氧化亚铁硫杆菌氧化黄铜矿的实验研究  

Experimental study on the oxidation of chalcopyrite by Acidothiobacillus ferrooxidans

作　　者：李娟[1] 陆建军[1] 陆现彩[1] 王汝成[1] 苏贵珍[1] 

机构地区：[1]南京大学内生金属矿床成矿机制研究国家重点实验室,南京大学地球科学系,南京210093

出　　处：《南京大学学报（自然科学版）》2009年第2期315-322,共8页Journal of Nanjing University（Natural Science）

基　　金：国家自然科学基金(40573001);国家重点基础研究发展计划(2007CB815603)资助成果

摘　　要：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.Chalcopyrite is an important ore mineral in sulfide deposits. The oxidation of chalcopyrite in the ore and tailings could cause seriously heavy metal pollution in mining district. It has been reported that certain bacterium generally participates in and evidently influences the decomposing of chalcopyrite. Acidothiobacillus ferrooxidans was selected to experimentally study the effects of bacteria on the oxidation of chalcopyrite. Inductively coupled plasma-atomic emission spectrometry （ICP-- AES） and pH meter were employed to analyze the compositions of experimental fluids. Raman spectrum and powder X-ray diffraction （XRD） were used to study the residual chalcopyrite and precipitates. The results indicate that Acidothiobacillus ferrooxidans greatly influences the pH and Eh of the solution and the oxidation of chalcopyrite. While the reproduction of bacteria and continuance of chalcopyrite oxidation, H＋ and Cu2＋ of the solution increased clearly, which leads to pH decrease and Eh increase. Acidothiobacillus ferrooxidans plays a key role in the oxidation of chalcopyrite in the inoculated experiments. In the initial stage, Acidothiobacillus ferrooxidans oxidizes Fe2＋ in chalcopyrite and the solution into Fe3＋. As the oxidation continuing and Fe3＋ increasing, chalcopyrite is oxidized and natural sulfur is formed by the cooperation of Acidothiobacillus ferrooxidans and Fe3＋. Thereafter Acidothiobacillus ferrooxidans oxidizes the natural sulfur into SO4^2＋. The combination of Acidothiobacillus ferrooxidans and Fe3＋ maintains the continuously oxidizing processes. With the oxidation of the chalcopyrite, a layer of secondary minerals is formed and then covers the chalcopyrite surface, which suppresses the rate of chalcopyrite decomposition.

关 键 词：黄铜矿 氧化亚铁硫杆菌 微生物氧化 氧化机理 

分 类 号：P599[天文地球—地球化学]