砷黄铁矿的电化学氧化行为及表面相构成  

Electrochemical Oxidation Behavior and Surface Phase Composition of Arsenopyrite

作　　者：俞娟[1,2] 张学良 陈天斯 马致远 Yu Juan;Zhang Xueliang;Chen Tiansi;Ma Zhiyuan(School of Metallurgical Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China;Shaanxi Province Metallurgical Engineering and Technology Research Centre,Xi'an 710055,China;Institute of Resource Utilization and Rare Earth Development,Guangdong Academy of Sciences,Guangzhou 510650,China;State Key Laboratory of Rare Metals Separation and Comprehensive Utilization,Guangzhou 510650,China)

机构地区：[1]西安建筑科技大学冶金工程学院,陕西西安710055 [2]陕西省冶金工程技术研究中心,陕西西安710055 [3]广东省科学院资源利用与稀土开发研究所,广东广州510650 [4]稀有金属分离与综合利用国家重点实验室,广东广州510650

出　　处：《稀有金属》2024年第10期1446-1458,共13页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51974222);广东省自然科学基金项目(2023A1515011847)资助。

摘　　要：通过电化学循环伏安法(CV)研究了砷黄铁矿在弱碱性溶液中的氧化过程,在相应的氧化电位下,对砷黄铁矿进行恒电位极化1800 s,获得稳定的表面氧化相。并采用X射线光电子能谱(XPS)和电化学阻抗(EIS)研究了电位对表面氧化相构成的影响及相应的膜层特征。结果表明,砷黄铁矿在0.25 V(阳极峰A2范围内)氧化,主要发生Fe的初步氧化溶解,Fe氧化生成Fe(OH)_(3),As氧化生成As_(2)O_(3),S氧化生成多硫化物和少量的SO_(3)^(2-)。在0.45 V(阳极峰A2)氧化,砷黄铁矿表面Fe(OH)_(3)含量由0.25 V的2%变为3.02%,可能存在Fe(III)-SO(亚硫酸铁),As氧化产生As_(2)O_(5),多硫化物S_(n)^(2-)的含量由0.25 V的1.93%提高到2.45%,达到最大。在0.6 V(阳极峰A3范围内)氧化,砷黄铁矿表面的Fe(OH)_(3)含量达到5.79%,Fe(III)-SO的含量进一步增大;As仍然主要以As_(2)O_(3)和As_(2)O_(5)的形式存在,As_(2)O_(5)的含量进一步提升;多硫化物发生氧化溶解生成SO_(4)^(2-),Sn^(2-)的含量降低到1.51%。未氧化砷黄铁矿的膜内层反应电荷转移电阻R_(2)值为46478Ω·cm^(2),在0.25 V氧化后R_(2)值升高到83946Ω·cm^(2),反映膜内层厚度的1/C2值达到最大,之后随着电位的提升,砷黄铁矿表面的多硫化物被氧化溶解,同时生成大量Fe(OH)_(3),R_(2)值和1/C_(2)值不断减小,R_(2)值由0.25 V的83946Ω·cm^(2)降低到0.45 V的39313Ω·cm^(2),最后降低为0.6 V时的11068Ω·cm^(2)。Arsenopyrite is often associated with stibnite as arsenic-bearing antimony gold ore,and because the two minerals have similar floatability,in the process of separating antimony and arsenic by traditional froth flotation,arsenopyrite is easily selected into the antimony concentrate,making the arsenic content in the antimony concentrate too high and difficult to meet the grade requirements,and there are problems such as large dosage of chemicals,low sorting efficiency,low recovery rate and complex process flow.Potentiometric flotation is a sorting technology that controls the surface potential of sulfide minerals,which in turn changes the surface of the minerals,affecting the hydrophilicity and hydrophobicity of the mineral surface,to achieve effective separation between different minerals,in order to achieve high selectivity and low chemical flotation reagents consumption of sulfide minerals.It can realize the flotation separation of arsenic and antimony with high selectivity and low chemical consumption,but there is no unified understanding of the oxidation behavior of arsenopyrite,the composition of the oxidation phase and the influence on the flotation behavior.The mineral working electrode was prepared by using the powder pressing method in the ratio of arsenopyrite powder∶analytically pure solid paraffin wax∶spectrally pure graphite powder=8∶1∶1(mass ratio).The platinum sheet was used as the auxiliary electrode and the saturated glycerol electrode(SCE)was used as the reference electrode.The oxidation process of arsenopyrite in weak alkaline solution was investigated by electrochemical cyclic voltammetry(CV),and the stable surface oxidation phase was obtained by constant potential polarization of arsenopyrite for 1800 s at the corresponding oxidation potential.X-ray photoelectron spectroscopy(XPS)and electrochemical impedance(EIS)were also used to study the effect of potential on the composition of the surface oxidation phase and the corresponding film layer characteristics.The results showed that:(1)O

关 键 词：砷黄铁矿 电化学氧化 循环伏安(CV) 电化学阻抗(EIS) X射线光电子能谱(XPS) 

分 类 号：TD913[矿业工程—选矿]