Mercury species and potential leaching in sludge from coal-fired power plants

Lin Chang; Yongchun Zhao; Yi Zhang; Xuehai Yu; Zenghua Li; Bengen Gong; Huan Liu; Shuzhou Wei; Hao Wu; Junying Zhang

doi:10.1016/j.jhazmat.2020.123927

Mercury species and potential leaching in sludge from coal-fired power plants

J Hazard Mater. 2021 Feb 5:403:123927. doi: 10.1016/j.jhazmat.2020.123927. Epub 2020 Sep 15.

Authors

Lin Chang¹, Yongchun Zhao², Yi Zhang³, Xuehai Yu³, Zenghua Li⁴, Bengen Gong⁴, Huan Liu⁴, Shuzhou Wei⁵, Hao Wu⁶, Junying Zhang⁷

Affiliations

¹ State Key Lab of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China; Shenhua Guohua (Beijing) Electric Power Research Institute Co. Ltd., Beijing 100018, China.
² State Key Lab of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address: yczhao@hust.edu.cn.
³ Shenhua Guohua (Beijing) Electric Power Research Institute Co. Ltd., Beijing 100018, China.
⁴ State Key Lab of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China.
⁵ Sanhe Power Plant Co., Ltd., Hebei, Lanfang 065201, China.
⁶ Guangzhou Hengyun Enterprises Holdings Limited, Guangzhou 510730, China.
⁷ State Key Lab of Coal Combustion, School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address: jyzhang@hust.edu.cn.

PMID: 33264977
DOI: 10.1016/j.jhazmat.2020.123927

Abstract

Wet flue gas desulfurization (WFGD) sludge, generated from the WFGD effluent treatment process, is suitable for multiple uses in various industries. However, risk assessments of its utilization are limited. Systematic study of Hg species occurrences, partitioning and risks of leaching is required, and these concerns were addressed in the present study. Hg temperature-programmed decomposition (Hg-TPD) and an improved European Community Bureau of Reference (BCR) method indicated residual Hg in WFGD sludge was related to HgS, and the content of this fraction was from 2 to 3%. HgCl₂, HgO and HgSO₄ were assigned to the water/acid-soluble fractions, and reducible Hg was related to Fe species in the sludge. Leachate evaluation of the WFGD sludge indicated potentially high Hg leaching risk. WFGD sludge with higher Hg concentrations and smaller particulate diameters exhibited greater leaching potential. Leaching of Hg from WFGD sludge in China into the environment was estimated at 7.46 t/yr.

Keywords: Leaching; Mercury species; Thermal stability; WFGD sludge.

Publication types

Research Support, Non-U.S. Gov't