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关于煤泥浮选药剂的研究摘要：随着煤炭技术的飞速进步，机械化开采造成细粒级原煤含量增加，这就使得对细粒级煤分选的研究变得日益重要。煤泥浮选是目前选煤厂处理煤泥的主流方式，因此对煤泥浮选的研究有着十分重要的意义。本文就是针对浮选药剂进行的研究，包括捕收剂、起泡剂的作用机理，以及与浮选效果紧密相关的药剂制度等。关键词：浮选 捕收剂 起泡剂 药剂制度 矿物的化学组成、晶体结构和表面性质决定了矿物的自然可浮性，换言之浮选是根据不同矿物的表面物理化学性质的差异，将目的矿物从原矿中分离出来。然而，自然界具有天然疏水性的矿物却为少数。为了更有利于浮选过程的快速顺利进行，可以事先加入某些药剂处理使目的矿物和非目的矿物的疏水性差异加大，人为地改变矿物的可浮性。换言之，在矿物浮选过程中，为了改变矿物表面的物理化学性质，提高或降低不同矿物的可浮性，并能够进行有效的分选，所使用的各种有机和无机化合物，称为浮选药剂。浮选药剂或用于调节矿浆的浮选性质，或用来改善气泡的浮选性质，为矿物的分选创造有利条件。能选择性地作用于矿物表面并使其疏水性的有机物质称为捕收剂。具有起泡作用的表面活性物质称为起泡剂。已经考虑对有用矿物采用什么方法进行分选后，就要决定药剂的种类、药剂用量、比例、加药顺序、地点和方法等，这就是药剂制度。1、 捕收剂1.1捕收剂提高矿物表面疏水性的作用机理 捕收剂是最重要的一类浮选药剂，其作用主要是使矿物表面疏水化，降低矿物表面的润湿性，从而提高矿物的可浮性。现代泡沫浮选所用的捕收剂除了烃类油外，都是极性和非极性基两部分组成的异极性有机化合物，捕收剂分组组成中的极性基（亲固）与矿物表面有相当的作用活性，以某种键力作用下能比较牢固地吸附在矿物表面上，这时矿物表面的部分不饱和表面能降低，键能趋于饱和；而分子中的非极性基对外只呈现微弱的分子间力，这使非极性基就像其母体烃不易被水润湿。 于是捕收剂分子或离子作为一个整体在矿物便面吸附呈现一种定向排列，极性亲固基朝向矿物表面，非极性基朝向水介质起到排水亲气的作用，造成矿物表面的疏水化，并使其易于向气泡粘附。1.2捕收剂增大矿物在气泡上的附着力和缩短附着时间的作用机理 捕收剂亲固基与矿物表面的结合力，因大大超过了水分子与矿物表面的结合力，使捕收剂能破坏原来水分子与矿物表面之间的联系，取而代之的便是结合力更强、吸附更牢固的捕收剂。 矿物表面吸附捕收剂后，使矿物表面不饱和键能在很大程度上得到补偿，矿物表面吸附的捕收剂的疏水效应对水产生强烈的排斥作用。捕收剂降低了矿物表面水化层的稳定性，并使其厚度变薄。当矿物表面的疏水性到达一定程度后，即矿物表面水化层的稳定性降低到一定程度，水化层就会出现破裂，只剩下残余的水化层，这时矿物与气泡相互接触摩擦碰撞，就会实现三相润湿周边，实现矿粒与气泡粘附。 2、 起泡剂2.1起泡剂阻碍或减轻气泡相互兼并的作用机理 往溶液中充入空气时，起泡剂分子在气泡表面发生定向排列（非极性基插入气泡内部，极性基受到偶极水分子的强烈吸引伸向水里），由于极性水分子与起泡剂极性基之间发生强烈的水化作用，使气泡表面形成具有一定厚度和一定构架的“水化外壳”保护层，它有一定的强度并使气泡表面有一定的刚性和弹性，如果要破坏这层保护膜往往需要比较大的外力作用。由于水化外壳层的“保护”作用，可以防止或减轻气泡彼此接近或相互碰撞时的兼并现象，提高了气泡的稳定性。同时，在起泡剂极性基的作用下，气泡表面水膜的蒸发和流动都大为减弱，使水膜变薄的速度减缓，降低气泡的破裂或兼并趋势，有利于气泡的稳定。此外，气泡表面总是带相同电性的，同种电荷的相互排斥作用也可阻碍气泡的兼并，增加气泡的相对稳定性。2.2起泡剂增加气泡机械强度的作用机理 当气泡未受到外力作用时，气泡为球形且在球形气泡的壁上分布有许多定向排列的起泡剂分子，可以认为，气泡表面起泡剂分子的吸附密度以及气液界面的张力沿整个气泡表面是均匀一致的。 当气泡受到外力作用发生变形，在变形区域内起泡剂分子吸附密度瞬时下降，表面张力显著增大。由于表面能的降低是一种自发进行过程，所以这时气泡便获得了较大的“收缩力”，以克服外力作用和恢复气泡原来的形状，增强了气泡抵抗外力变形的强度。 由上述可知，起泡剂可以增强气泡抵抗外力的能力，使气泡不易受外力作用而破裂，提高了气泡的机械强度。2.3起泡剂降低气泡在矿浆中升浮速度的作用机理 没有吸附起泡剂的气泡，受介质阻力后很容易变形，利于上浮的运动，其向上升浮阻力小，升浮速度快，相反，吸附有起泡剂的气泡升浮速度则比较慢。主要是因为吸附有起泡剂的气泡壁上有一层水化外壳保护，并一起随气泡运动，气泡的水化层与主题溶液中的偶极水分子必然产生强烈的内聚吸引作用，于是增大了气泡升浮的粘滞阻力，降低气泡的升浮速度。此外，吸附有起泡剂的气泡，如前所述由于不易变形而常成球体，受到的阻力较大，这样也会减慢气泡的升浮速度。 气泡升浮速度的减慢，增加了气泡在矿浆内的停留时间，有利于提高矿粒和气泡接触和碰撞的几率，改善气泡的矿化条件。此外气泡速度的减慢，使气泡间相互碰撞的能量和几率减小，气泡不易兼并，有利于气泡的相对稳定。2.4捕收剂使气泡易于形成并改善气泡分散度的作用机理 目前浮选生产上使用的起泡剂基本上都是有机异极性表面活性物质，其特点是能显著降低气液界面张力，所以消耗同样多的外界功即可形成更多的气液界面，即在充其量相同的条件下，与不加起泡剂相比可以形成更多细小的气泡。 实验表明，在清水条件下，如果形成的气泡直径为4到5毫米，加入一定量起泡剂后，气泡的直径平均可以降低到0.8到1毫米或更细一些。一般地，充气量一定，气泡越小，所形成的气液分选界面越大，这有助于疏水性矿粒和气泡粘附，所以浮选过程希望获得比较细的一些气泡。3、 药剂制度3.1制定浮选方案 制定浮选方案时应注意：先浮可浮性好的，后浮可浮性差的；抑制可浮性差的矿物，抑制容易被抑制的矿物；如果两种矿物的可浮性相似应先浮选数量少的矿物，抑制数量多的矿物，以得到比较好的浮选指标；活化量少的矿物，抑制量多的矿物以提高分离效果；浮选价值高的矿物，抑制价值低的矿物，以易于达到浮选目的；浮选精矿质量要求高的矿物，抑制精矿质量要求低的矿物等等3.2选择药剂 选择药剂时应注意几个问题：同一体系中，捕收剂与抑制剂经常相互影响。表现为捕收剂与抑制剂用量同多同少和捕收剂与抑制剂作用同强同弱；同一体系中的活化剂与抑制剂相互影响，活化剂活化某种矿物，用量增加时同时也活化数种矿物，抑制剂与活化剂相似；浮选过程中，如果起泡剂使用恰当，保证数量合适、粘度合乎要求的泡沫，有利于提高浮选过程的选择性，如果浮选过程产生过粘的泡沫，往往不会得到高质量的精矿，确定起泡剂的最佳用量还应考虑到与其配合使用的捕收剂情况。3.3药剂的合理添加3.3.1加药顺序 根据药剂的作用机理，确定合理的加药顺序。一般按下列顺序添加：PH调整剂-活化剂（抑制剂）-捕收剂-起泡剂。3.3.2加药地点 加药地点对发挥药剂效力关系很大，为了充分发挥药剂的作用一些难溶的捕收剂，也可以加在球磨机中。容易溶解的捕收剂、活化剂和起泡剂一般加在浮选前的搅拌桶中。如两种药剂能互相反应又相互抵消作用，则应分别加入，一般让前一种药剂充分作用后，再加第二种药剂。3.3.3加药方式 加药方式主要有两种：集中加药和分批加药。集中加药药剂浓度在一点比较高，作用强，可以提高浮选过程初期的浮选速度。浮选初期通常选择性最好，提高浮选初期的浮选速度对分选很有意义。添加方便、操作简单，经常采用。分批添加可以维持浮选整个过程有比较均衡的浓度，对提高一些较难浮物料的回收率有较大意义。3.3.4混合用药 混合用药也称联合用药，是两种或两种以上同一类型或不同类型的药剂按一定比例加入到浮选中，有利于提高精矿品位和回收率。一般而言混合加药比单独加药效果要好，回收率也会较高，浮选速度也会较快。3.3.5药剂的预处理 浮选药剂的预处理包括：配置水溶液，对于易溶于水的药剂，一般配置成5%到10%的水溶液使用；加溶剂配置，一些不溶于水，但溶于某些溶剂的药剂，可以将其溶于溶剂中；配置成悬浮液或乳浊液使用；一些难溶的脂肪类药剂，配药时加入药剂总量10%左右的碳酸钠，使其皂化；为了提高药剂在矿浆中的分散度或溶解度可以采用乳化或气溶胶的方法等等4、 结论： 浮选药剂是浮选法分离各种矿物的关键因素。一个浮选厂生产技术指标的好坏与浮选药剂的选择以及药剂制度的制定紧密相关。浮选技术的进步与发展，在很大程度上是依赖于浮选药剂的探索和研发，因此弄清浮选药剂的作用机理有着十分重要的指导意义。 参考文献：谢广元 选矿学 中国矿业大学出版社胡熙庚，黄和慰，毛钜凡等 浮选理论与工艺 中南工业大学出版社朱建光 浮选药剂 中南工业大学出版社蔡璋 浮游选煤与选矿 煤炭工业出版社 任务书任务下达日期： 20* 年 2 月 20日设计（论文）日期：20*年 2 月20 日至20*年6 月10 日设计（论文）题目：龙宇煤业公司3.0Mt/a矿井型选煤厂初步设计设计（论文）专题题目： 关于煤泥浮选药剂的研究设计（论文）主要内容和要求：（1）完成一座3.00Mt/a矿井型选煤厂方案优化及主厂房工艺布置，资料来自E层60%，F层40%；要求精煤灰分10.5%, 水分12.0%。具体工作：（a）对所给煤质资料进行审核、整理与分析；分组、分级判断与综合；可行方案设计与产品预测；方案比较与最佳流程确定；流程设计与计算；设备选型与计算。（b）进行工业广场总平面布置、车间布置以及图纸绘制。要求至少绘制7张图纸（包括车间工艺布置图4张、工艺流程图1张、设备流程图1张及工业广场总平面图1张）。（c） 详细编制设计说明书及投资经济概算说明书。（2）撰写30005000字的专题论文1篇。（3）翻译专业外语文章1篇（3000字以上）。院长（系主任）签字： 指导教师签字： 中 国 XX 大 学本科生毕业设计姓 名： 学 号： 学 院： 专 业： 矿 物 加 工 工 程 设计题目： 龙宇煤业公司3.0Mta矿井型选煤厂初步设计专 题： 离心力场在选煤中的应用 指导教师： 职 称： 20xx年 6月 徐州总 目 录 第一部分 毕业设计说明书 第二部分 毕业设计概算书第三部分 专题论文 第四部分 专业英文翻译附 录 图纸列表参考书目第一部分毕业设计说明书中 国 XX 大 学第二部分毕业设计概算书中 国 XX 大 学第三部分专题论文中 国 XX 大 学第四部分专业英文翻译中 国 XX 大 学附 录图纸列表参考书目中 国 XX 大 学外文文献原文Rate of water transfer to flotation froth in the flotation of low-rank coal that also requires the use of oily collectorFeridun Boylu (a) , Janusz S. Laskowski (b), (a) Istanbul Technical University, Faculty of Mines, Mineral Profcessing Engineering Department, 34469 Maslak, Istanbul, Turkey(b) Department of Mining Engineering, University of British Columbia, Vancouver, B.C., CanadaReceived 23 June 2007; received in revised form 14 July 2007; accepted 18 July 2007Available online 1 August 2007AbstractThe entrainment of hydrophilic gangue particles in flotation is related to the amount of water reporting to the froth. It is well established that the amount of water reported to the froth is controlled by frother concentration. As it is shown in this paper, in the flotation systems in which emulsified oily collector is also used (e.g. coal flotation), solids recovery strongly depends on the collector dosages as also does the water recovery. While the tests carried out at low (1000 g/t) and high (8000 g/t) oil dosages show different effects of frother additions on water transfer rates to the froth, all the experimental points when water transfer rates are plotted versus solids transfer rates to the froth converge on one single curve. This suggests that the effect of both the frother and collector on water transfer rates is first of all determined by the transfer of solids to the froth, and thus by the effect of these two agents on the solids transfer to froth. 2007 Elsevier B.V. All rights reserved.Keywords: Froth flotation; Coal flotation; Entrainment; Agglomerate flotation; Water recovery1. Introduction Frothers are utilized in flotation processes to enhance generation of fine bubbles and to stabilize froth. The effect of frothers on bubble size and foam stability has been extensively studied and it was shown that the CCC (critical coalescence concentration) and DFI (dynamic foamability index) describe well frother ability to reduce bubble size and produce stable foam (Cho and Laskowski, 2002; Laskowski et al., 2003; Grau et al., 2005; Melo and Laskowski, 2006). The frother concentration directly affects the bubble size (by controlling bubble coalescence). Better selectivity and higher recoveries are reported at finer bubble sizes. The presence of frother also affects the amount of water transferred to froth products (Rahal et al., 2001, Melo and Laskowski, 2006) and thus affects entrainment of hydrophilic ultra fine gangue minerals (Engel-brecht and Woodburn, 1975; Trahar and Warren, 1976;Warren 1985; Smith and Warren, 1998). The relationship between frother characteristics expressed by critical coalescence concentration (CCC) and dynamic foamability index (DFI) and the effect of frother on water recovery and entrainment were investigated by Melo and Laskowski (in press) who studied different frothers in the flotation of metallurgical and low-rank coals. In case of three phase systems containingalso solid particles, these particles, their size, surface properties and concentration, affect froth characteristics(Dippenaar, 1982; Johansson and Pugh, 1992; Tao etal., 2000; Schwartz and Grano, 2005). Although Malysa(1998) suggested that while the presence of solid particles affects foam stability and liquid contents in the foam, the general relationships between the liquid content and frother concentration measured in foams should not be altered by the presence of solid particles, it is still unclear how to use the information on the fundamental properties of flotation frothers in predicting the behavior of the froth in a real flotation system. In flotation of some minerals so-called oily collectors, water-insoluble hydrocarbons, are utilized. For instance, while flotation of bituminous coals can be carried out using only a frother, in the flotation of less hydrophobic, sub-bituminous coals (also anthracites and oxidized coals), also a collector is required and commonly emulsified kerosene or diesel oil are used. In general, oily hydrocarbons are known to flatten froth in a flotation cell. However, the addition of oil to a stirred suspension of fine hydrophobic particles leads to agglomeration of these particles. The oil agglomeration of fine coal by hydrocarbons relies on the formation of large agglomerates strong enough to be separated by screening from the pulp. With the oil dosages lower than a few percent the recovery of combustible matter tend to deteriorate since the agglomerates formed under such conditions are not strong enough to withstand handling/ screening. But since the agglomerates formed at low oil dosages result in a formation of loose aggregates which easily entrap air bubbles such aggregates can be recovered by flotation, and a simultaneous use of a frother provides quite good flotation results (Wojcik and Al-Taweel, 1984; Bricker et al., 1991). Thus, the effect of oil (e.g. diesel oil, kerosene) used in the flotation tests with coal may result from: (i) making coal particles more hydrophobic and thus facilitating particle-bubble attachment, or (ii) selective agglomeration of coal fines. It is difficult to discriminate between the two mechanisms. Woodburn et al. (1984) in their studies on coal flotation selected the conditions that favour agglomeration of fine coal particles: very intense conditioning (30 min at 1750 rpm in a Denver flotation cell) and huge quantities of kerosene (3.5% to 17.7%).They showed that water recovery in the froth product that followed such a conditioning procedure strongly increased with the dosage of oil. This was clearly the case when the fine coal particles were agglomerated and the agglomerates were recovered by flotation. The flotation results of Melo and Laskowski (in press) were obtained while working with a sub-bituminous coal using only 3 kg of diesel oil/t of coal (0.3%). This oil consumption was more than 10 times lower than in Woodburn et al.s tests. The emulsified diesel oil was conditioned with pulp for 30 s only. The amount of diesel oil that was used was sufficient to improve flotation (which was still poor with about 2025% yields of the froth product) but the process was not likely to be an agglomerate flotation. Thus, it seems that the water transfer to the froth can be much lower if the used oil makes the particles more hydrophobic but does not produce agglomeration of the floating particles. The objective of this research project was to study the effect of both a frother (MIBC) and a collector (emulsified diesel oil) on water transfer to the froth, and entrainment in flotation of a low-rank coal. 2. Materials and methods2.1. Coal sample A low-rank sub-bituminous coal (LS-20) provided by the Luscar Sterco mine, Alberta, Canada, was used in the tests.The sample was crushed and pulverized below 150 m (d90),and kept in plastic bags for flotation tests. The proximate analysis of coal and the X-ray analysis of coal mineral matter are given in Tables 1 and 2, respectively.2.2. Reagents In flotation tests, emulsified diesel oil (EDO) and MIBC(methyl iso-butyl carbinol) were used as collector and frother,respectively. Following Good et al. (1994) who showed a very positive effect of n-octanol on wettability of a low-rank coal by liquid hydrocarbons, we emulsified diesel oil with a 2% addition of n-decanol. Decanol was used in our tests since it is practically insoluble in water and thus all added amount stays in the organic phase. 2% by weight of decanol was added to diesel oil and the system was heated up to 6070 C during 30 min of mixing. The solution of decanol in diesel oil was cooled down to room temperature. In emulsifying process(performed in a Warring Blender at 21,000 rpm for 5 min) 5% of the diesel oil containing 2% decanol was emulsified in water. The prepared emulsion was stable and phase separation was observed only after one week. All the flotation experiments were performed with a freshly prepared emulsion.2.3. Batch flotation tests Flotation tests were carried out at 10% solids content by wt.A 3 L Open-top Leeds flotation cell was used; the froth products were collected at different froth thickness over 30 s and 60 s intervals. The pulp level and froth thickness during the flotation tests were controlled and maintained constant. The entrainment degree was calculated by following the procedure proposed by Warren (1985). In this procedure, the batch flotation tests using only frother are performed; the ash recoveries (%) and corresponding water amounts (%) are determined for the certain flotation time intervals. Then, the curve of “Recovery of Ash” (y axis) versus “Recovery of Water” (x axis) is plotted and the slope of this curve giving an intercept at y axis (inherent ash content at true flotation) is assumed as entrainment degree. In our tests the entrainment degrees were calculated at very low and very high emulsified diesel oil doses. Our previous study (Boylu and Laskowski,2006), which was focused on determination of entrainment degree, indicated the lowest entrainment degree at the collector dosage which was just enough to float hydrophobic particles. Since the equation illustrating the relation between the amount of water and solid particles content directly gives the data similar to the entrainment degree, the experimental data obtained in this study were evaluated depending on the initial rate of water and solids transfer. The water transfer rates/initial water transfer rates were calculated following the procedure described by Melo and Laskowski (in press).Fig. 1. Amount of water reporting to the froth as a function of: (a) EDO dosages, (b) frother concentration at 1000 g/t EDO, and (c) frother concentration at 8000 g/t of EDO.3. Results and discussion3.1. Effect of EDO (emulsified diesel oil) and frother dosage on water transfer to the froth Since large water recoveries were reported by Woodburn et al. (1984) at high oil dosages (agglomerate flotation), and low by Boylu and Laskowski (2006) and Melo and Laskowski (in press) at low oil dosages, we first tested the effect of the dosage of emulsified oil. As Fig. 1a reveals, while low amount of water is recovered in the froth at 1000 g/t and 2000 g/t of EDO, the amount of water transferred to froth increases dramatically at 6000 and 8000 g/t of EDO. The MIBC concentration was kept constant in this first series of tests (7.2 ppm). The two series of tests that followed were carried out at 1000 g/t of EDO (Fig. 1b) and 8000 g/t of EDO (Fig. 1c)varying frother concentration. The effect of frother concentration is different in these two cases. With 1000 g/t of EDO in the low MIBC concentrations range (1.2 ppm to 4.8 ppm)increasing concentration of MIBC depressed the amount of water transferred to froth, but this trend is reversed when the MIBC concentrations was higher than 4.8. At high oil dosages(8000 g/t of EDO), the water transfer to froth was high even at low MIBC concentrations (2.4 ppm) and increased further when this concentration was increased. These results then confirm very well the findings reported by Woodburn et al.(1984) at high oil dosages, and those of Melo and Laskowski (in press) reported at low oil dosages. More detailed information on the experiments with 8000 g/t EDO is given in Fig. 2. As these figures demonstrate, the effect of frother concentration on the amount of water recovered in froth (at 8000 g/t of EDO) is not very pronounced, especially when the tests are carried out at a froth thickness of 3 cm (this is also sown in Fig. 1c). It is obvious that under the conditions of large dosages of EDO the amount of water is first of all determined by the dosage of oil. Fig. 2. Effect of frother concentration and froth thickness on the amount of water transferred to the froth at 8000 g/t of EDO. The initial rate of water transfer to froth is clearly dependant on frother concentration at 1000 g/t of EDO (Fig. 3a) and does not depend much on frother concentration at 8000 g/t of EDO(Fig. 3b). Fig. 4 confirms that the water transfer to the froth is affected and controlled by the oil dosages. 3.2. Effect of frother/EDO dosages on the initial water transfer rates and the entrainment degree Since the amount of water transferred to the froth is generally linked to the entrainment degrees, and the amount of water in froth and the entrainment degrees are controlled by frother and frother/collector combinations, the effects of frother and collector dosages were also examined.Fig. 3. Dependence of the rate of water transfer on frother concentration at 1000 g/t of EDO (a) and 8000 g/t of EDO (b)Fig. 4. Effect of EDO dosages at 7.2 ppm of MIBC on water transfer rates to froth. The data points for 4000 g/t and 6000 g/t of EDO overlap. The effects of EDO and frother (MIBC) concentrations on the initial water transfer rates and entrainment degrees are illustrated in Figs. 5 and 6. As seen from Fig. 5, the initial water transfer rates to the froth increase and then remain constant at the EDO concentrations higher than 4000 g/t. At EDO concentrations lower than 4000 g/t the entrainment degrees are practically constant, whereas at the higher EDO concentrations, although the water transfer rate was constant, the entrainment degrees dramatically increase. This can possibly be explained by particle agglomeration and likely entrapment of some gangue particles within the loose agglomerates. In this study, the entrainment degree was analyzed following the procedure described by Warren (1985) and 150 m coal samples were used. As a matter of fact, since only particles finer than 50 m can report to froth via entrainment this analysis would have been more sensitive if the tests had been carried out using such a fine fraction. Boylu and Laskowski (2006) based their calculations of the entrainment degree on the behavior of the 50 m size fraction by extracting the data of the 50 m fraction from the complete size distribution. The data in Fig. 5, however, represents the floated material with its original size distribution. Since over the higher than 4000 g/t EDO dosage range the water transfer to the froth is constant, increasing entrainment degrees shown in Fig. 5 in this EDO dosages range can be assigned to the entrapment. As seen, the steepness of the “entrapment curve” is Fig. 5 at low and high EDO dosages is very different. While this steepness at low EDO dosages seems to represent a true entrainment, the very steep portion of the curve at a high EDO dosage should be ascribed to both entrapment and entrainment.Fig. 5. Effect of EDO concentration on initial rate of water transfer and entrainment degree.Fig. 6. Summarized results illustrating the effect of frother concentration for two and three phase flotation systems. The froth thickness is 3 cm. The results for waterMIBC and waterMIBC coal were taken from Melo and Laskowski (2007). The empty points show the initial mass recovery rate. CCC w f stands for the critical coalescence concentration for the MIBCwater system. While Fig. 5 illustrates the effect of EDO dosages at a certain frother concentration, Fig. 6 illustrates the effect of frother concentration on initial rate of water transfer, and accompanying entrainment degrees for two extreme EDO dosages: 1000 g/t and 8000 g/t. Entirely different effect of frother concentration on water transfer was found at the low (1000 g/t) and high (8000 g/t) EDO dosages. At EDO dosage of 8000 g/t, increasing frother concentration resulted in higher water transfers but remained constant at the frother concentrations higher than 4.55 ppm. In contrast, for the 1000 g/t EDO dosage, increasing frother concentration results in lower water transfer rates to the froth and the lower entrainment degrees As in the previous case of high EDO dosages, the effect of frother concentration entirely changes at the concentrations higher than about 4 ppm. Fig. 6 nicely confirms the correlation between the water transfer rates to froth and entrainment degree. In both cases, a low and high dosage of EDO, the correlation is good. Different in both cases is the effect of frother concentration. The results for the same coal quoted after Melo and Laskowski (in press) and obtained at 3000 g/t EDO, are just situated between the two extremes for low and high doses of EDO. So, while the low dosages of EDO reduce the water transfer rates to froth, at high dosages of EDO these water transfer rates are much higher even at lower frother concentrations. Since increasing dosages of oil can only increase hydrophobicity of coal particles, these results suggest that while initial increase in hydrophobicity of the floating particles reduces the water transfer rates, at high coal particle hydrophobicity and high dosages of emulsified oil some other factors must come to the play. These results imply that agglomerate flotation is taking places at high oil dosages and they are consistent with Woodburn et al. (1984) who reported that for high oil dosages the amount of water transferred to froth was extremely high. As already mentioned, several factors such as particle size, hydrophobicity, nature of the collector etc., control water transfer to froth. Zheng et al. (2006) evaluated different models of water recovery in flotation. In one of these models the water flow to concentrate is linked directly with the concentrate solids flow rate. Fig. 7 shows the relationship between the transfer rate of water to froth product and the mass transfer rate of solids to froth product. As the correlation coefficients calculated separately for 1000 g/t of EDO (empty circles in Fig. 7) and for 8000 g/t of EDO (filled squares) show the correlations are very good. This indicates that the solids content in the froth may be a primary factor determining the amount of water. If so, the collector and frother dosages affect the water transfer to the froth only because they determine the recovery of solids.Fig. 7. Relationship between volumetric transfer rate of water to concentrate and the mass transfer rate of solids to concentrate (Qw and Fs represent the volumetric transfer rate of water and the mass transfer rate of solids to froth products, respectively).The obtained results seem to indicate that while the flotation process at 1000 g/t resembles a typical emulsion flotation, the process at 8000 g/t is probably an agglomerate flotation. While in the former case the effect of the oily collector results from making coal particles more hydrophobic, in the latter case the overall effect results from agglomeration of coal particles by added oil. In the low oil dosages range the water transfer rates to froth are low, and so also low is the entrainment (Fig. 5). This is very different at the high oil dosages. In the range of oil dosages exceeding 4000 g/t the water transfer rates are dramatically higher and so also much higher are the entrainment degrees which can be possibly linked to the particle agglomeration.4. ConclusionsIn this project, the effect of frother on the flotation of low-rank coal with emulsified oily collector is studied. Two different effects of frother concentration for two extreme collector dosages were found: for low collector dosages the flotation system requires higher frother concentrations to reach the stable froth conditions, for higher collector dosages selectivity deteriorates and this is particularly clear when water transfer to froth is monitored. The results imply that while at low oil dosages the presence of oil makes coal particles more hydrophobic, at higher oil dosages the coal particles get agglomerated.References Boylu, F., Laskowski, J.S., 2006. The true flotation and entrainment in coal flotation. Proc. 15th Int. Coal Preparation Congress, vol. 1.China University of Mining and Technology Press, Beijing, pp. 406416. Bricker, Y., Szymocha, K., Pawlak, W., Kramer, J., Ignasiak, B., 1991.Feasibility of Aglofloat process for deashing and desulfurization of high sulfur coals. In: Dugan, P.R., Quigley, D.R., Attia, Y.A.(Eds.), Processing and Utilization of High-Sulfur Coals IV.Elsevier, pp. 357376. Cho, Y.S., Laskowski, J.S., 2002. Effect of flotation frothers on bubble size and foam stability. Int. J. Miner. Process. 64, 6980. Dippenaar, A., 1982. The destabilization of froth by solids. Int. J.Miner. Process. 9, 114. Engelbrecht, J.A., Woodburn, E.T., 1975. The effects of froth height, aeration rate, and gas precipitation on flotation. J. South Afr. IMM76, 125131. Good, R.J., Badgujar, T.L.H., Huang, K., Handur-Kulkarni, S.N.,1994. Hydrophilic colloids and the elimination of inorganic sulfur from coal. Colloids Surf. 93, 3948. Grau, A., R., Laskowski, J.S., Heiskanen, K., 2005. Effects of frothers on bubble size. Int. J. Miner. Process. 76, 225233. Johansson, G., Pugh, R.J., 1992. The influence of particle size and hydrophpobicity on the stability of mineralized froth. Int. J. Miner.Process. 34, 121. Laskowski, J.S., Tlhone, T., Williams, P., Ding, K., 2003. Fundamental properties of the polyoxypropylene alkyl ether flotation frothers.Int. J. Miner. Process. 72, 299. Malysa, K., 1998. Water contents and distribution in flotation froth. In:Laskowski, J.S., Woodburn, E.T. (Eds.), Frothing in Flotation II.Gordon and Breach, pp. 81108. Melo, F., Laskowski, J.S., 2006. Fundamental properties of flotation frothers and their effect on flotation. Miner. Eng. 19, 766773. Melo, F., Laskowski, J.S., in press. Effect of frothers and solid particles on the rate of water transfer to the froth. Int. J. Miner. Process. Rahal, K., Manlapig, E., Franzidis, J.P., 2001. Effect of frother type and the concentration on the water recovery and entrainment recovery relationship. Miner. Metall. Process. 18, 138141. Smith, P.G., Warren, L.J., 1998. Entrainment of particles into flotation froths. In: Laskowski, J.S. (Ed.), Frothing in flotation. Gordon and Breach, pp. 123145. Schwartz, S., Grano, S., 2005. Effect of particle hydrophobicity on particle and water transport across a flotation froth. Colloids Surf.256, 157164. Tao, D., Luttrell, G.H., Yoon, R.H., 2000. A parametric study of froth stability and its effect on column flotation of fine particles. Int. J.Miner. Process. 59, 2543.Trahar, W.J., Warren, L.J., 1976. The floatability of very fine particles a review. Int. J. Miner. Process. 3, 103131. Warren, L.J., 1985. Determinations of the contributions of true flotation and entrainment in batch flotation tests. Int. J. Miner.Process. 14, 3344. Wojcik, W., Al-Taweel, A.M., 1984. Beneficiation of coal fines by aggregative flotation. Powder Technol. 40, 179185.Woodburn, E.T., Flynn, S.A., Cressey, B.A., Cressey, G., 1984. The effect of froth stability on the beneficiation of low-rank coal by flotation. Powder Technol. 40, 167177. Zheng, X., Franzidis, J.P., Johnson, N.W., 2006. An evaluation of different models of water recovery in flotation. Miner. Eng. 19, 871882.中文翻译:水转移到浮选的低阶煤的泡沫中需要油性捕收剂摘要： 在浮选中，水量是和夹带的亲水性煤矸石粒度密切相关的。众所周知，浮选的水量报告由起泡剂浓度决定。正如本文中，在浮选系统中，也可用于乳化油的捕收剂（如煤浮选），固体回收很大程度上依赖于捕收剂的剂量，也适用于水回收。在测试中，在低（1000克/吨）和高（8000克/吨）油用量显示起泡剂的添加对水的传输速率不同的效果的泡沫，所有的实验点时，水的传输速率固体传输速率的泡沫聚集在一个单一的曲线作图。这表明，起泡剂和捕收剂对水传输速率的效果主要取决于固体到泡沫的转移，通过这两种药剂对固体的影响，固体传送到泡沫。关键词：泡沫浮选 煤泥浮选 夹带 聚团浮选 水回收 1、 引言 起泡剂在浮选过程中使用，以提高微细的气泡的生成，并以稳定的泡沫。气泡的大小与泡沫的稳定性，起泡剂的效果被广泛研究，它被示出的CCC（临界凝聚浓度）和DFI（动态起泡性指数）以及起泡能力，重新杜奇气泡的大小和产生稳定的泡沫（Cho和Laskowski，2002年；Laskowski 等人，2003; Grau等人，2005年， Melo and Laskowski，2006年）。起泡剂浓度直接影响泡沫大小（通过控制气泡的合并）。更好的选择性和更高的回收率取决于更精细的泡沫尺寸。起泡剂的量也影响水转移到泡沫产品（Rahal等人, 2001；Melo和Laskowski, 2006），从而影响夹带的亲水性超微细脉石矿物（Engel-brecht 和Woodburn, 1975；Trahar 和 Warren, 1976；Warren 1985；Smith 和Warren, 1998）。起泡剂的特性之间的关系所表达的临界凝聚浓度（CCC）和动态的发泡性指数（DFI）和起泡剂水回收效果和夹带的研究，Melo and Laskowski研究不同的起泡剂在浮选冶金和低煤级煤。在三相系统中也包含固体颗粒的情况下，这些颗粒中，它们的大小，表面的亲水性和浓度，影响泡沫特性(Dippenaar，1982；Johansson和Pugh, 1992；Tao 等人，2000；Schwartz 和Grano，2005)，而固体粒子的存在影响泡沫稳定性和泡沫中液体，一般，液体的含量和测量泡沫材料中的起泡剂的浓度之间的关系不应改变固体颗粒的存在，仍不清楚如何使用的基本性质的信息，在一个真正的浮选系统中，预测泡沫浮选的起泡剂的行为。表一：煤的工业分析煤水分/%灰分/%挥发分/%干燥无灰基挥发分/%固定碳/%数据3.6434.627.4844.555.5在浮选一些所谓的矿物油状的捕收剂，不溶于水的烃类被利用。比如，烟煤浮选时，可以仅使用起泡剂，在浮选的疏水性较低的次烟煤（或无烟煤和氧化煤），捕收剂是必需的，并使用常用乳化煤油或柴油。一般来说，油性烃是已知的压平在浮选槽中的泡沫。然而，细憎水颗粒的搅拌悬浮液中，油导致这些颗粒的附聚。油团聚细粒煤的碳氢化合物的形成依赖于大团聚足够强的从矿浆分离筛选。 随着油用量低于百分之几的回收可燃物有恶化的倾向，因为在这样的条件下形成的团块是不是强大到足以承受处理筛选。但由于结块形成低油剂量产生一个松散的集合体，容易破坏气泡的总量，并同时使用起泡剂提供很好的浮选结果Wojcik 和 AlTaweel,，1984；Bricker等人，1991)。因此，与煤的浮选试验中使用的油（例如，柴油，煤油）的效果可能会导致：（i）使煤颗粒的疏水性，从而促进粒子气泡附着，或（ii）选择性结块煤粉。这是难以区分的两种机制。Woodburn等人（1984）在他们所研究的浮选选择条件有利于集聚的细煤颗粒非常激烈的在丹佛浮选机作用在1750转（30分钟）和大量的煤油（3.5至17.7）。他们发现，遵循这样一个调节过程中的泡沫产品，水回收油的用量大大增加。这是清楚的情况时，细煤颗粒团聚和结块回收的浮选。 浮选结果表明Melo和Laskowski工作时仅使用3公斤的柴油/吨的煤与亚烟煤（0.3）。石油消费量低于Woodburn等人的测试10倍以上。乳化柴油和矿浆作用只有30秒。使用的柴油的量是足以改善浮选（这仍然是较差的泡沫产物与约20-25的产率），但过程不像团块浮选。因此，似乎转移到泡沫的水可以低得多，如果所使用的油使颗粒更疏水，则不产生浮动颗粒的附聚。本研究项目的目的是研究的一个起泡剂（MIBC）和捕收剂（乳化柴油），水转移到泡沫并夹带的低煤级煤的浮选效果。2、材料和方法2.1、煤样 加拿大阿尔伯塔省Luscar Sterco矿提供了一个低阶的次烟煤样（LS-20）。样品进行粉碎，粉碎低于150微米（D90），并保存在塑料袋中用于浮选测试。分别在表1和表2中给出了煤和煤矿物物质的X-射线分析。2.2、试样 浮选试验，乳化柴油（EDO）和MIBC（甲基异丁基甲醇）被分别用作捕收剂和起泡剂。根据Good等人（1994）的结果显示了积极的影响正辛醇对润湿性的低阶煤液体碳氢化合物，我们除正癸醇外还使用乳化柴油2%。癸醇在我们的测试中使用，因为它是几乎不溶于水，因此所有的添加量留在有机相中。将2（重量）的癸醇加入到柴油中，并将该体系加热至60-70，30分钟的混合。癸醇在柴油中的溶液被冷却至室温。 在乳化过程中（在Warring Blender中在21,000转，5分钟执行）的5的含有2癸醇的柴油在水中乳化。所制备的乳液是稳定的，并仅在一个星期后观察到相分离。所有的浮选试验进行使用新鲜制备的乳液。表二X-射线分析的矿物质中的LS-20校准方程式煤LS-20石英SiO242.2白云母KAl2AlSi3O10(OH)232.3高岭石Al2Si2O5(OH)416.9石膏CaSO42H2O3.0方解石CaCO35.6总计100.02.3、单元浮选试验 浮选试验共进行了10的固体含量（重量）。使用A 3 L顶开利兹浮选机在不同的泡沫厚度超过30秒和60秒的时间间隔收集的泡沫产品。浮选试验期间的矿浆液面和泡沫厚度控制和保持恒定。夹带度应用Warren（1985）提出的程序计算。在此过程中，批处理执行仅使用起泡剂的浮选试验；灰分回收率（）与对应的水的量（）为一定的浮选的时间间隔确定。然后，以“回收率”灰（y轴）与“回收水”（X轴）绘制曲线，这条曲线的斜率在y轴上的截距（固有的灰分含量在真正的浮选）被假设为夹带度。在我们的测试中夹带度非常低和非常高的乳化柴油