Enhanced solidification/stabilization (S/S) of fluoride in smelting solid waste-based phosphogypsum cemented paste backfill utilizing biochar: Mechanisms and performance assessment.

Autor: Wang D; School of Resources and Safety Engineering, Central South University, Changsha, 410083, China. Electronic address: daolinw@csu.edu.cn., Tao Y; School of Resources and Safety Engineering, Central South University, Changsha, 410083, China. Electronic address: yunbo.tao@csu.edu.cn., Feng Y; School of Resources and Safety Engineering, Central South University, Changsha, 410083, China. Electronic address: yan.feng@csu.edu.cn., Zhu D; Guizhou Lufa Industrial Co., Guiyang 550300, China. Electronic address: debinzhu0605@163.com., Zhang Q; School of Resources and Safety Engineering, Central South University, Changsha, 410083, China. Electronic address: zhangqinli@126.com., Chen Q; School of Resources and Safety Engineering, Central South University, Changsha, 410083, China. Electronic address: qiusong.chen@csu.edu.cn.
Jazyk: angličtina
Zdroj: Journal of environmental management [J Environ Manage] 2024 Sep; Vol. 367, pp. 122088. Date of Electronic Publication: 2024 Aug 07.
DOI: 10.1016/j.jenvman.2024.122088
Abstrakt: Phosphogypsum (PG) cemented paste backfill (CPB) is a primary non-hazardous method for treating PG. However, using traditional binders like cement increases global carbon emissions and mining operational costs while complicating the reduction of fluoride leaching risks. This study introduces a novel PG-based CPB treatment method using steel slag (SS) and ground granulated blast furnace slag (GGBFS) as binders, calcium oxide as an exciter, with biochar serving as a fluoride-fixing agent. We investigated the effect of biochar addition on the hydration and solidification/stabilization (S/S) of fluoride in SS and GGBFS-PG-based materials (SSPC). The results indicated that the optimal strength and performance for fluoride S/S were achieved with a biochar addition of 0.2 wt%. Compared to the control group without biochar, the strength increased by 54.3%, and F leaching decreased by 39.4% after 28 days of curing for SSPC. The addition of 0.2 wt% biochar facilitated heterogeneous nucleation and acted as a microfiller, enhancing SSPC's properties. However, excessive biochar reduced the compactness of SSPC. Additionally, the distribution of fluoride was strongly correlated with P, Ca, Fe, and Al, suggesting that fluoride S/S is linked to the formation of stable hydration products like fluorapatite, fluorite, and complexes such as [AlF 6 ] 3- and [FeF 6 ] 3- . These findings offer a promising approach for the safe treatment of PG and the beneficial reuse of solid waste from SS and GGBFS.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
Externí odkaz: