Study on physicochemical characteristics, solidification and utilisation of tannery sludge gasification ash

Weiwei Zhang; Youqing Wu; Sheng Huang; Shiyong Wu; Jinsheng Gao

doi:10.1016/j.jenvman.2022.114584

Study on physicochemical characteristics, solidification and utilisation of tannery sludge gasification ash

J Environ Manage. 2022 May 15:310:114584. doi: 10.1016/j.jenvman.2022.114584. Epub 2022 Feb 19.

Authors

Weiwei Zhang¹, Youqing Wu², Sheng Huang³, Shiyong Wu³, Jinsheng Gao³

Affiliations

¹ Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai, 200237, China.
² Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Engineering Research Center of Coal Gasification, East China University of Science and Technology, Shanghai, 200237, China. Electronic address: wyq@ecust.edu.cn.
³ Department of Chemical Engineering for Energy Resources, East China University of Science and Technology, Shanghai, 200237, China; Shanghai Engineering Research Center of Coal Gasification, East China University of Science and Technology, Shanghai, 200237, China.

PMID: 35192982
DOI: 10.1016/j.jenvman.2022.114584

Abstract

Gasification is an attractive method for tannery sludge (TS) disposal because of its advantages: volume reduction, stabilisation, harmlessness, and energy recovery. TS reduction ash (A_R) and TS oxidation ash (A_O), simulated from a downdraft fixed bed gasifier (DFBG) and an updraft fixed bed gasifier (UFBG), were investigated on their physicochemical characteristics, solidification behaviour, and value-added utilisation. Results showed that the main mineral matters in A_R and A_O consisted of Fe-oxids and Fe-Cr compounds, and the DFBG was more suitable for TS gasification than the UFBG because of the lower content of Cr(Ⅵ) in A_R. With the addition of waste glass bottles (W_GB), the ash fusion temperatures (AFTs) and leaching concentrations of heavy metals in A_R and A_O decreased significantly, and the heavy metals in A_R and A_O were successfully immobilised by the wrapping effect of the molten W_GB. Moreover, gasification ash, as an auxiliary material for rock wool, reduced the AFTs and viscosity coefficient of the main chemical compositions in rock wool. With the addition of A_R, the occurrence of Fe-containing compounds and the extremely low risk of leaching toxicity of heavy metals were observed. The maximum addition proportion of gasification ash was dependent on the maximum content of Fe₂O₃ allowed in the raw materials of rock wool, and its addition ratio must be below 15%.

Keywords: Physicochemical characteristics; Rock wool; Solidification; Tannery sludge gasification ash; Value-added utilisation; Wrapping effect.

MeSH terms

Coal Ash
Incineration
Metals, Heavy*
Sewage* / chemistry
Temperature

Substances

Coal Ash
Metals, Heavy
Sewage