嗜酸嗜热菌FD-LH对高矿浆浓度黄铜矿的生物氧化

研究耐高铜离子浓度的嗜酸嗜热菌FD-LH对梅州黄铜矿生物氧化的特性,考察不同温度、pH值、高矿浆浓度对梅州黄铜矿生物氧化速率的影响,并初步研究串级浸矿工艺的浸出特性.结果表明,在70℃,pH值1.5时黄铜矿浸出效果最佳.FD-LH菌具耐高矿浆浓度(15%~20%)的能力.在矿浆浓度15%时,采用分批浸矿工艺,8 d铜的浸出率为92.0%;采用串级浸矿工艺,8 d铜浸出率高达97.4%.串级浸矿工艺有利于提高铜的浸出速率和浸出率.     

黄铜矿和黄铁矿无捕收剂浮选和分离的研究

本文给出了有、无硫化钠存在时,黄铜矿和黄铁矿的无捕收剂浮选行为。研究表明,黄铜矿具有良好的自诱导可浮性,浮选的电位范围和pH范围较宽;弱酸性和碱性介质中,黄铁矿自诱导浮选差,没有任何可浮电位范围。然而,硫化钠的添加,明显促进了黄铁矿的无捕收剂浮选。天然矿石浮选试验表明,自诱导和硫诱导浮选技术能够有效地浮选和分离黄铜矿和黄铁矿。通过HS~-离子吸附量的测定、矿物表面中性硫量提取分析、矿浆电位测试和量子化学计算,较详细地研究了黄铜矿和黄铁矿无捕收剂浮选的机理。研究结果表明,矿物表面中性硫是主要疏水体。     

柠檬酸强化黄铜尾矿的生物浸矿

通过摇瓶试验研究混合硫杆菌浸出黄铜矿尾矿砂,并初步探讨不同矿浆质量浓度和柠檬酸质量浓度对浸提实验的影响。研究结果表明,添加柠檬酸在一定质量浓度范围内对黄铜矿尾矿砂的硫杆菌浸提有促进作用。在整个浸提实验中,浸矿效率最高达到44.8%,溶液中柠檬酸质量浓度和矿浆质量浓度都会直接影响细菌的氧化活性和浸矿效果。     

Electrochemical and spectroscopic study of interfacial interactions between chalcopyrite and typical flotation process reagents

Comparative voltammetry and differential double-layer capacitance studies were performed to evaluate interfacial interactions between chalcopyrite (CuFeS₂) and n-isopropyl xanthate (X) in the presence of ammonium bisulfite/39wt% SO₂ and caustic starch at different pH values. Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, contact angle measurements, and microflotation tests were used to establish the type and extent of xanthate adsorption as well as the species involved under different mineral surface conditions in this study. The results demonstrate that the species that favor a greater hydrophobicity of chalcopyrite are primarily CuX and S0, whereas oxides and hydroxides of Cu and Fe as well as an excess of starch decrease the hydrophobicity. A conditioning of the mineral surface with ammonium bisulfite/39wt% SO₂ at pH 6 promotes the activation of surface and enhances the xanthate adsorption. However, this effect is diminished at pH ≥ 8, when an excess of starch is added during the preconditioning step.     

Nonlinear dissolution reaction of chalcopyrite

The dissolution experiments of chalcopyrite in 2 mol/L NaCI solutions at 70℃ show that the dissolution rate of chalcopyrite oscillates non-periodically with reaction time while in acid solutions (pH = 1.45-2.45) and far from Cu saturation concentration, and Cu concentration oscillates chaotically in solution of weak to intermediate acidity (pH = 3.66-7.0). In nonequilibrium and open systems, the nonlinear coupling between the dissolution of chalcopyrite and formation of cuprous chloride complexes and precipitation of hemitite caused by CI- , H+ and O2 is the internal mechanism of oscillatory changes of dissolution rate, and the nonlinear coupling between the dissolution of chalcopyrite and precipitation of atacamite induced by CI- and H+ has caused the chaotic oscillation of Cu concentration. There are consistence and difference between reaction rate oscillation and Cu concentration oscillation. However, both of them suggest that the dissolution of chalcopyrite in NaCI solution is a nonlinear reaction process.     

Dual effects of sodium sulfide on the flotation behavior of chalcopyrite: I. Effect of pulp potential

This study explores the flotation behavior of chalcopyrite in the presence of different concentrations of sodium sulfide (Na₂S·9H₂O) at pH 12 under controlled potential conditions. It was observed that the flotation of chalcopyrite is not depressed completely when the pulp potential is low, even at high concentrations of sodium sulfide, i.e., 10?1–10?2 mol/L. However, a partial and controlled oxidation of pulp does enhance the effectiveness of sodium sulfide on the depression of chalcopyrite. Characterization of the chalcopyrite particle surface by X-ray photoelectron spectroscopy allowed the identification of hydrophilic and hydrophobic surface species, which are responsible for the depression and flotation of chalcopyrite. Changes in pulp potential were found to be an effective float controlling parameter, by which Na2S can be used to initiate or depress the flotation behavior of chalcopyrite.     

中等嗜热菌浸出黄铜矿的温度影响规律及种群组成分析

在不同温度条件下进行浸出实验.研究结果表明:中等嗜热菌在12～55℃时可保持浸矿活性,其最适生长温度为45～50℃,温度达到60℃时初始阶段还保持一定活性,但几天后菌浓度逐渐降低,种群比例发生较大变化;克隆文库分析表明:45℃和60℃条件下浸矿细菌主要为Leptospirillum ferriphilum,Acidithiobacillus caldus,Sulfobacillus thermotolerans和Acidosphaera rubrifaciens,其中Leptospirillum ferriphilum菌所占比例较大,是浸矿过程中的优势菌种.60℃条件下浸出过程中还存在古生菌Ferroplasma cupricumulans,古生菌可以利用其他浸矿菌产生的有机物为能源生长.它们之间对浸出所起的作用是相辅相成的,可共同促进黄铜矿的溶解.     

氧化亚铁硫杆菌对黄铜矿表面性质及其浸出的影响

通过测定吸附量、Zeta电位和接触角,并通过对原子力显微镜表面进行表征及摇瓶浸出试验考察不同能源(Fe2+、单质硫和黄铜矿)培养的氧化亚铁硫杆菌A.ferrooxidans对黄铜矿表面性质的影响及其与黄铜矿浸出的关系。研究结果表明:不同能源培养的A.ferrooxidans菌对黄铜矿表面性质的影响规律相似;A.ferrooxidans菌均能快速吸附在黄铜矿表面,而矿驯化的A.ferrooxidans菌在矿表面的附着能力更强;细菌的吸附使黄铜矿的等电点朝细菌的等电点方向偏移,且由于在黄铜矿表面生成了硫膜和不稳定铜硫化物使得黄铜矿表面接触角增大,疏水性增强;在浸矿初期,细菌与黄铜矿作用以直接作用机理为主。     

Hydrometallurgical application for treating a Nigerian chalcopyrite ore in chloride medium: Part I. Dissolution kinetics assessment

The dissolution kinetics of a Nigerian chalcopyrite ore in hydrochloric acid was studied in this article. Acid concentration, reaction temperature, and ore particle size were chosen as experimental parameters. The chemical and morphological studies of the ore before and after leaching at optimal conditions were carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It is revealed that increasing the acid concentration and system temperature and decreasing the ore particle size greatly enhances the dissolution rate. The dissolution kinetics was found to follow the shrinking core model for the diffusion control mechanism where the activation energy (E_a) of 32.92 kJ·mol?1 was obtained for the process and supported by morphological changes at a higher dissolution of 91.33%.     

氧化亚铁硫杆菌氧化黄铜矿的实验研究

黄铜矿是自然界中最为常见的含铜硫化物,矿石或尾矿中黄铜矿的风化往往会导致严重的矿区重金属污染,细菌的参与可以改变黄铜矿的氧化分解行为.本文通过对比实验系统研究了氧化亚铁硫杆菌（Acidothiobacillus ferrooxidans）对黄铜矿氧化分解的影响.利用等离子光谱仪（ICP-AES）、pH计、X射线衍射仪（XRD）和激光拉曼光谱分别测定了实验溶液的成分变化以及黄铜矿表面沉淀的物质组成.结果表明,细菌对实验溶液的pH值、Eh值和黄铜矿的氧化进程起着重要的控制作用.随着反应的进行及细菌的生长,溶液的pH值呈下降趋势,Eh值呈上升趋势,H＋和Cu2＋离子浓度升高.实验表明,细菌是整个氧化过程的主导因素,反应初期,Acidothiobacillus ferrooxidans氧化溶液和黄铜矿中的Fe2＋成Fe3＋ 随着反应的进行和Fe3＋的增多,在Acidothiobacillus ferrooxidans和Fe3＋的共同作用下,黄铜矿被氧化,并可生成自然硫,自然硫进而被Acidothiobacillus ferrooxidans氧化为SO42- Fe3＋对黄铜矿的化学氧化作用和细菌的生物氧化作用持续进行,构成了黄铜矿的氧化过程.反应后期,Fe3＋以次生沉淀形式覆盖在矿物表面,沉淀物对黄铜矿的溶出有抑制作用.