Batch Leaching Characteristics of Heavy Metals in FGD Gypsum

WANG Shaojing; WU Xiaoqin; LIU Cheng; YU Zhi

doi:10.3969/j.issn.1003-6504.2017.03.010

Abstract：Leaching experiment is a commonly method in study of the mobility of heavy metals in solid waste.In order to reveal the characteristics of migration of heavy metals such as Cr,As,Ni and Pb in FGD gypsum components,leaching experiments and occurrence mode experiment were conducted on FGD gypsum.The results showed that oxide was the main components in all heavy metal components.Moreover,there was a descending sequence of Pb,As,Cr,and Ni in the sample FA1,and As,Pb,Ni,and Cr in the sample FA2 according to mobility characteristics.The buffer solution of acetic acid and sodium acetate with pH value of 4.0 and 4.5 was selected as leaching solution,and leaching period was seventeen days.The leaching experimental results indicated that leaching rate of every heavy metal component increased with leaching time increasing.Leaching rate of Cr,Ni and Pb component could be increased with pH value of leaching solution decreasing.The occurrence mode of every heavy metal component influenced leaching rate deeply.In leaching solution,Cr,As,Ni,and Pb ions from sample FA1 and Cr,Pb ions from FA2 were out of the standard of surface water environmental quality.So the potential disadvantage of heavy metal components to environment must be considered in the practice utilization of FGD gypsum.