Secondary Minerals of Weathered Orpiment-Realgar-Bearing Tailings in Shimen Carbonate-Type Realgar Mine,Changde, Central China  

作　　者：ZHU Xiangyu WANG Rucheng LU Xiancai 

机构地区：[1]State Key Laboratory for Mineral Deposit Research,School of Earth Sciences and Engineering,Nanjing University

出　　处：《矿物学报》2013年第S1期147-147,共1页Acta Mineralogica Sinica

摘　　要：Formation and dissolution of secondary arsenic minerals often play significant roles in controlling arsenic mobility in contaminated environments, especially in sulfide mines. Weathering of the orpiment and realgar-bearing tailings from the Shimen realgar deposit, the largest realgar deposit in Asia, were studied. An integrated mineralogical analysis by using X-ray powder diffraction (XRD), Raman spectrum, scanning electron microscope (SEM) and transmission electron microscope (TEM) reveals four kinds of As-bearing secondary minerals including arsenic oxides, arsenates, As-gypsum, and As-Fe minerals. The precipitation of arsenates is due to interaction of As-bearing run-off waters and the underlying carbonate rocks, or the transformation of gypsum into arsenates or As-bearing gypsum through SO42-/HAsO42- substitution. Ca-arsenates are mainly weilite and pharmacolite with Ca/As atomic ratio of 1. Scanning transmission X-ray microscope (STXM) and X-ray absorption fine structure (XAFS) reveal that the valence of arsenic is mainly +3 and +5.Formation and dissolution of secondary arsenic minerals often play significant roles in controlling arsenic mobility in contaminated environments, especially in sulfide mines. Weathering of the orpiment and realgar-bearing tailings from the Shimen realgar deposit, the largest realgar deposit in Asia, were studied. An integrated mineralogical analysis by using X-ray powder diffraction (XRD), Raman spectrum, scanning electron microscope (SEM) and transmission electron microscope (TEM) reveals four kinds of As-bearing secondary minerals including arsenic oxides, arsenates, As-gypsum, and As-Fe minerals. The precipitation of arsenates is due to interaction of As-bearing run-off waters and the underlying carbonate rocks, or the transformation of gypsum into arsenates or As-bearing gypsum through SO42-/HAsO42- substitution. Ca-arsenates are mainly weilite and pharmacolite with Ca/As atomic ratio of 1. Scanning transmission X-ray microscope (STXM) and X-ray absorption fine structure (XAFS) reveal that the valence of arsenic is mainly +3 and +5.

关 键 词：WEATHERING ARSENIC TAILINGS secondary ARSENIC minerals Shimen REALGAR deposits 

分 类 号：TD926.4[矿业工程—选矿]