不同水环境条件下辉锑矿的溶解及其产物中锑的形态分布  

Dissolution of Stibnite and Morphological Distribution of Antimony in Its Products under Different Aqueous Conditions

作　　者：李鑫[1] 郭清海[1] 赵倩 Li Xin;Guo Qinghai;Zhao Qian(School of Environmental Studies,China University of Geosciences,Wuhan 430078,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430078

出　　处：《地球科学》2024年第11期4022-4034,共13页Earth Science

基　　金：国家自然科学基金项目(Nos.42077278,42277188).

摘　　要：辉锑矿(Sb2S3)的溶解是水环境中锑的重要来源,水中溶解态锑的毒性、迁移性及生物可利用性与其形态密切相关,但当前学界对辉锑矿溶解产物中锑的形态分布的认识并不一致,对于其中锑的特殊形态——硫代锑酸盐的认识的争议尤为突出.鉴于此,我们在不同水环境条件下系统研究了辉锑矿的溶解过程及其对硫代锑酸盐形成的影响,以期为准确评价辉锑矿溶解的环境效应提供依据.结果表明:单一辉锑矿在酸性‒弱碱性条件下的溶解不能形成硫代锑酸盐,在碱性条件下则可形成三硫代锑酸盐和四硫代锑酸盐;在反应系统中总锑含量与天然水中总锑含量相当的情况下,辉锑矿的溶解不可能形成硫代锑酸盐的多聚物.此外,不同类型还原态硫或适量雌黄的共存以及水中离子强度的增加均可促进硫代锑酸盐的形成,过量的雌黄则会抑制其形成.水中S(-II)/Sb摩尔比是控制硫代锑酸盐形成的重要因素.在考察天然水环境中辉锑矿淋滤的环境影响以及淋滤过程中硫代锑酸盐的形成潜力时,S(-II)/Sb摩尔比是应重点参考的关键指标.The dissolution of stibnite(Sb2S3)is an important source of antimony in the aqueous environment,and the toxicity,mobility and bioavailability of dissolved antimony in water are closely related to its morphology,but the current understanding of the morphological distribution of antimony in the dissolution products of stibnite is not consistent,and the understanding of the particular form of antimony,thioantimonate,is particularly controversial.In this context,it systematically investigated the dissolution process of stibnite and its effect on the formation of thioantimonate under different aqueous conditions,to provide a basis for the accurate evaluation of the environmental effects of stibnite dissolution.The results show that the dissolution of stibnite under acidic-weak alkaline conditions does not lead to the formation of thioantimonate,while under alkaline conditions trithioantimonate and tetrathioantimonate can be formed;the dissolution of stibnite is unlikely to lead to the formation of poly-thioantimonate when the initial total antimony content in the reaction system is comparable to that in natural water.In addition,the coexistence of different types of reduced sulfur or moderate amounts of orpiment and an increase in the ionic strength of the water can promote the formation of thioantimonate,which is inhibited by excess orpiment.The S(-II)/Sb molar ratio in water is an important factor in controlling the formation of thioantimonate;the S(-II)/Sb molar ratio is a key indicator to be considered when examining the environmental impact of stibnite leaching in natural water environments and the potential for thioantimonate formation during leaching.

关 键 词：水环境 辉锑矿 形态分布 硫代锑酸盐 环境效应 环境地质 水文地质. 

分 类 号：P64[天文地球—地质矿产勘探]