磁选在复杂难选矿浮选流程中的合理应用

对于磁性和可浮性都较好的矿物,用单一的选矿方法往往不能有效分离,将磁选和浮选有机的结合,才能获得较好的分离效果。本文以应用实例结合理论研究对磁选在复杂难选矿浮选流程中的合理应用加以陈述。     

Structural tuning of wide‐gap chalcopyrite CuGaSe2 thin films and highly efficient solar cells: differences from narrow‐gap Cu(In,Ga)Se2

Simultaneous realization of high values of open circuit voltage (V_oc), fill factor (FF), and energy conversion efficiency (η) in wide‐gap CuGaSe₂ (CGS) solar cells has long been one of the most challenging issues in the realm of chalcopyrite photovoltaics. In this communication, structural tuning of CGS thin films by means of controlling the amount of Se flux used during CGS film growth and improvements in solar cell performance (V_oc > 0.9 V, FF > 0.7, and η > 10%) are demonstrated. Systematic variations in CGS film properties with the Se flux and correlation with device properties are shown. The unique CGS thin‐film growth kinetics, which are different from narrow‐gap Cu(In,Ga)Se₂, are also presented and discussed. This development of double digit efficiency for CGS solar cells opens a new frontier for the broad application of a new class of chalcopyrite‐based devices. Copyright © 2014 John Wiley & Sons, Ltd.     

Analysis of current-voltage characteristics of Al/p-ZnGa2Se4/n-Si nanocrystalline heterojunction diode

The polycrystalline ZnGa₂Se₄ thin film was prepared by thermal evaporation technique on n-Si wafer followed by annealing at 700 K. Then, the Al/p- ZnGa₂Se₄/n-Si/Al heterojunction diode was fabricated. XRD pattern shows that the annealed ZnGa₂Se₄ film has a polycrystalline structure. AFM images indicate that the ZnGa₂Se₄ film is formed of nanoparticles. The dark current-voltage characteristics of the heterojunction diode at various temperatures have been investigated to determine the electrical parameters and conduction mechanism. The Al/p-ZnGa₂Se₄/n-Si/Al diode shows a rectification ratio of 2.644 × 10² at ±2 V at room temperature. It was found that at forward bias voltages ≤0.5 V, the conduction mechanism of the diode is controlled by the thermionic emission mechanism, while at bias voltages higher than 0.5 V, it is controlled by the space charge limited current mechanism. The series resistance R_s, the ideality factor n and the barrier height ?_b values of the diode are determined by performing different plots from the forward current-voltage characteristics. The reverse current mechanism of the diode is controlled by the carrier generation-recombination process in the depletion region. The obtained results show that the Al/p-ZnGa₂Se₄/n-Si/Al heterojunction is a good candidate for the electronic device applications.     

Effect of temperature,oxygen partial pressure and calcium lignosulphonate on chalcopyrite dissolution in sulfuric acid solution

The pressure leaching mechanism of chalcopyrite was studied by both leaching tests and in-situ electrochemical measurements. The effects of leaching temperature, oxygen partial pressure, and calcium lignosulphonate, on copper extraction and iron extraction of chalcopyrite pressure leaching were investigated. The leaching rate is accelerated by increasing the leaching temperature from 120 to 150 °C and increasing oxygen partial pressure to 0.7 MPa. The release of iron is faster than that of copper due to the formation of iron-depleted sulfides. Under the optimal leaching conditions without calcium lignosulphonate, the copper and iron extraction rates are 79% and 81%, respectively. The leaching process is mixedly controlled by surface reaction and product layer diffusion with an activation energy of 36.61 kJ/mol. Calcium lignosulphonate can effectively remove the sulfur passive layer, and the activation energy is 45.59 kJ/mol, suggesting that the leaching process with calcium lignosulphonate is controlled by surface chemical reactions. Elemental sulfur is the main leaching product, which is mixed with iron-depleted sulfides and leads to the passivation of chalcopyrite. Electrochemical studies suggest that increasing the oxygen partial pressure leads to increasing the cathodic reaction rate and weakening the passivation of chalcopyrite.     

黄铜矿浮选工艺及捕收剂研究进展

阐述了黄铜矿的矿物特征和浮选特性,对黄铜矿的浮选工艺、新型浮选捕收剂以及浮选捕收剂的组合应用进行了概述,认为研制出捕收性能强、选择性好的新型捕收剂是黄铜矿浮选捕收剂的发展方向。     

硫化铜、铅矿物浮选分离研究现状及发展趋势

在矿产资源开发强度日益增大的大环境里,人们对多金属复杂矿石的利用和研究的兴趣也越来越大。本文通过对硫化铜、铅矿物的浮选分离进行总结,认为目前研究最多的是优先浮选流程、混合浮选流程和等可浮流程,指出了常用的捕收剂和抑制剂等药剂制度。介绍了铜铅混合精矿分离常用的方法,包括重铬酸盐法、亚硫酸(盐)法和其他多种方法。阐述了多种方铅矿抑制剂的抑制机理。对硫化铜、铅矿物的浮选电化学研究成果进行了全面总结,分析了黄铜矿、方铅矿单矿物的电化学特性,综述了两种单矿物的人工混合矿的电化学分离条件以及电化学控制浮选和原生电位浮选的理论内涵,并指出了下一步研究的方向。     

EPS-contact-leaching mechanism of chalcopyrite concentrates by A. ferrooxidans

The effect of extracelluar polymeric substances（EPS） on the bioleaching chalcopyrite concentrates in the presence of ironand sulphur-oxidizing bacteria （A. ferrooxidans） was studied. The bacterial number, pH, redox potential, and the concentrations of Fe^2＋ and Cu^2＋ ions were investigated. The leached residues were analyzed by the X-ray diffraction and FT-IR. The results indicate that the EPS makes the bacteria adhere to the chalcopyrite surface easily and it is helpful for bacteria in disadvantageous environment At the same time, EPS film layer with Fe^3＋ deposits on the surface of chalcopyrite and becomes a barrier of oxygen transfer to chalcopyrite to passivate chalcopyrite, and creates the high redox potential space through concentrating Fe^3＋ ions to accelerate bioleaching pyrite in chalcopyrite concentrates. The results suggest that EPS formation promotes bioleaching pyrite and inhibits bioleaching chalcopyrite, especially under high potential condition.     

微生物浸出黄铜矿适应性研究

采用微生物浸矿技术,以西部矿业黄铜矿为对象,进行了从黄铜矿中提取铜的实验研究。菌种为氧化亚铁杆菌（T.f）。先进行菌种富集制备T．f菌浸出液,用细菌摇瓶浸出法做实验,了解影响浸出率的各种技术因素。研究结果得出,西部矿业黄铜矿在一般温度（25℃）下,T．f菌浸液的起始pH值为2．5,细菌浸出效果良好,浸出率平均在40％～65％之间,最高达到67％左右。为明确了解T．f菌浸出的效果,进行了无菌化学浸出的平行实验,两组系列实验结果得出,在整个浸出过程中,有菌浸出与无菌浸出相比,前期有菌浸出占有明显优势,但在后期浸出,效果与无菌浸出相当。这是由于有菌浸出后期pH值较前期低,不利于细菌的生长繁殖,此时,浸出时应使用pH值控制器,使其pH保持在合适的范围内,就能继续高的浸出速率。     

低品位黄铜矿在嗜热布氏酸菌下的循环伏安分析

电解液中含与不含布氏酸菌时,采用循环伏安法研究了黄铜矿-碳糊电极与电解液之间的电化学行为,并探讨了温度、阴极电位、Fe2+和Cu2+对循环伏安曲线的影响. 结果表明,低品位黄铜矿在0.45 V出现生成多硫化合物的氧化峰,在-0.25和-0.43 V出现生成Cu5FeS4和Cu2S的还原峰. 温度升高促进黄铜矿氧化分解,65℃时的峰电流为35℃时的2倍. 添加适量Fe2+和Cu2+能促进黄铜矿的氧化分解.