Emission-to-ash detoxification mechanisms of co-combustion of spent pot lining and pulverized coal

Zihong Chen; Jingyong Liu; Laiguo Chen; Fatih Evrendilek; Wuming Xie; Xieyuan Wu; Jinwen Hu; Weixin Li

doi:10.1016/j.jhazmat.2021.126380

Emission-to-ash detoxification mechanisms of co-combustion of spent pot lining and pulverized coal

J Hazard Mater. 2021 Sep 15:418:126380. doi: 10.1016/j.jhazmat.2021.126380. Epub 2021 Jun 11.

Authors

Zihong Chen¹, Jingyong Liu², Laiguo Chen³, Fatih Evrendilek⁴, Wuming Xie¹, Xieyuan Wu¹, Jinwen Hu¹, Weixin Li⁵

Affiliations

¹ School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
² School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China. Electronic address: Liujy@gdut.edu.cn.
³ State Environmental Protection Key Laboratory of Urban Ecological Environment Simulation and Protection, South China Institute of Environmental Sciences, Ministry of Ecology and Environment of the People's Republic of China, Guangzhou 510655, China.
⁴ Department of Environmental Engineering, Bolu Abant Izzet Baysal University, Bolu 14052, Turkey.
⁵ Guangdong Provincial Key Laboratory of Radioactive and Rare Resource Utilization, Guangdong Provincial Institute of Mining Applications, Shaoguan 512026, China.

PMID: 34329026
DOI: 10.1016/j.jhazmat.2021.126380

Abstract

In response to the global initiative for greenhouse gas emission reduction, the co-combustion of coal and spent pot lining (SPL) may cost-effectively minimize waste streams and environmental risks. This study aimed to quantify the emission-to-ash detoxification mechanisms of the co-combustion of SPL and pulverized coal (PC) and their kinetics, gas emission, fluorine-leaching toxicity, mineral phases, and migrations. The main reaction covered the ranges of 335-540 °C and 540-870 °C while the interactions occurred at 360-780 °C. The apparent activation energy minimized (66.99 kJ/mol) with 90% PC addition. The rising PC fraction weakened the peak intensity of NaF and strengthened that of Ca₂F, NaAlSiO₄, and NaAlSi₂O₆. The addition of PC enhanced the combustion efficiency of SPL and raised the melting temperature by capturing Na. PC exhibited a positive effect on solidifying water-soluble fluorine and stabilizing alkali and alkaline earth metals. The leaching fluorine concentrations of the co-combustion ashes were lower than did SPL mono-combustion. The main gases emitted were HF, NH₃, NO_x, CO, and CO₂. HF was largely released at above 800 °C. Multivariate Gaussian process model-based optimization of the operational conditions also verified the gas emissions results. Our study synchronizes the utilization and detoxification of SPL though co-combustion and provides insights into an eco-friendlier life-cycle control on the waste-to-energy conversion.

Keywords: Evolved gases; Fluorine; Kinetics; Leaching; Mineral transformations.

Publication types

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

MeSH terms

Coal Ash*
Coal*
Fluorine
Gases
Water

Substances

Coal
Coal Ash
Gases
Water
Fluorine