LIU Qiyuan1,2,3, CHEN Binghui1,2,3, ZHOU Yongzhang1,2,3, ZOU Qi1, CHEN Ying1, CHENG Yinying1
（1.School of Earth Science and Geological Engineering, Sun Yat-sen University, Guangzhou 510275, China;
2.Guangdong Provincial Key Laboratory of Geological Processes & Mineral Resources Survey，Guangzhou 510275, China;
3.Center for Earth Environment & Resources, Sun Yat-sen University, Guangzhou 510275, China）
Abstract: Acid mine drainage (AMD) is a potential environmental problem. The oxidation of sulfide minerals contributes to the formation of AMD and heavy metal contamination around mine wastes. Secondary minerals produced by the oxidation process play an important role in controlling heavy metal pollution. Therefore, samples collected from four sediments with different colors in Caoduikeng AMD were analyzed and secondary minerals in the AMD were commonly found. The composition of sediments was analyzed by ICP-MS and XRD and the morphology of secondary minerals was characterized by SEM. Our study suggests that secondary minerals are rich and different in various sediment layers and becoming more complex from the uppermost to the lowest layer. They are mainly copiapite, coquimbite and jarosite in the uppermost sediment layer (S1), hotsonite, kornelite,rozenite and jarosite in the ocher sediment (S2), kaatialaite, magnesiocopiapite, botyogen as well as rich lishizhenite in the greyish-green sediment layer(S3), and more jarosite, schwertmannite, halotrichite, melanterite and magnesiocopiapite in the lowest layer. Of the studied secondary minerals, jarosite is the most common mineral that occurs in schistose and rhomb structure, and some of them intergrowth with schwertmannite. Schwertmannite occurs in aggregates as urchin-like, acicular, scaly-like and near spherical rosette. Gypsum is also an abundant mineral that occurs in perfect crystals. The secondary minerals affect the activation of heavy metals in AMD and purify harmful elements to some extent so as to reduce the AMD pollution.
EARTH AND ENVIRONMENT Vol.45, No.3, Tot No.317, 2017, Page 259-266
