聚乙二醇对氧化亚铁硫杆菌浸出黄铜矿的影响

为提高黄铜矿生物浸出率,研究聚乙二醇(PEG)对Acidithiobacillus ferrooxidans strain XZ11 Fe2+氧化活性和黄铜矿生物浸出过程的影响,并采用SEM和EDS对浸出后矿物表面形貌和相组成进行表征。结果表明:相对分子质量大于200的PEG对Acidithiobacillus ferrooxidans Fe2+氧化活性具有一定的促进作用,添加30 mg/L PEG 2000时,浸出20 d后,铜浸出量高达451.70 mg/L,较不添加FEG时提高了1.11倍;添加PEG时,黄铜矿表面的侵蚀面呈沟壑状,出现溶蚀坑,并生成Fe3+的羟基化多聚物Fe(Ⅲ)—O—OH。PEG的添加提高了浸出体系中细菌浓度和Fe3+浓度,加速了黄铜矿的溶解。     

低温下YL15对黄铜矿和斑铜矿的协同浸出及电化学研究

采用生物浸出和电化学测试,研究低温10℃下AcidithiobacillusferrivoransYL15对黄铜矿和斑铜矿的协同浸出过程,结合不同的电化学测试手段探究其电化学溶解和表面钝化行为。结果表明:不同矿物体系的生物浸出和电化学行为存在极大差异。协同浸出组的浸出率最高,达到了48.4%,斑铜矿的次之,且两者都远高于黄铜矿的16.4%。斑铜矿的加入降低了氧化还原电位并维持到一个适宜的范围(400~420 mV),加快了矿物的氧化。另外,通过电化学测试,发现协同浸出组的电位降低、电流升高和阻抗减小、氧化速率大幅提高。     

黄铜矿与斑铜矿在酸性细菌培养基中的电化学溶解对比(英文)

采用电化学测试和X射线光电子能谱(XPS)测试分析黄铜矿与斑铜矿在酸性细菌培养基中的电化学溶解过程。斑铜矿直接氧化反应比还原反应更容易发生,但黄铜矿既难被氧化,又难被还原。斑铜矿具有更高的氧化速率,从而比黄铜矿更容易被溶解。铜蓝(CuS)是黄铜矿与斑铜矿溶解过程的中间产物。因此,斑铜矿的溶解途径主要为直接氧化过程,中间产物铜蓝(CuS)可能限制其进一步溶解。黄铜矿的溶解途径包含了还原-氧化过程,其中,黄铜矿首先被还原为与斑铜矿类似的中间产物,再进一步被氧化,并产生铜蓝(CuS),而黄铜矿的最初还原过程是其溶解过程的主要限制步骤。     

Bioleaching of chalcopyrite by pure and mixed culture

The bioleaching of chalcopyrite in shake flasks was investigated by using pure Acidithiobacillusferrooxidans and mixed culture isolated from the acid mine drainage in Yushui and Dabaoshan Copper Mine in China, marked as YS and DB, respectively. The mixed culture consisted mainly of Acidithiobacillus fOrrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum spp. （Leptospirillum ferriphilum and Leptospirillum ferrooxians）. The results show that the mixed culture is more efficient than the pure Acidithiobacillus ferrooxidans because of the presence of the sulfur-oxidizing cultures that positively increase the dissolution rate and the recovery of copper from chalcopyrite. The pH value decreases with the decrease of chalcopyrite leaching rate, because of the formation ofjarosite as a passivation layer on the mineral surface during bioleaching. In the bioleaching using the mixed culture, low pH is got from the sulfur oxidizing inhibiting, the formation ofjarosite. The copper extraction reaches 46.27% in mixed culture and 30.37% in pure Acidithiobacillusferrooxidans after leaching for 75 d.     

Bioleaching of chalcopyrite by UV-induced mutagenized Acidiphilium cryptum and Acidithiobacillus ferrooxidans

The original strains Acidithiobacillus ferrooxidans GF and Acidiphilium cryptum DX1-1 were isolated from the drainage of some caves riched in chalcopyrite in Dexing Mine in Jiangxi Province of China.The optimum temperature and pH for growth were 30℃and 3.5 for Ac.cryptum DX1-1,and 30℃and 2.0 for At.ferrooxidans GF,respectively.For Ac.cryptum DX1-1,the optimum UV radiating time was 60 s and the positive mutation rate was 22.5%.The growth curves show that Ac.cryptum after mutagenesis reached stationary phase ...     

生物浸出过程中黄铜矿钝化的控制方法(英文)

在细菌浸出黄铜矿的过程中,黄铜矿表面钝化是普遍现象,成为生物浸铜技术的瓶颈问题。对比研究了普通浸出与强化浸出(加入玻璃圆珠)对铜浸出的影响。结果表明,玻璃圆珠的加入改善了浸出条件,削弱了黄铜矿的钝化效应,使黄铜矿的Cu浸出率从50%提升至 89.8%。扫描电镜(SEM)和X射线衍射(XRD)分析发现,添加玻璃圆珠的黄铜矿表面没有黄钾铁矾沉淀,钝化作用不明显;而不加玻璃圆珠的黄铜矿表面附着厚厚的结构致密的黄钾铁矾,钝化严重,从而阻碍了黄铜矿的溶解和浸出。     

Photogenerated-hole scavenger for enhancing photocatalytic chalcopyrite bioleaching

The effects of photogenerated-hole scavengers (ascorbic acid, oxalic acid, humic acid and citric acid) on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans (A. ferrooxidans). Four sets of bioleaching experiments were performed: (1) visible light + 0 g/L scavenger, (2) visible light + 0.1 g/L of different scavenger (ascorbic acid, oxalic acid, humic acid and citric acid), (3) dark + 0.1 g/L of different scavenger (ascorbic acid, oxalic acid, humic acid and citric acid), and (4) dark + 0 g/L scavenger (control group). The results showed that ascorbic acid and oxalic acid could act as photogenerated-hole scavengers and significantly enhance chalcopyrite bioleaching under visible light. The dissolved copper in the light group without scavenger was only 18.7% higher than that of the control group. The copper extraction rates of the light groups with oxalic acid and ascorbic acid were respectively 30.1% and 32.5% higher than those of the control group. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analyses indicated that ascorbic acid and oxalic acid as photogenerated-hole scavenger could capture photo-generated holes and inhibit jarosite formation on the chalcopyrite surface, thereby enhancing bioleaching of chalcopyrite under visible light.     

可见光和Cd2+对黄铜矿生物浸出的催化作用(英文)

利用扫描电镜(SEM)、同步辐射X射线衍射(SR-XRD)和X射线光电子能谱(XPS)研究在酸性氧化亚铁硫杆菌存在下,可见光和镉离子(Cd²⁺)对黄铜矿生物浸出的影响。生物浸出28天后的结果表明,光照下铜的溶解提高4.96%;Cd²⁺单独存在对黄铜矿的浸出有轻微的抑制作用;可见光和50mg/LCd²⁺同时存在时,溶解铜的浓度提高14.70%。化学浸出结果表明,可见光能促进体系中铁元素的循环。SEM结果显示,Cd²⁺在可见光下促进酸性氧化亚铁杆菌在黄铜矿表面的附着。综合SR-XRD和XPS结果可知,可见光和Cd²⁺促进黄铜矿的浸出,但不会抑制钝化物的形成。提出可见光和Cd²⁺对黄铜矿生物浸出协同催化作用机制的模型。     

绢云母对黄铜矿微生物浸出的影响

采用以Acidithiobacillus ferrooxidans为主的混合菌,研究绢云母对微生物浸出黄铜矿的影响。结果表明,铜的浸出率随着绢云母粒度的减小而增加,随着绢云母质量分数的增加而呈先升高后降低的趋势。在添加粒度为-33μm、质量分数为5.0%的绢云母时,铜的最高浸出率为54.88%,比不添加绢云母时的铜浸出率提高了约12%,表明绢云母能促进黄铜矿的微生物浸出。绢云母的加入可使浸出体系pH值降低,最终pH值低于1.22。在浸出过程中,新生成的物质主要是铵黄铁矾,它覆盖于黄铜矿的表面,对微生物浸出铜有一定的阻碍作用。     

Study on bioleaching of primary chalcopyrite ore with thermoacidophilic archae

A high temperature-tolerating thermoacidophilic archae （TA） was isolated from water samples collected from a hot sulfur-containing spring in the Yunnan Province, China, and was used in bioleaching experiments of a low-grade chalcopyrite ore. The TA grow at temperatures ranging from 40 to 80℃, with 65℃ being the optimum temperature, and at pH values of l.5 to 4.0, with an optimum pH value of 2.0. The bioleaching experiments of the chalcvpyrite ore were conducted in both laboratory batch bioreactors and leaching columns. The results obtained from the bioreactor experiments showed that the TA bioleaching rate of copper reached 97% for a 12-day leaching period, while the bioleaching rate was 32.43% for thiobacillus ferrooxidans （Tf） leaching for the same leaching time. In the case of column leaching, tests of a two-phase leaching （196 days）, that is, a two-month （56 days） Tf leaching in the first phase, followed by a 140-day TA leaching in the second phase were performed. The average leaching rate of copper achieved for the 140-day TA leaching was 195mg/（L.d）, while for the control experiments, it was as low as 78mg/（L .d） for the Tf leaching, indicating that the TA possesses a more powerful oxidizing ability to the chalcopyrite than Tf Therefore, it is suggested that the two-phase leaching process be applied to .for the heap leaching operations, whereas, the TA can be used in the second phase when the temperature inside the heap has increased, and the primary copper sulfide minerals have already been partially oxidized with Tf beforehand in the first phase.     

Effects of microorganisms on surface properties of chalcopyrite and bioleaching

The alteration of surface properties of chalcopyrite after biological conditioning with Acidithiobacillusferrooxidans and Acidithiobacillus caldus was evaluated by Zeta-potential, adsorption studies, FT-IR spectra and contact angle measurement. The Zeta-potential studies show that the iso-electric point（IEP） of chalcopyrite after bacterial treatment moves towards the IEP of pure cells, indicating the adsorption of cells on chalcopyrite surface. The FT-IR spectra of chalcopyrite treated with bacterial cells show the presence of the cell functional groups signifying cells adsorption. Due to the formation of elemental sulfur and intermediate copper sulphides on chalcopyrite surface, the contact angle and surface hydrophohicity of chalcopyrite increase at the initial bioleaching stage. Chalcopyrite bioleaching by Acidithiobacillus ferrooxidans has higher copper extraction, which agrees with the fact that Acidithiobacillus ferrooxidans adsorbed on chalcopyrite surface is much more than Acidithiobacillus caldus. The results support the direct mechanism of sulfide oxidations in bioleaching chalcopyrite.     

Effect of temperature-induced phase transitions on bioleaching of chalcopyrite

The phase transformation of chalcopyrite and the effect of its phase status on bacterial leaching were studied. Under the protection of high-purity argon, different temperatures (203, 382 and 552 °C) were applied to natural chalcopyrite to complete the phase change. In addition, the chalcopyrite was bioleached before and after the phase change. The results show that the chalcopyrite heated at 203 and 382 °C remained in the α phase, whereas the chalcopyrite changed from α to β phase at 552 °C. The leaching rates of chalcopyrite after the phase transitions at 203, 382 and 552 °C were 32.9%, 40.5% and 60.95%, respectively. Further, the crystal lattice parameters of chalcopyrite increased and lattice energy decreased, which were the fundamental reasons for the significant increase in leaching rate. Electrochemical experiments demonstrated that with increasing annealing temperature, the polarization resistance decreased and corrosion current density increased. The higher the oxidation rate was, the higher the leaching rate was.     

黄铁矿对砷黄铁矿生物浸出的影响

为探明黄铁矿在砷黄铁矿生物浸出过程中的作用与影响,选择纯黄铁矿和砷黄铁矿组成的矿浆浸出体系,考察黄铁矿和砷黄铁矿质量比以及黄铁矿粒度对体系中砷的浸出率以及砷的氧化状态的影响。结果表明：砷的浸出率随黄铁矿与砷黄铁矿质量比的增加而升高,随黄铁矿粒度的增加而减少。当黄铁矿的粒度小于74μm、黄铁矿与砷黄铁矿质量比为10：2时,砷的最高浸出率为97.7%,比不添加黄铁矿时砷的浸出率提高了约43.18%。且黄铁矿可以加速As(Ⅲ)转化为As(Ⅴ),降低矿浆对细菌的毒害,使生物浸出体系细菌密度提高、pH下降、氧化还原电位φh升高并与砷黄铁矿形成原电池效应,从而促进砷黄铁矿的浸出。     

Microbial leaching of marmatite by Acidithiobacillusferrooxidans and Acidithiobacillus thiooxidans

1 Introduction Microbial leaching of metals from sulfide minerals has been practiced over hundreds of years without realizing that microorganisms were involved. Copper, zinc, gold, etc can be recovered from sulfide ores by microbial leaching[1?5]. Zinc s…     

黄铜矿生物浸出过程的硫形态转化研究进展

黄铜矿生物浸出过程中会生成元素硫及其他含硫中间产物和衍生物,它们对黄铜矿溶解产生钝化或促进作用。研究黄铜矿生物浸出过程的硫形态转化,可以有效了解阻碍或促进黄铜矿生物浸出的关键物质形态以及影响这些形态形成的机制,从而为进一步了解黄铜矿的钝化机制、揭示黄铜矿的溶解机制奠定理论基础。介绍了黄铜矿生物浸出过程产生的含硫中间产物和衍生物及其硫形态转化研究的进展。     

中度嗜热菌浸出黄铜矿过程表面产物解析

采用X射线衍射(XRD)与X射线光电子能谱(XPS)研究黄铜矿在中度嗜热菌浸出过程中的表面产物变化。结果表明,在A. caldus,S. thermosulfidooxidans与L. ferriphilum浸出过程中,一硫化物(CuS)、二硫化物(S22?)、元素硫(S0)、多硫化物(Sn2?)与硫酸盐(SO42?)是黄铜矿表面的主要产物。在A. caldus浸出黄铜矿过程速率较慢,这主要是由于黄铜矿的不完全溶解产生多硫化物,限制了进一步的溶解。在S. thermosulfidooxidans与L. ferriphilum浸出黄铜矿过程中,多硫化物与黄钾铁矾是钝化膜的主要成分。元素硫不是导致黄铜矿生物冶金过程钝化的主要物质。     

嗜酸氧化亚铁硫杆菌在黄铜矿表面的短期吸附实验研究(英文)

为了探明细菌在黄铜矿表面的吸附机制,采取短期吸附的实验方法,研究吸附时间、矿浆浓度、细菌浓度、pH值和离子强度等因素对吸附行为的影响。结果表明,细菌吸附量随初始细菌浓度和矿浆浓度的增加而增大。Acidithiobacillus ferrooxidans在黄铜矿表面的最佳吸附pH范围为1-3。离子强度的增大会抑制细菌吸附,这一现象可以通过双电层理论得到很好的解释。细菌与黄铜矿的吸附行为受疏水性和静电作用力共同影响。     

Effect of pH values on extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans during chalcopyrite bioleaching

The effect of pH values on the extracellular protein and polysaccharide secretions of Acidithiobacillus ferrooxidans was comparatively investigated in different phases of bacterial growth during chalcopyrite bioleaching. The results indicate that the extracellular protein is always more than the extracellular polysaccharide secreted by attached cells on the chalcopyrite, on the contrary, and is always less than the extracellular polysaccharide secreted by free cells in the solution at bacterial adaptive phase, logarithmic phase and stationary phase whenever pH value is at 1.0, 1.5, 2.0 or 2.5; free cells are mainly through the secretion of extracellular polysaccharide rather than the extracellular protein to fight against disadvantageous solution environment, such as high concentration of metal ions and unsuitable pH solution; both amounts of polysaccharide and protein secreted by attached cells are mainly positively related to the solution acidity rather than the total concentration of soluble metal ions. The experimental results imply that bacteria are mainly through secreting more extracellular polysaccharide to fight against disadvantageous environment and the extracellular protein perhaps plays an important role in oxidation–reduction reactions in the bioleaching system.