Aluminium sulfate synergistic electrokinetic separation of soluble components from phosphorus slag and simultaneous stabilization of fluoride

Bangjin Chen; Hailin Li; Guangfei Qu; Jieqian Yang; Caiyue Jin; Fenghui Wu; Yuanchuan Ren; Ye Liu; Xinxin Liu; Jin Qin; Lingrui Kuang

doi:10.1016/j.jenvman.2022.116942

Aluminium sulfate synergistic electrokinetic separation of soluble components from phosphorus slag and simultaneous stabilization of fluoride

J Environ Manage. 2023 Feb 15:328:116942. doi: 10.1016/j.jenvman.2022.116942. Epub 2022 Dec 7.

Authors

Bangjin Chen¹, Hailin Li¹, Guangfei Qu², Jieqian Yang¹, Caiyue Jin¹, Fenghui Wu¹, Yuanchuan Ren¹, Ye Liu¹, Xinxin Liu¹, Jin Qin¹, Lingrui Kuang¹

Affiliations

¹ Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, Kunming, 650500, Yunnan, China; National-Regional Engineering Research Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming, 650500, Yunnan, China.
² Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Yunnan, Kunming, 650500, Yunnan, China; National-Regional Engineering Research Center for Recovery of Waste Gases from Metallurgical and Chemical Industries, Kunming, 650500, Yunnan, China. Electronic address: qgflab@sina.com.

PMID: 36495822
DOI: 10.1016/j.jenvman.2022.116942

Abstract

In this study, fluoride (F) was stabilized and soluble components, namely phosphate (P), K, Ca, Cr, Mn, and Pb, were extracted from phosphorus slag (PS) by using aluminum sulfate (AS) synergistic electrokinetic. PHREEQC simulation was used to determine the occurrence form of each ion in the PS. The mechanisms by which various electrokinetic treatment methods affected conductivity and pH distribution were carefully investigated. Electrokinetic treatment increased P concentration of the anode chamber from 22.7 mg/L to 63.39 mg/L, whereas K concentration increased from 15.26 mg/L to 93.44 mg/L. After AS-enhanced electrokinetic treatments, the concentrations of the different components were as follows: P, 131.66 mg/L; K, 198.2 mg/L; and Ca, 331.3 mg/L. The removal rate of soluble P in PS slices increased to 80.88% by 1.5 V/cm of treatment, and it increased to 94.04% after AS enhancement treatment. For water-soluble F, the removal rate from the PS slices in the anode region was 86.03%, decreasing F concentration in the electrode chamber to 9.57 × 10^-3 mg/L. Different extraction efficiencies and stability levels of each component in the PS were regulated at various electrode regions by using different processes such as electromigration, electro-osmotic flow, flocculation, and precipitation. Good results can be obtained if fluoride is solidified concurrently with the removal or recovery of P, K, Ca, and other elements using 2%-4% AS enhanced electrokinetic treatment. Furthermore, CaSO₄·2H₂O whiskers were produced in the electrode regions when AS content was 6%. The findings of this study indicated that the AS synergistic electrokinetic method is suitable for stabilizing F and removing heavy metals from PS, thus providing a promising technology for recycling valuable components such as P, K, Ca, and Sr and for the simultaneous production of CaSO₄·2H₂O whiskers. This study provides insights for developing novel technologies for the clean treatment and high-value utilization of PS.

Keywords: Aluminum sulfate; Electrokinetic treatment; Fluoride; Phosphate; Phosphorus slag.

MeSH terms

Alum Compounds
Aluminum
Fluorides*
Phosphorus*

Substances

Fluorides
Phosphorus
Aluminum
aluminum sulfate
Alum Compounds