥浮沉资料表2.1-15、2.1-16、2.1-17、2.1-18可以看到:两矿煤泥的主导密度级为1.4kg/l,含量较大,占50%左右。煤泥总灰分差距较大,且2.0kg/l以下的含量也高,为20%以上,总体呈现“两头多中间少”。通过对以上两矿原煤资料的分析,两种原煤的密度组成相近,原煤牌号相同,除此之外,两矿的粒度组成的分布,小筛粉、小浮沉所体现出来的性质也相近,灰分随密度、粒度变化的规律一致,在此再次说明该两煤种具备混合入洗的先决条件。表2.1-15 凉水井矿自然级煤粉浮沉试验报告 密度级/(kg/L)产率灰分/%浮物累计沉物累计占本级/%占全样/%产率/%灰分/%产率/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 2.036.01 1.94 83.95 100.00 36.96 36.01 83.95 总 计100.00 5.40 36.96 表2.1-16 凉水井矿破碎级煤粉浮沉试验报告密度级/(kg/L)产率灰分/%浮物累计沉物累计占本级/%占全样/%产率/%灰分/%产率/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 2.016.21 0.11 84.62 100.00 22.36 16.21 84.62 总 计100.00 0.71 22.36 表2.1-17 榆阳矿自然级煤粉浮沉试验报告密度级/(kg/L)产率灰分/%浮物累计沉物累计占本级/%占全样/%产率/%灰分/%产率/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 2.012.21 1.06 78.35 100.00 17.89 12.21 78.35 总 计100.00 8.69 17.89 表2.1-18 榆阳矿破碎级煤粉浮沉试验报告密度级/(kg/L)产率灰分/%浮物累计沉物累计占本级/%占全样/%产率/%灰分/%产率/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 2.033.22 0.05 82.21 100.00 33.90 33.22 82.21 总 计100.00 0.15 33.90 2.1.2两矿原煤可选性研究及分组分级讨论一、两矿浮沉资料的整理及可选性研究1、由表2.1-7、2.1-9的浮沉资料报告中将资料整理综合累计如下:2.1-19 凉水井矿500.5mm综合级可选性研究表密度级/(kg/L)产率灰分/%浮物累计沉物累计0.1占本级/%占全样/%产率/%灰分/%产率/%灰分/%密度级产率/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 2.013.13 8.15 87.41 100.0 18.38 13.13 87.41 合计100.00 62.05 18.38 煤泥5.60 3.68 55.16 总计100.00 65.73 20.44 图2.1-1 凉水井矿500.5mm综合级可选性曲线由表2.1-19可绘制图2.1-1分析表2.1-19浮沉试验结果综合表及图2.1-1可选性曲线可知:(1)、该矿的主导密度级为-1.3kg/L,其占本级产率为52.54%,占本级产率为32.60%,灰分为3.37%。(2)、该矿中1.8 kg/L密度级含量为85.67%,灰分为7.16%,符合精煤灰分要求;这时的0.1含量为2.09%。(3)、该矿中1.8 kg/L密度级含量为14.33%,灰分为85.45%。这表明该煤综合样的高密度物含量一般,因此该煤的总灰分处于中等水平,为20.44%。(4)、当要求精煤灰分为7.51-8.0%时,取精煤灰分为7.50%,则理论精煤产率86.25%,理论分选密度为1.95kg/L,邻近密度物含量为1.2%,扣除1.8kg/L的密度级的灰分为85.45%,想排除高灰矸石是比较容易实现的。2、由表2.1-8、2.1-10的浮沉资料报告中将资料整理综合累计如下:2.1-20 榆阳矿500.5mm综合级可选性研究表密度级/(kg/L)产率灰分/%浮物累计沉物累计0.1占本级/%占全样/%产率/%灰分/%产率/%灰分/%密度级产率/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 2.014.55 3.52 82.45 100.0 18.32 14.55 82.45 合计100.00 24.22 18.32 煤泥2.20 0.54 23.33 总计100.00 24.76 18.43 图2.1-2 榆阳矿500.5mm综合级可选性曲线由表2.1-20可绘制图2.1-2分析表2.1-20浮沉试验结果综合表及图2.1-2可选性曲线可知:(1)、该矿的主导密度级为-1.3 kg/L,其产率为52.06%,灰分为2.89%。(2)、该矿中2.0 kg/L密度级含量为85.45%,灰分为7.40%,符合精煤灰分要求;这时的0.1含量为1.20%。(3)、该矿中1.8 kg/L密度级含量为15.76%,灰分为79.85%。这表明该煤综合样的高密度物含量一般,因此该煤的总灰分处于中等水平,为18.43%。(4)、当要求精煤灰分为7.51-8.0%时,取精煤灰分为7.50%,则理论精煤产率85.41%,理论分选密度为1.99kg/L,邻近密度物含量为1.2%,扣除1.8kg/L的密度级的灰分为79.85%,想排除高灰矸石是比较容易实现的。二、分组、分级分析1、分组讨论本厂是矿区型选煤厂,设计入洗原煤是由两个矿井来煤,对原煤的是否混合入洗,应该是我们设计时重点考虑的问题,如果两矿原煤能够混合入洗,可以大大减少基建投资、简便工艺环节、降低加工费用、便于操作管理。分组入选是指将可采、可运的不同原煤,从入厂到产品出厂都分系统处理,此时选煤厂要建立完全独立的不同系统,流程复杂,投资大,管理也比较困难。判断原煤是否分组的条件为:(1)、原煤牌号不同;(2)、选后产品有特殊要求;(3)、精煤硫分相差悬殊;(4)、用密度基元灰分曲线判断,根据原煤的可选性曲线,在同一坐标中,画出各自的密度基元灰分曲线:若当一定时,5%时,不需要分组;若当一定时,0.05时,不需要分组。由以上条件,判断本厂原煤是否需要分组。(1)两矿牌号完全相同,都同属动力煤品种,故具备不需分组的先决条件;(2)选后产品主要做动力发电,用户相同,且用户对该品种煤的质量要求一致,故可以考虑不必分组;(3)由前面对煤质的分析讨论可知,两矿硫分含量均较低,无需分组;(4)以凉水井矿浮沉可选性研究数据表2.1-19及榆阳矿浮沉可选性数据表2.1-20及两矿的可选性曲线图2.1-1及图2.1-2分析整理,可得两矿的-曲线分析数据,见表2.1-22所示:表2.1-21 两矿-曲线分析分组凉水井榆阳密度kg/L浮物产率%基元灰分%密度kg/L浮物产率%基元灰分%1.352.54 6.051.352.06 6.19 1.477.62 16.211.473.07 15.35 1.582.80 21.211.580.30 22.30 1.684.07 26.911.681.88 25.01 1.784.78 29.511.783.02 27.00 1.885.67 33.651.884.24 30.22 1.986.87 37.851.985.45 33.45 由表2.1-21画出-曲线图如下:图2.1-3 两矿-曲线分组分析图从图2.1-3分析可知,当取理论分选密度p=1.9时,=4.3%5%,且当密度在1.9kg/L时,均小于5%。经过以上综合、分析讨论,说明该两矿原煤具备混合入洗的条件,并且采用混合入洗,完全能够遵循最大产率原则,所以在本厂最终设计将采用混合入洗的方法。2、两矿煤质资料综合及分级讨论根据以上对两矿原煤的分析和讨论,以及在入洗过程是否需要分组的讨论,其结论是两矿原煤不分组。根据设计资料两矿比例为7:3,下面将以上煤质资料按该比例进行数据综合整理。(1)、两矿原煤大筛分资料的综合根据表2.1-2、表2.1-5将筛分资料按凉水井矿煤70%,榆阳矿煤30%的比例综合,得到两矿原煤大筛分综合表,见表2.1-22所示;表2.1-22 两矿原煤大筛分试验结果综合表(2)、两矿煤自然级与破碎级筛分资料的综合根据以上对两矿原煤的分析和讨论,以及在入洗过程是否需要分组的讨论,其结论是两矿原煤不分组。根据设计资料两矿比例为7:3,下面将以上煤质资料按该比例进行数据综合整理。表2.1-23 凉水井矿煤+50mm破碎级筛分表粒 级产物名称质量/kg占本级产率/%占全样产率/%Mad / %Ad / %St,ad / %Qgr,admmMJ/kg50 25煤362.30 72.06 28.51 6.9315.70 0.17 25.319 25 13煤54.60 10.86 4.30 7.0814.83 0.19 25.675 13 6煤29.00 5.77 2.28 7.3913.04 0.20 26.170 6 3煤24.30 4.83 1.91 7.0913.20 0.19 26.201 3 0.5煤23.60 4.69 1.86 6.4913.26 0.20 26.124 0.50煤9.00 1.79 0.71 7.522.66 0.34 22.530 500合计502.80 100.00 39.56 15.34 0.18 表2.1-24 榆阳矿煤+50mm破碎级筛分表 粒 级产物名称质量/kg占本级产率/%占全样产率/%Mad / %Ad / %St,ad / %Qgr,admmMJ/kg50 25煤357.20 69.79 6.12 2.86 64.32 1.53 19.356 25 13煤78.80 15.40 1.35 2.84 50.47 1.55 22.520 13 6煤28.50 5.57 0.49 3.20 43.71 1.47 23.689 6 3煤17.70 3.46 0.30 2.81 43.75 1.78 23.927 3 0.5煤20.70 4.04 0.35 3.12 39.29 1.74 24.691 0.50煤8.90 1.74 0.15 1.71 35.67 1.75 25.120 500合计511.80 100.00 8.77 58.82 1.55 将表2.1-23和表2.1-24综合起来得到两矿原煤+50mm破碎级筛分试验综合表,见表2.1-25所示:表2.1-25 两矿原煤+50mm破碎级筛分试验综合结果表粒级凉水井矿K3= 27.69%榆阳矿K4= 2.63%K3+K4=占本级占全样灰分校正灰分占本级占全样灰分校正灰分占全样校正前灰分校正后灰分12345678910111250-2572.06 19.95 15.70 15.40 69.79 1.84 64.32 62.55 21.79 19.80 19.38 25-1310.86 3.01 14.83 14.53 15.40 0.40 50.47 48.70 3.41 19.06 18.59 13-65.77 1.60 13.04 12.74 5.57 0.15 43.71 41.94 1.74 15.62 15.20 6-34.83 1.34 13.20 12.90 3.46 0.09 43.75 41.98 1.43 15.14 14.75 3-0.54.69 1.30 13.26 12.96 4.04 0.11 39.29 37.51 1.41 15.23 14.82 -0.51.79 0.50 22.66 22.36 1.74 0.05 35.67 33.90 0.54 23.76 23.34 合计100.0 27.69 15.34 15.05 100.00 2.63 58.82 57.05 30.32 19.11 18.69 由两矿的大筛分表(表2.1-2和表2.1-5),可知两矿的自然级筛分组成表,结合上述两矿破碎级筛分表(表2.1-23和表2.1-24)可得两矿自然级与破碎级筛分组成综合表,见表2.1-26所示:(3)、两矿煤自然级与破碎级浮沉资料的综合将表2.1-7、2.1-8、2.1-9、2.1-10综合,得到两矿煤自然级与破碎级浮沉试验综合表,见表2.1-28所示: 由表2.1-28可将两矿浮沉资料整理综合为表2.1-29所示:表2.1-28 两矿煤自然级与破碎级50-0.5mm浮沉试验综合表表2.1-29 两矿混合煤50-0.5mm浮沉试验综合表密度级/(kg/L)产率灰分/%浮物累计沉物累计0.1占本级/%占全样/%产率/%灰分/%产率/%灰分/%密度级产率/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 2.014.82 13.16 86.43 100.0 19.50 14.82 86.43 合计100.00 88.84 19.50 煤泥4.55 4.23 51.05 总计100.00 93.07 20.93 由此表画出两矿煤的可选性曲线如下图2.1-4:图2.1-4 两矿混煤可选性曲线分析表2.1-29浮沉试验结果综合表及图2.1-4可选性曲线可知:(1)混合后两矿的主导密度级仍为-1.3 kg/L,其产率为51.36%,灰分为3.24%。(2)该混合煤中1.8 kg/L密度级含量为83.96%,灰分为7.11%,在要求的灰分范围内,分选密度可达1.8 kg/L。(3)该混合煤中1.8 kg/L密度级含量为17.03%,灰分为82.18%,表明该煤综合样的高密度物含量并不高,因此该混合煤的总灰分中等,为20.93%。(4)由于1.8kg/L密度级的灰分为82.18%,假设排除的矸石全部为+1.8kg/L 的高密度物,该矸石的灰分较高,同上,想排除高灰矸石是比较容易的。 (5)当要求精煤灰分为7.51-8.0%时,取精煤灰分为7.50%,则理论精煤产率84.90%,理论分选密度为1.98kg/L,邻近密度物含量为32.50%,扣除沉矸后的0.1含量为5.4%。根据中国煤炭可选性等级评定标准(GB/T16417-1996),混合后,该煤的可选性等级为易选煤。4、分级分析 分级入选是指不同粒级的煤分别选用不同的分选方法,也叫作分别入洗。是否分级入洗主要取决于分选工艺的不同,同时,也要考虑不同粒度级的性质的差异。是否分级入选,取决于以下因素:(1)各粒级煤的性质。一般在正常分选条件下,不同粒级煤有如下特征:在同一分选条件下,粒度越细,分选密度越高,否则应考虑分级入洗。(2)分选的工艺和设备限制。若采用斜立轮分选、动筛排矸必须按设备允许的入料粒级分级。(3)用密度-基元灰分曲线判断,根据原煤的可选性曲线,在同一坐标中,画出各自的密度基元灰分曲线:当一定时,5%时,需要分级;当一定时,0.05 时,需要分级。由以上条件,判断本厂原煤是否需要分级,分析如下:(1)先分别分析两矿原煤的筛分大样表2.1-1、2.1-2的大于50mm粒级的量和矸石等级,在前面煤质基础资料的分析中已经发现两矿原煤均属于中矸,且+50mm级分别占全样的27.69%、2.63%。所以有必要对+50mm的大块单独处理,故无需+50mm分级,具体工艺还要在后面的设计讨论中最终确定。(2)针对粒度级-0.5mm以下的煤泥分选,一般采用细粒度重选和浮选工艺,所以在对主导粒度范围分级分析时,先不考虑-0.5mm级原煤泥。(3)根据分选设备的特点:根据国内外分选设备的粒度限制,应满足设备的粒度要求。该设计入洗的两矿煤样,在用户对产品质量的要求范围内分选(即理论分选密度下分选),均属于易选煤(前面已作分析),所以对分选设备选择空间很大。(4)根据产品结构定位,该厂入洗原煤主要出动力煤,对产品粒度的要求高。粒度不同价格不同,所以考虑分级。(5)各粒级煤的性质对分级入洗的影响 一般在正常分选条件下,不同粒级煤有如下分选特征:粒度越细,分选密度越高,则各粒级的-曲线应有如下形式(见图2.1-5),否则应考虑分级入选。由以上条件,判断本厂入选原煤是否需要分级。在进行分级讨论之前,需要将两矿煤各粒级的自然级浮沉试验数据综合起来,整理出的综合表见表2.1-30 和表2.1-31 所示;将上述两表整理得到两矿各粒级的密度-灰分曲线讨论分级的数据,见表2.1-32所示:表2.1-32 两矿混合后自然级综合的各粒级密度-灰分曲线分级数据50mm50-2525-1313-66-33-0.5密度基元灰分密度基元灰分密度基元灰分密度基元灰分密度基元灰分密度基元灰分1.253.58 1.253.891.253.401.253.071.252.691.252.401.358.61 1.359.341.358.631.358.051.357.441.356.241.4522.14 1.4522.141.4519.611.4519.141.4517.971.4516.651.5533.55 1.5534.091.5533.861.5530.291.5529.601.5528.201.6544.26 1.6542.911.6542.301.6537.601.6537.501.6536.301.7551.45 1.7548.921.7548.591.7543.571.7543.851.7543.411.9064.08 1.9062.231.9060.841.9056.981.9052.631.9055.032.3589.86 2.3587.282.3588.312.3584.022.3581.992.3582.18由上表绘出两矿混合后各粒级自然级的-曲线,见图2.1-6所示:图2.1-6 两矿混合煤各粒级的-曲线表2.1-30 两矿混合后50-0.5mm自然级各粒级筛分浮沉试验综合表表2.1-31 两矿混合后50-0.5mm破碎级各粒级筛分浮沉试验综合表由图2.1-6可知,六个粒度的原煤在理论分选密度范围内,基本符合如图2.1-5所示的规律,即在上图中,密度级从左到右递增的顺序,相应的各粒度级的-曲线从右到左分布,故能说明该煤种符合入洗不分级的优势,虽然在有的密度范围内,各条曲线都相近。从总体上来看,还是符合以上规律。由上图分析可知,五条曲线相隔很近,当=1.90时,=5%,故需要分级入选。即+13mm粒级和-13mm粒级需要分别入选。2.2选煤工艺的初定和技术经济比较由于初步设计经验缺乏的限制,可能在对煤质的分析以及对各种工艺的评定比较浅显,在这样的情况下,只有采取多种预选方案,来弥补因经验不足而带来的缺陷。因此,在下面的分选工艺的选定中,初步做了四个方案进行技术经济比较,从而找到最能适应该入洗原煤的工艺方法。下面将选定的五个方案进行技术经济比较。2.2.1 初步选定的方案分析根据前面对原煤性质的分析以及对资料综合和按比例综合后的入洗原煤的可选性研究,以及初步方案预测中煤产率不足1%,不在分选出中煤产品。初步确定了1)+50mm动筛排矸+50-13mm两产品跳汰+13-0.5mm两产品跳汰。2)+50mm动筛排矸+50-13mm两产品跳汰+13-0.5mm 两产品重介旋流器。3)+13mm两产品重介+13-0.5mm两产品跳汰。4)+13mm两产品重介+13-0.5mm两产品重介旋流器四个分选工艺,下面将各个流程分析如下:一、+50mm动筛排矸+50-13mm两产品跳汰+13-0.5mm两产品跳汰该流程主要适用于易选、中等可选煤。由于跳汰机受入料粒度的影响,设置动筛排矸,由煤质资料得出直接出精煤。块末煤分别采用两产品跳汰工艺,该流程简单,管理方便,投资少,技术经验成熟可靠,但分选精度及自动化程度低,一定程度上受浮选司机个人技术经验影响。二、+50mm动筛排矸+50-13mm两产品跳汰+13-0.5mm 两产品重介旋流器块煤跳汰适用于易选的动力煤分选,该流程同流程一相比主要是末煤采用两产品重介旋流器,能够在一定程度上提高末煤的分选精度,厂房布置难度降低。不足之处是既有跳汰又有重介增加管理难度。三、+13mm两产品重介+13-0.5mm两产品跳汰该流程使用于块煤量大,含矸量多,末煤中等可选的煤,我国东北和华北许多选煤厂采用此流程,块煤上限为300mm或以上时可以替代大块煤手选作业,优点是分选效率高便于管理,缺点是末煤分选精度低。四、+13mm两产品重介+13-0.5mm两产品重介旋流器此流程也采用分级入洗。采用全重介工艺流程,块、末煤分别采用不同的重介质分选机,分选精度高、效率高、自动化程度高。缺点设备维修量大,基建投资、生产费用高,管理困难。以上是对本次设计所预先选用的工艺的特点和依据进行了详细的分析说明,在后续的工作中,将对以上五个方案进行预测和技术经济比较。2.2.2 方案的预测一、+50mm动筛排矸+50-13mm两产品跳汰+13-0.5mm两产品跳汰根据选煤工艺设计与管理P103 表4-2可知,动筛跳汰I取0.10,块煤跳汰I 取0.13,末煤跳汰I取0.20。预测过程见表2.2-12.2-3,产品实际平衡表见表2.2-4。表2.2-1 动筛排矸分配率表 I=0.10 D50=1.91密度原 煤平均密度T值X值分配率分配率矸石精 煤占全样/%灰分/%占全样/%灰分%占全样/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 2.03.87 89.86 2.20 1.87 1.32 96.90 96.90 3.75 89.86 0.12 89.86 合计28.63 18.50 3.90 88.78 24.73 7.41 表2.2-2 块煤跳汰分配率表I=0.13 D50=1.88密度原 煤平均密度T值X值分配率分配率矸石精煤 占全样/%灰分/%占全样/%灰分%占全样/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 2.03.79 87.78 2.20 3.60 2.54 100.00 100.00 3.79 87.78 0.00 87.78 合计22.79 22.24 4.63 80.34 18.16 7.43 表2.2-3 末煤跳汰分配率表 I=0.20 D50=1.77密度原 煤平均密度T值X值分配率分配率矸石精煤占全样/%灰分/%占全样/%灰分%占全样/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 2.04.83 82.76 2.20 1.50 1.06 93.27 93.27 4.51 82.76 0.33 82.76 合计32.96 18.52 5.25 77.24 27.70 7.39 表2.2-6 选煤综合产品设计平衡表产品占全样/%灰分/%精煤50mm24.73 7.41 50-13mm18.16 7.43 13-0.5mm28.10 7.45 小计70.99 7.43 矸石50mm3.90 88.78 50-13mm4.63 80.34 13-0.5mm4.85 82.64 小计13.39 83.63 煤泥原生6.39 29.17 浮沉4.23 51.06 次生5.00 19.53 小计15.62 32.02 合计100.00 21.47 三、+13mm两产品重介+13-0.5mm两产品跳汰 根据选煤工艺设计与管理P103 表4-2、4-3可知,块煤重介E取0.03,末煤跳汰I 取0.20。末煤跳汰见表2.2-3,块煤两产品重介见表2.2-7,产品实际平衡表见表2.2-8。表2.2-7 块煤两产品重介分配率表E=0.03 D50=1.84密度原 煤平均密度T值X值分配率分配率中+矸精 煤 占全样/%灰分/%占全样/%灰分%占全样/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 2.07.66 88.83 2.20 8.10 5.73 100.00 100.00 7.66 88.83 0.00 88.83 合计51.42 20.16 8.18 87.18 43.25 7.49 表2.2-8 选煤综合产品设计平衡表产品占全样/%灰分/%精煤13mm43.25 7.49 13-0.5mm27.70 7.39 小计70.95 7.45 矸石13mm8.18 87.18 13-0.5mm5.25 77.24 小计13.43 83.29 煤泥原生6.39 29.17 浮沉4.23 51.06 次生5.00 19.53 小计15.62 32.02 合计100.00 21.47 四、+13mm两产品重介+13-0.5mm两产品重介旋流器根据选煤工艺设计与管理P103 表4-3可知,块煤重介E取0.03,末煤两产品重介旋流器E 取0.04。,块煤两产品重介见表2.2-7,末煤两产品重介旋流器见表2.2-5,产品实际平衡表见表2.2-9。表2.2-9 选煤综合产品设计平衡表产品占全样/%灰分/%精煤13mm43.25 7.49 13-0.5mm28.10 7.45 小计71.35 7.47 矸石13mm8.18 87.18 13-0.5mm4.85 82.64 小计13.03 85.49 煤泥原生6.39 29.17 浮沉4.23 51.06 次生5.00 19.53 小计15.62 32.02 合计100.00 21.47 经过以上四个方案的预测,每个方案的产品平衡表都能够与入洗原煤平衡,证明每个方案的预测都真实有效。为了确定出适合该入洗原煤的最终方案,将在后面的设计中进行方案的技术经济比较。2.2.3、方案的技术经济比较 一、技术比较该入洗原煤预选的五个方案的各个技术参数及最综经济指标见表2.2-23,经过对下表的分析,将各个工艺的技术指标和产品的结构的关系总结如下:流程一:动筛排矸,块末煤分别跳汰,由于跳汰分选精度不是很高,因此精煤损失较为严重,由此得到的精煤产量较低。但是由于其生产工艺简单,投资及生产成本均较低,所以也占据一定得市场。流程二:动筛排矸、块煤跳汰、末煤重介选,该流程技术指标很容易实现,要求跳汰分选密度分别为1.91、1.60,这对跳汰分选的生产操作是很容易实现。且产品的质量指标也容易实现,精煤产率较高,该流程可以考虑选用,最终还要通过经济比较再来衡量选取。流程三:+13mm斜轮、-13mm两产品跳汰,分级入洗,发挥了斜轮分选机处理块煤的优势,提高了生产效率。流程四:+13mm斜轮、-13mm两产品重介旋流器,分级入洗,充分发挥了旋流器对末煤分选的优势。表2.2-10 预测方案技术统计表方案序号方案名称作业I(Ep)分选密度精煤矸石产率%灰分%产率%灰分%1动筛排矸,块煤跳汰,末煤跳汰动筛排矸0.11.9124.73 7.41 3.90 88.78 块煤跳汰0.151.8818.16 7.43 4.63 80.34 末煤跳汰0.21.7727.70 7.39 5.25 77.24 合计70.59 7.40 13.78 81.55 2动筛排矸,块煤跳汰,末煤重介旋流器动筛排矸0.11.913.90 88.78 6.39 29.17 块煤跳汰0.151.884.63 80.34 4.23 51.06 末煤重介旋流器0.04228.10 7.45 4.85 82.64 合计70.99 7.43 13.39 83.63 3+13两产品重介,末煤跳汰+13mm两产品重介0.031.8443.25 7.49 8.18 87.18 末煤跳汰0.21.7727.70 7.39 5.25 77.24 合计70.95 7.45 13.43 83.29 4+13两产品重介,末煤两产品重介旋流器+13mm两产品重介0.03 1.8443.25 7.49 8.18 87.18 末煤重介旋流器0.04228.10 7.45 4.85 82.64 合计71.35 7.47 13.03 85.49 二、经济比较经济比较主要根据现有市场对不同质量产品价格的定位,最后扣除原煤和加工费之后所能得到利润的多少最终确定流程,根据指导教师所提供的价格表2.2-11,计算所选方案的经济效益。表2.2-11 现有煤炭市场价格表及加工费产品价格加工费产品灰分价格,元/t选煤方法费用,元/t原煤A20.00%400跳汰21.7原煤A20.00%300块煤跳汰末煤重介23.7精煤A=7.51%-8.00%700块煤重介末煤跳汰23.7煤泥60%0块煤重介末煤重介25.3煤泥200矸石80%5见表2.2-11现有煤炭市场价格的分析,当产品结构为精煤和矸石时,保证精煤产率最大从而获得较大的经济利益。由所给价格制定各方案的经济比较表2.2-12,从表中分析可知,块末煤全重介的经济利益较高,主要优势在于精煤产率较高,排除的矸石产品相对较纯,资源利用率高。根据以上全面的技术经济分析,以及各个流程的有缺点分析,对于本厂的入洗原煤来说,选用块末煤全重介是比较经济合理。同时,该工艺还适合于当煤种向更差方向变化的适应,选择此工艺是即现实又长远的选择。表2.2-12 经济比较表选煤方法精煤产率精煤灰分矸石产率矸石灰分精煤售价¥/t矸石售价¥/t原煤价格¥/t加工成本¥/t利润/(万元)吨煤利润/(元)动筛排矸,块煤跳汰,末煤跳汰70.59 7.40 13.78 81.55 700530021.769247.50 173.12 动筛排矸,块煤跳汰,末煤重介旋流器70.99 7.43 13.39 83.63 700530023.769555.63 173.89 +13两产品重介,末煤跳汰70.95 7.45 13.43 83.29 700530023.769447.85 173.62 +13两产品重介,末煤两产品重介旋流器71.35 7.47 13.03 85.49 700530025.369915.99 174.79 2.3 选定流程的介绍及流程计算根据前面对几个预选流程的预测和比较,已选定块煤两产品重介末煤两产品重介旋流器为主洗工艺,但是针对这个大的方向的确定,是选用有压还是无压两产品重介旋流器以及与之相应匹配的一系列的具体工艺流程将在下面分别作出选择或介绍。2.3.1 辅助工艺的确定一、是否预先脱泥的讨论1、选前脱泥的优缺点分析:(1)优点:选前脱泥分选精度高,效率高。由于入料中非磁性物(煤泥)含量少,故产品脱介效果好,介质消耗也低。而且在介质系统中可以不必专设分流环节,或者只需要少量分流,因而悬浮液密度的调节变得十分简捷,只需控制补加清水量一个因素,使悬浮液性质相对比较稳定。(2)缺点:设选前脱泥,工艺环节增多,工艺布置相对复杂;预先脱除的原生煤泥,需要专门分选处理,反而使系统变得更为复杂。目前作为粗煤泥单独分选可供选择的方法,都不同程度的存在一些问题,工艺效果尚不理想。若勉强为之,则使得综合精煤产率不升反降,得不偿失。如果找不到合适的粗煤泥分选手段,则预先脱出的原生煤泥只有全部去浮选,浮选成本高的问题便仍然得不到改善。2、选前不脱泥优缺点分析:(1)优点:因选前不脱泥,简化了工艺环节,紧凑了工艺布置,带来了诸多其它好处。有一种观点认为,对某种工艺的取舍不能只从理论去分析论证,必须从工程角度全面考虑技术、经济、操作、管理诸多因素,综合分析、权衡利弊。(2)缺点:从理论上讲,选前不脱泥对分选精度,尤其是对细粒级物料的分选精度会造成一定影响。原生煤泥量大,且易泥化的原煤影响尤甚。3、脱泥与不脱泥的选择:根据以上介绍的预先脱泥与不脱泥的优缺点,根据入洗原煤资料分析,其原生煤泥量(0.5mm)为6.39%10%。考虑到随着重介旋流器直径的增大,其有效分选下限会有所提高,块煤重介分选密度高,重液中容泥量小。为了使各粒级都得到有效的分选,得到最大的精煤产率,以及降低介质损耗和介质循环量,从而减小脱介筛面积,降低磁选机负荷,使磁选机效率提高,且0.50.25mm级占0.5mm粒级的41.86%,脱泥可降低浮选中粗颗粒含量。故最终决定采用预先脱泥的两产品重介质旋流器流程。预先脱泥多采用1mm脱泥,脱泥效率可达到90%,所以在此亦采用1mm的预先脱泥,粗煤泥采用粗煤泥分选设备。主要的粗煤泥分选设备优缺点如下: 螺旋分选机螺旋分选机是一种依靠液流的流动特性,在重力和离心力作用下,实现不同密度矿物分离的分选设备。具有分选精度较高(E=0.150.20)、分选密度上限高、设备简单、操作方便、质量轻、生产成本低等优点;但也存在处理能力低、占地面积大、分选密度低时分选效果差、不易调整分选参数等缺点。干扰床分选机(TBS分选机)TBS分选机是一种利用上升流在分选槽中产生紊流的干扰沉降分选设备。其优点是对粗煤泥分选效果良好,分选精度高(E=0.0950.12),能够得到较低灰分的精煤和较高灰分的尾煤,并且设备运行稳定,性能可靠,占地面积一般,适合各种分选密度的要求,易于调整分选参数。但TBS的入料粒度上限与下限比最好为4:1,即入料粒度范围较小,且控制系统复杂,造价昂贵。煤泥重介质旋流器煤泥重介旋流器是利用离心沉降原理进行分选的设备,本身没有运动部件,结构简单。但其介质系统是独立的,多一套介质系统,控制复杂,调节困难,且从选煤厂应用的效果来看,并不是很理想。综上考虑,且结合入料原煤的可选性分析,其可选性等级为易选,分选密度高,最终决定采用螺旋分选机来对10.25mm粗煤泥进行分选。螺旋分选机对粗煤泥分选效果的预测结果,见表2.3-1。表2.3-1 1-0.25mm 螺旋分选机产品实际产率及灰分计算表 I=0.20 D50=1.65密度原 煤平均密度T值X值分配率分配率矸石粗精煤 占全样/%灰分/%占全样/%灰分%占全样/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 2.02.52 82.74 2.20 2.07 1.46 98.08 98.08 2.47 82.74 0.05 82.74 合计8.31 31.70 2.93 76.01 5.38 7.58 二、有压或无压两产品旋流器的选择重介质旋流器的分选过程,可以用“分离锥面”的学说来概括,即在旋流器内存在一个低密度与高密度物体的分离界面,这个界面是轴向零速面与径向零位面的综合面,其形状基本上是锥形,该界面上的介质密度一般等于矿粒的分离密度。矿粒进入旋流器后,在离心力的作用下,位于“分离锥面”内部的高密度矿粒则有中心向外移动,如它的密度高于“分离锥面”附近悬浮液的密度,则该矿粒将越过“分离锥面”进入下降流,并由底流口排出。反之,则停留于上升液流中,并由溢流口排出。在“分离锥面”外部的低密度矿粒,则向中心移动,如它的密度低于“分离锥面”附近悬浮液的密度,则该矿粒将越过“分离锥面”进入上升流,并由溢流口排出。反之,则停留于下降流中,并由底流口排出。有压入料方式的特点是物料与悬浮液是混合有压切线给入的,一进入旋流器,矿粒与悬浮液就同时具有了很高的切向速度。如果入料压头调节得当,从入料的初始阶段就能达到最佳分选状态,从而最大限度地利用了物料在旋流器内的分选时间和分选空间。有压给料重介旋流器分选下限很低,可到0.15mm。中心无压入料方式的主要特点是被选物料与重介悬浮液是分开进入旋流器的。其中80%90%的悬浮液是从筒体下部切向有压给入,剩余的10%20%的悬浮液则随同被选物料由筒体上部中心口“无压”落入(高差约2.5m)。因此被选物料进入旋流器后的初始切向速度几乎为零。尔后,随着矿粒在轴向和径向上的位移,在旋转悬浮液的带动下,才逐渐增大本身的切向速度,并逐渐接近旋转悬浮液的切向速度。这一现象说明入料在起始阶段与悬浮液在旋转速度上存在较大差异,这种差异对入选物料将产生实际分离密度增大的影响,尤其对细粒物料影响更为明显。从上述内容可以看出,有压入料在某些方面(尤其是分选下限可以很低)确实是优于无压入料,又考虑到厂房布置及原煤的可碎性。通过反复的思考,最后还是青睐于有压两产品重介旋流器。13mm分级、1mm预先脱泥后,有压两产品重介质旋流器分选产品预测,见表2.3-2。表2.3-2 两产品重介旋流器分配率计算表 E=0.04 D50=1.90密度原 煤平均密度T值X值分配率分配率矸石精煤 占全样/%灰分/%占全样/%灰分%占全样/%灰分/%1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00 12.00 2.04.19 82.76 2.20 5.06 3.58 100.00 100.00 4.19 82.76 0.00 82.76 合计28.56 18.52 4.40 81.44 24.16 7.08 三、浮选工艺的确定根据前面选定的分选工艺,为实现选煤厂的洗水闭路循环,因此考虑对微细粉煤(0.25mm)的分选和回收,只有靠浮选联合工艺才能够得以实现。对煤泥浮选,主要有浮选机和浮选柱两种大类的分选设备,由于浮选柱分选上限比较低但煤泥0.045mm的仅占4.5%,所以选择机械搅拌式浮选机。通过合理控制用水量,矿浆浓度适合直接浮选,本设计采用直接浮选流程。下面为浮选产率预测,见表2.3-3和图2.3-1.表2.3-2 浮选煤泥浮沉试验表0.25mm产率/%灰分/%占本级/%占全样/%灰分/%14.00 15.00 16.00 31.93 2.24 2.81 20.99 1.47 6.54 8.19 0.57 17.36 3.97 0.28 27.63 1.25 0.09 37.70 1.28 0.09 46.38 2.49 0.17 56.50 29.90 2.10 82.95 100.00 7.02 32.06 图2.3-1煤泥浮沉曲线图由图2.3-1取浮选精煤灰分7.5%,精煤产率65%,精煤数量为4.56%。则浮尾灰分77.68%,数量为2.46%。 由概算书中安装汇总表中浮选车间设备购置费为6406461元,安装费为902573元。这里仅简算浮选车间效益。 精煤效益=4.56%*4000000*(700-300-100)=54720000 元/年初步投资=6406461+902573=7309034 元回收期=7309034/54720000=0.133 年 注 100元/吨为其它费用折计。2.3.2设计工艺流程的整体描述及工艺流程图1、受煤系统凉水井矿原煤从矿井采出后,卸到容受漏斗,容受漏斗有受储兼用,容受漏斗通过一台震动给料机给到一条皮带运到原煤准备车间。榆阳矿原煤通过火车运至凉水井矿区经翻车机给入受煤坑,之后经两台震动给料机给入一条皮带运至主厂房。2、原煤准备 由于本厂省去了破碎环节,故不设置准备车间,原煤仓经过一条皮带将原煤送至主厂房顶层,经过除铁器后由皮带将原煤均匀配给两台等厚分级筛,筛上进入块煤重介系统,筛下进入1mm脱泥筛,脱泥后的筛上末煤进入末煤重介系统,筛下则进入精煤泥桶。3、重介系统 (1)块煤重介系统 分级筛筛上进入斜轮重介分选机,产出的精煤经过固定筛预先脱介之后,进入直线振动筛,脱介脱水后的块精煤通过精煤上仓皮带后上仓。斜轮出的矸石经过固定筛预先脱介之后,进入直线振动筛,脱介脱水后的块矸石经过溜槽至矸石上仓皮带后上仓。精煤固定筛筛下经分流后的合格介质进入块煤磁选机,剩下的进入合格介质桶,精煤和矸石直线筛筛下稀介质进入块煤磁选机,磁选精矿至浓介桶,尾矿至块煤磁尾桶, (2)末煤重介系统脱泥筛筛上通过溜槽溜到混料桶,再用泵打入到两产品重介旋流器,产出的精煤经过弧形筛预先脱介之后,进入直线振动筛完成脱介,然后进入精煤离心机脱水,最终得到的末精煤,落到上仓皮带后进入末精煤仓,产出的矸石经过弧形筛预先脱介之后,进入直线振动筛完成脱介,得到的末矸石,经转载皮带转载到末矸上仓皮带后进入末矸仓,精煤固定筛筛下经分流后的合格介质进入末煤磁选机,剩下的进入合格介质桶,精煤和矸石直线筛筛下稀介质进入块煤磁选机,磁选精矿至浓介桶,尾矿至煤泥水桶,离心液给到精煤压滤机进行压滤。4、浮选系统 煤泥水桶内物料经泵送至水力分级旋流器,其底流进入螺旋分选机中,溢流则进入到浮选系统。螺旋分选机所出精煤经脱水后掺入到末精煤产品中去,其底流则进入浮选尾煤浓缩机处理。 水力分级旋流器溢流进入矿浆预处理器,通过调浆加药后自流给料到浮选机中,浮选精矿经浮精缓冲桶由泵打入到快速精煤压滤机,压滤后的浮选精煤经由刮板和皮带转载到末精皮带后上末精煤仓,滤液则作为循环水流入到厂外的循环水池。5、煤泥水系统浮选尾矿自流入尾煤浓缩机,经过澄清后溢流水作为循环水,其底流被泵送至压滤车间压滤后作为压滤尾煤泥,做民用;尾煤压滤机的滤液则作为循环水使用。6、产品装车系统块精煤、末精煤煤分别通过皮带运到块精煤仓、末煤仓,块精煤仓上面先经分级后,筛上进行破碎,筛下和破碎后产物在经分级后分别入仓。末精煤仓设配仓刮板,均匀分配到末精仓。仓底设两条装车轨道,轨道设有轨道衡。而矸石运至矸石仓后,采用汽车外运进行销售。场内设煤泥晾干场,压滤煤泥通过汽车外运进行销售。工艺流程图见图纸。2.4流程计算工艺流程计算时必须遵守数量、质量平衡的原则。内容包括:数质量流程计算、水量流程计算、介质流程计算以及编制产品最终平衡表,介质平衡和消耗指标表等。2.4.1 数质量流程计算选煤厂小时处理能力:。1、入厂原煤Q=757.6t/h,r=100.00% ,Ad=21.47%。2、原煤分级作业:原煤分级采用等厚筛,筛分效率按90%计算。入料:Q=757.6t/h r=100.00% Ad=21.47% 筛上+13mm粒级产品:Q=452.3t/h r=59.70% Ad=20.75% 筛下-13mm粒级产品:Q=305.3t/h r=40.30% Ad=22.54%3、分选作业分选作业详细计算见表2.4-1。4、煤泥水系统的数值量煤泥水系统的数值量见煤泥水系统数值量计算表,在此不作过多陈述。2.4.2 介质流程计算介质流程计算的主要内容是:根据工艺要求及有关作业的效率,确定流程中某些环节的悬浮液的性质及数量;按质量平衡原理,计算出各环节悬浮液的数量及质量指标,其中包括:悬浮液的体积、悬浮液中的固体量、磁性及非磁性数量、悬浮液密度及悬浮液中的含水量。1、常用的公式:G=Gf+Gc ,g=gf+gc;,; ,;, ; ,;其中:Q:入洗的煤量 (t/h);V:重介质悬浮液体积量 ();:重介质悬浮液密度 (t/);G:重介质悬浮液中的固体含量 (t/h);Gf:重介质悬浮液中的磁性物含量 (t/h);Gc:重介质悬浮液中的非磁性物含量 (t/h);g:单位体积悬浮液中的固体含量 (t/);gf:单位体积悬浮液中的磁性物含量 (t/);gc:单位体积悬浮液中的非磁性物含量 (t/);W:悬浮液中的水量 ();:单位体积悬浮液中的含水量 ();:悬浮液中固体的比重;f:悬浮液中磁性物的比重;c:悬浮液中非磁性物的比重;rf:悬浮液固体中的磁性物总量 (%);rc:悬浮液固体中的非磁性物总量(%),rf+ rc=100%;WQ:煤中所含的水分,包括入选原煤水分和产品水分。2、所需的煤质资料煤泥水的含水量;煤泥水的干煤泥量:Gn=Q;煤泥水的体积:;煤泥水的体积:gn=Gn/Vn;式中:Wn:煤泥水的含水量();WQ:入选煤的水分(%);Q:入选煤量(t/h);Gn:煤泥水的干煤量(t/h);:入选煤的煤泥含量(%);Vn:煤泥水的体积()。3、工作介质悬浮液的性质悬浮液的密度: 式中:工作悬浮液中固体的体积浓度(以小数表示),m3/m3; :工作悬浮液中的固体的真密度,g/cm3。工作悬浮液要保证其稳定,那么其组成成分必须满足一定的要求,即最大非磁性物含量的要求,计算公式如下:式中 c0、cx :分别为入料和浓介质中含非磁性煤泥的数量,%;g0、gx:分别为入料和浓介质中单位体积的固体重量,t/m3; 0、x : 分别为入料和浓介质的密度。4、分选作业的计算循环悬浮液量的确定:块煤取0.8-1.0 m3/t原煤;三产品重介旋流器取3.5-4.0 m3/t原煤。分选块煤时有浮物带出的悬浮液占工作介质的80-90%,沉物带出的占20-10%。为了简化计算,设悬浮液的性质与工作介质相同。用重介旋流器分选末煤时,溢流及底流悬浮液性质发生了变化,在设计时先选定溢流及底流中悬浮液的密度,底流中的非磁性物含量,然后计算其他参数。取溢流中悬浮液密度比工作介质低0.04-0.17,底流悬浮液密度比工作介质高0.4-0.7,底流中磁性物含量比工作介质高5-15%。选定溢流、底流密度后,即可按下式计算:V1=V2+V3;V11= V22+ V33;式中:1、2、3:分别为工作悬浮液入料、溢流、底流时的密度(t/);V1、V2、V3:分别为工作悬浮液入料、溢流、底流时的体积()。5、脱介及磁选作业的计算较为简单,在此不一一列出。具体各作业的计算数据见表2.4-2至2.4-13。表2.4-1 分选作业各作业计算数据汇总表表2.4-1 分选作业各作业计算数据汇总表(续表1)表2.4-2 块煤介质系统各作业计算数据汇总表表2.4-2 块煤介质系统各作业计算数据汇总表(续表1)表2.4-3 块煤介质系统平衡表项目各项指标G/t*h-1Gc/t/h-1Gf/t*h-1W/m3*h-1进入原煤带入煤泥水29.415 29.415 0.000 108.559 脱介用循环水264.033 脱介用清水132.016 稀释用水0.262 补充水24.472 补加新介质0.618 0.031 0.587 合计30.033 29.446 0.587 529.343 排出精煤产品带走0.079 0.008 0.071 61.431 矸石产品带走0.015 0.001 0.013 21.158 浓缩机溢流磁选尾煤29.940 29.437 0.503 446.754 合计30.033 29.446 0.587 529.343 差额0.000 0.000 0.000 0.000 表2.4-4 块煤循环介质系统平衡表项目各项指标V/m3*h-1G/t*h-1Gc/t/h-1Gf/t*h-1W/m3*h-1进入循环介质桶精煤脱介返回合格介质191.044 215.559 21.556 194.003 137.873 矸石脱介返回合格介质120.192 135.615 13.562 122.054 86.741 补加浓介质342.686 529.471 26.474 502.998 224.437 补加清水24.472 24.472 合计678.395 880.645 61.591 819.054 473.523 排出循环介质678.395 880.645 61.591 819.054 473.523 差额0.000 0.000 0.000 0.000 0.000 表2.4-5 块煤系统水耗及介耗项目总耗量/t*h-1每吨原煤耗量/kg水量消耗循环水264.033 583.812 清水132.016 291.906 合计396.049 875.718 介质消耗精煤带走量0.071 0.157 矸石带走量0.013 0.030 小计0.085 0.187 磁选尾矿损失0.503 1.112 合计0.587 1.299 表2.4-6 块煤系统质量平衡表项目质量Q占全样灰分水分Mtt/h%进入原煤447.43 59.060 20.66 19.4 原生煤泥4.84 0.639 29.17 19.4 小计452.263 59.699 20.75 19.4 排除精煤产品精煤355.83 46.970 7.48 14.722 煤泥0.008 0.075 30.66 14.722 小计355.839 47.045 7.52 矸石产品矸石67.03 8.848 86.85 23.992 煤泥0.001 0.013 30.66 23.992 小计67.031 8.861 86.77 磁尾29.437 3.798 30.66 合计452.307 59.705 20.75 表2.4-7 末煤介质系统各作业计算数据汇总表表2.4-7 末煤介质系统各作业计算数据汇总表表2.4-7 末煤介质系统各作业计算数据汇总表(续表)表2.4-8 末煤介质系统平衡表项目各项指标G/t*h-1Gc/t/h-1Gf/t*h-1W/m3*h-1进入原煤带入煤泥水52.346 52.346 0.000 64.501 脱介用循环水227.470 脱介用清水113.735 稀释用水0.134 补充水44.032 补加新介质0.315 0.016 0.299 合计52.661 52.362 0.299 449.871 排出精煤产品带走0.150 0.040 0.110 57.784 矸石产品带走0.023 0.003 0.020 10.512 浓缩机溢流磁选尾煤52.488 52.319 0.169 381.575 合计52.661 52.362 0.299 449.871 差额0.000 0.000 0.000 0.000 表2.4-9 末煤循环介质系统平衡表项目各项指标V/m3*h-1G/t*h-1Gc/t/h-1Gf/t*h-1W/m3*h-1进入循环介质桶精煤脱介返回合格介质720.768 640.105 170.621 469.484 513.123 矸石脱介返回合格介质194.530 315.739 41.046 274.693 112.228 补加浓介质115.529 178.499 8.925 169.574 75.664 补加清水44.032 44.032 合计1074.859 1134.343 220.592 913.751 745.047 排出循环介质1074.859 1134.343 220.592 913.751 745.047 差额0.000 0.000 0.000 0.000 0.000 表2.4-10 末煤重介质系统水耗及介耗项目总耗量/t*h-1每吨原煤耗量/kg水量消耗循环水227.470 846.510 清水113.735 423.255 合计341.205 1269.766 介质消耗精煤带走量0.110 0.409 矸石带走量0.020 0.074 小计0.130 0.483 磁选尾矿损失0.169 0.631 合计0.299 1.114 表2.4-11 末煤系统数量平衡表项目质量Q占全样灰分水分Mtt/h%进入原煤261.75 34.551 21.43 19.36 原生煤泥6.97 0.920 29.17 19.36 小计268.71 35.470 21.63 19.36 排除精煤产品精煤183.07 24.165 7.08 23.992 煤泥1.31 0.173 29.88 23.992 小计184.37 24.337 7.24 矸石产品矸石33.30 4.396 81.44 23.992 煤泥0.26 0.035 29.88 23.992 小计33.56 4.431 81.03 磁尾50.75 6.699 29.88 合计268.69 35.467 20.73 表2.4-12 煤泥水系统各作业计算数据汇总表项 目各项指标Q(t/h)r(%)Ad%V(m3/t)W(m3/t)q(g/l)R(%)分级旋流器入料脱泥筛下、末煤磁尾116.115.3231.87913.99836.6127.027.21排料溢流53.27.0232.06734.19698.7572.4113.14底流62.98.3131.7179.79137.843502.19螺旋分选机入料底流62.98.3131.7179.79137.843502.19排料粗精40.75.387.58116.4289.253502.19粗尾22.22.9376.0163.3848.593502.19震动弧形筛入料粗精40.75.387.58116.4289.253502.19排料筛上40.75.387.5845.0317.86904.50.44筛下00071.3971.3900煤泥离心机入料筛上40.75.387.5845.0317.86904.50.44排料粗精37.34.157.5836.2311.2400离心液3.30.437.588.86.63370.42.03浮选入料溢流53.27.0232.06734.19698.7572.4113.14筛下00071.3971.3900出料浮精34.64.567.5126.7103.67272.733浮尾18.62.4677.68607.49595.0930.6331.98精煤快开压滤机入料末精离心液9.221.2211.4128.9128.89263.15 3.13 粗煤泥离心液3.30.437.588.86.63370.42.03浮精34.64.567.5126.7103.67272.733排料浮精476.218.2744.7313.4滤液000268.2268.200尾煤浓缩机入料粗尾22.22.9376.0163.3848.593502.19浮尾18.62.4677.68607.49595.0930.6331.98出料浓尾40.85.3876.7788.3861.18401.51.5溢流000582.49582.4900尾煤快开压滤机入料浓尾40.85.3876.7788.3861.18401.51.5出料煤泥40.85.3876.7728.616.36滤液000146.82146.8200表2.4-13 全系统水量平衡表 选煤过程中用水项目水量/m3*h-1选煤过程中排水项目水量/m3*h-1循环水13mm分级喷水125.4 清水块精产品带走水61.4 1mm脱泥喷水0.0 块矸产品带走水21.2 块煤脱介筛一段喷水308.9 末精产品带走水28.0 末煤脱介筛一段喷水266.1 末矸产品带走水10.6 块煤系统补加水24.5 粗精煤带走水11.2 块煤系统稀释水0.3 压滤精煤带走水13.4 末煤系统补加水44.0 尾煤泥带走水16.4 末煤系统稀释水0.1 原煤带入系统水56.4 浮精快开清洗滤布水141.1 浮尾快开清洗滤布水102.0 小计1068.8 小计162.2 清水块煤脱介筛二段喷水87.1 循环水加压过滤机滤液268.2 末煤脱介筛二段喷水75.1 浓缩机溢流653.9 浮选精煤消泡水快开压滤机滤液146.8 小计162.2 小计1068.9 全部用水量1231.0 排除总水量1231.1 表2.4-14 全系统数质量平衡表产品名称数量灰分Ad/%水分Mt/%产率/%小时产量Q/t日产量/t年产量/t精煤块精精煤46.97 355.8 5693.3 1878789.6 7.48 14.7 煤泥0.08 0.6 9.1 3012.1 30.66 14.7 小计47.05 356.4 5702.4 1881801.7 7.52 14.7 末精精煤23.03 174.5 2792.0 921367.3 6.93 13.8 煤泥0.09 0.7 10.5 3455.9 29.88 13.8 小计23.12 175.2 2802.5 924823.2 7.02 13.8 粗精煤4.95 37.5 599.8 197928.9 7.58 23.1 压滤精煤6.21 47.0 752.5 248340.4 8.27 22.1 合计81.32 616.1 9857.3 3252894.2 7.44 15.5 矸石块矸矸石8.85 67.0 1072.5 353917.7 86.9 24.0 煤泥0.01 0.1 1.6 532.0 30.7 24.0 小计8.86 67.1 1074.1 354449.8 86.77 24.0 末矸矸石4.40 33.3 532.9 175840.6 81.44 24.0 煤泥0.03 0.3 4.2 1382.1 57.52 24.0 小计4.43 33.6 537.0 177222.7 81.25 24.0 尾煤泥浮尾2.46 18.6 297.7 98244.6 77.68 28.6 粗尾2.93 22.2 354.9 117120.8 76.01 小计5.38 40.8 652.6 215365.4 76.77 28.6 合计18.68 141.5 2263.8 747037.9 82.58 25.3 总计100.00 757.6 12121.0 3999932.0 21.47 2.5 设备选型及计算2.5.1 选型与计算的原则和规定1、设备选型原则:(1)所选设备的型号和台数,应与设计厂型相匹配,尽量采用大型设备,充分估计到机组间的配合与厂房布置的紧凑,便于生产操作。(2)所选设备的类型应适合原煤特性与产品质量要求。(3)应选用高效率、低消耗、成熟可靠的产品。(4)尽可能选用同类型,同系列的设备产品,便于检修和备件的更换。优先选用具有“兼容性”的系列设备,便于新型设备对老型设备的更换,也便于更新和改扩建。(5)在设备选用的过程中,贯彻国家当前的技术经济政策,考虑长远规划。设备招标应考虑性能价格比,切忌一味追求低价格。2、不均匀系数在选煤厂生产过程中,原煤的数量和质量具有不均衡性,随时都可能产生波动。为保证选煤厂均衡生产,在确定设备的型号和台数时,需要用各作业的处理量乘以不均衡系数。按设计规范,各车间设备选型的不均衡系数取值如下:(1)由矿井直接来煤,从受煤仓至配(原)煤仓的各环节,设备的处理能力不均衡系数取1.201.30。(2)由标准轨距车辆来煤,从受煤仓至配(原)煤仓的各环节,设备的处理能力不均衡系数应不大于1.5,当采用翻车机或浅受煤槽等方式卸煤和受煤时,配(原)煤仓前各环节设备的处理能力应与翻车机或浅受煤槽的卸车能力相适应。(3)在配(原)煤仓以后,设备的处理能力不均衡系数,对煤流系统取1.15;对煤泥水系统和重介质悬浮液系统,水量取1.25,干煤量取1.15;矸石系统取1.5。2.5.2 主要设备选型与计算一、筛分设备筛分设备的选型计算是依据筛分机的单位符合定额计算。先计算出分级产品所需要的筛分机面积,再根据面积选择筛分机。计算公式如下: 式中:F:所需筛面面积,m2;Q:入料量,t/h;k:不均衡系数;q:单位负荷定额 t/(m2h)。确定了所需的筛分面积后,可使用下式确定所需的筛分机台数:式中:F:所需筛面面积,m2;n:所需的筛分机台数;F:筛分机单台有效面积。计算过程如下:1、13mm分级筛:所以 =1.15*757.6/60=14.52=14.52/10.1=1.44取整:n=2(台),选取等厚筛设备型号为ZDS2148。2、200mm分级筛: 本设备采取圆振动,筛网自制,根据经验选取。3、100mm分级筛:所以 =1.15*356.4/110=3.73=3.73/3=0.62取整:n=1(台),选取等厚筛设备型号为DD1740。4、预先脱泥筛: =1.15*304.2/10=34.98=34.98/18=1.95取整:n=2(台) ,选取直线振动筛,筛设备型号为ZKS3060。5、脱介直线振动筛和弧型筛:(1)、块精煤直线振动筛选型: =1.15*359.6/14=29.54=29.54/18=1.64取整:n=2(台) ,选取直线振动筛,筛设备型号为ZKS3060。(2)、末精煤直线振动筛选型: =1.15*189.6/10=21.84=21.84/14=1.56取整:n=2(台) ,选取直线振动筛,筛设备型号为ZKS2460。(3)、块矸直线振动筛选型: =1.5*67.7/12=8.46=8.46/9.5=0.89取整:n=1(台) ,选取直线振动筛,筛设备型号为ZKB1756。(4)、末矸直线振动筛选型: =1.5*34.6/10=5.19=5.19/8.4=0.62取整:n=2(台) ,选取直线振动筛,筛设备型号为ZKB1556。二、破碎设备破碎设备的选型计算一般采用单台设备处理能力,所需设备台数按下式计算:式中:n:所需的筛分机台数,台;Q:入料量,t/h;k:不均衡系数;Qe:破碎机单台处理量,t/(h台)。其计算如下:根据单位小时处理能力选取破碎机机型为2PGC-600750,处理能力:60t/h=1.1575.6/100=0.87; 取整:n=1(台)但是破碎机属于易损设备,应考虑备用,所以选用2台破碎机。三、分选设备(1)、1、主选斜轮重介质分选机块煤重介质分选机的生产能力都可以采用单位符合定额计算,或由产品目录查取。 采用单位负荷定额计算时,所需要的斜轮的台数可按下式计算: =1.15*452.3/(100*2.6)=2.00取整n=2(台),选取设备型号为 LZX-2.6.(2)、重介质旋流器采用泵给料的两产品旋流器,重介质旋流器采用单台处理能力来计算。计算公式如下: 式中:n:所需的筛分机台数;Q:入料量,t/h;k:不均衡系数;Qe:单台设备处理量 t/(h台)。其计算如下:根据单位小时处理能力选取直径为1000mm的两产品重介旋流器,处理能力为120t/h,所需旋流器台数: =1.15268.7/180=1.72;取整n=2(台)。(3)、对于浮选机,其单位体积处理量为0.61.0t,取0.7t;初步选取XJM-S16浮选机,则所需台数 =(1.15770.1+1.25*53.2/1.5)/11/64/0.85=1.55;取整n=2(台)。四、磁选机介质流程采用的筛下稀介直接磁选,为了保证磁选效果,采用磁选机为逆流式双滚筒永磁式磁选机。所需磁选机台数可以按下式计算:式中:n:所需的磁选机的台数Q:入料量,t/h;k:不均衡系数;Qe:单台设备处理量 ,t/(h台);计算如下:(1)、块煤磁选机查工艺设备的选型与计算表5-27,选取型号CTXN-1030,其单台处理量为260m3/h,在煤泥水系统中取k=1.25,所以 =1.25 808.76/260=3.88;取整:n= 4(台)(2)、末煤磁选机查工艺设备的选型与计算表5-27,选取型号CTXN-1030,其单台处理量为260m3/h,在煤泥水系统中取k=1.25,所以 =1.25531.82/260=2.56;取整:n=3(台)。五、脱水设备离心机选型是根据单台处理能力进行计算的。计算公式如下:式中:n:所需的台数;Q:入料量,t/h;k:不均衡系数;Qe:单台设备处理量 ,t/(h台)。计算如下:(1)、末精煤离心机的计算:查工艺设备的选型与计算表5-29,选取TLL1000的立式螺旋刮刀卸料离心脱水机,其单台处理量Qe =120,所需台数为: =1.15 184.4/120=1.77;取整:n=2(台);(2)、粗煤泥离心机的计算:查工艺设备的选型与计算表5-29,选取LLL1200的立式螺旋刮刀卸料离心脱水机,其单台处理量Qe =70,所需台数为:在跳汰中煤离心脱水中: =1.25 40.7/70=0.73;取整:n=1(台);(4)、压滤机根据单台设备的处理能力进行选取。六、浓缩机浓缩机的计算选型根据选矿机械P379表4.3-2选取XGN-20两台。主要设备选型及辅助设备选型明细表分别见表2.5-1、2.5-2、2.5-3、2.5-4、2.5-5。表2.5-1 主要设备选型明细表作业名称设备名称规格型号入料不均衡系数K单位负荷单台处理量计算面积单台参数计算台数选择台数干矿量(t/h)矿浆量(m3/h)13mm分级等厚筛ZDS2148 13mm757.5 1.15270-120021mm脱泥直线振动筛ZKS3060(0.75)305.3 1.151035.11 181.95 2块煤重介斜轮LZX-2.6452.3 1.15200-3002末煤重介有压两产品旋流器FXZ-1000268.7 1.15 120-2501.7 2块精一次脱介条缝筛1.00mm380.8 1.152块精二次脱介直线振动筛ZKS3060(0.75)359.6 1.151234.46 181.9 2块矸一次脱介条缝筛1.00mm71.4 1.52块矸二次脱介直线振动筛ZKB1756(0.75)67.7 1.5128.46 9.50.89 1末精一次脱介弧形筛FH1520(1mm)226.7 1.152末精二次脱介直线振动筛ZKS2460(0.75)189.6 1.151021.81 141.56 2末矸一次脱介弧形筛FH1520(1mm)42.0 1.52末矸二次脱介直线振动筛ZKB1556(0.75)34.6 1.5105.19 8.40.62 2块煤系统磁选永磁筒式磁选机CTXN-103055.9 808.76 1.25 230-2604末煤系统磁选永磁筒式磁选机CTXN-103061.2 531.82 1.25230-2603表2.5-1 主要设备选型明细表(续表)末精离心脱水立式刮刀卸料离心机TLL-1000(0.5)184.4 1.150-1502粗煤泥分级煤泥分级旋流器组FX350836.6 1.25480-8002粗煤泥分选螺旋分选机2NXL650137.8 1.2570-90m3/组2组粗煤泥筛分脱水震动弧形筛VSB24206040.7 1.2520-501粗煤泥离心脱水粗煤泥离心机LLL-120040.7 1.2550-801矿浆预处理矿浆预处理器KY-3.0770.1 1.2515001浮选机械搅拌式浮选机XJM-S1653.2 1.250.883.07 641.3 2备1浮精脱水快开隔膜压滤机KM300-160047.0 1.2520-303备1尾煤浓缩尾煤浓缩机XGN-20(选矿机械)40.8 715.06 1.2545-652尾煤压滤快开隔膜式压滤机40.8 1.2520-302备1块精200mm分级圆振动筛块精破碎双齿辊破碎机2PGC-600*75075.660-1251备1块精100mm分级圆振动筛DD1740240-3601表2.5-2 皮带选型计算表项目带速速度系数带宽选取带宽煤流量物料容量断面系数倾角系数手选效率不均衡系数皮带条数块精煤出厂皮带30.920.65 1000356.4 0.94350.91.151块矸出厂皮带2.50.970.34 80067.1 0.94350.921.51末矸出厂皮带2.50.970.24 80033.6 0.94350.921.51浮精转载皮带2.50.970.24 80047.0 0.943511.152末精出厂皮带2.50.970.54 1000222.2 0.94350.921.151受煤坑上仓皮带30.920.53 1000227.3 0.94350.851.151原煤仓进主厂房30.920.95 1200757.6 0.94550.851.151矿井至原煤仓皮带30.920.78 1200530.3030.94550.881.151原煤分级筛分配皮带30.920.88 1200757.60.945511.151表2.5-3 刮板选型计算表项 目速 度原料堆密度选取槽宽校核槽宽有效面积装满系数煤流量倾角系数不均衡系数数量精煤快开压滤机刮板0.50 0.85 0.80 0.45 0.2680 0.65 209.20 0.85 1.15 2 尾煤快开压滤机刮板0.50 1.00 0.80 0.19 0.2680 0.30 42.85 0.85 1.25 2 产品仓配煤刮板0.70 0.85 1.00 0.08 0.3350 0.65 32.59 1.00 1.15 1 原煤仓配仓刮板0.60 0.90 1.20 0.93 0.52 0.65 530.32 1.00 1.15 1 2.5-4 仓的选型计算表2.5-4 桶的选型计算表2.6选煤工艺布置2.6.1 总平面布置选煤厂总平面布置综合考虑了厂区的四季风向、原料煤进煤方向、产品走向、水源电源来向等因素。厂区主导风向为东南风,受煤坑位于厂区东南方向,主厂房位于中部偏西,煤泥浓缩机位于主厂房右方。总平面的布置力图使原料煤进煤配煤方便,粉尘集中地尽可能置于下风口。选煤厂生产辅助设施尽量与主厂房集中 布置,各车间注重紧密衔接,整个主厂房布置力求紧凑合理,降低厂房高度,并强化室内采光。煤流走向:2.6.2 原煤受煤、配煤选煤厂原煤来自于凉水井矿、榆阳矿,凉水井矿来煤由竖井箕斗提升,采用容受漏斗进行缓冲;榆阳矿煤通过标轨运至选煤厂受煤坑。其工艺布置要求如下:容受漏斗上部应安装300300mm铁篦(水平固定筛),超大块物料经人工处理。采用叶轮给煤机给煤。受煤坑长为96m,宽为14m,深10m,横跨于双线之间,受煤坑上部应安装300300mm铁篦(水平固定筛),超大块物料经人工处理。铁篦边缘也两侧建筑(柱、墙)留有人行道(700mm)。仓内设煤位自动指示器及信号装置,煤仓倾角选用60o。采用叶轮给煤机给煤并实现配煤。为防止堵仓可采用风力破拱清仓装置,因原煤水分较低,受煤坑两端设有通风设施和通风设备。受煤坑地面四周建防雨及排水设施。受煤坑底部设集水池和排污泵。受煤坑一端设楼梯间、配电室,另一端设简易楼梯。原煤仓直径20,高54.3m,与受煤坑通过18的皮带相连,与容受漏斗通过16的皮带相连。为了达到洗选最优化,需配煤入洗,除受煤坑配煤外,还设置原煤仓进行配煤。2.6.3 主厂房1、主厂房结构特点主厂房采用防震设计,抗震烈度等级为6级,主厂房框架尽量保持完整,少设地下设施。为便于设备检修和配件提升,主厂房内设有7.07.0的主提升孔和7.04.5的副提升孔。设两道主楼梯,以满足上下岗人员之间的联系。为减少电缆的敷设量,主厂房设变压器室、配电室。在充分考虑到设备检修空间、吊装空间的情况下,尽量减少厂房高度和厂房面积,重选与浮选采用联合建筑,并全厂房屋顶采用网架封顶,同时浮选车间与重选车间之间设置350mm沉降缝。2、主厂房布置要求设备布置紧凑、合理,但又不拥挤,留有操作检修空间和面积。同类型机械设备考虑互换性和灵活性。大多采用自流作业。同一类型或同一系统的设备在同一标高上布置,同时排列整齐。厂内检修、运输、人行的主要通道的宽度为1.52.0m,次要通道为800mm。输送机的走廊、地道中的人行道为800mm,双输送机中间的人行道不小于1000mm,另一侧不应小于500mm。溜槽、管路的坡度保证了物料畅通且避免过大,砸压设备。辅助及生活设施:生产技术检查的煤样室面积在40m2。车间调度室设在振动较小的地点,一般面积为36m2。快浮室的位置布置在主机的同层较近的地方,面积一般为20m2左右。变压器室宜设在靠近负荷中心进出线方便的厂房底层,避开西晒。每间配电室面积一般为30m2,远离振动较大煤尘较多的设备附近。3、原煤准备部分由于本厂未设置破碎环节,故未单独设准备车间,原煤通过201皮带运送到主厂房,通过皮带对两台等厚分级筛进行配料。两台等厚筛布置在+18.6m平面,10-11,A-B跨内和10-11,C-D跨内,为了降低粉尘对厂房的影响,两台等厚筛采取喷水湿筛。分级后的筛下物料进入到等厚筛正下方的+12.6m平面上的预先脱泥筛进行1mm脱泥。4、块煤系统块煤分选由两台斜轮分选机完成,物料由等厚筛筛上经溜槽给入两台主洗斜轮,主选分选机布置在12.6m平面,精、矸脱介筛均布置在+12.6m平面,精煤筛上直接通过溜槽给到+8.1m平面的出厂皮带。浓介桶、合介桶布置在标高+0.00m平面上。5、末煤系统在本设计中,末煤分选由两套有压两产品旋流器系统构成。两台旋流器纵向布置在标高+18.6m平面,6-7,A-B和6-7,A-B跨内,两台脱泥筛筛上分别自溜到两个混料桶中;两个混料桶分别布置在+0.00平面,9-10,A-B和9-10,C-D跨内,两台混料桶中的物料和悬浮液分别被泵送至两台旋流器;精、矸脱介筛均布置在+12.6m平面,精煤筛上通过溜槽给到+8.1m平面的精煤离心机,离心后的产品直接通过溜槽进入到+4.80,7-8跨内的6209上仓皮带。6、粗煤泥回收系统本厂采用两台螺旋分选机对10.25mm粗煤泥进行分选,螺旋分选机布置在+18.6m平面的B-C、6-7跨内;其入料前的两组精煤水力分级旋流器组布置在+24.0m平面的6-7、B-C跨内。螺旋分选机的溢流依次经过振动弧形筛和立式煤泥离心机脱水后成为精煤泥并通过溜槽直接进入精煤上仓皮带;振动弧形筛布置在+12.6m平面的7-8、B-C跨内,立式精煤泥离心机布置在+8.1m平面的7-8、B-C跨内。螺旋分选机的底流则自流进入尾煤浓缩机进行处理。7、浮选系统本厂采用直接浮选工艺。矿浆预处理器与浮选机采用一对二布置,两台浮选机布置在+18.6m平面,矿浆预处理器布置在+18.6m平面。浮选精矿先自流到位于+0.00平面上的浮精桶中,然后由泵打入到位于+12.6m平面上的三台快速精煤压滤机,快开压滤机滤液自流进入厂外循环水池。浮选精矿通过位于+8.1m平面1-2、2-3、3-4跨内的4213、4214、4215刮板转载进入末精煤上仓皮带后上仓。2.6.4 产品仓选煤厂的精煤、矸石三个产品均采用仓来装车,精煤通过火车外运,矸石通过汽车运出。2.6.5 煤泥压滤车间主厂房外设浓缩机及泵房,选煤厂生产用循环水主要有此提供,不足部分由清水泵补充。浓缩池建筑形式为半地上式,既减少了建筑投资、又便于煤泥水自流,一旦发生故障,有利于人工清理煤泥。选煤厂共有两个浓缩机,分别布置在主厂房东南方向。煤泥浓缩机底流由泵打至煤泥压滤机压滤,溢流作为循环水。2.7 生产技术检查选煤厂生产技术检查是指导生产,加强生产管理,把好产品质量数量关必不可少的重要环节。有了技术检查,生产过程中各项技术经济指标才能得以顺利地完成。通过日常生产检查,可以了解选煤厂产品的数质量情况,掌握洗选设备的运行状态以其技术指标,了解主要分选设备的分选效率和分选精度,并以此为依据,指导生产实际操作,控制生产指标,及时了解生产情况,作为选煤司机操作的依据。2.7.1检查的内容与项目日常生产检查及目的是把日常快速检查所采的煤样,按规程缩分出一部分留作班、日、月综合煤样,分别做班、日、月煤样试验分析项目,供分析班、日、月的生产情况。(1)、快速检查快速检查项目、试验用煤样质量及试验间隔时间可参照表2.7-1制定。(2)、班检查 入选原料煤及各种洗选最终产品班积累样灰分测定按国标MT/T808-1999进行。根据需要还可作入选原料煤低于分选密度的上浮物灰分测定;浮选入料、精煤、尾煤及煤泥回收筛精煤班积累样做灰分测定;煤泥分选机的原料、精煤、尾煤班积累做灰分测定。班检查项目见表2.7-2。(3)、日检查用加权平均或算术平均方法计算人选原料煤、洗选最终产品和中间产物的灰分;洗水、沉淀池溢流的固体含量;浮选入料和尾煤的固体含量;浮选和煤泥分选机原料、精煤、尾煤和煤泥回收筛精煤的灰分。检查当日入厂原料煤的煤层或分矿的比例。(4)、月综合计算人厂原料的灰分。筛选厂的最终产品按规定方法进行筛分试验,其筛分粒级应与分级筛的筛孔相同。入选原料煤和洗选最终产品(精煤、矸石等)按规定方法进行筛分、浮沉试验。筛分粒级一般为四级。表2.7-1快速检查项目、煤样质量及试验间隔时间煤样名称试验项目试验用煤样质量或体积试验时间间隔入选原料煤快速浮沉35kg24h重介选末精煤快速浮沉2kg3040min快速灰分2kg4060min块精煤快速浮沉2kg12h块矸石快速浮沉34kg24h末精煤快速浮沉2kg12h末矸石快速浮沉34kg24h粗煤泥快速浮沉45kg抽查浮选精煤快速灰分23kg12h浮选尾煤快速灰分0.5kg28h入仓末精煤快速灰分3kg4060min入仓块精煤快速灰分3kg4060min入仓矸石快速灰分3kg4060min洗水固体含量14L抽查浮选入料固体含量1L1h尾煤水固体含量1L8h浓缩入、溢、底流固体含量1L根据需要浮选和煤泥分选机原料、精煤、尾煤都应做筛分试验。煤泥分选机原料和产物,每季度做一次浮沉试验。当浮选入料发生明显变化时或出现尾煤灰分过低时,应及时做分步释放浮选试验。入选原料煤和最终精煤中小于0.5mm级按MT58做筛分试验;矸石中小于0.5mm级每半年做一次筛分试验。人选原料煤中小于0.5mm级(包括自然级和浮沉煤泥)按MT56做浮沉试验。每季测定并计算最终精煤的数量和质量指标及其构成,测出主选、再选、煤泥回收筛、浮选精煤等占最终精煤的百分比和灰分。由日检查结果用算术平均法算出洗水和煤泥沉淀池溢流水的固体含量。具体见表2.7-2。表2.7-2 选煤厂的班、日、月检查项目煤样名称试验项目子样最小质量或体积采样最大间隔时间(min)月试验煤样最小质量(kg)备注班日月入厂原料煤灰分计算灰分5kg20含矸率抽查洗选精煤灰分计算灰分筛分浮沉2kg1kg20500300矸石浮沉灰分计算灰分筛分浮沉23kg34kg20500800浮选尾煤精煤灰分计算灰分固体含量筛分1L302洗水固体量固体量1L120沉淀池入料计算灰分筛分1L1202沉淀池溢流固体含量固体量1L60采样6h精煤、离心机和脱水筛精煤、浮选精煤、尾煤水分1kg视销售情况定抽查冬季每班测定耙式浓缩机溢、底流固体含量筛分1L1202筛下水、滤液、离心液固体含量筛分1L120抽查2.7.2 技术检查取样设置1、质量检查(1)、准备车间到原煤仓的上仓皮带上设置采样点,在皮带走廊附近设有技术检查室,对入选原煤的质量进行检查。(2)、主厂房重介分选机同层设快浮室,对重介产品做快浮、快速检查,为重介分选机的司机提供调整设备的依据。(3)、矸石去上仓皮带的溜槽上设采样点,对矸石进行质量检查。(4)、在精煤、矸石的上仓皮带设置采样点,实现最终产品的质量检查。(5)、在浮选缓冲桶处设置采样点,检查浮选入料的浓度。(6)、原生煤泥浓缩机底流设有采样点,检查浮选机的入料浓度;尾煤浓缩机底流设有采样点,检查尾煤压滤机的入料浓度。2、重介悬浮液密度控制由于本厂采用全重介流程实现分选,因此重介悬浮液浓度的控制很重要。(1)、在合格介质桶上设置自动测浓度的仪器。(2)、在连接合格介质桶与分选机的管道上设置采样点。3、数量检查(1)、在受煤坑处设置电子皮带称实现对入厂原煤的数量检查。(2)、在产品装车仓下设置轨道衡,实现对产品数量的检查。2.7.3 检查室快浮室:与脱介筛同层,做快浮、快灰试验,为重介浮选司机提供调整依据。煤检室:设在主厂房一层,进行更详细数质量检查。化验室:办公楼在一起,进行月综合检查。3 建筑物和构筑物3.1 概述神冬选煤厂为独立的矿区型选煤厂,设计能力为入洗原煤4.00Mt/a。该厂建于凉水井矿区,位于神木县锦界镇,西距榆林市85公里,东距神木县城25公里,省道204、榆神高速公路、神延铁路紧邻工业广场,交通条件便利,地理位置优越。3.1 气象级地震资料厂区属温带大陆性季风气候,冬季干燥寒冷,夏季炎热多雨,年平均气温12.8,一月平均气温-3.5,七月平均气温26.7。极端最高气温 42.7,极端最低气温-24.8。无霜期188天至211天。年平均降水量494.6-619.6毫米。年日照2665.4小时。神木地区是地震多发区,历史上曾多次发生中强地震,造成了巨大损失。3.3 建筑物及构筑物设计3.3.1 建筑设计本厂的原煤采用原煤仓储存,入厂原煤通过容受漏斗和受煤坑输送。煤流从容受漏斗和受煤坑下经钢结构皮带走廊运至原煤仓。原煤仓整体是钢筋混凝土落地圆筒仓,带地下室,内径20米,容量11500t,“W”形锥壳漏斗,由6根柱子支撑,柱子式放射状布置,漏斗与筒壁脱开,筒壁采用滑模施工,锥壳收头,锥壳顶。原煤仓中倒锥壳漏斗壁的应力较大,采用无粘结预应力技术。该项新技术系将钢筋涂包隔离后埋入构件之内,按后张法施加预应力。主厂房分五层布置,标高分别为:+0.00m、+4.80m、+8.1m、+12.6m、+18.6.m、+24.0m。采用框架结构,长度方向为10跨,第一、二、五、七、八、十跨跨距为7000mm,第四、六、九跨跨距为7500mm,第四跨跨距为3500mm。宽度方向为3跨,跨距均为:7000mm。先浇整体钢筋混凝土框架结构,砖填充墙,屋盖采用网架结构。门窗一律采用钢门窗,特殊类型的门采用钢木大门,地下室及有放水要求的结构采用放水混凝土。主厂房通过皮带走廊向南与产品仓连接。浓缩机池为半地上式钢筋混凝土结构,池壁采用钢筋混凝土结构,池底为毛石混凝土。池底与其相连部分分结构用缝分开。所有建筑物立面外墙均为清水墙。3.3.2 结构设计1、主要工业建筑的承重结构采用钢筋砼框架结构,基础为砼单独基础。2、辅助建筑采用混合结构,墙下为条行基础,地下及半地下建筑考虑防水措施。3、本工程抗震设防烈度为6度。4 给水排水4.1给水水源选煤厂所用清水、生活用水、生产用水及消防用水均来自场内水源井。生活用水水质符合现行的生活用水卫生标准(GB5749-85);生产用水水质符合煤炭设计规范有关规定。4.2用水量和水压1、用水标准及用水量生活用水应符合卫生部门颁布的有关城市饮用水标准。生产用水按下面指标控制:(1)悬浮液含量:清水400Gmg/L,循环水1000mg/L;(2)悬浮液粒度:除了洒水除尘不大于0.3mm外,其余不超过0.7mm;(3)氢离子浓度及硬度:PH=6-9,不超过10mg当量/L。生产用补充清水量:386.08 m3/h;生产用循环水量:575.17 m3/h;生活用水量:10 m3/h;消防用水量:400 m3/一次火灾。2、水压生产用补充清水水压:0.1-0.2Mpa;生产用循环水水压:0.1-0.3MPa;生活用水水压:0.3MPa。3、由于选煤厂浮选车间、配电室和集中控制室为易燃部位,除室外考虑消防栓设置及消防水量问题外,还应在相应部位设置干粉灭火器和泡沫灭火器。生活区视情况另行处理。4.3给水系统1、选煤厂分设两套给水系统。一套为服务于生产、生活的清水系统,另一套为维持正常生产需要的循环水系统。清水系统的水源来自于场内水源井,经泵房加压后经输水管路一部分作为脱节筛喷水,一部分作为浮选床泡沫喷淋水、车间卫生用水等。清水经加压后送至室外消防栓,可做消防用水。循环水来自洗选过程的煤泥水。废水浓缩机的溢流进入循环水池,经泵房加压后经输水管路供全厂生产循环使用。2、选煤厂清水及循环水厂外管均采用焊接钢管,法兰连接,地沟敷设,最小埋深为-1.00m。4.4排水为达到工业“三废”排放标准要求,选煤厂生产用水实现闭路循环,全部煤泥厂内回收。选煤厂厂内生产污水以煤泥水为主,主要来至浮选尾矿、压滤滤液、事故放水、地板冲洗水。煤泥水经尾煤浓缩机、废水浓缩机沉降,回收煤泥。厂内跑、冒、滴、漏、冲地板水及事故放水由集中水池收集,然后用泵打到废水浓缩机,进入循环水系统,使生产废水得到充分利用。雨水、生活污水流入厂区排水系统统一处理。厂区排水管道主要沿厂区地形和道路敷设至附近排水沟。管路采用混凝土排水管,埋深1.20m左右。5 生产辅助设施5.1机电修理车间机修车间负责全厂的生产控制系统检修维护、电气设备的检修与维护,并负责主洗设备的检修维护,原煤、装车、压滤三个车间分别具有自己的机修工,负责本车间的机械设备维护,水洗车间的机修工,主要负责本车间范围内的管道、溜槽的“跑、冒、滴、漏”现象的处理及防治工作。根据选煤厂设计规范,机修车间有700m2,并且有1600m2的检修广场。设备管理指导方针:坚持设计、制造与使用相结合,维护与计划检修相结合,修理、改造与更新相结合,专业管理与群众管理相结合,技术管理与经济管理相结合的五条原则,对设备实行分级管理(国发198768号文件,设备管理条例)。机电修理车间主要设备见表5-1。表5-1 机电修理车间主要设备表名称型号台数车床C650 1020300002C630 30028001C620 20020002C615 1507501铣床X63wT卧式万能铣床(3201250)1钻床Z35摇壁钻床(=35mm)2HS-3立式钻床(=35mm)1刨床B.36056牛头刨床1B2D10A龙头刨床1磨床M6020万能工具磨床1砂轮机S3S-300砂轮机1液压机Y32-S0回挂万能液压机1空气重锤C41-560起重机电动单梁起重机1直流电焊机AX-B5 N=8.7KW2交流电焊机BS-B5 N=8.7KW25.2介质制备车间神冬选煤厂重介质拟购买介质,通过介质制备车间制备成合格介质,介质由火车运输,介质的储备在介质制备车间,由合介管道将介质送往主厂房内。5.3压缩空气供应1、原煤仓、装车仓、上仓处设高压风枪,防止物料堆积,需供应高压空气;2、选煤厂内混料桶需高压风,以防介质沉积;3、加压过滤机所需高压风和低压风;4、容受漏斗、受煤坑卸煤用高压风防堵;以上压缩空气均由高压风机房供应。6 电 气6.1供配电6.1.1 电源及供电方式选煤厂动力电源采用交流380v电压等级。选煤厂为矿区型选煤厂,电源引自附近地区的变电所两独立母线上。两回路分别处于使用和备用状态,作到一回路出故障时,另一回路能正常供电,保证生产正常进行。6.1.2 供配电系统选煤厂高压配电室位于主厂房一楼。4台变压器将6kv电压进行电压变换至380v/220v。4台变压器中编号为T31、T32、T33的额定容量为1600KVA。变压器位于主厂房一楼与高压配电室毗邻,其中T31、T32供电范围为主厂房配电室、原煤配电室、浓缩配电室、生产水泵房配电室、介质库配电室,化验室、煤样室、生产控制中心电源等,T71设在装车车间二楼,主要向装车配电室供电,T81设在压滤车间一楼,主要向压滤配电室供电。T33主要向主厂房大型水泵及压滤照明、检修设备供电。全厂共六个低压配电室,分别为受煤坑、主厂房、压滤、浓缩、装车、生产水泵房配电室。各个低压配电室主要通过抽屉式低压开关柜向各个用电设备供电。全厂总装机容量大约为5260千瓦。每年用电量为27772800度,平均电耗为6.9度/吨入洗原煤,平均每天用电量为84160度。主要电器性能:1、变压器性能:型号为S10-Mb-1600/6.3的变压器,额定容量为1600KVA,额定电压为63005%/ 400v,额定电流为146.3/2303A,额定频率为50Hz,三相,冷却方式为ONAN,连接组标号为Dyn11,短路阻抗为4.43%,绝缘水平为L1:60,AC25/AC:5。2、高压隔离开关主要隔离电源并造成明显的断点,以保障电气设备能够安全进行检修。它没有专门的灭弧装置,不能关断负荷电流。3、高压熔断器用来保护电气设备免受过载电流和短路电流的危害。4、母线又称流排,指高、低压配电室中的电源线,由它向各高、低压开关柜供电。5、互感器用来将一次回路的交流电压、电流按比例降至规定标准,以便向仪表、继电器等低压电器供电,组成低压二次回路,并对一次侧高压回路进行测量、调节和保护。6.1.3照明1、照明不设专用变压器,采用动照合一方式,380V/220V三相四线制,灯头电压均为220V。照明单独计费。2、主场防首层设照明总配电箱,电源有低压配电室单独供电。其他各建筑物内照明电元均与动力电源分开提供,在配电室及主要通道,可设置应急灯作为事故照明。6.1.4防雷1、+15m以上建筑物和构筑物均设防雷保护,发给保护装置以避雷带为主。屋顶挑檐设闪避器,取建筑物钢筋水泥柱的主钢筋做防雷引下线,其连接处必须做延长焊接,并与作为接地极的基础地板钢筋牢固焊接。2、接地:变压器中性点之间接地,接地电阻不大于4。其他所有电器设备均采用接零保护,电器设备不带金属外壳应与电源中性线可靠连接。电源中性线在每个建筑物进线处应进行重复接地,接地电阻应不大于4,否则增设接地极。6.2集中控制与自动化根据生产的要求和工艺流程的特点,本设计对全厂主要生产设备采用了微机集中控制,以期达到保证洗选指标、稳定产品质量、减少机电设备故障、提高生产效率的目的。6.2.1控制系统为满足生产工艺要求,根据可靠、实用、先进、合理的原则,本厂采用可编程序控制器为主要控制元件的集中控制系统,以减少对全厂主要生产设备的集中控制和设备 运转状态的集中监视以及设备故障自动处理和报警。集中控制系统主要由主机、信号模拟盘、控制操作台、现场信号箱、电源组成。6.2.2 控制原则1、纳入集中控制的设备,按工艺要求设置电器连锁,其他采用就地控制的设备不设置电器连锁。2、纳入集中控制的设备,按逆煤流方向启动,顺煤流方向停车。3、集中控制采用允许制。即启车前集中控制室预先发出启动预告信号,待现场各岗位回答允许信号后才能启车,否则系统不能启动。4、系统在集中控制方式时,纳入集中控制的设备不能就地启动,但可就地停车。5、集中启动时,任一设备因故未能启动时,启动过程立即停止并报警。6、运行过程中,全厂洗选系统任一 设备发生异常,均能就地紧急停车。纳入集中控制的设备发生异常,操作现场及集中控制室均能紧急停车,并由该设备使,处于逆煤流方向的所有设备均紧急自动连锁停车。6.3通讯调度根据生产管理的要求,拟在选煤厂各主要生产及管理岗位设置通讯调度电话以实现厂内外的通讯联络及生产调度。7 铁路运输7.1本厂区各铁路专用线的技术条件1、铁路等级为级企业线,运输量为4.00Mt/a。2、限制坡度:4%。3、最小曲率半径:500m。4、机车类型:前进型及上游型机车,牵引重量按机车的一半计为1750吨。7.2股道设置1、正线:2条。2、受煤坑线:2条3、精煤装车线:2条。4、煤泥、材料、油脂线:1条。5、停车线:1条。8 采暖通风与药剂库8.1 概述1、本设计只考虑选煤厂各主要建筑物岗位操作区域的采暖以及煤尘较大的生产环节的通风除尘。采暖系统各种参数的选择及计算按供暖通风设计手册进行。2、气象资料气象条件均为附近地区参考值。(1)、采暖室外计算温度:-15;(2)、冬季通风计算温度:-22;(3)、采暖天数:116d;(4)、最大冻土深度:5.44m。8.2 采暖为创造一个良好的生产环境,以利于提高劳动生产率并保证各种设备的正常运转,选煤厂工业广场内的主要生产厂房及经常有人的辅助生产建筑物加以散热器集中采暖,经常无人的皮带走廊等初步采暖。1、系统为机械循环采暖系统,由锅炉房供给,通过室外管网送至各建筑物;2、各建筑物耗热量计算以供暖通风设计手册为依据;3、各建筑物采用上供下回式双管供暖系统。8.3 室外供热管道1、蒸汽管道在地沟和栈桥内敷设,主要干管采用半通行地沟,回水管道采用地沟敷设,压缩空气管道组为埋地敷设。2、蒸汽管道采用柱石保温,埋地敷设的管道需进行防腐处理。3、主厂房供暖用专管供应。4、选煤厂供暖由厂内锅炉房供应,蒸汽量70吨/小时。8.4 通风除尘1、厂区的原煤粉煤含量不大,但外在水分一般都比较低,且本地区空气较干燥,湿度小。原煤在运输转载、筛分及破碎过程中极易产生煤尘。因此,在原煤受煤、筛分和破碎系统均设置有通风除尘装置。2、原煤经过洗选后,产品水分增大,因此,全厂各建筑物主要以自然通风为主,个别粉尘大的地方采取喷水灭尘措施和强制通风除尘设施。各室通风除尘要求如下:化验室及煤样室均设有密封装置及吸尘罩,室内散发的煤尘及有害气体经净化处理后用通风机排入大气中。8.5 药剂库选煤厂的油脂由铁路油罐车运输,油罐车卸油用油鹤,油桶卸油用泵房内的泵接软管处理。也考虑由铁路运输用油泵把油脂和药剂打入油脂库和药剂库,浮选药剂考虑用煤油和松节油两种,药剂贮存考虑2个月,因此,设52.8m3油罐三个,其中一个备用。药剂库的油泵房设有两台2CY-38/1.8-1油泵,其中一台备用,油是极易燃烧的危险品,所以将油脂库有明火的建筑物的上风向和其它建筑物的下风向,以免发生火灾。选煤厂主导风向为东南风,故油脂库设在厂区东北部。9 工业场地总平面9.1 原始资料1、选煤厂厂型、工艺流程图、建筑物和构筑物的轮廓尺寸、选煤各系统联系图。2、原料、电源、水原来向及产品运输方向。3、工业场地实测的地形图和区域位置图。4、厂区工程地质、水文地质、气候气象及地震资料。9.2 总平面布置9.2.1 布置原则1、选煤厂总平面布置力求紧凑、灵活、安全、经济,同时综合考虑原料、电源、水原来向及产品运输方向。2、总平面布置充分考虑地形地貌的特征。为便于煤泥水及厂内污水自流,将主厂房布置在地势较高的自然地段。浓缩池尽量靠近主厂房,以缩短管桥和循环水的管道的长度。3、考虑主导风向的影响。把易产生的煤尘的车间和建筑物布置在主要车间及生活区的下风口,以减少煤尘对主要车间和生活区的环境污染。4、考虑厂内防火、安全及交通便利。5、辅助车间布置在距服务对象较近且交通便利的地方。9.2.2 场地功能区分整个工业广场分为两部分。广场远离厂区的西部部及北部部为办公室及生活区,广场东部为生产厂区。其中生产厂区又可划分为四个功能区。生产厂区东端为产品装车系统;生产厂区南部为原煤仓;生产厂区东南部为洗选加工和煤泥处理系统;生产厂区中南部为机修场地。9.2.3 总平面布置神冬选煤厂为大型矿区选煤厂,接收两矿井原煤。根据厂址地形、铁路接轨站的位置、原煤和产品流向要求,厂区铁路站场布置在厂区东部地势平坦的地段。主厂房布置在自然坡度平缓,地质条件好的土层上。受煤环节采用受储兼用的双排受煤坑,将其布置在铁路站场内侧第1、2股受煤线下。装车仓采用圆形跨线仓,为保证装车方便和装车时间要求,将其布置在第3、4股道上。主厂房的产品分四条皮带分别装入产品仓中。因为主厂房浮选机的安装较高,浮选尾煤泥水自流至耙式浓缩机中,将耙式浓缩机布置在主厂房右后方,距离较近,标高略低的位置上。辅助车间的布置:辅助生产的建筑物尽量接近服务对象,并且满足防火、安全、环保等要求。9.2.4辅助车间的布置辅助生产的建筑物尽量接近服务对象,并且满足防火、安全、环保等要求。电源引自区域变电所,选煤厂变电所在主厂房西北方进出线方便,接近负荷中心。防火,防尘条件好。将生产水池、生活水池和泵房,布置在主厂房右侧接近主厂房的位置,一方面便于主厂房用水,另一方面,也考虑了水源供水方便。机修车间布置,处于厂区中北部。接近铁路、铁路及仓库,运输较方便,设置了专用场地。锅炉房的能源主要为厂内的煤泥,其布置在压滤车间附近,使得燃料供应方便,能够及时供暖。油脂药剂库布置在离火车线较近位置。为了防止火灾发生危害,在药剂油脂库周围建筑高大围墙。库前设有运输到了和消防回车场地,并接近油脂药剂铁路油罐卸油台。介质库布置在靠近材料线的一端,且靠近主厂房的位置,方便购置介质和对厂房进行介质供应。压风机房布置在厂区东侧,远离粉尘污染单位,安全可靠。销售煤样室布置在铁路线附近,方便取、制样工作。9.2.5行政、生活福利设施的布置行政楼、技术楼布置在厂前区公路旁;食堂、厂区服务社布置在生活区中部,方便职工使用;浴室与锅炉房接近,便于供应热水;汽车存放场地、招待所等布置在距离厂正门较近处,方便与外界联系。生活区布置在上风向,避免的污染,同时设置了公园供大家休息运动。9.2.6运输1生产所需主要材料和辅助材料、设备及配件、煤泥均采用汽车运输。2为便于厂内材料、设备、产品的生产运输以及消防急救,选煤厂各主要车间及系统均设有厂区道路,主干道路面宽10.0m或9.0m,次干道路面宽6.0m或7.0m。采用200mm厚混凝土层,专用场地采用予制混凝土块,设置于主厂房及其他建筑物的主要门之前。9.2.7场地利用系数及绿化为美化厂区环境,减少粉尘污染和隔绝机械运转噪音,选煤厂在道路两旁、车间及周围周边、生活办公区可大量种植树木花草。无建筑物或构筑物的空余地段应大面积植草种树。其总平面布置图见附录10 技术经济10.1 劳动定员1、劳动定员按选煤厂各生产岗位配备,管理人员、服务人员及其他人员按选煤厂设计规范比例配备。2、劳动定员配备时,各类人员所占比例如下:生产工人在籍系数取1.35;管理人员在籍系数取1.0,占生产工人出勤人数的8%;服务人员占生产工人出勤人数的6%;其他人员占生产工人出勤人数的1%。根据选煤厂设计规范,4.00Mt/a矿区型选煤厂全员效率指标60t/工,取90t/工。日处理原煤量=4000000/330=12121.2t/日;每日生产人员出勤人数=134.6,取135人;管理人员人数=9.98,取10人;每日生产工人出勤人数135-10125(人);生产人员在籍人数1251.35+10178(人);服务人员人数1786%11(人);其他人员人数1781%2(人)。选煤厂劳动定员汇总表见表10.1-1。表10.1-1 劳动定员汇总表定员名称出勤人数在籍人数一班二班三班合计生产工人535320126178管理人员101010服务人员111111其他人员222合计7653201492013、全厂各岗位生产工人定员明细表见表10.1-2。表10.1-2 生产工人定员明细表选煤厂生产工人劳动定员明细表工种名称出勤人数合计在籍系数在籍人数一班二班三班1.受煤系统(含原煤仓)原煤皮带运转工336给料机工人448容受漏斗工112受煤坑地面工224检修工1135小计11113251.35342.主厂房皮带运转工112刮板运转工112分级筛操作工112脱泥筛操作工112斜轮分选机操作工112两产品重介旋流器司机112脱介筛运转工224分级旋流器操作工112磁选机运转工112离心机运转工224浮选机操作工224快开压滤机操作工112螺旋维护工112煤泥振动弧形筛112介质桶操作工224泵类运转工336检修工22812小计24248561.35763.浓缩车间浓缩机工336检修工22小计33281.35114.压滤车间压滤司机224泵类运转工224检修工22小计442101.35145.产品装仓皮带运转工224刮板运转工112分级破碎机操作工112产品装仓运转工336给料机工人336检修工1157小计11115271.3537生产工人总计53532012617210.2选煤成本产品成本反映了生产产品时原材料、劳动消耗的水平,也体现着整个选煤厂能给社会提供积累及其获得利润的高低程度。在产品价格一定的条件下,只有通过降低成本,才能增加利润。10.2.1 产品销售收入本厂为炼焦煤选煤厂,为提高经济效益,应以实现精煤产品的最大回收率为原则。产品销售价按当地市场价格记取,选后产品销售收入见表10.2-1。表10.2-1 产品销售收入表品种灰份产率产量价格合计Ad(%)(%)万t/a元/t万元块精煤7.52 47.05 188.18 700131726.12 末精煤7.32 34.28 137.11 70095976.48 煤泥76.77 5.38 21.54 20430.73 矸石84.93 13.29 53.17 5265.84 合计21.47100400.00 228399.16 10.2.2 计算方法及依据分离前成本是指按成本项目单计的费用总额,以全部折合量为核算对象计算各项目单位成本。按照材料、工资、电力、折旧、其它支出对生产产品所发生的费用分类,成为分离前成本。原煤价格和加工费按照方案比较时的来计算,将加工费参考选煤工艺设计与管理P313 表8-4按比例摊到每一项中,分离前成本见表10.2-2。其中:1、入洗原煤价格按当地实际价格计取,吨原煤购入价:300元;2、加工费:23.39元/吨原煤。表10.2-2 分离前成本表成本项目单位成本,元/t总成本,万元原料煤300.00 120000.00 辅助材料4.14 1654.17 工资3.26 1303.49 电费2.25 899.87 福利基金0.41 165.42 折旧基金2.22 886.64 大修理基金1.03 410.23 摊销费0.13 52.93 销售费用0.83 330.83 其它材料2.48 992.50 其他费用2.05 820.47 利息支出1.62 648.44 产品总成本320.41 128165.00 其中:选煤加工费23.39 8165.00 10.2.3分离后成本块精煤产量188.18万吨,末精煤产量137.11万吨,矸石产量为53.17万吨,煤泥产量为21.54万吨。块精煤价格为700元/吨,末精煤价格为700元/吨。矸石价格为5元,煤泥价格为20元/吨,销售收入为228399.16万元。分离后成本见表10.2-3。(1)等比系数块精煤等比系数末精煤等比系数矸石等比系数煤泥等比系数(2)折合量块精煤折合量188.181188.18万吨末精煤折合量137.111137.11万吨矸石折合量53.170.00710.38万吨煤泥折合量21.540.030.62万吨(3)分离前单位成本分离前单位成本元/吨(4)分离后成本块精煤成本188.18756.8673917.42万元 末精煤成本137.11756.8653856.70万元矸石成本0.38756.86149.17万元煤泥成本0.62756.86241.70万元表10.2-3 分离后成本表产品名称年产量比率折算量分离后总成本分离后单位成本万吨万吨万元元/吨块精煤188.18 1.00 188.18 73917.42 392.80 末精煤137.11 1.00 137.11 53856.70 392.80 矸石53.17 0.0071 0.38 149.17 2.81 煤泥21.54 0.03 0.62 241.70 11.22 合计400.00 326.28 128165.00 10.2.4 技术经济评价与指标1、财务分析利润228399.16-128165.00100234.16万元;上缴利税33%,即100234.1633%33077.27万元;最终利润10234.1633077.2737156.89万元;吨煤成本费=25.02元/吨;静态回收期年,折合为4.56个月。11 环境保护11.1 主要污染源及其控制措施设计依据:(1)、工业“三废”排放实行标准GBJ4-73;(2)、城市区域环境噪声标准GBH2.2-82;(3)、工业企业噪声控制设计规范GBJ78-85;(4)、污水综合排放标准GB8978-88。1、选煤厂主要煤尘污染源有受煤漏斗、受煤坑、原煤筛分、煤泥晾干场;废渣污染源有矸石堆放场;噪声污染源有鼓风机、空压机、电振给煤机、振动筛、破碎机、各类水泵及下料溜槽。各种污染物的排放状况见表11.1-1。表11.1-1 选煤厂污染物排放表污染物名称重地单位排放量或强度备注矸石Kt/a煤泥t/h生产废水M3/h煤尘受煤漏斗原煤筛分原煤破碎煤泥晾干场噪声各类风机DB(A)95电振给煤机DB(A)85振动筛DB(A)90破碎机DB(A)95各类水泵DB(A)75下料溜槽DB(A)952、各类污染源的防治措施:(1)、废渣:选煤厂的废渣主要是矸石。在厂区南侧设置矸石仓,随时准备用汽车运至矸石堆放场地,避免对厂区环境的污染。(2)、生产废水:选煤厂生产废水主要是煤泥水。生产过程中,各用水环节应尽量按工艺的要求控制好水的使用量,保持洗水的平衡,力争不向厂外排煤泥水,或尽量少排煤泥水。(3)、受煤漏斗、受煤坑、原煤筛分、煤泥晾干场时产生煤尘的尘源。在干燥季节应实施喷水,以增大原煤水分,减少受煤坑机准备车间的粉尘量。(4)、尽量采用符合环保要求的噪声低、振动小的先进设备。对噪音和振动较大的设备如振动筛、泵、各类通风机等均采取防震、防噪措施,使其符合环保有关规定。对容易产生噪声的溜槽,采取加橡胶衬里、加导向板、降低角度的措施降噪。通过各种降噪手段,力争使主厂房周围及工业广场的噪声降至84B(A)以下。(5)、应加强对核子秤探头铅壳的保据,严防射线外漏,探头尽量高吊安装,远离过道及岗位。11.2厂区绿化1、生活办公区、道路两旁、闲置空地、噪声源及煤尘源周围均为绿化区域,整个工业广场绿化面积在15000 m2以上,以达到绿化系数为20%的要求。2、对主厂房、压风机房等高噪声密集区及煤泥晾干场等高煤尘扩散区应设置小型专用林带,以发挥树木的隔声、吸尘作用。3、生活办公区、闲置空地等绿化区可由适合本地气候的花草灌木配以雕塑和水池组成。12 劳动安全12.1预防自然灾害的措施1、防暴雨、洪水措施为了排泄工业广场地面的雨季时的积水,防止洪涝的危害,在选煤厂工业广场内设置了地沟。各车间室内地平面均高于室外约300mm600mm,且高于实测最高洪水位标高。2、地震设防措施选煤厂各建筑物、构筑物均按6度设防。选煤厂原煤储存车间、产品装车仓上均设置喷雾消尘措施,电机按防爆选取。3、防雷措施选煤厂主要建筑物以及易受雷击的设施均装设避雷装置和避雷保护。12.2防火措施1、防火措施选煤厂工业广场内各建筑物之间的距离保证了足够的防火及采光等安全卫生要求。2、防爆措施选煤厂电缆,电线敷设,电器设备均按有关规程规定,厂房使用的压力容器上均设有安全阀。12.3防机械伤害和人身安全措施1、厂各车间内运转设备保证有足够的操作空间、检修空间、人行通道,并执行与此有关的规定。2、各设备传动部件外露时均设有防护罩或栏杆。3、各车间内所有安装孔、安装门、洞孔楼梯、平台走桥等,均设有栏杆或活动盖板。4、各车间地面设置的排水沟均有盖板,集水坑或水池设有栏杆。12.4防触电伤害措施各车间电机外壳均有接地措施来保证操作人员的人身安全。设备的启动与停车设有联系信号,以防止事故发生。12.5安全救护各车间都与厂内公路相通,车间设有主楼梯、安全门、联系楼梯,在任何情况下都能尽快、及时的疏散。1 概算编制说明1.1 工程概况及投资范围 本工程设计是神冬选煤厂的初步设计。该厂原设计处理能力4.00Mt/a,入洗原煤来自凉水井矿和榆阳矿,洗选动力煤。工程投资范围包括主厂房及其他车间系统的土建工程、安装工程、设备购置、工程建设其它费用及基本预备费。1.2 编制依据及取费标准1.2.1编制依据依据煤炭部制订的煤炭建设工程造价计算标准及有关规定进行计算及调整。1.2.2 概算指标1、土建工程采用能源基19911131号文颁发的煤炭工业地面建筑工程概算指标(90统一基价),并根据煤规字1995第176号文规定的93统一基价系数进行调整,或按选煤厂设计手册中的指标放大6倍。2、安装工程采用能源基19911131号文颁发的煤炭机电安装工程概算指标,并根据煤规字1995第176号文规定的93统一基价系数和百分率指标,进行调整计算。以上指标均调整至2000年造价水平。1.2.3 价格 (1)、设备购置:主要设备及大部分设备价格采用询价方式获得,不足部分参考煤炭工业常用设备价格汇编(1999年版)。设备运杂费为6%。 (2)、材料价格:参考榆林市工程造价信息及西北煤炭工程造价信息(1999 第4期)中邢台矿务局建设材料价格信息。1.2.4 取费标准土建工程、安装工程均按煤规字(1995)第175号文规定的取费标准计取。税金:按3.4%计取。费率详见下表: 表1.1-1 建筑安装工程各项费率表序号项目其他直接费现场经费间接费利润劳动保险税金1土建工程5.588.0910.167.705.103.402安装工程27.2235.9354.5666.004.713.401.2.5 基本预备费基本预备费:按6%计取。1.2.6 概算总投资本工程概算总投资25508.26万元。其中土建工程19073.80万元;设备购置 2823.69万元;安装工程439.34万元;其他费用3171.43万元。2 概算结果汇总表2-1 投资汇总表序号费用名称土建工程(万元)设备购置(万元)安装工程(万元)其他费用(万元)合计吨煤投资 元/t比重%一主要设施13624.142541.32395.4016560.87 41.40 49.39 二其它设施5449.66282.3743.935775.96 14.44 17.23 直接费小计19073.80 2823.69439.340.0022336.8355.84 66.62 三其它费用1727.571727.57 4.32 4.32 小计19073.80 2823.69 439.34 1727.57 24064.40 80.21 95.69 四基本预备费6%1443.86 1443.86 3.61 4.31 合计19073.80 2823.69 439.34 3171.43 25508.26 83.82 100.00 表2-2 土建概算表2-2 土建概算(续表)表2-2 土建概算(续表)表2-3 安装汇总序号生 产 环 节设备购置(元)安装费用(元)其 中主要材料安 装工 资一原煤准备4140398 697741 253540 444201 80026 二重选车间5909888 910599 288287 622311 113158 三浮选车间6406461 902573 239591 662982 121608 四煤泥水系统4417502 622359 165207 457152 83853 五产品装车系统4538979 820769 369023 451746 80222 小计25413228 3954041 1315649 2638392 478868 其他2823692 439338 146183 293155 53208 合计28236920 4393379 1461832 2931547 532075 表2-5 其他费用序 号工程或费用名称计算公式及说明金额(元)一建设单位管理费1、工程招标费按建安工作量0.5%计取219672、地质勘探费估列10000二工程监理费工程总投资1.5%3350525三联合试运转费按直接费的4%计取4958438四勘察设计费工程总投资(3-7)%8934733合计17275663 表2-4 车间设备表2-4 车间设备(续表)表2-4 车间设备(续表)表2-4 车间设备(续表)表2-4 车间设备(续表)表2-4 车间设备(续表)表2-4 车间设备(续表)浅析褐煤应用技术摘要: 进入十二五,褐煤的开发利用越来越被重视,本文系统的介绍了我国褐煤的工业用途,简述了各种工艺特点及开发的前景方向。关键词: 褐煤; 工艺; 应用技术中图分类号: TQ53文献标识码: A文章编号: 0253- 2336 ( 2004) 08- 0012- 03Analysis of lignite application technologyAbstract: Into the Twelve Five, the development and utilization of lignite is increasingly being taken seriously, the thesis present the industrial use of lignite systematic and outlined a variety of process characteristics and development prospects direction.Key words: lignite; crafts; application technology1前言褐煤,又名柴煤,是煤化程度最低的矿产煤。一种介于泥炭与沥青煤之间的棕黑色、无光泽的低级煤,可分为硬褐煤和软褐煤,褐煤孔隙率高,化学反应强,煤中含氧量大(15%30%),大部分以官能团的形式存在,以酚羟基(OH)为主,其次是羧基(COOH)和羰基(=CO),甲氧基(OCH)较少1。在空气中容易氧化,不易存储和运输。褐煤的用途十分广泛,含有丰富的腐植酸和褐煤蜡,褐煤提取的腐植酸可以改良土壤,促进农作物的生长,也可以作为深井钻探所用泥浆的调整剂,提高转谈质量。褐煤蜡是制造涂料、油漆、橡胶添加剂、润滑油和高级蜡纸的原料,深加工潜力巨大。据第三次全国煤炭资源调查,我国已探明的褐煤保有储量为1311.42亿t,约占煤炭保有储量的13%。以内蒙古东北部地区最多,约占全国褐煤保有储量的3/4,西南地区以云南省为主占1/5,东北、华北和中南地区的褐煤仅占全国的5%左右2。2 传统褐煤应用技术 2.1褐煤制活性炭褐煤制得的活性炭在工艺和产品上具有如下特点:褐煤反应性高,易于活化,设备生产能力大;价格低廉,易于获得;与烟煤相比,褐煤无需破粘等特殊处理,工艺过程简单;褐煤质地软,多用于制软质粉状活性炭,其产品具有敞开孔隙结构,微孔容积,比表面积,碘值较低,焦糖等大分子吸附量高。 现在成熟的制造工艺为褐煤半焦压块活化工艺,即先把褐煤炭化成半焦,然后粉碎至0.1mm以下,加沥青粘结剂成型压块,破碎压块后加入活化炉活化,经筛分和磨细可制得粉状和粒状活性炭,澳大利亚和欧洲均采用此工艺。美国的酸洗工艺制得活性炭表面积达3000m2/g。国内大连理工大学采用扎兰诺尔褐煤加碳酸钾制得活性炭表而积可达1600 m2/g;采用平庄褐煤加入氯化钾制得活性炭表面积为1200 m2/g;采用黄县褐煤加碳酸钾快速热解制得了碘值为520mg/g的活性炭。 流化床一步法制造活性炭是近年来发展的煤制活性炭新工艺。该法将原料筛分后直接送入流化床,在初始流化速度下炭化和活化,活化温度和活化气体分布均匀,可有效地活化原料。既可处理粉状又可处理粒状原料,生产工艺还简单,受到了高度重视3。2.2 制褐煤蜡褐煤制褐煤蜡历史悠久,1905年就已工业投产。褐煤蜡来源于成煤植物的有机化合物,它没有致癌作用,广泛应用在日用品、轻化工、纺织、造纸等工业。 由褐煤提取褐煤蜡,通常采用萃取的方法,选取合适的萃取溶剂是关键技术,其次由工艺决定。大多工艺采用多次错流萃取和多级逆流萃取,萃取效果好,但是溶剂消耗量大,能耗高。用二氯乙烷/乙醇混合液作为萃取剂,采用多级逆流循环萃取方式工艺,对褐煤蜡进行粗蜡脱树脂,蜡的氧化精制,制得了性能优良的十余种蜡制品4。2.3热干燥脱水发电一体化褐煤在高温下经受脱水和热分解作用后转化成具有烟煤性质的提质煤,日立公司的一体化加速旋风提质干燥工艺具有代表性。该工艺把褐煤电厂锅炉和褐煤提质干燥一体化,利用电厂的锅炉烟气进行提质干燥。全过程分为2个阶段:一是加速剪切提质干燥阶段:颗粒的外在水分几乎全部气化,内在水分约50%60%气化,煤的表面在高温烟气的作用下向接近烟煤的性质变化。煤失去一部分结晶水;二是旋风紊动提质干燥阶段:煤在巨大的离心立场下,与烟气分离,煤的内在水分进一步被气化,煤的结构进一步破坏,失去50%左右的结晶水。褐煤经过这两个阶段的提质干燥作用,含水率大幅降低,结构被很大程度的破坏,变成了具有烟煤特性的优质动力煤5。2.4制水煤浆水煤浆技术可分为常规水煤浆技术、精细水煤浆技术、低热值煤泥水煤浆和低阶煤水煤浆技术。低变质煤由于较高的内在水分不能直接制浆,褐煤含水率高只能用加热蒸发的方式进行脱水,传统的干燥方法是利用烟道气与褐煤直接接触使之受热,水分蒸发而干燥,效率高;由于褐煤燃点低,干燥过程中局部过热,使煤质变坏,且干燥后水分复吸严重。采用热水干燥与制浆工艺可解决该为题,热水干燥工艺即将煤水浆装入高压容器内,密闭后抽真空后加热,模拟煤在自然界中高温高压的变质过程,使褐煤改质。可制得浓度为60%的低阶煤水煤浆6。3新应用技术及实验研究3.1太阳能干燥褐煤我国褐煤产地的太阳能资源丰富,全年日照时数为22003300h,每平方米上一年内接受的太阳能辐射总量为50168400MJ,具有良好的利用条件;褐煤颜色深,对太阳能吸收率高,在太阳能辐射下能达到较高温度,能高效去除褐煤内在水分,太阳能非聚焦集热一般温度在100摄氏度以下,能避免高挥发分褐煤干燥过程中存在的安全隐患。太阳能辐射强度是褐煤太阳能干燥的关键因素,直接影响褐煤温度和空气的温湿度。物料的外部形状、堆积方式和物料的内部特性也影响干燥效果,将自然摊晒和太阳能干燥条件下褐煤干燥比较可知,自然摊晒下褐煤温度仅为53度,太阳能干燥技术将褐煤干燥温度提高到78度,最终能将褐煤的水分由23.08降至4.61%,而自然摊晒仅为10.82%。因此,太阳能干燥技术有效地利用太阳能,提高了褐煤的干燥温度,加快褐煤的干燥速率,缩短干燥周期,达到更好的干燥效果7。3.2微波热解技术褐煤传统的热解工艺具有热解速度慢能耗高等缺点,并且不能获得具有较好利用价值的热解炉气,微波热解褐煤,可使褐煤内外部同时受热,对加热物质具有一定的穿透作用,热解速度快,在实验条件下,17min即可将褐煤热解过程进行完毕,热解速度较常规方法快,对榆林褐煤热解实验的实验炉气,其有效成分浓度较高,可进一步作为化工原料进行处理,并且热解后的煤成分达到兰炭的要求8。目前,微波热解褐煤刚刚处于实验室阶段,报道很少。3.3微生物降解褐煤1981年,德国的Fakoussa首次利用硬煤作为微生物生长的唯一碳源和能源研究煤的微生物转化利用,一年以后,Cohen和Gabriele采用两株白腐菌Polyporus versicolor和Poria monticolor接种高度风化的褐煤,使其完全液化,为研究褐煤的转化利用问题提供了一个新的思路。褐煤是由芳香化环组成并由盐桥、脂肪链等连接起来的大分子网状结构化合物,它很难进入微生物细胞内,所以褐煤的生物降解是由微生物分泌到细胞外的一些碱性物质、生物酶、螯合剂、表面活性等起作用的。目前已报道的降解褐煤的微生物大多是木质素。降解菌,A.Maka却报道了一些能在褐煤存在条件下分泌碱性物质的非木质素降解菌,也具有降解褐煤的活性,而降解褐煤的微生物却不一定可以降解木质素9。对降解产物的生物活性研究表明:微生物降解褐煤产生的腐植酸,与未降解的褐煤腐植酸相比,前者对土壤微生物区系具有明显的刺激作用,对种子发芽和幼苗生长具有刺激作用,对大豆根瘤菌在大豆上的结瘤具有明显的促进作用,对箩卜枯萎病病菌、土壤脲酶活性具有抑制作用,其中最令人瞩目的是降解产物具有分子固氮活性(由降解前的128%增至341%),表明褐煤经微生物降解后其腐植酸生物活性明显增强10。 3.4 褐煤液化液化是通过化学方法将褐煤转变成液体产品,分为直接液化和间接液化。目前用于褐煤液化的方法是直接液化。褐煤碳含量比烟煤低, H/C高,且结构单元中有较多的羧基、氧桥、羰基和亚甲基,是比较容易直接液化的煤种。褐煤直接液化过程一般为:煤糊制备、液相加氢、气相加氢和产品精制等四个阶段。典型且成熟的工艺有溶剂精炼煤法、德国直接液化新工艺IGOR工艺、氢煤法、HTI工艺、Exxon供氢体溶剂法、神华煤液化工艺。目前褐煤液化工业投产的只有云南先锋煤液化厂,采用直接液化技术,规模为年处理(液化)褐煤原煤257万t,气化(含发电17万kW)用原煤253万t ,合计年用原煤510万t。年产汽油、柴油和液化石油气等102万t。总投资为102亿元,生产成本为17美元/桶,具有良好的经济效益和社会效益11。3.5褐煤气化褐煤气化指以褐煤为原料,以氧气(包括空气、富氧和纯氧)和水蒸气为气化介质,在气化炉内的高温条件下,将煤中所含的碳、氢转化为一氧化碳、氢气等有效成分。褐煤气化包括两个步骤:首先进行初步热解制得半焦、焦油及煤气,然后发生焦炭的气化反应。主要的气化方法可分为:移动床气化、流化床气化、气流床气化。移动床气化分为:混合发生炉煤气、水煤气生产、移动床加压气化;流化床气化分为:常压流化床气化工艺、加压流化床气化工艺、比较成熟的温克勒气化工艺;气流床气化可分为:KT气化法、谢尔气化法、德士古气化法、四喷嘴对置式水煤浆气化技术、GPS气流床气化技术。煤气的有效成分是CO、H2和CH4。可用做工业煤气、城市煤气等燃料,可用做化工合成气,可用做IGCC,可用做冶金还原气,可制羰基化产品,可综合利用,回收苯、酚等产品。4 结语本文仅是粗略的介绍了长期以来褐煤的加工利用,还有一些体质技术未能详细介绍,随着烟煤及无烟煤的进一步减少,褐煤的开发利用已被高度重视,其具有广泛的利用途径,不能仅仅把它作为一般燃料而白白烧掉,在当今倡导节能减排的大的社会形势下,既要做到褐煤资源的合理利用,又要尽量减少对环境的污染排放。在传统的利用技术基础上积极进行新技术的开发与应用。参考文献:1 戴和武,杜铭华,谢可玉,等 . 我国低灰分褐煤资源及其优化利用 J 中国煤炭,2001,27 ( 2) : 14 182 尹立群.我国褐煤资源及其利用前景J.煤炭科学技术 ,2004,32 (8):12-14.3 杨绍斌等.褐煤制活性炭J.煤炭转化1994.24 张声俊等.褐煤蜡的工业制备及精制技术J.2011.5 陈海旭. 我国褐煤燃前脱灰脱水提质现状.煤炭科技*加工转化.6 董平.洁净煤与褐煤水煤浆技术.应用能源技术97/37 罗炉林.太阳能干燥褐煤的实验研究.8 马红周.微波热解的实验研究.煤炭燃烧9 Maka A, Srivastava VJ, et al. Biological solubilization of untreated North Dakota lignite by a mixed bacteral and mixed bacteral/fungal cul-ture. Appl Biochem Biotech, 1989,20/21:71572910 袁红莉等.不可再生能源物质褐煤的生物可持续发展问题展望.院士论坛11董洪峰.我国褐煤的综合利用途径及前景展望.煤炭技术.2008.91 英文原文Quantifying rheological and ne particle attachment contributions to coarse particle recovery in otationD. Xu a, I. Ametov a, S.R. Grano b,a Ian Wark Research Institute, The ARC Special Research Centre for Particle and Material Interfaces, University of South Australia, Mawson Lakes, SA 5095, Australiab Institute for Mineral and Energy Resources, The University of Adelaide, SA 5005, AustraliaAb s t r a c t This study focused on the otation behaviour of very coarse quartz particles in the presence of ne silica and alumina, both of which were used as pulp viscosity modiers. A decrease in the contact angle of the coarse quartz particles, caused by the attachment of ne particles was believed to be the principal mech- anism accounting for the noted depression. Only small surface coverage of attached ne particles may dramatically decrease the quartz particle recovery because the otation behaviour of the coarse particles was very sensitive to particle hydrophobicity, e.g. less than 5% surface coverage is able to decrease thecontact of particles from 83 to 81 and causes a decrease in recovery from 60% to 20%. The effect ofremoving the ne particles from the pulp, by the process known as desliming, on the otation behaviour of coarse quartz particles was also investigated. The results showed that desliming is benecial for the recovery of coarse quartz particles. Furthermore, the recovery of coarse quartz particles attached with ne particles can be restored by conducting otation in high viscosity medium where glycerol was used as the viscosity modier.Keywords: Desliming Fine particle Coarse particle Rheology1. IntroductionDetachment of particles from bubbles is one of the key issues responsible for the low recovery of coarse particles. For coarse par- ticles attached to bubbles, the particlebubble aggregates must withstand the various forces which are operational in the otation cell to be successfully transported to the pulp/froth interface. A property-based otation model, developed at the Ian Wark Re- search Institute (The Wark otation model) (Duan et al., 2003; Pyke et al., 2003) suggests that a key parameter which directly con- trols the stability of a particlebubble aggregate and which quan- ties the mean shear forces acting on the bubbleparticle aggregate is the mean turbulent energy dissipation. A decrease in the mean turbulent energy dissipation throughout a otation cell may benet the recovery of coarse particles due to the reduction of shear forces acting on the particles attached to the bubbles, increasing the stability of the bubbleparticles aggregates. Other studies have shown that increasing the viscosity of the pulp results in a decrease in turbulent energy dissipation in a otation cell (Kitano et al., 1981; OConnor et al., 1990).It has also been suggested that slurry rheology is an important factor for otation due to its marked effect on cell hydrodynamics, including gas dispersion throughout the cell (OConnor et al., 1990; Deglon et al., 2007). OConnor et al. (1990) found that a decrease in pulp viscosity in a viscous slurry resulted in a decrease in the bub- ble size due to increased turbulence in the cell. However, Deglon et al. (2007) found the opposite trend for the change in bubble size, in a study of Bindura nickel ore slurries. According to Deglon et al. (2007), the bubble size decreases with an increase in the solids concentration. Deglon et al. (2007) proposed that the decrease in bubble size was due to the high yield stress in the slurry, which caused a more concentrated energy dissipation near the impeller and leads to the production of small bubbles. A decrease in the gas hold up was also attributed to the high yield stress of the slurry, which prevents the dispersion of bubbles through the cell (Deglon et al., 2007).An increase in slurry viscosity may be achieved by increasing the percent solids, particularly using ne particles as the viscosity modier. An example of the effect of particle concentration on the rheology of titanium dioxide suspensions was reported by Yang et al. (2001). At relatively low volume fraction of the titanium diox- ide (U = 0.109), the suspension shows Newtonian behaviour, i.e. the viscosity is independent of the shear rate. An increase in the solids volume fraction to U = 0.174 results in shear-thinning behaviour, with the viscosity decreasing with an increase in shear rate. With a further increase in the solids volume fraction the rhe- ological behaviour of the suspension remained shear-thinning, but the apparent viscosity values increase considerably by almost three orders of magnitude at U = 0.431 (Yang et al., 2001). Similar trends in rheological behaviour was observed for slurries of dolomite (Deglon et al., 2007), galena (Gao and Forssberg, 1993; Wang and Forssberg, 1995), quartz (Prestidge, 1997a,b) and coal (Tangsathitkulchai, 2003), though changes in ow behaviour occur at different volume concentrations of the particles.One of the drawbacks of using ne particles to modify the vis- cosity is the possible interaction between coarse and ne particles, which may cause a decrease in the otation recovery of the coarse particles by reducing the hydrophobicity of the coarse particles. Thus, ne particles may modify the otation behaviour of coarse particles through both viscosity modication and ne particle attachment to coarse particles. This paper investigates the effect of ne particles on the otation of coarse particles through rheo- logical modication and/or ne particle attachment mechanisms.2. Experimentala) MaterialSamples of quartz (GEO Discoveries, Australia) were ground and screened to two coarse size fractions of interest, namely 150 300 lm and 600850 lm. Each size fraction of ground quartz were cleaned using the procedure outlined by Pashley and Kitchener(1979). Namely, the particles were washed in concentrated hydro- chloric acid three times (2 h each time) and then rinsed with copi- ous amounts of Milli-Q water several times until the pH value of the Milli-Q water (5.6) was restored. The particles were then im-mersed in a 30% NaOH solution at 60 C for 1 min, followed bythe same rinsing procedure. The particles were then dried in a clean oven at 110 C overnight and stored in capped bottles in adesiccator under vacuum.Trimethylchlorosilane (TMCS) solutions in cyclohexane were used for particle methylation (Pashley and Kitchener, 1979). Since TMCS readily reacts with water, the methylation reaction was per- formed in a glove box under nitrogen atmosphere. Different con- centrations of TMCS were prepared by diluting the required volumes of TMCS in cyclohexane. The cleaned quartz were weighedinto a beaker and heated in an oven at 110 C overnight to removethe physisorbed moisture. Particles with various contact angles were obtained using solutions of different TMCS concentrations and reaction time. All glassware was cleaned and dried before use.Fine alumina (Hydral 710, Alcoa of Australia Limited) and silica (SigmaAldrich Inc., USA) were used to adjust the pulp viscosity. The choice of these particles is based on the fact that at pH 9, alu- mina is positively charged (Johnson et al., 2000), and may interact with coarse quartz particles. In contrast, silica has a negative zeta potential in the 39 pH range (Ametov and Prestidge, 2004), and is not expected to interact with quartz. The condition of pH 9, i.e., the pHIEP of alumina was used because particle interaction, and consequently viscosity, is most signicant at this pH value. The aggregates may facilitate the attachment. Thus, rheological and ne particle attachment contributions to otation response may be discerned. To contrast the effect of particle interaction in the case of the alumina particles, silica was also examined as a model system that would exhibit lower particle interaction under these conditions. Therefore, using alumina and silica, the effect of colloidal particles on the viscosity of the suspending medium and the otation behaviour of the coarse quartz may be considered, as a rst approximation, as an investigation for the cases of inter- acting and non-interacting ne particles. Characterisation of ne alumina and silica is presented in the next section.Characterisation of ne particlesZeta potential of alumina and silica particlesZeta potential of silica and alumina was determined from the particle dynamic mobility using the Nano-ZS Zetasizer instrument(Malvern Instruments Ltd., Worcestershire, UK) in electrophoretic light scattering mode for dilute particle suspensions.Dilute silica and alumina suspensions were prepared at 0.5 wt.% solids, in 10-3 M KCl and dispersed with a magnetic stirrer for30 min. The suspension was allowed to stand for 5 min, and the colloidal particles (5 lm in size) in the supernatant were si- phoned off for the zeta potential measurement. The suspension pH was altered to a desired value with HCl and KOH solutions,and allowed to equilibrate for 10 min before the samples were di- rectly injected into a disposable capillary cell for zeta potential measurements. The measurements were performed over the pH range 59.5 for alumina. The zeta potential of the silica was inves- tigated over pH range 39.Particle size distribution of alumina and silicaThe particle size distribution of alumina and silica was deter- mined by laser diffraction using a Mastersizer 2000 (Malvern Instruments Ltd., UK). The basic particle size sensor comprises an optical measurement unit which supplies information to a com- puter to process data and perform the analysis.Ultrasonication for 5 min and a polyphosphate dispersant (i.e., Calgon) were used to achieve full dispersion of both alumina and silica particles.Slime coating of ne particle on quartz surfaceScanning electron microscopy (a PHILIPS XL-20 electron micro- scope) was used to determine the adsorption of ne silica and alu- mina particles on the surface of coarse quartz particles. The samples were mounted onto the sample holder using double-sided sticky tape and were coated with a thin carbon layer using a vac- uum evaporator.Slurry rheologyThe rheological behaviour of the silica and alumina suspensions was investigated using a Haake RotoVisco RV1 rheometer (Thermo Electron GmbH, Germany) tted with the concentric cylinder (Cou- ette) sensor. Each slurry sample (100 cm3) was prepared by adding known weights of ne silica or alumina particles to known volumes of the 10-3 M KCl solution at pH 9. Prior to the rheology measurement,the suspensions were stirred for 1 h using an overhead stirrer. In the measurement, the shear rate increased from 0 s-1 to 1000 s-1 (an upward curve) and then decreased down to 0 s-1 (a downwardcurve) in 200 s. The rheological parameters were automatically re- corded by a computer. The percentage of ne alumina and silica is shown as volume% in all cases using 2.65 g/cm3 and 3.95 g/cm3 density for silica and alumina respectively to convert the mass of ne particles to corresponding volume.MethodologyFlotationFlotation tests on coarse quartz particles were carried out according to the owsheet shown in Fig. 1. Quartz particles (60 g) of various mean contact angle values and particle sizes were oated in a 1.5 dm3 bottom driven otation cell. All otation tests were carried out at an impeller speed of 600 rpm. Air was intro- duced into the otation cell at a ow rate of 3.5 dm3/min (Jg = 0.4 cm/s). Dowfroth 250 (170 g/t, 8 ppm in solution) was used as frother. Froth depth was 3 1 cm. Quartz particles were hydro- phobised to the target value of contact angle before the otation test. Four concentrates were collected, cumulatively at 0.5 min, 2 min, 4 min and 8 min. Make-up water was used to the cell to keep the interface at the same level during the otation tests.The viscosity of the suspending medium was increased by: (i) using glycerol (95% purity)/water mixtures instead of water and(ii) by the addition of the colloidal alumina or silica particles at dif- ferent volume concentrations. Flotation tests in water and the glyc- erol/water mixtures were conducted at pH 7. In the case where ne particles were used to increase the viscosity of the suspending medium, 10-3 M KCl solution was used as a background electro lyte, and the pH of the slurry was maintained at 9.To determine the recovery of coarse quartz particles in the o- tation tests in the presence of alumina and silica, the concentrates and tailings were wet screened at 38 lm to remove the ne parti- cles. To estimate the experimental errors, all tests were performedin triplicate.2.3.2. Experimental otation rate constantAssuming that froth otation is a rst-order kinetic process, the otation recovery, Rt, at time t may be described by the following expression:Rt Rmax 1 - exp-kt1where k is the otation rate constant and Rmax is the otation recov- ery at an innite time.A nonlinear least square regression was used to calculate k and Rmax from the best t of the curve of experimental otation recov- eries versus time using Eq. (1). These otation rate constants are referred to as the experimental otation rate constants in the text. Small variations in the otation recovery versus time data may re- sult in different values of otation rate constant. To minimise er- rors associated with the calculations of the rate constant, the tests were carried out in triplicate and the average values of ota- tion recovery at each time were used to calculate the rate constant.DeslimingThe otation recovery of coarse quartz particles generally de- creased in the presence of the colloidal silica and alumina particles, presumably due to the adsorption of ne particles onto the surface of the coarse quartz. To investigate whether the adsorption of nes was reversible, a series of desliming tests was carried out. The des- liming procedure is schematically presented in Fig. 2. Slurry, con- taining coarse quartz and ne silica or alumina particles was placed in the otation cell as per the standard otation procedure. The coarse quartz particles were allowed to settle. The superna- tant, containing ne particles was then decanted, the cell was re-lled with the 10-3 M KCl solution and the otation test wasperformed. In a different test, the desliming procedure was re- peated twice to increase the amount of removed ne particles. The otation test was also conducted following the procedure de- scribed above.Contact angle measurementAdvancing mean contact angles of the quartz particles in water were measured using DCAT 11/DCAT 11EC, DataPhysics Instru- ments (Germany). This instrument allows measurements of the contact angle and surface energy of cylindrical samples in accor- dance with the Washburn technique (Muganda et al., 2011). Eq.(2) was used to calculate the contact angle for two-liquid systems. where c is the surface tension of the liquid, l is the viscosity of the liquid, and q is the density of the uids. The subscripts 1, 2 refer to the liquid where the contact angle is determined and calibrating li- quid respectively. The contact angle in water was measured using cyclohexane as the calibrating liquid. Thus, in Eq. (2) cos h2 = 1. Gi-ven other parameters (c, l, q, and x2/t which could be determined during the measurement), the contact angle may be determined.3. ResultsCharacterisation of the ne alumina and silicaZeta potential of alumina and silica particlesFig. 3 shows the zeta potential of alumina and silica particles as a function of pH at ionic strength of 10-3 M KCl.It is apparent that at pH 9, alumina is slightly positively charged (+2 mV) and silica is negatively charged (-40 mV). The results are consistent with those reported elsewhere (Ametov and Prestidge, 2004; Johnson et al., 2000). Particle size distribution of the ne alumina and silicaFig. 4 shows the particle size distribution data for the ne par- ticles of both alumina and silica. Evidently, a broader size distribu- tion for the silica than the alumina particles is observed. The mass mean size (D 4,3) of the ne silica and alumina particles are3.09 lm and 3.10 lm respectively. The size distribution shown to characterise the ne particles may not be the actual particle size distribution in the otation cell due to aggregation or dispersion effects under shear conditions.Rheology of the ne alumina and silica suspensionsThe ow curves for alumina and silica suspensions as a function of solids percent (v/v) are presented in Fig. 5a and b respectively.The measurements were performed at pH 9 in 10-3 M KCl solution, at which pH the zeta potential of alumina and silica particles is+2 mV and -40 mV, respectively (Fig. 3). Alumina suspensions ex- hibit shear-thinning behaviour, i.e. the viscosity of the suspensionsdecreases with an increase in the shear rate. At the low value of zeta potential, the van der Waals attractive forces are dominant, and alumina particles readily aggregate when the suspension is at rest. Under shear, the large particle aggregates are separated into smaller units and, at very high shear, into individual particles. Such a process rheologically manifests itself as shear-thinning behaviour.Silica suspensions show Newtonian behaviour, i.e., the viscosity of the suspension is independent of the shear rate. At pH 9 in 10-3 M KCl solution, the zeta potential of the silica particles is -40 mV,and the electrostatic repulsion dominates the inter-particle interactions. The strong electrostatic repulsion ensures good dis- persion of particles resulting in Newtonian behaviour.The apparent viscosities (at a shear rate of 500 s-1) of the silicaand alumina suspensions as a function of solids volume fraction are shown in Fig. 6. Evidently, the apparent viscosity increases with an increase in the solids concentration. In the case of alumina, the increase in the apparent viscosity is much steeper than for silica, also due to the nature of the inter-particle interactions in alumina (the van der Waals attraction) and silica (the electrostatic repul- sion) suspension. The aim of this investigation was to use twotypes of colloidal particles to increase the pulp viscosity, and then to ascertain the effect of the higher viscosity on the otation recov- ery of coarse quartz. Of course, the value of the viscosity attained by the addition of these types of particles is required to be compa- rable. Two values of the viscosity were selected for investigation, i.e., 12 mPa s and 30 mPa s. From Fig. 6, and 2% (v/v) alumina and 3% (v/v) silica suspensions provide a viscosity of 12 mPa s. To ob- tain a slurry viscosity of 30 mPa s, 4% (v/v) alumina and 30% (v/v) silica are required, respectively.Effect of ne silica and alumina on coarse quartz otationThe recovery of coarse quartz particles (600850 lm, mean contact angle 81) in the presence of ne alumina and silica as afunction of otation time is presented in Fig. 7. The recovery of coarse quartz particles decreased dramatically, from 27% to 2%, for tests in which the slurry contained 2% (v/v) alumina. A further increase in the volume fraction of alumina, to 4%, did not affect the outcome of the otation tests. The effect of silica at 3% (v/v) was less severe, i.e. the recovery of coarse quartz decreased to 13%. Increasing the concentration of ne silica to 30% (v/v) resulted in a further decrease in coarse quartz recovery to 3%.Evidently, both types of ne particles negatively affected the recovery of coarse quartz particles. In the case of alumina, whichis positively charged under the test conditions (pH 9, 10-3 MKCl), some degree of interaction with the coarse quartz particles was expected. Adsorption of hydrophilic alumina particles onto the surface of hydrophobic quartz may lead to a decrease in the mean contact angle of the coarse quartz surface, and therefore de- crease coarse particle recovery. However, a decrease in the ota- tion recovery of coarse quartz particles was observed in the presence of ne silica, though to a lesser degree. This was not ex- pected due to the surmised electrostatic repulsive force.The effect of the ne silica and alumina on the otation behav- iour of the coarse quartz particles was also investigated as a function of coarse quartz particle size range and mean contact angle. The results of otation tests for quartz particles in the150300 lm and 600850 lm size ranges are shown in Figs. 8 and 9, respectively.It is worth mentioning that the reason for using two different hydrophobicity ranges for the two size fractions is that for coarser particles, greater hydrophobicity is required to recover the parti- cles. The contact angle ranges shown in the study is the range where a reasonable recovery was obtained for the coarse particles in water only. Thus we can investigate the effect of ne particles on the recovery further.For coarse particles with a reasonably high mean contact angle (75 and 90 for quartz particles in the 150300 lm and 600 850 lm size ranges, respectively), the recovery of coarse quartz was not affected by the presence of ne silica and alumina in the pulp. The magnitude of the coarse quartz recovery remained as high as the value obtained in water. In contrast, for quartz particles with lower mean contact angle (50 and 18 in the 150300 lm size range and 83 for the 600850 lm size range) the otation recovery of coarse quartz decreased in the presence of ne alumina and silica. Notably, the effect of the ne alumina on the recovery of quartz was much stronger compared to that of the ne silica although the viscosity values in both cases were the same at 12 mPa s. It should be pointed out that in the case of coarse quartz particles with a contact angle of only 18 (150300 lm size range) (Fig. 3.6c), the effect of alumina and silica was comparable, i.e., the recovery of quartz decreased to a very low value of 3%.In previous work (Xu et al., 2011), it was demonstrated that the recovery of coarse particles increased with an increased medium viscosity, controlled by adding certain amount of glycerol. Particu- larly, when the medium viscosity is 7.6 mPa s, which is similar to that investigated in this work, 12 mPa s, the recovery of quartz par-ticles with a contact angle of 80 increased from 20% to 70%. It wasconcluded that an increase in medium viscosity may benet the otation recovery of coarse particles. However, in the presence of ne particles, the otation recovery of coarse particles decreased even though the viscosity was similar. A possible mechanism is discussed further below.The recovery of coarse quartz particles after 8 min of otation as a function of mean contact angle in the absence and presence of ne silica and alumina is shown in Fig. 10. Evidently, the recov- ery of the coarse quartz particles in the 150300 lm size range is less sensitive to the presence of ne alumina and silica (Fig. 10a). The otation recovery of the quartz particles in the 150300 lm size range with a mean contact angle of 75 in the presence of ne alumina or silica was as high as in the absence of ne particles, at 90%. For particles with a contact angle of 50 the recovery de- creased to 22% in the presence of the ne alumina, and to 68% in the case of ne silica. Particles with low hydrophobicity (h = 18) exhibited very low recovery (3%) in the presence of either ne sil-ica or alumina.Furthermore, the otation response of very coarse quartz particles (600850 lm) to the presence of silica or alumina was noticeably different. In the pulp containing silica particles (3%), the recovery of quartz with mean contact angle of 90 remained virtually the same as in water only (92%). The otation recovery of quartz particles with a mean contact angle of 83 was 60% inwater, and decreased to 50% in the presence of silica (Fig. 10b). There was only 30% recovery at a lower mean contact angle of 81 even in water only. With ne silica added to the pulp the quartz (81o) recovery decreased to 15%.In the presence of ne alumina, the otation recovery of coarse quartz with a mean contact angle of 90 was as high as in water only or as in the presence of silica (92% in both cases). In contrast,the recovery of coarse quartz particles with mean contact angle of 83 decreased from 60% in water to 10% in the presence of ne alu- mina (4%). Particles with a mean contact angle of 81 becameessentially unrecoverable in the presence of ne alumina particles.It is also shown in Fig. 10 (water only) that the oatability of very coarse particles is very sensitive to the hydrophobicity ofthe particles. A small decrease in the contact angle (from 83 to80) results in a dramatic decrease in the otation recovery (from 60% to 20%). Increasing the medium viscosity by ne particle addi-tion failed to increase the quartz particle recovery may be due to the adsorption of ne particles on the quartz surface, which resulted in a decrease in particle contact angle. By assuming thecontact angle of ne hydrophilic particles adsorbed onto the quartz surface is zero, only 4% surface coverage is sufcient to decreasethe contact angle of the quartz particles from 83 to 80 accordingto Cassies equation (Cassie and Baxter, 1944). This may explain why the otation recovery of coarse particles decreased in the presence of the ne particles, which in fact increase the pulp vis- cosity. The attachment of ne particles may dominate the effect of pulp viscosity for the otation behaviour of coarse particles.Effect of removal of ne particles (desliming) on coarse quartz particle recoverySince the presence of ne particles had a negative effect on quartz recovery, the effect of their removal in desliming was also investigated. The desliming procedure was outlined in the experi- mental section above. The effect of desliming on the coarse quartzparticles recovery on the size range of 600850 lm is shown inFig. 11.In the presence of alumina (2% v/v) (Fig. 11a) the otation recovery of quartz particles decreased from 60% to 10%. After a sin- gle stage of desliming, the recovery of coarse quartz particles in- creased from 10% to 50%. An additional desliming stage did not result in an appreciable increase in coarse quartz recovery. It seems reasonable to assume that, in the presence of alumina particles in the pulp, the otation recovery of coarse quartz may always be be- low that of the original value achieved in the complete absence of alumina particles. In the case of silica (3% v/v) suspension (Fig. 11b), the recovery of quartz particles (80o) also decreased, from 20% to 13%. A single stage of desliming did not improve the coarse quartz recovery. However, two stages of desliming process successfully restored the recovery of coarse quartz particles to the original value ob- tained in water only.Recovery of coarse quartz in glycerol/water mixtureIn the previous sections, it was shown that the recovery of coarse quartz decreases in the presence of ne particles, particu- larly in the case of alumina. It was also proposed that the loss of recovery of coarse particles was due to the decrease in particle hydrophobicity which resulted from the adsorption of ne hydro- philic particles onto the quartz surface. Additionally in previous work (Xu et al., 2011), it was demonstrated that the recovery of coarse quartz particles could be increased by conducting otation in a high viscosity medium. Moreover, in high viscosity medium coarse quartz particles with lower critical contact angle (Crawford and Ralston, 1988) were able to be recovered (Xu et al., 2011). Therefore, the question now becomes Is it possible to restore the otation recovery of coarse quartz particles decreased in the presence of ne alumina and silica by using a high viscosity med- ium? is logical and needs to be answered.In this investigation, the coarse quartz particles were condi- tioned in the presence the ne alumina (2% v/v) or silica (3% v/v) following the otation procedure described in the previous section. A single stage of desliming was carried out using a otation cell. Inthe control test, 10-3 M KCl solution was used to increase thepulp volume in the otation cell to the required volume and the otation was conducted. In the test investigating the effect of a high viscosity medium, the calculated amount of glycerol was added to ensure a 50% glycerol/water mixture with the viscosity of 7.6 mPa s, and the otation test performed. The recovery of quartz particles as a function of otation time in the control test (water) and in the test conducted in the 50% glyc- erol/water mixture are presented in Fig. 12. The otation data was tted using the rst order kinetic equation (Eq. (1). The otation rate constant and the maximum recovery at innite time Rmax are summarised in Table 1. It is apparent that the presence of ne particles in the pulp resulted in a decrease in the recovery of coarse quartz, an increase in the water recovery, as well as the otation rate constant (Table 1). The effect of the ne alumina on otation of quartz was more pronounced than that of the ne silica. A single stage of desliming, followed by otation in water, partially restored the recovery of the coarse quartz particles. The otation rate con- stant in both cases (for the presence of ne alumina and silica) also increased. It is notable that there is not much difference in water recovery with desliming which indicates that the increase in recov- ery with desliming is not due to increased entrainment. However, for otation tests after the single stage desliming but in the pres- ence of the 50% glycerol/water mixture showed that the coarse quartz recovery increased to a value higher than in the control tests. In fact, it was higher than the recovery of the coarse quartz in water in the absence of ne particles, i.e. marginally higher for ne alumina particles, and considerably higher in the case of the ne silica (Table 1). In contrast, the otation rate constant in the tests conducted in the 50% glycerol/water mixture decreased, sim- ilarly to what was observed and discussed in previous work (Xu et al., 2011). Furthermore, highest water recovery was observed in the 50% glycerol/water mixture for both cases (alumina and sil- ica) due to the increased pulp viscosity.4.DiscussionEffect of slime coating on quartz otationThe otation results indicate that ne particles in the pulp have a negative effect on the otation behaviour of the coarse quartz. The ne particles were used to increase the pulp viscosity and, pos- sibly, the otation recovery of coarse quartz particles. However, the otation recovery of quartz decreased. The supposition that the coarse particle recovery may increase in the presence of ne particles is based on previous work that increased viscosity (through addition of glycerol) increased coarse particle recovery (Xu et al., 2011). That the ne particles actually caused depression, while also increasing pulp viscosity, demonstrated that an addi- tional mechanism was at play.It was demonstrated in previous (Fig. 10 water only) and also in previous work (Xu et al., 2011) that the otation response of coarse particles is very sensitive to the particle hydrophobicity. Calcula- tions discussed previously, suggest that only very low surface cov- erages of hydrophilic ne particles (of the order of 5%) are required to reduce the contact angle below the critical value depressing o- tation. The decrease in the recovery of very coarse particles, even though in higher pulp viscosity, may be due to the fact that hydro- philic ne particles adsorbed on the quartz surface, and conse- quently reduce the contact angle of the coarse quartz particles to below the critical contact angle. More signicant decreases of recovery in the case of ne alumina than that of silica may be ex- pected due to the different nature of surface charge and propensity to adsorb onto the coarse quartz surface.To elucidate the possible mechanism of the decrease in recovery of quartz particles in the presence of ne alumina and silica, scan- ning electron microscopy (SEM) was used. Coarse quartz particles, collected from the tailings were gently washed with water and studied by SEM. The SEM images of the quartz particles are pre- sented in Fig. 13.Evidently, both types of particles, i.e. alumina (Fig. 13a) and sil- ica (Fig. 13b), adsorb onto the coarse quartz surface. Possibly, a greater amount of alumina is present on the quartz surface com- pared to silica. Moreover, the majority of the alumina particles ad- sorb on edges or steps on the quartz surface. This may be due to the higher surface energy of the edges, which are rougher compared to the crystal planes, and possibly provide more adsorption sites. An- other possible reason for greater quantities of alumina particles on the quartz surface is the self-aggregation of alumina particles. At pH 9, which is near the iso-electric point for alumina, the surface charge of alumina is low (zeta potential is +2 mV), the attractive van der Waals forces are dominant, and ne particles aggregate. Decreasing the pH to values further away from the iso-electric point may reduce the self-aggregation of alumina, but it may also promote adsorption of alumina onto the coarse quartz surface due to electrostatic interaction.It was reported earlier that both silica and TMCS treated quartz are highly negatively charged (the zeta potential is -40 mV) and,due to the dominant electrostatic repulsion, may not interact un- der the conditions of the experiment. However, the SEM image in Fig. 13b showed that ne silica particles also adsorb onto the sur- face of the coarse quartz, although to a lesser extent compared to alumina. Similarly to the ne alumina, ne silica particles also ad- sorb onto the edges and steps of the quartz surface. Although, the mechanism of adsorption of ne silica on the surface of hydropho- bic quartz is not understood, it is clear that only a small surface coverage of either ne alumina or ne silica are required to de- crease the contact angle of the coarse quartz particles below the critical value necessary for stable bubbleparticle attachment. Aspreviously outlined, the critical contact angle for 600850 lm size range is of the order of 85, with decreases in contact angle below 80 able to effectively depress otation completely. Surface cover-age of hydrophilic ne particles less than 9% is able to decrease the contact angle by 5 making the otation recovery of coarse parti-cles very sensitive to the surface coverage of ne hydrophilic par- ticles. This gives rise to the often noted knife-edge behaviour of coarse particles in plant practice.Effect of desliming on quartz recoveryAs shown earlier, the removal of ne particles from the pulp is, to some extent, benecial for the otation of coarse particles. A sin- gle stage of desliming increased the recovery of coarse quartz par- ticles in the presence of ne alumina, although in the presence of ne silica, it was rather unsuccessful. In contrast, adding a second stage of desliming for the alumina containing pulp was ineffective, but appreciably improved the recovery of quartz in the pulp con- taining ne silica. The positive effect of desliming may be attrib- uted to detachment of ne particles from the surface of the coarse particles, thus restoring the value of the contact angle. How- ever, it seems that the success of the desliming process depends on the type of the interaction between the ne and coarse particles, as well as on the concentration of ne particles in the pulp and, pos- sibly, turbulence and uid velocity in the otation cell (Edwards et al., 1980; Bandini et al., 2001).Restoring the recovery of quartz particles using high viscosity medium (50% glycerol/water mixture)In previous work (Xu et al., 2011) it was demonstrated that much higher otation recovery of coarse particles may be achieved in the high viscosity medium. This effect was attributed to changes in the hydrodynamic parameters in a otation cell, such as an in- crease in the mean bubble size, broadening of the bubble size dis- tribution and a decrease in local turbulent energy dissipation and uid velocity. In addition, it was shown that the critical contact an- gle, the minimum contact angle required for particles to oat, is lower in high viscosity medium. An increase in the medium viscos- ity reduces the kinetics of the bubbleparticle collection process, but at the same time, increases the maximum recovery of coarse particles. The decrease in otation rate constant in the high viscos- ity medium may be attributed to the decrease in turbulent energy dissipation and uid velocity, and consequently the decrease in bubble particle collision frequency. Conversely, low energy dissi- pation and uid velocity are favourable for greater stability of bub- bleparticle aggregates, and therefore the maximum recovery of the coarse particles increases.Adsorption of nes onto the surface of the coarse particles de- creases the coarse particle contact angle. In the cases, where the coarse particles become unrecoverable as a result of the adsorbed ne particles, their contact angle decreases to a value lower than the critical contact angle determined in water. Conducting the o- tation tests at higher viscosity is benecial to the recovery of the coarse particles in two ways: (i) the high viscosity medium de- creases turbulent energy dissipation in the otation cell, resulting in an increase in the stability of bubbleparticle aggregates and (ii) the contact angle of coarse particles does not need to be as high for the particles to be recovered. In practice, desliming is sometimes used to remove ne particles from the pulp and to reduce the amount of ne hydrophilic particles attached to the coarse parti- cles. This is recognition of the controlling behaviour of the ne par- ticles on coarse particle recovery, and the sensitivity of coarse particles to changes in contact angle. Moreover, desliming may also be accompanied by deliberate changes in pulp viscosity by the introduction of high viscosity media. This combination of ap- proaches has been used to successfully increase the recovery of coarse composite particles from an ore (Farrokhpay et al., 2011).5. ConclusionsThe depression of coarse particle recovery was due the attach- ment of ne hydrophilic particles, which resulted in a decrease in particle mean contact angle. Increasing the pulp viscosity using ne particles failed to benet the coarse particle recovery due to the dominant effect of ne particle attachment, which was attrib- uted to the fact that the otation recovery of coarse particle is very sensitive to particle hydrophobicity. Desliming was successful in restoring recovery to a degree probably due to detachment of ne hydrophilic particles and an increase in the contact angle of coarse particles. Further increases in the recovery of coarse particles were apparent with the high viscosity medium using glycerol as a vis- cosity modier.AcknowledgementFinancial support from AMIRA International, the Australian Re- search Council and University of South Australia, is gratefully acknowledged.ReferencesAmetov, I., Prestidge, C.A., 2004. Hydrophobic interactions in concentrated colloidal suspensions: a rheological investigation. Journal of Physical Chemistry B 108, 1211612122.Bandini, P., Prestidge, C.A., Ralston, J., 2001. Colloidal iron oxide slime coatings and galena particle otation. Minerals Engineering 14, 487497.Cassie, A.B.D., Baxter, S., 1944. Wettability of porous surfaces. Transactions of the Faraday Society 40, 546551.Crawford, R., Ralston, J., 1988. The inuence of particle size and contact angle inmineral otation. International Journal of Mineral Processing 23, 124.Deglon, D.A., Shabalala, N.Z.P., Harris, M.C., 2007. Rheological effects on gas dispersion. Minerals Engineering International Conferences: Flotation 07 Cape Town, Xstrata Process.Duan, J., Fornasiero, D., Ralston, J., 2003. Calculation of the otation rate constant of chalcopyrite particles in an ore. International Journal of Mineral Processing 72, 227237.Edwards, C.R., Kipkie, W.B., Agar, G.E., 1980. The effect of slime coatings of the serpentine minerals, chrysotile and lizardite, on pentlandite otation. International Journal of Mineral Processing 7, 3342.Farrokhpay, S., Ametov, I., Grano, S., 2011. Improving the recovery of low grade coarse composite particles in porphyry copper ores. Advanced Powder Technology 22, 464470.Gao, M., Forssberg, E., 1993. The inuence of slurry rheology on ultra-ne grinding in a stirred ball mill. In: 18th International Mineral Processing Congress. Sydney, Australian.Johnson, S.B., Franks, G.V., Scales, P.J., Boger, D.V., Healy, T.W., 2000. Surfacechemistryrheology relationships in concentrated mineral suspensions. International Journal of Mineral Processing 58, 267304.Kitano, T., Kataoka, T., Shirota, T., 1981. An empirical equation of the relative viscosity of polymer melts lled with various inorganic llers. Rheologica Acta 20, 207209.Muganda, S., Zanin, M., Grano, S.R., 2011. Inuence of particle size and contact angle on the otation of chalcopyrite in a laboratory batch otation cell. International Journal of Mineral Processing 98, 150162.OConnor, C.T., Randall, E.W., Goodall, C.M., 1990. Measurement of the effects of physical and chemical variables on bubble size. International Journal of Mineral Processing 28, 139149.Pashley, R.M., Kitchener, J.A., 1979. Surface forces in adsorbed multilayers of water on quartz. Journal of Colloid and Interface Science 71, 491500.Prestidge, C.A., 1997a. Rheological investigations of galena particle interactions.Colloids and Surfaces A: Physicochemical and Engineering Aspects 126, 7583.Prestidge, C.A., 1997b. Rheological investigations of ultrane galena particle slurries under otation-related conditions. International Journal of Mineral Processing 51, 241254.Pyke, B., Fornasiero, D., Ralston, J., 2003. Bubble particle heterocoagulation under turbulent conditions. Journal of Colloid and Interface Science 265, 141151.Tangsathitkulchai, C., 2003. The effect of slurry rheology on ne grinding in a laboratory ball mill. International Journal of Mineral Processing 69, 2947.Wang, Y., Forssberg, E., 1995. Dispersants in stirred ball mill grinding. Kona 13, 6777.Xu, D., Ametov, I., Grano, S.R., submitted for publication. Effect of medium viscosity on coarse particle otation. International Journal of Mineral Processing.Yang, H.-G., Li, C.-Z., Gu, H.-C., Fang, T.-N., 2001. Rheological behavior of titanium dioxide suspensions. Journal of Colloid and Interface Science 236, 96103.2 中文译文量化流变和细颗粒吸附对粗颗粒浮选的影响摘 要:本文研究了以细粒级二氧化硅和氧化铝作为矿浆浓度调节剂对粗石英颗粒可浮性的影响。由于细泥的附着引起石英接触角的较少是石英产率降低的主要机制,粗石英的可浮性对其本身的疏水性很敏感,较小面积覆盖细泥都会显著地降低回收率。例如少于5%的表面细泥覆盖可使接触角由83降到81,回收率由60%降到20%。同时实验研究了从矿浆中脱出细颗粒即脱泥过程对可浮性的作用。结果说明了脱泥对回收率有利,而且再使用甘油调高浮选介质粘度时可以保证存在细泥时石英的回收率。1 引 言低产率的关键因素是因为颗粒从气泡上脱落,由于颗粒附着在气泡上,矿化气泡要上浮到气液界面就必须克服由浮选机运转带来的各种阻力。一种由伊恩沃克研究院开发的基于属性的浮选模型沃克浮选模型,即平均湍流能的损耗直接决定矿化泡沫的稳定性和平均剪切力对矿化泡沫的作用。减小矿浆通过浮选槽过程中湍能的损耗可以减小剪切力对矿化泡沫的作用以及增加矿化泡沫的稳定性,其它研究证明增加矿浆粘度可以减少湍流能的损耗。同时有这样的观点:可浮性的重要因素之一是泥浆的流动性,是由于浮选机的流体力学有显著影响,包括气泡在整个浮选槽内的分布,发现降低粘滞矿浆的粘度结果增加了浮选槽内的湍流进而使气泡尺寸减小。然而,Deglon 等人(2007) 通过研究宾杜拉型镍矿泥浆提出气泡有相反的变化趋势。根据Deglon研究矿浆固体浓度提高气泡变小,由于矿浆中的高屈服压力使气泡变小,从而使叶轮附近产生较为集中的能力耗散进而生成小气泡。高屈服应力导致气体滞留量减少同时阻值气泡在浮选槽内的分散。增加固体颗粒含量可以增加矿浆粘度,尤其使用细颗粒作为粘度改性剂。Yang等人 (2001)提出改变固体浓度对二氧化钛悬浮液流变性的影响,在固体容积率较低(=0.109)时,矿浆为牛顿流体,粘度不随剪切率变化。在固体容积率=0.174时,矿浆发生剪切变稀,粘度随剪切率增加而减小。进一步增加固体容积率(=0.431),矿浆保持剪切变希,但是视粘度明显接近三个数量级增加。白云石矿浆、方铅矿矿浆、石英矿浆、煤矿浆在不同浓度时各自流变特性有
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