Bioleaching of copper sulphide concentrate using extreme thermophilic bacteria

An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C Following isolation and adaptation, the culture was used in a continuous multi-stage pilot plant employing standard mechanically agitated and aerated tanks, for the bioleaching of a mixed secondary copper sulphide-chalcopyrite concentrate. The culture exhibited stable leach performance over the period of pilot plant operation and overall copper extractions of higher than 97% were maintained. It was shown, however, that solids concentration had a significant effect on the copper bioleach kinetics. Increased solids concentrations resulted in a drop in redox potential and copper extractions in the first stage reactor. Batch chemical ferric leaches, performed at controlled redox potentials, indicated that reduced residence times may be possible in bioleach processes, using thermophiles, if high redox potential levels can be maintained.     

Bioleaching of a complex nickel–iron concentrate by mesophile bacteria

This work investigates the bioleaching of a complex nickel–iron concentrate (pentlandite, pyrrhotite, and minor amounts of chalcopyrite) using acidophile iron-oxidizing bacteria. It aims to improve the understanding of the mechanism of bacterial action on nickel sulphide bioleaching. The effects of the external addition of Fe(II) and the mineralogical assembly on the extraction of nickel are evaluated. A high nickel extraction (around 70%) can be achieved in batch experiments. Moreover, the external addition of iron has not shown any effect on the extraction of the metal, emphasizing the importance of pyrrhotite dissolution in the first step of bioleaching. It was also examined the morphological features of the sulphides as well as the leach residues and reactions products formed during bioleaching. It was noticed that elemental sulphur was produced on pyrrhotite surfaces, which dissolves ahead of pentlandite. A discussion on how galvanic interactions affect the reactivity of sulphide mineral and the formation of bioleaching products is also presented.     

Selective leaching of arsenic and antimony from a tetrahedrite rich complex sulphide concentrate using alkaline sulphide solution

Removal of impurity elements in copper metallurgy is one of the major problems encountered today since pure copper ore reserves are becoming exhausted and the resources of unexploited ores often contain relatively high amounts of impurity elements like antimony, arsenic, mercury and bismuth, which need to be eliminated. The present work is aimed at pre-treating a tetrahedrite rich complex sulphide concentrate by selective dissolution of the impurities, therefore, upgrading it for pyrometallurgical processing. To accomplish this, dissolution of antimony and arsenic by an alkaline sulphide lixiviant from the concentrate were investigated. The lixiviant proved selective and effective to dissolve these impurity elements from the concentrate with good recoveries. Further investigations on the factors influencing the leaching efficiency of the lixiviant were studied. The parameters considered were sulphide ion and hydroxide ion concentrations, mineral particle size, reaction temperature and leaching time. Analysis of the leach residue indicates that copper content of tetrahedrite has transformed into copper sulphides with the average chemical formula Cu_1.64S. The grade and economic value of the concentrate were improved greatly after sulphide treatment, and therefore, suitable as a feedstock for smelting. The impurities have been reduced to low levels which are tolerable in the smelting furnace and consequently reduce both the treatment and environmental problem encountered when such concentrate is processed pyrometallurgically.     

云南某锡铜硫化矿铜精矿降砷试验研究

针对云南某锡铜硫化矿砷含量高的特点,采用浮铜抑砷的工艺,利用对砷矿物抑制作用较强的组合药剂,及选择性较好的铜矿物捕收剂,通过一次粗选、一次扫选、五次精选,有效降低了铜精矿中砷含量。最终闭路试验获得铜品位为12.63%,回收率为73.71%,含砷为0.425%的铜精矿指标。     

复杂铜铅锌硫化矿浮选的研究

内蒙某铜铅锌硫化矿的铜铅锌品位低,矿物组成较复杂,并且铅锌矿物都存在不同程度的氧化.采用优先浮铅、浮铅的尾矿选锌的工艺,用SN-9和CD作方铅矿的捕收剂,38号黄药作锌矿物的捕收剂,在原矿品位为Pb 1.08%和Zn 2.43%时,获得品位41.8%、回收率60.96%的铅精矿和品位45.76%、回收率78.97%的锌精矿,铜主要富集在铅精矿中.     

高硫复杂难选铜铅锌选矿工艺流程试验研究

试验依据高硫复杂铜铅锌矿矿石性质的特点,采用磁选—浮选联合工艺流程。试验工艺流程关键技术是磁选脱除磁黄铁矿,应用优先浮选流程,优先浮选铜精矿进行铜硫分离,铜与铅锌分离采用高效抑制剂组合无氰无铬清洁分离工艺,获得了良好的试验指标,铜精矿、铅精矿、锌精矿的品位分别为21.96%、50.68%、41.58%,回收率分别为68.13%、52.24%、79.77%,为高硫复杂难选铜铅锌选矿提供了新途径。     

某块状硫化物型铜铅锌多金属矿选别工艺优化研究

新疆某复杂难处理铜铅锌多金属矿矿物组成复杂,由于次生铜离子的活化和弥散分布的金银矿物对黄铁矿和闪锌矿的活化作用,造成黄铁矿和闪锌矿具有良好的可浮性,而铅矿物嵌布粒度细,浮游性较差,采用石灰抑制黄铁矿和采用亚硫酸钠抑制闪锌矿时都对铅矿物造成较明显的抑制作用.生产中采用"铜铅混合浮选-铜铅分离-锌浮选"的工艺流程,存在有价...     

Bioleaching of copper ore flotation concentrates

The bioleaching of flotation concentrate is a new method for copper recovery that could form the basis of an economic and environmentally friendly process. The main objective of this work was to evaluate a bioleaching process from the treatment of two concentrates, (i) a copper gold bearing concentrate and (ii) an ordinary copper flotation concentrate, using mesophilic bacteria. The special gold-bearing copper flotation concentrate was obtained from the Polkowice Mine. The second material was an ordinary copper flotation concentrate purchased from the Lubin Mine. Bioleaching experiments were carried out in 250 ml Erlenmayer flasks and a rotating bioreactor (biorotor). The most important operating parameters were copper dissolution (%) and surface area. A culture of Thiobacillus ferrooxidans was used for the bioleaching tests. The bioleaching maximum was obtained at both 12% and 15% of the solid. The effect of pyrite addition on the kinetics of copper concentrate bioleaching was also investigated. It was established that 3% of pyrite causes an increase in the bioleaching process. In the case of ordinary flotation concentrate bioleaching, 65% of the recovery was obtained at the initial stage (48 h). In the second stage, the copper recovery slowly increased and after 312 h 86% of the copper recovery was obtained. On the other hand, the surface area of copper concentrate initially increased (at 24 h it was 8.67 m²/g) and then slightly decreased in the second stage.     

Bioleaching strategies for the treatment of nickel-copper sulphide concentrates

Different process options for the bioleaching of nickel-copper containing sulphide concentrates were evaluated. Tests in continuously operated reactor systems showed >98% nickel extractions over a range of temperatures, whereas for copper occurring as chalcopyrite, extractions of >95% could only be achieved at 70 °C. During further optimisation of the process the effects of process parameters such as grind size, residence time, redox potential and feed solids concentration on the leach kinetics, metal extractions and performance of both moderate thermophile and thermophile cultures were addressed. Redox control in the first-stage reactor of thermophilic systems resulted in considerably faster copper leach rates and extractions of up to 95% could be achieved at increased feed concentrations and coarser grind sizes. High redox levels in the secondary reactors ensured >98% nickel recoveries. These operating conditions and control strategies have the potential to increase the rates of nickel and copper extractions to the extent that leaching times could be considerably reduced.     

低品位砂岩型铀矿石微生物浸出试验研究

采用不同酸度和不同Fe~(3+)浓度的菌液,对取自新疆伊犁盆地的低品位砂岩铀矿石进行了浸出对比试验,研究矿石的浸出特征及酸度和Fe~(3+)浓度对浸出效果的影响。结果表明,铀的浸出主要发生在前8h,铀浸出最高速度达到16%/h左右,且浸出速度迅速衰减;铀的浸出与酸度正相关,Fe~(3+)浓度高于2.0g/L则对铀的浸出存在明显抑制作用,这可能与发生黄铁钾钒沉淀有关。浸出过程中体系pH和Eh分别上升和下降,变化幅度均与Fe~(3+)浓度呈反相关关系;综合试验成果认为,对研究区矿石而言,微生物浸出酸度5g/L、Fe~(3+)浓度1.5g/L的工艺条件是适宜的。     

低品位共伴生硫化铜钼矿选矿试验研究

本研究以蒙古某低品位铜钼矿为研究对象,以该试样中铜钼矿物的矿石性质特征分析为基础,通过粗选、精选条件影响及流程方案对比等试验研究,获得了阶段磨矿-铜钼等可浮工艺综合回收铜钼矿物的推荐方案。试验研究结果表明,该矿石中部分目的矿物以微细粒,或以复杂连生体赋存,且含磨矿易泥化的脉石矿物较多;且铜钼分离作业产出合格的钼精矿,主要依赖于铜钼混合精矿品质;为获取较优的品质铜钼混合精矿,以阶段磨矿调控目的矿物有效解离,以药剂制度调节铜钼等可浮过程,在优化铜钼混合浮选条件下,得到的铜钼混合精矿中Cu品位高于25%、Mo品位高于1%,Cu、Mo回收率大于88%的试验指标,实现了铜钼矿物的高效回收,为该类型铜钼矿资源开发利用提供参考。     

青海某铜锌硫化矿选矿试验研究

摘要:针对青海某铜锌硫化矿石开展试验研究,矿石性质研究表明,该矿铜矿物嵌布粗细不均匀,大约有15%的铜矿物呈微细粒（粒度小于10μm）包裹于脉石矿物中,难以得到有效回收,同时原矿含锌较低,含量在锌矿边界品位（0.5～1%）,可考虑伴生回收。针对该矿矿石性质,采用优先浮铜工艺,可有效实现铜、锌分离,获得了铜精矿品位18.66%、铜回收率83.90%、铜精矿含金3.06g/t,锌精矿品位41.69%、锌回收率29.49%的较好选矿指标。      

Bioleaching of a low-grade copper ore,linking leach chemistry and microbiology

Three largely-independent studies were undertaken on the same heap leach system during the period of transition from processing oxidised ores to sulfide ores: monitoring of heap solutions for microorganisms, analysis of samples from a spent heap, and column tests. Microbial cell numbers and diversity were monitored in process water samples from the transition heap over a four-year period. Cell numbers remained low throughout, 1–30 × 10⁴ cells mL⁻¹, possibly reflecting growth inhibition by the high element concentrations in process water. High iron, magnesium and aluminium concentrations in spent heap pregnant leach solution (PLS) are attributed to siderite and clinochlore dissolution and would be expected to impact on microbial growth. Planktonic cell numbers in a column leachate declined rapidly by two orders of magnitude when concentrations of ferric ion and sulfate exceeded 30 and 75 g L⁻¹, respectively. Nevertheless, a variety of bacterial strains closely related to Acidithiobacillus (At.) ferrooxidans, At. caldus, Leptospirillum (L.) ferriphilum, Acidimicrobium (Am.) ferrooxidans, Acidiphilium (Ap.) cryptum, an Alicyclobacillus-related strain and Sulfobacillus (S.) thermosulfidooxidans, and the archaeon Ferroplasma (F.) acidiphilum were isolated, mainly from the more acidic intermediate leach solutions (ILS). Overall, the results obtained from the use of culture-dependent and culture-independent methods of community analysis were complementary and consistent. The majority of identified genera and species were present in both the process water samples from the operating heap and the solutions and ore samples from the spent heap. In the spent heap, distinct populations dominated different sample types. Leptospirillum- and Acidithiobacillus-like strains dominated PLS samples and Leptospirillum also dominated seven of eight spent ore samples and all of the heap sediment samples, making it the primary iron(II) oxidising species.     

硫化铜矿生物浸出研究进展

近年来,生物浸矿技术在铜矿分离回收中得到了较为广泛的应用(生物浸出在硫化铜矿回收利用中得到了较为广泛的应用)。针对生物浸矿技术在硫化铜矿分离回收中的应用展开综述,同时对相关的最新理论研究等进行总结,提出了硫化铜矿生物浸矿技术目前存在的问题和几点建议,以期为硫化铜矿的回收利用提供指导。     

Dispersion effect on a lead–zinc sulphide ore flotation

This investigation was performed with samples from a lead–zinc sulphide deposit aiming at studying the influence of the dispersion degree of the particles in the pulp on lead and zinc flotation. Samples of ore and also of the minerals sphalerite, galena, pyrite, and dolomite were selected for the experiments. Nine types of dispersing agents and six blends among them were employed.A set of three dispersing agents was selected for the lead flotation and another set of three was chosen for zinc flotation. The criteria for the reagents selection were: high dispersion degree for galena and low for the other species, high dispersion degree for sphalerite and low for the other species, low dispersion degree for pyrite and high for the other species, and high dispersion degree for all species.Lead flotation experiments were performed under three conditions aiming at verifying the influence of the dispersing agent, of the pH, and of sodium carbonate. The zinc flotation tests were carried out at pH 10.5, modulated with lime.The use of dispersing agents in lead flotation did not improve the overall efficiency of the circuit for, despite improving the lead metallurgical recovery, they increase significantly the zinc losses in the lead concentrate.Sodium carbonate presented a low dispersion degree and did not affect the lead flotation results when compared with those achieved at natural pH and at pH 9.8 modulated with lime.Two dispersing agents were particularly effective in zinc flotation: dispersant 3223, a sodium polyacrylate, and sodium hexametaphosphate. Both reagents significantly enhanced zinc recovery without impairing the concentrate quality.     

Dynamic simulator of a rougher flotation circuit for a copper sulphide ore

This paper presents a dynamic flotation simulator intended for designing and testing automatic control strategies, for evaluating the transient behaviour of the flotation process, and for training purposes. The simulator is based on a non-linear dynamic model that is derived from phenomenological and empirical relationships. It incorporates a new way of representing the loading of the bubbles with the various mineral species considered. The simulator was designed for a particular flotation circuit and was fitted with plant data in order to reproduce the plant behaviour both qualitatively and quantitatively. Both identification and validation data sets were used. Model dynamics had to be tested using ARMAX type models identified with plant data, due to the highly stochastic characteristics of the process. Plant and simulator responses were compared in steady-state and in transient conditions using these models. Results indicate the simulator is adequate for the stated purposes.     

某白钨矿伴生多金属硫化矿选矿试验研究

某白钨矿共伴生有可综合回收的铜、银等多金属硫化矿,但该白钨矿矿物组成复杂,且各目的矿物嵌布粒度有差异性,分选难度大。根据原矿工艺矿物学特点,采用强磁选-浮选工艺综合回收该白钨矿多金属硫化矿,其中强磁选预选可抛掉51.34%的磁性脉石,能有效降低后续浮选难度和药剂耗量。强磁选-浮选工艺闭路试验获得了铜品位22.61%,铜回收率78.93%的铜精矿,银品位9185.50 g/t,银回收率29.86%的银精矿,研究成果为此类白钨矿共伴生铜、银矿物的综合回收提供了基础依据。     

The effect of galvanic interaction on the behaviour of the froth phase during the flotation of a complex sulphide ore

A literature review has shown that the chemical effects of grinding media on the flotation of real ores, especially those containing pyrite, are still not understood adequately. Many studies have been conducted on isolated minerals or in solutions only, and transport phenomena in the froth phase have generally been ignored in studies on galvanic interactions. A complex ore containing galena, sphalerite, chalcopyrite and significant quantities of magnetite, pyrrhotite and pyrite was used in batch flotation tests to study this problem. Metallic iron powder was added in different quantities to a ceramic ball mill in order to simulate the use of mild steel grinding media in flotation tests aimed at selectively floating chalcopyrite.An oxygen-saturated pulp milled in the presence of iron yielded the best recovery of chalcopyrite and copper-lead selectivity. Milling under a nitrogen atmosphere in the absence of metallic iron resulted in poor copper-lead selectivity. The galvanic interaction caused by the presence of iron yielded a stable, well-drained froth with low ratios of solids/water recovery and larger bubbles in the froth. However, milling in the absence of iron caused an extremely brittle froth with very fine bu bubbles, high recoveries of low grades of sulphur. In contrast with the improvement in the copper recovery and copper-lead selectivity obtained when the pulp was pre-aerated after milling in the presence of iron, no significant increase in the copper grade was observed after extensive pre-aeration when milling occurred in the absence of iron. The unsatisfactory flotation results in the absence of iron could be explained by the enhanced floatability of iron-bearing gangue minerals, which rupture films and suppress froth stability owing to bubble-overloading.     

国外某含硫磁铁矿石工艺矿物学研究

利用化学多元素分析、化学物相分析、光学显微镜等综合手段,对国外某含硫磁铁矿型矿石进行了系统的工艺矿物学研究。全面了解了该含硫磁铁矿石的化学组成、矿物组成及相对含量、矿石的自然类型、矿石的结构构造以及矿石矿物工艺粒度组成,阐明了影响选矿工艺的矿物学因素,并提出了提出适合该矿石的磨矿粒度以及工艺流程。