采矿外文翻译---闪锌矿中铁含量对浮选的影响.docx

科技论文effect of iron content in sphalerite on flotationa. boulton1 d. fornasiero* j. ralstonian wark research institute, university of south australia, mawson lakes, sa 5095, australiareceived 27 october 2004; accepted 28 march 2005. available online 25 may 2005.abstractthe effect of iron, substituted in the mineral lattice, on the froth flotation of sphalerite has been investigated at alkaline ph. it has been found that a critical copper sulphate concentration exists where sphalerite recovery is maximized, above which the recovery of sphalerite then decreases. the presence of iron in sphalerite is detrimental to the rate of sphalerite flotation and hence its recovery, with the coarser particles being more affected that the fines. the presence of iron reduces the activation of sphalerite by copper, which in turn results in a reduction in collector adsorption.keywords: froth flotation; flotation activators; flotation kinetics; particle sizearticle outline1. introduction 2. experimental section 3. results and discussion 4. conclusions acknowledgements references1. introductionas xanthate collectors have a relatively low affinity for zinc ions, activation of sphalerite by copper ions is generally required to float sphalerite. the activation of sphalerite involves the exchange of zinc for copper ions, thus providing a surface receptive towards collector adsorption (finkelstein, 1997). one of the main impurities present in sphalerite is iron, which substitutes for zinc atoms in the sphalerite lattice, thus reducing the number of zinc atoms available for exchange with copper. previous studies investigating the effect of iron content in sphalerite on copper activation, collector adsorption and subsequent sphalerite flotation have produced conflicting results (pomianowski et al., 1975, mukherjee and sen, 1976, solecki et al., 1979, nakahiro, 1980, harris and richter, 1985 and gigowski et al., 1991). for example, both an increase and decrease in copper activation, collector adsorption and froth flotation of sphalerite have been reported with increasing iron content in sphalerite. the loss of sphalerite to tailings in flotation circuits as a result of inadequate particle surface hydrophobicity reduces the economic viability of the processing operation. thus an understanding of the effect that iron in sphalerite has on the flotation behaviour of this mineral may allow us to maximise sphalerite recovery. in the present study, we have investigated the effect of iron content in sphalerite on sphalerite flotation as a function of particle size. these flotation results were correlated with the amount and type of copper and collector adsorbed on the sphalerite surface.2. experimental sectionthe chemical composition of the low iron content sphalerite sample, zns, (carthage, tn, usa) was 66.7% zn, 0.3% fe and 32.7% s (0.06% cu and 0.07% pb) while that of the high iron content sphalerite sample, (zn,fe)s, (broken hill, new south wales, australia) was 53.2% zn, 12.5% fe and 32.7% s (0.47% cu and 0.24% pb). scanning electron microscopy confirmed that the iron present in the sample was in fact incorporated in the sphalerite particles, and not present as individual pyrite inclusions. the collector, sodium iso-propyl xanthate (sipx), was re-crystallised from ethanol.zns and (zn,fe)s (250g each) were ground in a galigher mill with stainless steel rods and 0.3dm3 of demineralised water (ph12.0) to produce a flotation feed with a d90 of 45m. the sample was transferred to a 3.0dm3 agitair flotation cell and conditioned at ph11.0 with cuso4, collector and then frother (aerofroth 65) with each stage having a 2min conditioning period. the concentrates were then collected for 0.5, 2, 4 and 8min (for a total of 8min) of flotation by bubbling air through the mineral pulp at 4dm3/min. the 45m fraction of each concentrate and tail sample was passed through a pre-cyclone rig. the underflow was sized with a warman cyclosizer (6 size fractions collected) whilst the overflow constituted the sub 4m particle size fraction. all size fractions were analysed by icp-ms (amdel pty. ltd., australia) for total zinc and iron, and the relative amounts of zns and (zn,fe)s in each of the size fractions determined.a first order rate equation, r=rmax(1ekt), was used to fit the curves of flotation recovery, r, versus time, t, and to obtain the flotation rate constant, k, and maximum flotation recovery, rmax at each particle size.3. results and discussionthe cumulative recoveries of zns and (zn,fe)s as a function of particle size, flotation time and cuso4 concentration are shown in fig. 1. with no copper addition the total recoveries were too low for a size analysis of the concentrates. with cuso4, flotation recovery increases sharply with particle size up to approximately 25m, and then levels off or decreases for the coarser particles. this decrease in recoveries of the coarser particles is more pronounced at the higher cuso4 concentrations and for (zn,fe)s.fig. 1.(top) zns and (bottom) (zn,fe)s flotation recovery as a function of particle size, flotation time (0.5, 2, 4 and 8min) and copper sulphate concentration (from left to right: 1000, 2000 and 3000g/t) in mixed mineral experiments at ph11.0 in the presence of 150g/t sipx.view within articlethe flotation rate constant (k) and maximum recovery (rmax) obtained by fitting the recovery versus flotation time data with a first order rate equation are shown in fig. 2 as a function of particle size. at the lower cuso4 concentration the flotation rate constant and maximum recovery of sphalerite are relatively unaffected by the presence of iron in the sphalerite lattice. the increase in flotation rate constant with increasing particle size is relatively well understood and is attributed to an increase in bubbleparticle collision efficiency (e.g., pyke et al., 2003). the increase in k and rmax values of the fine particles with an increase in cuso4 concentration to 2000g/t is certainly related to an increase in bubbleparticle attachment efficiency, and therefore surface hydrophobicity, as the conditions inside the flotation cell are unchanged. at 2000g/t cuso4, nearly all the intermediate size zns particles can float (rmax close to 100%). the lower flotation rate constants and maximum recoveries of the coarser particles are mainly attributed to the increased detachment of these particles from bubbles in the regions of high turbulence inside the flotation cell (e.g., pyke et al., 2003 b. pyke, d. fornasiero and j. ralston, bubble particle heterocoagulation under turbulent conditions, journal colloid and interface science 265 (2003), pp. 141151. article | pdf (200 k) | view record in scopus | cited by in scopus (35)pyke et al., 2003). because this detachment is also dependent on particle hydrophobicity or the lack of it, an increase in cuso4 concentration decreases surface hydrophobicity (higher coverage by cu(oh)2, clarke et al., 1995) and therefore the flotation rate constant and maximum recovery of the coarser particles.fig. 2.flotation rate constant (top) and maximum recovery (bottom) for zns and (zn,fe)s as a function of particle size and copper sulphate concentration in mixed mineral experiments at ph11.0 in the presence of 150g/t sipx.view within articleat 3000g/t cuso4, the sphalerite flotation rate constant and maximum recovery decrease across the entire particle size range, with the decrease being more pronounced for the coarse particles than for the fine particles and for (zn,fe)s than for zns. this larger decrease in flotation observed for the coarser particles is not necessary linked to a higher coverage of their surface with copper hydroxide, but is certainly related to the larger effect that coarse particles have on their detachment from bubbles at a constant surface hydrophobicity (pyke et al., 2003).in alkaline ph domains, the activation of sphalerite is believed to firstly involve precipitation of copper hydroxides, followed by exchange of zinc atoms for copper atoms on the sphalerite surface (ralston and healy, 1980 and laskowski et al., 1997). hence the presence of iron in sphalerite results in a decrease in the number of copper atoms that could be incorporated in the sphalerite lattice. indeed, this is what we have found at a ph value of 5.0 with no increase in iron detected in solution (boulton, 2002). uvvisible and infrared studies on individual zns and (zn,fe)s samples of similar surface area have shown that without prior activation of sphalerite with cuso4 the uptake of xanthate at ph11.0 was close to zero. this indicates that sipx does not interact with zinc or ferric species on the sphalerite surface, in agreement with the flotation results showing low flotation recoveries in the absence of cuso4. with cuso4, the adsorption of xanthate on zns is double than on (zn,fe)s, with maximum adsorption occurring at around 10min. copper(i) xanthate was the only surface xanthate species detected (boulton, 2002).4. conclusionscopper sulphate concentration is critical in controlling sphalerite recovery at alkaline ph. a critical level of copper sulphate concentration exists where sphalerite recovery is maximized, above which the recovery of sphalerite decreases as a result of excess copper hydroxide on the sphalerite surface.the presence of iron in the sphalerite lattice has a detrimental effect on the flotation of sphalerite because copper activation is reduced, which in turn results in a reduction of xanthate adsorption as copper(i) xanthate.most of the non-floating sphalerite particles are fine particles, because of their low collision efficiency with bubbles. the coarser particles are more affected than the fines by the presence of iron in sphalerite and by excess addition of copper sulphate.acknowledgmentsthe authors wish to thank the financial support of the australian research council (arc), the university of south australia and the australian mineral industries research association (amira).references（1）boulton, 2002 boulton, a., 2002. improving sulphide mineral flotation selectivity against iron sulphide gangue. ph.d. thesis, university of south australia.（2）clarke et al., 1995 p. clarke, d. fornasiero, j. ralston and r.st. smart, a study of the removal of oxidation products from sulfide mineral surfaces, minerals engineering 8 (1995), pp. 13471357. article | pdf (672 k) | view record in scopus | cited by in scopus (13)（3）finkelstein, 1997 n.p. finkelstein, the activation of sulphide minerals for flotation: a review, international journal of mineral processing 52 (1997), pp. 81120. article | pdf (2583 k) | view record in scopus | cited by in scopus (57)（4）gigowski et al., 1991 b. gigowski, a. vogg, k. wierer and b. dobias, effect of fe-lattice ions on adsorption, electrokinetic, calorimetric and flotation properties of sphalerite, international journal of mineral processing 33 (1991), pp. 103120. abstract | pdf (543 k) | view record in scopus | cited by in scopus (6)harris and richter, 1985 p.j. harris and k. richter, the influence of surface defect properties on the activation and natural floatability of sphalerite. in: k.s.e. forssberg, editor, flotation of sulphide minerals, elsevier, amsterdam (1985), pp. 141158.（5）laskowski et al., 1997 j.s. laskowski, q. liu and y. zhan, sphalerite activation: flotation and electrokinetic studies, minerals engineering 10 (1997) (8), pp. 787802. article | pdf (873 k) | view record in scopus | cited by in scopus (25)（6）mukherjee and sen, 1976 a.d. mukherjee and p.k. sen, floatability of sphalerite in relation to its iron content, journal of mines, metals and fuels 24 (1976) (10), pp. 327330.（7）nakahiro, 1980 nakahiro, y., 1980. copper ion adsorption on sphalerites of various iron contents. memoirs faculty of engineering, kyoto university 42 (1), 112.（8）pomianowski et al., 1975 pomianowski, a., szczypa, j., poling, g.w., leja, j., 1975. influence of iron content in sphaleritemarmatite on copper ion activation in flotation. in: proceedings of the 11th mineral processing congress, cagliari, pp. 639653.（9）pyke et al., 2003 b. pyke, d. fornasiero and j. ralston, bubble particle heterocoagulation under turbulent conditions, journal colloid and interface science 265 (2003), pp. 141151. article | pdf (200 k) | view record in scopus | cited by in scopus (35)闪锌矿中铁含量对浮选的影响a. boulton1 d. fornasiero* j. ralsto伊恩沃克研究所，南澳大利亚大学，澳洲大学摘要铁的作用，在矿物晶格取代对闪锌矿浮选，已展开调查，在碱性ph值。人们已经发现，一个关键的硫酸铜浓度存在那里闪锌矿回收率最大化，上面其中闪锌矿复苏后下降。闪锌矿中铁的存在是不利于闪锌矿浮选回收率，因为粗颗粒更多的影响细粒。铁的存在通过导致减少对捕收剂吸附的铜降低了闪锌矿的活化。关键词： 泡沫浮选，浮选活化剂，浮选动力学;粒度文章概要1。介绍2。实验部分3。结果和讨论4。结论鸣谢参考资料一 引言由于黄药捕收剂有锌离子，铜离子活化的闪锌矿相对低亲和力是一般需要漂浮闪锌矿。闪锌矿的活化涉及锌，铜离子交换，从而提供一个表面吸附（芬克尔斯坦，1997年）接受捕收剂。目前在闪锌矿的主要杂质之一，是铁，这在闪锌矿晶格锌原子取代，从而减少了交流与铜，锌原子数目。调查中铁铜活化，捕收剂吸附浮选闪锌矿和闪锌矿随后含量的影响的研究已经产生（pomianowski等人。，1975年，mukherjee和sen，1976年，solecki等。，1979年，nakahiro，1980年，harris和richte，1985年和gigowski等。，1991）。举例来说，既增加和铜活化，捕收剂的吸附和闪锌矿浮选的减少已经以在闪锌矿中铁的含量的增加被证实。在浮选回路中闪锌矿浮选流失到尾矿是由于不健全的颗粒表面疏水性的结果降低了加工操作的经济可行性。因此，大意是一个在铁闪锌矿对这种矿物浮选行为可能使我们能够最大限度地闪锌矿复苏的认识。在本研究中，我们调查了为颗粒大小的函数闪锌矿浮选铁闪锌矿中含量的影响。这些结果与浮选的数量和类型的铜和捕收剂对闪锌矿表面吸附相关2 试验部分 对低铁含量闪锌矿样品，硫化锌，（迦太基，田纳西州，美国）为66.7，锌，铁0.3和32.7秒（0.06，0.07，铅和铜）的化学成分，而高铁闪锌矿样品的含量（锌，铁）新（布罗肯山，新南威尔士，澳大利亚）为53.2，锌，铁和12.5，32.7秒（0.47，0.24，铅和铜）。扫描电子显微镜证实，在样本的铁是在闪锌矿颗粒纳入事实，不作为单独的黄铁矿包裹体存在。该捕收剂，钠异丙酯黄药（sipx），是从乙醇中再次结晶。 硫化锌和（锌，铁）秒（每250克）是在一个不锈钢棒和galigher磨0.3不含矿物质水（ph值12.0），以生产出45微米d90 1浮选饲料dm3的。该样本是转移到3.0 dm3的agitair浮选机，在ph值11.0与硫酸铜，捕收剂，然后起泡剂各有一个2分钟内调节阶段（aerofroth 65）为条件。当时的集中收集了0.5，2 4和第8分钟（为8分的总浮选）由鼓泡通过4 dm3/min矿产纸浆空气。在-45微米每一集中，尾样本比例是通过预先气旋钻机。潜流与一沃曼cyclosizer（6大小馏分收集）虽然溢出规模，构成了4次微米粒径的一小部分。所有大小形态分析的icp - ms（amdel pty有限公司，澳大利亚）的总锌和铁，硫化锌的数量和相对数量（锌，铁）s在分数的大小确定。 第一个反应速率方程：r = rmax的（1 - 电子克拉），以适应采用浮选回收法，俄，与时间t的变化曲线，并获得了浮选速率常数，k和浮选回收率最高，rmax的在每个粒子的大小。 3 结果与讨论 硫化锌累计回收率（锌，铁）s作为一个粒子的大小，浮选时间，硫酸铜浓度函数如图所示。1。此外，由于没有铜的总回收率分别为1的精矿粒度分析太低。与硫酸铜，大幅度增加，粒径浮选回收率提高到约25微米，然后回落或减少的粗颗粒。这在粗颗粒回收率的下降在高浓度和硫酸铜（锌，铁）中更明显。图。1。（顶部）和硫化锌（下）（锌，铁）s作为一个粒子的大小，浮选时间（0.5，2，4和8分）和硫酸铜浓度（函数浮选回收率从左至右：1000，2000和3000克/吨）的混合实验，在ph 11.0矿物中存在的150克/吨sipx。 浮选速率常数（k）和最大回收率（rmax的）从合适的回收率与一阶速率方程浮选时间获得的数据得到显示在图fig. 2作为颗粒大小的作用。二为颗粒大小的函数。在低浓度的硫酸铜浮选速率常数和最大的闪锌矿回收率相对由铁闪锌矿晶格中的存在不会受到影响。在浮选速率随粒径的不断提高，比较好理解，是由于在泡沫粒子碰撞的效率（例如，派克等人的增加。，2003）。在k的增加和细颗粒rmax的值与在硫酸铜浓度增加至2000克/吨当然也关系到一个泡沫粒子附着效率的提高，因此表面的疏水性，为气泡内的浮选条件不变。在2000克/吨硫酸铜，几乎所有的中间硫化锌颗粒大小可浮动（rmax的接近100）。较低的浮选速率常数和粗颗粒回收率最高，主要归因于在高紊乱区域的浮选气泡内部这些粒子从气泡上增加分离度（例如，派克等人。2003年）。因为这解离度也依赖于颗粒疏水性或缺乏，在硫酸铜浓度的增加依赖降低表面疏水性（被氢氧化铜高覆盖，克拉克等人。，1995），因此浮选速率常数和最大的回收率在粗颗粒。图。2。浮选速率常数（上）和最大的恢复（下）的硫化锌和（锌，铁）s作为一个粒子的大小和功能的硫酸铜浓度混合矿物在ph 11.0实验中存在的150克/吨sipx。 在3000克/吨硫酸铜，闪锌矿浮选速率常数和最大回收率在整个范围内，细颗粒和粗颗粒（锌，铁）比硫化锌减少更加明显。这种浮选较大的跌幅为粗颗粒的观察，没有铜的氢氧化物表面覆盖率高，但肯定是涉及到较大的粗颗粒有泡沫解离度已在恒定的表面疏水性（派克等基地。，2003）。在碱性ph值域，闪锌矿的活化被认为是首先涉及铜氢氧化物沉淀，其次为闪锌矿表面上（ralston和 healy 1980年，laskowski等，1997）。因此，闪锌矿中铁的结果存在，在铜可以在闪锌矿晶格的原子数目减少。事实上，这是我们在p