The influence of pyrite content on the flotation of chalcopyrite/pyrite mixtures

In the flotation of copper ores, several processing plants report that copper recovery is affected by the proportion and reactivity of pyrite in the ore, with the effect becoming more intense when the feed particles are finer as a result of regrinding. In this work, a mixed model mineral system consisting of chalcopyrite (CuFeS₂) and pyrite (FeS₂) with varying pyrite content (20–80 wt.%) was used to investigate the effect of pyrite on the pulp chemistry and chalcopyrite recovery. Flotation tests showed that chalcopyrite flotation rate, recovery and grade, as well as the pulp oxidation potential, decreased with increasing pyrite content whilst pyrite recovery increased. Surface analysis (XPS, ToF-SIMS and EDTA) indicated that copper activation of pyrite increased with increasing pyrite content, facilitating pyrite recovery. The decrease in chalcopyrite recovery can be attributed to increased surface oxidation.     

铜离子对闪锌矿、黄铁矿浮选的选择性活化机理研究

本文对铜离子活化闪锌矿(ZnS)和黄铁矿(FeS2)的表面化学、溶液化学以及两种矿物的浮选分离进行了综合评述,分析讨论了铜离子浓度、活化时间、pH值、表面电荷、表面氧化程度、矿浆电位等主要因素对闪锌矿和黄铁矿活化浮选的影响.为生产实践中闪锌矿、黄铁矿的绿色、高效浮选分离提供一定的理论及技术支撑.     

石英与蛇纹石异相凝聚及其对黄铁矿浮选的影响

通过单矿物和人工混合矿的浮选试验、Zeta电位测试、吸附量测试,研究了蛇纹石和石英异相凝聚的机理,以及对黄铁矿浮选的影响,以进一步探索多种矿物的体系中,蛇纹石对硫化矿物浮选影响的主要原因。结果表明:通过添加石英,可以恢复黄铁矿对捕收剂的吸附量,减弱蛇纹石的不良影响,不同粒级的石英与蛇纹石的异相凝聚作用强弱不同,粒级越细的石英,与蛇纹石的异相凝聚作用越强。     

Effects of free cyanide and cuprous cyanide on the flotation of gold and silver bearing pyrite

At gold and silver mineral processing plants, cyanide species are always present in the process water recycled to flotation circuits, despite the cyanide destruction process. The effect of cyanide, in particular, cuprous cyanide on gold and silver flotation has not been well understood. In the present study, free cyanide and cuprous cyanide species were isolated and their effects on the flotation of a pyritic ore were evaluated. It was found that free cyanide depressed gold and silver flotation through their carrier, pyrite. Cuprous cyanide mainly in the form of Cu(CN)₃²⁻ depressed pyrite flotation similarly as free cyanide. Electrochemical studies including open circuit potential (OCP), cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques were carried out to understand the underpinning depression mechanism of cyanide species on pyrite flotation using xanthate as collector. It was found that all surface electrochemical reactions were inhibited by either free cyanide or cuprous cyanide. The surface layer as a result of xanthate adsorption on pyrite was completely removed in the presence of these cyanide species, which was suggested to contribute to the hydrophilic pyrite surface.     

The effect of temperature on the pulp and froth phases in the flotation of pyrite

The effect of temperature on the flotation of pyrite has been investigated. At temperatures below ambient an increase in temperature results in an increase in the rate of flotation of fast-floating particles but has a minimal effect on that for slow-floating particles. At temperatures greater than ambient the dominant effect of increasing temperature is to decrease the viscosity of the water thus increasing the rate of elutriation of the gangue back to the pulp. In general an increase in temperature resulted in an increase in the rate of pyrite recovery and the sulphur grades and a decrease in the water recovery and size of the bubbles in the pulp.     

Pyrrhotite oxidation and its influence on alkaline amine flotation

In the production of ground calcium carbonate (GCC) for the paper industry, pyrrhotite dramatically reduces the GCC brightness and the removal of pyrrhotite through froth flotation is essential. The present study aims to study the effect of pyrrhotite oxidation on flotation recoveries during typical GCC flotation (i.e. alkaline pH, CaCO₃ saturation, amine collector). EDTA extraction and measurements of Eh (redox potential) showed a significant difference in pyrrhotite surface oxidation state when comparing exposure times of 40 and 60 min, the latter being significantly more oxidised. Microflotation results show that when pyrrhotite is exposed to air extending for more than 5 min at pH 8, the recoveries drop significantly. At higher pH, recoveries were generally low at all exposure times tested. Flotation recoveries showed strong correlation with zeta potential measurements. Bench scale flotation experiments on a sulphide bearing marble, confirmed that pyrrhotite oxidation significantly lower the GCC quality at low collector concentrations. By increasing the amine concentration, the flotation performance became independent of pH and exposure time.     

The influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore

In this paper, the influence of the oxidation state of pyrite and arsenopyrite on the flotation of an auriferous sulphide ore was investigated by different techniques, including electrode, pulp potentials, DRIFT spectroscopy and microflotation tests. In addition, the gold and sulphide recoveries were also investigate, in a laboratory-scale cell, as a function of pulp potential and reagent concentration. It was verified that the presence of oxidation products on the sulphide mineral surface demands a higher collector concentration in order to achieve a satisfactory sulphide recovery. The electrochemical behaviour of pyrite and arsenopyrite indicated that a nitrogen atmosphere can lead to a low pulp potential, which inhibits the formation of oxidation products, enhancing both the free gold and sulphide recoveries. Although copper sulphate activates even oxidised sulphide surfaces, it does not improve free gold recovery.     

Effect of powerful nanosecond electromagnetic impulses on surface and flotation properties of carbonate-bearing pyrite and arsenopyrite

The effect of powerful nanosecond electromagnetic impulses (PEMI) on the surface and flotation properties of arsenopyrite and carbonate gold-bearing pyrite from the Darasunsk deposit has been studied. X-ray-phase diffractometry, X-ray photoelectronic and IR Fourier-spectroscopy, and raster electronic microscopy were employed in investigations. It was established that the alteration of the phase composition of surface depends non-linearly on terms of treatment (dry or wet) and the number of electromagnetic impulses used and has appreciable influence on oxidation and hydrophobicity of minerals, thus allowing the selective separation of pyrite from arsenopyrite by flotation in the neutral medium. __________ Translated from Fiziko-Tekhnicheskie ProblemyRazrabotki Poleznykh Iskopaemykh, No. 5, pp. 105–118, September–October, 2008.     

射流曝气耦合臭氧-过氧化氢协同氧化强化处理选矿废水试验研究

针对臭氧氧化工艺处理选矿废水在高污染污负荷条件下氧化性能不足及曝气设备易于结垢堵塞的问题,采用射流曝气耦合臭氧/过氧化氢协同氧化工艺处理选矿废水,考察了澄清预处理、水力停留时间、臭氧和过氧化氢投加量等工艺条件对处理效果的影响,并分析了不同污染物负荷条件下耦合工艺药剂投加量及直接运行成本。结果表明,射流曝气耦合臭氧/过氧化氢协同氧化工艺处理选矿废水效果良好,抗冲击能力强,原水需经沉淀预处理再氧化,可根据原水水质变化灵活调整氧化药剂的投加量,将废水处理至不影响回用程度的工艺条件为:臭氧投加量110~240 g/m3、过氧化氢投加量为2~4 L/ m3,水力停留时间约30 min。不同污染物负荷条件下处理成本为3.0-8.8元/吨水,该工艺是一个有前景的选矿废水处理研究和工程应用方向。     

The influence of particle shape properties and associated surface chemistry on the flotation kinetics of chalcopyrite

The role of particle shape properties in determining flotation kinetics was investigated in this study. −150/+75 μm chalcopyrite was floated in a microflotation cell, and shape properties of the timed concentrates were quantified using a mineral liberation analyser - a mineralogical characterisation system based on automated scanning electron microscopy. It was found that, when floated in the absence of collector, particles with angular shape features reported to the concentrate faster than round particles. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) showed that angular particles also exhibited surface chemistry characteristics favourable for flotation. When particle floatabilities were high (i.e. when floated in the presence of potassium amyl xanthate), shape properties were not found to contribute significantly to the rates at which particles floated.     

低灰浮选尾煤的磨矿脱泥浮选工艺试验研究

针对河北唐山地区煤炭黏土含量大、多高灰细泥、浮选效率低的问题,采用磨矿、小锥角水力旋流器脱泥、分步释放浮选等试验方法进行了浮选工艺试验研究。结果表明：采用150 mm与75 mm旋流器串联脱泥工艺,底流和溢流灰分差值为13.05%,说明旋流器串联脱泥工艺起到了较好的效果,能分离部分高灰细粒级煤泥,对底流进行分步释放浮选试验研究,在保证精煤质量前提下,精煤产率也相应得到提高,说明采用小锥角水力旋流器对原煤泥进行浮选前脱泥,能够有效降低高灰细粒级对浮选的影响,提高精煤的浮选效率;浮选尾煤灰分仍然较低,为38.27%,对低灰尾煤进行磨矿-脱泥-浮选试验,精煤产率为35.47%,综合精煤产率（占全级）相比较原煤泥直接浮选提高率达54.20%。     

铁介质磨矿对锂辉石和绿柱石浮选影响的分子模拟计算研究

利用分子模拟计算方法,研究了铁球作为磨矿介质,十二胺和油酸钠分别作为捕收剂,锂辉石和绿柱石与捕收剂在磨矿前后的相互作用能。结果表明,这两种典型硅酸盐矿物经过铁球磨矿后,矿物表面吸附的铁,使阳离子捕收剂十二胺与矿物的相互作用能增大,阴离子捕收剂油酸钠与矿物的相互作用能减小,进而影响捕收剂与矿物之间的相互作用。总体来讲,锂辉石和绿柱石经过铁球磨矿后,一般会阻止十二胺阳离子捕收剂在矿物表面的吸附,而对于油酸根阴离子捕收剂,则起到一定的活化作用,有利于油酸根离子在矿物表面的吸附。     

电磁波预处理对黄铁矿碎磨经济性的试验分析

为解决当前传统碎磨流程能耗高、效率低的问题,并结合电磁波选择性、整体性、高效性的加热特性,试验探究经不同时间电磁波预处理后的矿石进行破碎、磨矿过程中产量、能耗、粒度及效率等经济性指标的变化。试验结果表明,电磁波作用能够有效提高破碎产量,而产品粒度不受影响;能够有效降低磨矿产品加权平均粒度,降低磨矿时间。将矿石置于输出功率为800 W的电磁波场中预处理180～240s,能够有效提高碎磨产量及效率,降低流程能耗。如电磁波预处理240s时,比未预处理的碎磨流程节能5.96%,破碎产量提高57.84%,磨矿产量提高26.23%,碎磨经济性显著提高。     

新型抑制剂BK511在某矿铜钼分离浮选中的试验研究

研究采用新型抑制剂BK511,对强捕收剂黄药浮选的铜钼混合精矿进行了铜钼分离浮选试验研究。试验采用两次铜钼分离粗选、钼粗精矿一次精选后再磨、再经五次精选工艺流程,获得了钼精矿含钼45.31%,含铜1.14%,钼回收率89.94%的浮选指标。试验结果表明,BK511对采用强捕收剂黄药浮选的铜钼混合精矿中的铜矿物,具有较好的抑制作用。     

阶段磨选新工艺在东山选矿厂的应用研究

通过对东山选矿厂湿式自磨－球磨连续磨矿工业存在问题的分析及实施室阶段磨选试验的研究结果,提出了阶段磨选工艺。生产调试和流程考查表明,东山选矿厂采用阶段磨选工艺可获得精矿品位和回收率双提高的较好指标。     

炼焦中煤的尺度效应及对浮选的影响

为了考察煤泥粒度变细对浮选效果的影响,从不同细度颗粒的几何特征、润湿热及浮选行为3方面探讨了炼焦中煤的尺度效应。使用BET比表面测定仪、微量热仪分别研究了炼焦中煤粒度减小对其比表面积、总孔容和平均孔径及润湿热的影响,用Young-Laplace方程分析了基于毛细管作用捕收剂吸附的变化,通过半经验公式计算了颗粒粒径及润湿性对上浮概率的影响,并进行了不同细度超低灰精煤的浮选试验。研究表明,随着炼焦中煤粒度的变细,其比表面积和总孔容呈数倍增大,Ⅱ类孔增多,平均孔径增加;基于毛细管作用的捕收剂吸附增强,对去离子水的润湿热值急剧降低;存在最佳粒度范围使颗粒的上浮概率最大,中等紊流强度的浮选环境中,控制疏水颗粒粒径在-200+45 μm或亲水性颗粒粒径在-10 μm或+45 μm均可强化浮选回收。相同浮选药剂条件下,煤泥粒度越细,煤的回收率越难以保障,并且水回收率呈增加趋势,浮选效率降低。     

陕西某铜金矿矿石性质研究及对选矿工艺的影响

针对陕西某铜金矿利用多种分析检测手段对矿石的化学成分、矿物组成、矿石粒度以及矿石结构等进行了详细研究。该矿中的有用矿物主要有黄铁矿、磁铁矿、黄铜矿,含少量的赤铁矿、辉钼矿等。脉石矿物主要以石榴子石、绿帘石、阳起石为主,含少量方解石、石英绿泥石等。金主要赋存在硫化矿中。详细的工艺矿物学研究结果建议该铜金矿采用优先浮选或混合浮选的工艺流程进行选别。     

碳纳米球储氢材料的制备及影响因素研究

无烟煤经过脱灰、炭化和预石墨化处理,然后添加活性金属,用充氢反应球磨法制得碳纳米球储氢材料.研究了原料预处理、充氢压强、活性金属等对材料储氢性能的影响.高能反应球磨时,物料在较短时间内即可达到30～50 nm,并具有较高的储氢密度和较低的放氢温度.镁和碳在储氢过程中存在协同效应,Al,Co,Fe,Ni金属催化剂能显著改善储氢材料的吸放氢性能,并对镁碳协同储氢有促进作用.     

Adsorption of copper sulphate on PGM-bearing ores and its influence on froth stability and flotation kinetics

Copper sulphate is used as an activator in the flotation of base metal sulphides as it promotes the interaction of collector molecules with mineral surfaces. It has been used as an activator in certain platinum group mineral (PGM) flotation operations in South Africa although the mechanisms by which improvements in flotation performance are achieved are not well understood. Some investigations have suggested these changes in flotation performance are due to changes in the froth phase rather than activation of minerals by true flotation in the pulp zone. In the present study, the effect of copper sulphate on froth stability was investigated on two PGM containing ores, namely Merensky and UG2 (Upper Group 2) ores from the Bushveld Complex of South Africa. Froth stability tests were conducted using a non-overflowing froth stability column. Zeta potential tests and ethylenediaminetetraacetic acid (EDTA) tests were used to confirm the adsorption of reagents onto pure minerals commonly found in the two ores. The results of full-scale UG2 concentrator on/off copper sulphate tests are also presented. The UG2 ore showed a substantial decrease in froth stability in the order of reagent addition: no reagents > copper > xanthate > copper + xanthate, while Merensky ore showed a slight decrease. It was shown through zeta potential measurements that copper species were to be found on plagioclase, chromite, talc and pyrrhotite surfaces and through EDTA extraction that this copper was in the form of almost equal amounts of Cu(OH)₂ and chemically reacted copper ions on the Merensky and UG2 ore surfaces. In certain cases, the presence of copper sulphate and xanthate substantially increased the recovery, and therefore the implied hydrophobicity, of pure minerals in a frothless microflotation device. It was, therefore, proposed that increases in hydrophobicity beyond an optimum contact angle for froth stability, were the cause of instabilities in the froth phase and these were found to impact grade and recovery in a full-scale concentrator. Differences in the extent of froth phase effects between the different ores can be attributed to differences in mineralogy.     

高钙高硅铜矿中铜及伴生金银浮选回收试验研究

高钙高硅铜矿中元素铜及伴生金银的回收价值高,但实际生产中这些有价成分的回收指标较低,导致企业经济效益不理想。针对矿石性质,采用石灰和硫化钠为矿浆调整剂,丁基黄药与丁基铵黑药联合使用作为捕收剂,在磨矿细度-74μm粒级含量占70%的基础上,进行了浮选药剂优化和闭路试验。在石灰用量1 000g/t、硫化钠用量400g/t、丁基黄药用量400g/t、丁基铵黑药用量50g/t、松醇油用量84g/t的药剂制度下,采用两次粗选、两次精选、一次扫选、中矿顺序返回的浮选闭路流程,最终获得Cu品位21.45%、回收率90.46%,Au品位7.92g/t、回收率79.39%,Ag品位453.50g/t、回收率81.82%的铜精矿。与生产现场指标相比,不仅提高了矿石中铜的浮选回收率,而且极大地提高了矿石中伴生金银的回收效果,浮选指标较为理想。