基于光谱分析的砷黄铁矿生物浸出过程中铁/砷/硫形态转化研究  

Fe, As and S Speciation Transformation During Arsenopyrite Bioleaching Based on Spectral Analysis Technology

作　　者：陈红瑞 张多瑞 聂珍媛[1] 郑雷[2] 张丽丽[3] 杨洪英[4] 夏金兰[1] CHEN Hong-rui;ZHANG Duo-rui;NIE Zhen-yuan;ZHENG Lei;ZHANG Li-li;YANG Hong-ying;XIA Jin-lan(Key Lab of Biometallurgy of Ministry of Education,School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China;Beijing Synchrotron Radiation Facility,Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China;Shanghai Synchrotron Radiation Facility,Shanghai Institute of Applied Physics,Shanghai Synchrotron Radiation Facility,Shanghai 201204,China;School of Metallurgy,Northeastern University,Shenyang 110819,China)

机构地区：[1]生物冶金教育部重点实验室,中南大学资源加工与生物工程学院,湖南长沙410083 [2]中国科学院北京高能物理研究所,北京同步辐射装置,北京100049 [3]中国科学院上海应用物理研究所,上海光源,上海201204 [4]东北大学材料与冶金学院,辽宁沈阳110819

出　　处：《光谱学与光谱分析》2020年第3期934-940,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金-辽宁联合基金项目(U1608254);国家自然科学基金项目(51774342)资助

摘　　要：基于同步辐射装置的As/S的K边及Fe的L边X射线吸收近边结构光谱(XANES)和X射线衍射(SR-XRD),结合扫描电镜(SEM)、傅里叶红外光谱(FTIR)、电感耦合等离子体发射光谱(ICP-AES)及各项浸出参数的测定,系统研究了(中度嗜热菌、嗜热硫化杆菌)浸出砷黄铁矿过程中铁、砷、硫的形态转化。结果表明,在生物作用下,砷黄铁矿的溶解速率明显高于化学浸出体系,伴随矿物溶解释放到溶液中的砷和铁在生物浸出体系中主要为As(Ⅴ)和Fe3+,而在无菌化学浸出体系则主要为As(Ⅲ)和Fe2+;细菌胞外多聚物(EPS)在细菌与硫化矿物的相互作用过程中起着至关重要的作用, FTIR的结果表明,生物浸出体系中吸附在矿物表面的吸附菌的EPS中蛋白质和多糖的含量均高于游离菌EPS;SEM的结果表明,砷黄铁矿表面在生物浸出过程中逐渐被腐蚀,且有浸出产物覆盖,而化学浸出10 d后,矿物表面依旧比较光滑;SR-XRD的结果表明,元素硫(S0)、黄钾铁矾和砷酸铁在生物浸出第4 d生成,并随时间延长逐渐累积,最终成为浸出渣中的主要成分。Fe的L边XANES结果表明,在细菌作用下矿物表面逐渐被Fe(Ⅲ)浸出产物覆盖;As的K边XANES结果表明,浸出渣中砷的价态包括As(-Ⅰ), As(Ⅲ)和As(Ⅴ),拟合结果表明,经过10 d的生物浸出,砷黄铁矿、雌黄(As2S3)和砷酸铁在矿渣中所占的比例分别为18.6%, 23.5%和57.9%,化学浸出10 d后,矿渣中除未溶解的砷黄铁矿外,仅有少量砷酸铁(6.2%)形成;S的K边XANES拟合结果表明,经过10 d的生物浸出,砷黄铁矿、 S0、硫代硫酸盐、施氏矿物和黄钾铁矾在矿渣中所占的比例分别为15.3%, 23.7%, 3.5%, 11.3%和46.2%,而在化学浸出10 d后的矿渣中,仅拟合到少量S0(7.8%)。基于上述结果可以得出,铁、砷、硫在砷黄铁矿生物作用下的形态转化过程分别为:Fe(Ⅱ)-Fe(Ⅲ), As(-Ⅰ)-As(Ⅲ)-As(Ⅴ), S-→S0→S2O■→SO■。结合溶液中的浸出参数发现,随�In the present study, the bioleaching of arsenopyrite by the moderately thermoacidophilic strain Sulfobacillus thermosulfidooxidans YN-22 was investigated based on iron, arsenic, and sulfur speciation analysis by synchrotron radiation As/S K-, and Fe L-edge X-ray absorption near edge structure(XANES) spectroscopy, X-ray diffraction(SR-XRD), accompanied by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), andinductively coupled plasma-atomic emission spectroscopy(ICP-AES) with the determination of the leaching parameters. The results showed that the presence of bacteria significantly promoted the dissolution of arsenopyrite, and dissolved As and Fe in the bioleaching solutions mainly existed as As(Ⅴ) and Fe3+, while were mainly As(Ⅲ) and Fe2+in the chemical leaching. Extracellular polymeric substances(EPS) plays a critical role in the interactions between bacteria and minerals during bioleaching, and the FTIR analysis of the EPS showed that the contents of protein and polysaccharides of the adhered cells were higher than those of the free cells. Results of SEM showed that the surface of the arsenopyrite was gradually corroded, and some secondary products were formed during bioleaching, while for the sterile control experiment, the mineral surface was only slightly corroded, and only a few products were found after 10 days of chemical leaching. The results of SR-XRD showed that elemental sulfur(S0), jarosite and ferric arsenate were detected after day 4, and gradually developed into the main components of the residues in the bioleaching experiment. Fe L-edge XANES analysis showed that during the bioleaching of arsenopyrite by Sulfobacillus thermosulfidooxidans, the Fe(Ⅱ) species was gradually converted to Fe(Ⅲ) species with time. As K-edge XANES analysis showed that valences of arsenic in the bioleached residues included As(-Ⅰ), As(Ⅲ) and As(Ⅴ), the fitted results of the As K-edge XANES spectra showed that the residue composition of arsenic species for the same leached

关 键 词：X射线吸收边装置光谱 砷黄铁矿 嗜热硫氧化硫化杆菌 生物浸出 形态转化 

分 类 号：TF18[冶金工程—冶金物理化学]