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。     

砷黄铁矿在酸性体系下的电化学氧化

在酸性体系下研究砷黄铁矿的电化学氧化。结果表明:砷黄铁矿首先被氧化为As2S2,覆盖于电极表面,使电极表面发生钝化;随着电位的继续升高,As2S2被氧化生成亚砷酸,随后亚砷酸被氧化为砷酸,亚铁离子被氧化成铁离子。不同pH和温度下的腐蚀动力学研究表明,随着pH值的增大,体系的腐蚀电位正移,腐蚀电流密度减小;随着温度的升高,砷黄铁矿的腐蚀电位负移,腐蚀电流密度增大。说明在研究的pH及温度范围内,降低体系的pH或提高温度都有利于砷黄铁矿的氧化。交流阻抗研究结果表明,不同电位下电极表面发生的电化学反应机理不同,测定结果与线性扫描的研究结果相吻合。     

氧化亚铁硫杆菌（SH—T）氧化毒砂的机理

采用优良的氧化亚铁硫杆菌SH-T菌株对含金毒砂势光片和纯毒砂粉末进行氧化试验,并作了定量定域的显微观察分析,研究了每一阶段毒砂表面的性质和毒砂氧化膜的形成过程,毒砂在细菌氧化后覆盖了黄色氧化膜,抑制了细菌的快速氧化。用X射线粉晶衍射法对细菌氧化产物进行物相分析,结果表明氧化物的主要成分为黄钾铁矾,其次为砷华,细菌氧化膜的X射线光电子谱分析表明毒砂晶体中As表现出[AsS]^2→As(Ⅲ）→As(Ⅴ）的价态变化过程,揭示了细菌氧化过程中毒砂形貌变化规律和晶体的内在联系。     

Bioleaching of refractory gold ore （ Ⅱ ）——Mechanism on bioleaching of arsenopyrite by Thiobacillus ferrooxidans

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Submicro-battery effect and selective bio-oxidation model of gold-bearing arsenopyrite by Thiobacillus ferrooxidans

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Galvanic effect of magnetite on electrochemical oxidation of arsenopyrite in acidic culture medium

The galvanic interaction of arsenopyrite—magnetite in acidic culture medium was investigated by electro- chemical measurements, X-ray photoelectron spectroscopy characterization and leaching experiments. The results indicated that the rest potential of magnetite was 321 mV, which was more anodic than 223 mV of arsenopyrite, and the galvanic current was 7.40 µA, verifying the existence of the galvanic interaction between arsenopyrite and magnetite. The galvanic potential and polarization curves suggested that the redox behaviors of arsenopyrite dominated the overall galvanic interaction. The galvanic interaction enhanced the electrochemical dissolution of arsenopyrite with the generation of more oxidation products (S⁰, SO₃^2—, SO₄^2— and AsO₃^3—) on arsenopyrite and an increase in the chemical reactivity of the surface. Leaching experiments of 6 days showed that the presence of magnetite improved the arsenic release from arsenopyrite by 30 mg/L, and further confirmed the enhanced oxidation of arsenopyrite when coupled with magnetite.     

氨性溶液中砷黄铁矿阳极氧化过程的电化学

通过电化学研究 ,考察了氨溶液中砷黄铁矿的阳极氧化反应。实验表明氧化生成的表面膜对反应有抑制作用 ,该膜具有多孔性 ,可使反应继续进行。低温时 ,阳极氧化过程由电化学反应控制 ;高温时 ,反应受扩散过程控制。氨浓度对氧化过程的反应速率没有显著影响 ,溶液中Cu2 能降低氧化峰电位 ,改变氧化表面膜的形态 ,使膜的孔隙增大 ,反应速度加快。砷黄铁矿的阳极氧化总反应为FeAsS 11H2 O =Fe(OH) 3 SO2 -4 HAsO2 -4 18H 14e。     

Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans and Leptospirillum f errooxidans

Bioleaching of marmatite flotation concentrate by Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans was investigated at 35℃, the initial pH value of 2.0 on an orbital shaker with 160 min^-1 over a period of 10 days. Experimental results indicate that the adapted strains increase markedly the dissolution rate and the leac-hing ratio of marmatite. Pulp density also affects the bioleaching of marmatite. Massive elemental sulfur and jarosite form during the leaching process in the systems inoculating the adapted strains in pure and mixed cultures;and acid product is enhanced, which decreases the pH below to 2.0 in latter leaching period. Marmatite preferentially dis-solves during the bacterial leaching of complex sulfides. Compared with the pure cultures of original and adapted strains, the adapted strains of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans in mixed cultures are more efficient in the oxidation of marmatite.     

高铁酸盐(Ⅵ)与毒砂表面的作用机理及其对黄铜矿与毒砂浮选分离的影响（英文）

通过浮选试验、接触角测量、吸附量测试、交流阻抗测试和XPS分析研究一种新型环保抑制剂高铁酸钾(K₂FeO₄)在乙基黄药捕收剂体系下对毒砂和黄铜矿的抑制作用。结果表明,在pH值为4～11的范围内,高铁酸钾强烈抑制毒砂,在pH 8或10时,采用5×10^-4 mol/L K₂FeO₄和5×10⁵ mol/L PEX可以实现黄铜矿与毒砂的浮选分离。在K₂FeO₄和PEX存在时,毒砂的接触角和黄药吸附量显著降低。LEIS测量表明,高铁酸盐的加入可以显著增加毒砂表面的阻抗。XPS分析进一步证实,高铁酸盐加速毒砂表面的氧化。     

Influence of mechanical activation on leaching kinetics of arsenopyrite

The influence of mechanical activation on the leaching kinetics of arsenopyrite was studied using a planetary centrifugal mill. It shows that mechanical activation can enhance the leaching process of arsenopyrite in a nitric-sulfate acidic solution. The leaching ratio within 20 min leaching time can increase from 2 % to 80 %～ 100 % ; 10 and 20 minties‘ activation can depress the apparent activation energy of leaching reaction from 54.5 kJ/mol to 39.0 kJ/mol and 34.0 kJ/mol, respectively. This means that the leaching reaction becomes little dependent on tempeerature, and arsenopyrite can change from refractory to flexible one; mechanical activation also increases the interplanar distance between crystal faces. The displacement of atoms from its equilibrium position indicates the increase in inner energy.     

Bioleaching of anilite by Acidithiobacillus ferrooxidans

In order to characterize the efficiency of copper bioleaching from anilite using pure cultures of Acidithiobacillus ferrooxidans in the absence and presence of ferrous sulphate,the experiments were carried out in shake flasks with or without 4 g/L ferrous sulphate(FeSO_4·7H_2O)at pH 2.0,150 r/min and 35℃.The tests show that Acidithiobacillus ferrooxidans is unable to attack anilite in iron-free 9K medium.Anilite is rapidly oxidized by bacterial leaching when ferrous sulphate is added.Chemical oxidation o...     

阴离子对嗜酸氧化亚铁硫杆菌生长和硫氧化活性的影响

以嗜酸氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans, ATCC23270)为对象,研究NO_3~-、SO_4~(2-)、Cl~-和PO_4~(3-)对Acidithiobacillus ferrooxidans生长和硫氧化活性的影响.结果表明:不同阴离子对Acidithiobacillus ferrooxidans硫氧化表观活性的影响效应不同,其影响由大到小的顺序依次为Cl~-,NO_3~-,SO_4~(2-)和PO_4~(3-);在高浓度PO_4~(3-)的胁迫(300 mmol/L)下,细菌所表达蛋白质的总数量减少,但同时表达一些特异性蛋白质,这说明细菌可通过抑制一些在正常条件下表达的蛋白质,同时表达一些新的蛋白质来应对无机离子的胁迫效应.     

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…     

Bacterial leaching of chalcopyrite and bornite with native bioleaching microorganism

A native mesophilic iron-oxidizing bacterium, Acidithiobacillus ferrooxidans, has been isolated （30 ℃） from a typical, lead-zinc concentrate of Dachang Mine in the region of Liuzhou located in the southwest of China. Two typical copper sulfide minerals, chalcopyrite and bornite, were from Meizhou Copper Mine in the region of Guangdong Province, China. Variation of pH and cell growth on time and effects of some factors such as temperature, inoculation cell number, and pulp density on the bioleaching of chalcopyrite and bornite were investigated. The results obtained from the bioleaching experiments indicate that the efficiency of copper extraction depends on all of the mentioned variables, especially the pulp density has more effect than the other factors on the microorganism. In addition, the results show that the maximum copper recovery was achieved using a mesophilic culture. The copper dissolution reached 51.34% for the chalcopyrite while it was 72.35% for the bornite at pH 2.0, initial Fe（ Ⅱ ） concentration 9 g/L and pulp density 5%, after 30 d.     

Sulfur activation-related extracellular proteins of Acidithiobacillus ferrooxidans

The fractions of the extracellular proteins of Acidithiobacillus ferrooxidans grown on two different energy substrates, elemental sulfur and ferrous sulfate,were selectively prepared with hot water treatment and distinctly shown by two-dimensional gel electrophoresis.Some protein spots with apparently higher abundance in sulfur energy substrate than in ferrous sulfate energy substrate were identified by using MALDI-TOF/TOE Based on peptide mass fingerprints and bioinformatical analysis,the extracellular ...     

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.     

生物浸铀中影响嗜酸氧化亚铁硫杆菌活性的氟毒物活性形态(英文)

为了确定浸矿菌耐氟的机制,在氟化物存在的条件下,驯化铀矿浸出菌嗜酸氧化亚铁硫杆菌ATCC23270,研究溶液中含不同氟浓度、不同pH值时铀矿浸出菌的活性变化,以及有无蛋白酶K处理时铀矿浸出菌细胞内氟浓度的变化情况。采用铂电极和Ag/AgCl参比电极测量氧化还原电位,以作为细菌不同活性的参照指标,采用氟离子选择性电极测定细胞内的氟浓度。结果表明,真正影响铀矿浸出菌活性的是HF,溶液pH值增加以及溶液中与氟有较强络合能力的离子浓度的变化,也会引起耐氟菌假象的出现。浸矿菌的耐氟能力可能与细胞壁和细胞膜上的一些蛋白密切相关。     

采用中温菌和常温菌浸出含砷金精矿

考察了不同矿浆浓度和接种量对细菌浸出含砷金精矿的影响。结果表明：中度嗜热嗜酸铁氧化菌MLY和嗜酸氧化亚铁硫杆菌（Acidthiobacillus ferrooxidans,At.f）的浸矿效果不同。MLY和At.f对含砷金精矿的浸出机理也不同;接种MLY的矿浆中,可能主要是溶液中的细菌将Fe^2＋氧化为Fe^3＋,再由Fe^3＋氧化溶解矿物,即以间接浸出作用为主;而接种At.f可能首先是At.f被吸附到矿物表面,通过细菌与矿物之间的某种界面作用引起矿物溶解,矿物溶解产生的Fe^2＋被游离菌氧化成为Fe^3＋,从而溶解矿物,即At.f浸出可能包括直接作用和间接作用的共同效应。