A Robust Recovery of Ni From Laterite Ore Promoted by Sodium Thiosulfate Through Hydrogen-Thermal Reduction

Shoujun Liu; Chao Yang; Song Yang; Zhongliang Yu; Zhao Wang; Kang Yan; Jin Li; Xingyang Liu

doi:10.3389/fchem.2021.704012

A Robust Recovery of Ni From Laterite Ore Promoted by Sodium Thiosulfate Through Hydrogen-Thermal Reduction

Front Chem. 2021 Jun 25:9:704012. doi: 10.3389/fchem.2021.704012. eCollection 2021.

Authors

Shoujun Liu^{1

2

3}, Chao Yang^{2

3}, Song Yang^{1

2}, Zhongliang Yu^{2

4}, Zhao Wang^{1

2}, Kang Yan^{1

2}, Jin Li^{2

5}, Xingyang Liu^{1

2}

Affiliations

¹ College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, China.
² Shanxi Engineering Center of Civil Clean Fuel, Taiyuan University of Technology, Taiyuan, China.
³ Key Laboratory for Coal Science and Technology of Ministry of Education and Shanxi Province, Taiyuan University of Technology, Taiyuan, China.
⁴ School of Chemistry and Environmental Science, Shangrao Normal University, Shangrao, China.
⁵ Taiyuan Green Coke Energy Co. Ltd., Taiyuan, China.

Abstract

Laterite ore is one of the important sources of nickel (Ni). However, it is difficult to liberate Ni from ore structure during reduction roasting. This paper provided an effective way for a robust recovery of Ni from laterite ore by H₂ reduction using sodium thiosulfate (Na₂S₂O₃) as a promoter. . It was found that a Ni content of 9.97% and a Ni recovery of 99.24% were achieved with 20 wt% Na₂S₂O₃ at 1,100°C. The promoting mechanism of Na₂S₂O₃ in laterite ore reduction by H₂ was also investigated. The thermogravimetric results suggested the formation of Na₂Mg₂SiO₇, Na₂SO₃, Na₂SO₄, and S during the pyrolysis of laterite with Na₂S₂O₃, among which the alkali metal salts could destroy the structures of nickel-bearing silicate minerals and hence release Ni, while S could participate in the formation of the low-melting-point eutectic phase of FeS-Fe. The formation of low-melting-point phases were further verified by the morphology analysis, which could improve the aggregation of Ni-Fe particles due to the capillary forces of FeS-Fe as well as the enhanced element migration by the liquid phase of sodium silicates during reduction.

Keywords: ferronickel; hydrogen reduction; laterite ore; magnetic separation; mechanism; sodium thiosulfate.