弱碱性溶液中硫砷铜矿的电化学氧化过程及表面相构成  

Electrochemical oxidation process and chemical composition of surface phase on enargite in weak alkaline solution

作　　者：俞娟[1,2] 孟必成 黄文龙 李林波 YU Juan;MENG Bi-chen;HUANG Wen-long;LI Lin-bo(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)

机构地区：[1]西安建筑科技大学冶金工程学院,西安710005 [2]陕西省冶金工程技术研究中心,西安710055

出　　处：《中国有色金属学报》2020年第2期467-478,共12页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51304151);陕西省教育厅资助项目(18JK0474);陕西省自然科学基础研究计划面上项目(2018JM5135)。

摘　　要：采用循环伏安(CV)和X射线光电子能谱(XPS)对硫砷铜矿在pH值为9.2溶液中的电化学氧化过程以及电位对硫砷铜矿表面氧化相的构成影响进行研究。结果表明:硫砷铜矿在电位0.17 V(氧化峰A1电位范围)氧化,主要发生Cu部分离开矿物表面进入溶液形成缺铜硫化物(Cu3 xAsS4)的初步氧化过程,表面不存在Cu(Ⅱ)的氧化相,S氧化形成少量的S2 n,As不发生氧化。当氧化电位提高到0.3 V(氧化峰A2电位范围),大量的Cu离开矿物表面进入溶液,表面仍然不存在Cu(Ⅱ)的氧化相,可能存在少量的CuSO4,但处于检测下限,表面存在一定量的Sn^2-,不存在As的氧化相。当电位提高到0.5 V(氧化峰A2电位范围),发生Cu和As的氧化沉积过程,分别在矿物表面形成Cu(Ⅱ)氧化相(Cu(OH)2,CuSO4)和As2O3氧化相。此外,表面还存在一定的Sn^2-相。当电位提高到0.8V(氧化峰A3电位范围),表面形成一定量的Cu(Ⅱ)氧化相(Cu(OH)2和CuSO4),As仍然以As2O3的形式存在,S除形成CuSO4外,部分仍以Sn^2-的形式存在。The electrochemical oxidation process of enargite in solution at pH=9.2,and influence of potential on the chemical composition of surface phase were studied by cyclic voltammetry(CV)and X-ray photoelectron spectroscopy(XPS).The results show that the primary oxidation process relates to the formation of copper-deficient(Cu3-xAsS4)sulfide induced by the dissolution of partial Cu into solution mainly occurs on enargite at the oxidation potential of 0.17 V(in the potential range of oxidation peak A1),and these is no Cu(Ⅱ)oxidation products existed in the surface film of enargite.A small amount of Sn^2-forms through the S oxidation,and the As oxidation do not occur.When the oxidation potential increases to 0.3V(in the potential range of oxidation peak A2),plenty of Cu left the surface of sample and dissolves into solution.There are still no existence of the oxidation products of Cu(Ⅱ).A small amount of CuSO4 might exist,but its content is below low limit of detection.The Sn phase is present in the surface film,but there are no existence of the oxidation products of As.The oxidation and deposition processes of Cu and As occur at the oxidation potential of 0.5 V(in the potential range of oxidation peak A2),and it results in the formation of the Cu(Ⅱ)oxidation products(Cu(OH)2 and CuSO4)and As2O3.Additionally,some Sn phase is still present in the surface film.A certain amount of Cu(Ⅱ)oxidation product of Cu(OH)2 and CuSO4,are formed on sample when the oxidation potential increases to 0.8V(in the potential range of oxidation peak A3).The As element is still present in the form of As2O3 and parts of S element exists in the form of Sn^2-besides some S element is oxidized to CuSO4.

关 键 词：电化学氧化 硫砷铜矿 亲水相 疏水相 XPS 

分 类 号：TD91[矿业工程—选矿]