A green process for the conversion of hazardous sintering dust into K2SO4 and NH4Cl fertilizers

Qiren Wang; Xin Ma; Shuai Wang; Zhanfang Cao; Zongwei Hua; Hong Zhong

doi:10.1016/j.jenvman.2022.116676

A green process for the conversion of hazardous sintering dust into K₂SO₄ and NH₄Cl fertilizers

J Environ Manage. 2023 Jan 15;326(Pt A):116676. doi: 10.1016/j.jenvman.2022.116676. Epub 2022 Nov 9.

Authors

Qiren Wang¹, Xin Ma², Shuai Wang¹, Zhanfang Cao¹, Zongwei Hua¹, Hong Zhong³

Affiliations

¹ Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, And College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan, China.
² Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, And College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan, China. Electronic address: maxin2013@csu.edu.cn.
³ Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, And College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, Hunan, China. Electronic address: zhongh@csu.edu.cn.

PMID: 36368205
DOI: 10.1016/j.jenvman.2022.116676

Abstract

Sintering dust from the steelmaking industry is a hazardous waste that is rich in valuable metals. The purpose with the present study has been to design an efficient process for the preparation of K₂SO₄ and NH₄Cl fertilizers by using sintering dust as raw material. The K, S, and Cl in the sintering dust were selectively and efficiently leached using water. The leaching of Ca impurities was then greatly reduced and the appearance of Zn and Mg was avoided. The Cl^- ions in the leachate were, thereafter, adsorbed by a 201 × 7 resin to form a K₂SO₄ solution. Finally, the loaded Cl^- on the resin was desorbed to form a NH₄Cl solution, and the resin was regenerated and recycled. The purified solutions were crystallized to prepare K₂SO₄(s) and NH₄Cl(s) products, which met the national standard of China for superior potassium sulfate and ammonium chloride, to be used for agricultural use. The recoveries of K, Cl, and S from the sintering dust were 80.78%, 92.63%, and 93.92%, respectively. Notably, the Mn content in the leaching residue increased from 9.08% to 14.19%. This could be used for the conversion of Mn impurities into recyclable manganese-rich raw materials. This green process enables an effective extraction of important impurities in hazardous sintering dust, thereby providing a new potassium source for potash fertilizer manufacturing with notable economic and environmental benefits.

Keywords: Ion exchange; K(2)SO(4) fertilizer; NH(4)Cl fertilizer; Sintering dust; Water leaching.

MeSH terms

Dust*
Fertilizers*
Potassium / chemistry
Sulfates

Substances

Fertilizers
potassium sulfate
Dust
Sulfates
Potassium