较低温度下细菌浸出黄铜矿工艺影响因素研究

以黄铜矿为研究对象，在温度较低的浸出条件下（15℃）采用正交试验的方法考察了矿石粒度、矿浆浓度、酸度、接种量以及起始Fe²⁺浓度对氧化亚铁硫杆菌（T.f菌）摇瓶浸出黄铜矿浸出过程的影响。试验结果表明：初始Fe²⁺浓度对细菌浸铜工艺影响最为显著；在15℃下的最佳浸出工艺条件为初始Fe²⁺浓度为6g/L，酸度控制在pH=2.0，接种量保持在15%，矿浆浓度为15%，矿石粒度为-200目。     

硫杆菌的化学诱变及对低品位黄铜矿的浸出

用盐酸羟胺将氧化铁硫杆菌优势菌(T、f菌)化学诱变后对低品位黄铜矿进行细菌浸出，结果表明，盐酸羟胺化学诱变能够使T．f菌产生较明显的变异，能较好地提高菌种的活性和对低品位黄铜矿的牛物浸出性能。经盐酸羟胺化学诱变，T．f诱变菌的活性比原始T．f菌提高了57．4％，对黄铜矿的浸出率提高了11．5％，达到浸出终点的时间比原始T．f菌减少了5～10d。     

银催化铜矿石的细菌浸出

黄铜矿是所有铜矿物中较难浸出的矿物之一。利用氧化亚铁硫杆菌氧化浸出以黄铜矿为主的德兴铜矿原矿，当处理１ｋｇ矿石添加０１６和０３２ｇ银时，经过２１天浸出，铜的浸出率从未加银的２８２％分别提高到７７５％和７９７％。银的催化作用可能是通过改变矿物表面电化学性质，发生电化学反应而实现的。浸渣的Ｘ射线衍射结果表明，矿物表面有Ａｇ２Ｓ生成。通过育种方法可得到耐受银的质量浓度为１００ｍｇ／Ｌ的浸矿菌株。     

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.     

Cooperative bioleaching of chalcopyrite and silver-bearing tailing by mixed moderately thermophilic culture: An emphasis on the chalcopyrite dissolution with XPS and electrochemical analysis

In this work, the interactions between one sample of silver-bearing tailing (223 g/t silver) and chalcopyrite during bioleaching by mixed moderately thermophilic culture were investigated. Bioleaching results showed that copper can be almost totally extracted from chalcopyrite as the result of addition of the silver-bearing tailing, and silver (Ag) extraction can be significantly improved with the addition of chalcopyrite. Hence, cooperative bioleaching process of chalcopyrite and the chosen silver-bearing tailing was feasible. Ag mainly occurred as silver sulfate (Ag₂SO₄), and further work of enhancing the Ag extraction and its recovery is currently in progress. The catalytic effect of the silver-bearing tailing on chalcopyrite dissolution was investigated mainly with X-ray photoelectron spectroscopy (XPS) and electrochemical analysis. Results proved that the presence of the silver-bearing tailing enhanced the oxidation rate of chalcopyrite and also eliminated the passivation effect of polysulfide, thus resulting in an extremely high copper extraction.     

Cooperative effect of chalcopyrite and bornite interactions during bioleaching by mixed moderately thermophilic culture

The cooperative interactions between chalcopyrite and bornite during bioleaching by mixed moderately thermophilic culture were investigated mainly by bioleaching experiments and electrochemical experiments. Bioleaching results showed that a cooperative effect existed between chalcopyrite and bornite. When the mass ratio of chalcopyrite to bornite was 3:1, an extremely high copper extraction of more than 88% was achieved after bioleaching for 27 days. One of the major reasons for the cooperative effect was that a certain redox potential range (370–450 mV vs. Ag/AgCl) could be maintained for a long period of time during bioleaching due to the mixture of chalcopyrite and bornite. Electrochemical measurements revealed that chalcopyrite was much easier to be reduced than oxidized, while bornite was prone to be directly oxidized. Hence, galvanic effect between chalcopyrite and bornite enhanced the reduction of chalcopyrite to secondary copper-iron species and promoted the oxidative dissolution of bornite. Therefore, redox potential controlling and galvanic effect both contributed to the cooperative bioleaching of chalcopyrite and bornite.     

Bioleaching of chalcopyrite by Acidianus manzaensis under different constant pH

The bioleaching of pure chalcopyrite by thermophilic Archaea strain Acidianus manzaensis YN-25 under different constant pH was first comparatively investigated. Then the relevant sulfur speciation was analyzed by synchrotron radiation based X-ray diffraction (SR-XRD) and S K-edge X-ray absorption near edge structure (XANES) spectroscopy. The acidity of the leaching solution was monitored at 3-h intervals to make it steady at pH 1.25, 1.50, 1.75, 2.00, 2.25 and 2.50, respectively. Leaching results showed that the copper ion extraction increased during chemical leaching but decreased during bioleaching when pH value decreased from 2.50 to 1.25. SR-XRD analysis showed that, during bioleaching, new elemental sulfur (S⁰) phase was detected at all tested pH cases; new jarosite phase was detected at cases of pH 1.50 to 2.50; and jarosite gradually became a major phase when pH value increased. XANES analysis further showed that covellite was detected during bioleaching at cases of pH 1.25 to 2.00 at higher redox potential (ORP) value, while chalcocite and bornite were detected at cases of pH 2.25 and 2.50 at lower ORP value. These results suggested that the formation of S⁰ was mainly accounting for hindering the dissolution of chalcopyrite while the formation of bornite could accelerate the dissolution of chalcopyrite by A. manzaensis.     

Acidic sulphate leaching of chalcopyrite concentrates in presence of pyrite

Copper concentrates with mineralogy dominated by chalcopyrite have slow leaching kinetics at atmospheric pressure in sulphate media because of the formation of passivation layer on its surface during the leaching. To enhance the leaching rate of the copper concentrate, pyrite was added to act as a catalyst. Pyrite and copper sulphide minerals then form a galvanic cell which increases both the copper leaching rate and yield. Effect of parameters such as solution redox potential, temperature, initial acid concentration, solids content, total initial iron concentration and pyrite to copper sulphide minerals mass ratio were investigated. Mineralogical analyses by XRD were performed on selected leach residues and the feed materials. A copper recovery higher than 80% in 24 h was achieved at a redox potential of 410 mV vs Ag, AgCl, a temperature of 85 °C, 15 g/L of initial acid concentration, a solid content of 7.8% (w/v), a total initial iron concentration 5 g/L and pyrite to copper sulphide minerals mass ratio 2:1. XRD patterns on leach residues showed that candidates for surface passivation, i.e. jarosite and elemental sulphur, were formed at high total initial iron concentrations.     

Sol-gel assisted preparation and characterization of silver indium diselenide powders

AgInSe₂ powders were successfully prepared via mixing sol-gel derived precursors, followed by a selenization process. To obtain the pure AgInSe₂ compound, excess amounts of In³⁺ ions were added into the starting solution to compensate the loss of In₂O₃ during the selenization process. A figure that depicts the relationship between the resultant compounds and different selenization temperatures was constructed according to the formed phases. The Raman spectrum and Rietveld refinement confirmed that the prepared AgInSe₂ belonged to the chalcopyrite structure. With increasing selenization temperatures, the AgInSe₂ powder particle sizes as well as the crystallinity increased significantly. The AgInSe₂ formation mechanism during the selenization process is proposed as a two-step process. Ag₂Se is formed in the first step and then induces the second-step reaction to produce AgInSe₂. The sol-gel route with a selenization process is introduced as a new approach to fabricate pure AgInSe₂ powders for use in thin-film solar cells.     

黄铜矿和铁闪锌矿自诱导和外控电位浮选研究

研究了黄铜矿、铁闪锌矿自诱导和外控电位浮选的基本行为。结果表明，黄铜矿在较宽的pH范围内均可实现自诱导浮选，并且通过外控电位可以控制它的浮选行为；铁闪锌矿在酸性条件下可实现自诱导浮选，通过外控电位也可以控制它的浮选行为；碱性条件下铁闪锌矿不能实现自诱导浮选，通过外控电位也难以改变它的浮选行为。通过测量循环伏安曲线，分析了两种矿物表面氧化形成的产物，元素硫是主要的疏水体。