Selective nitridation-corrosion process to recover vanadium, titanium, chromium, and iron from vanadium slag

Qingqing Hu; Shilong Pan; Xudong Gao; Yongjie Liu; Qingyun Huang; Yang You; Zhixiong You; Xuewei Lv

doi:10.1016/j.jenvman.2022.116604

Selective nitridation-corrosion process to recover vanadium, titanium, chromium, and iron from vanadium slag

J Environ Manage. 2023 Jan 1;325(Pt B):116604. doi: 10.1016/j.jenvman.2022.116604. Epub 2022 Oct 27.

Authors

Qingqing Hu¹, Shilong Pan¹, Xudong Gao², Yongjie Liu¹, Qingyun Huang³, Yang You¹, Zhixiong You⁴, Xuewei Lv⁵

Affiliations

¹ College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, PR China.
² College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, PR China; College of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331, PR China.
³ College of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing, 401331, PR China.
⁴ College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, Chongqing, 400044, PR China. Electronic address: youzx@cqu.edu.cn.
⁵ College of Materials Science and Engineering, Chongqing University, Chongqing, 400044, PR China; Chongqing Key Laboratory of Vanadium-Titanium Metallurgy and New Materials, Chongqing University, Chongqing, 400044, PR China.

PMID: 36308966
DOI: 10.1016/j.jenvman.2022.116604

Abstract

Vanadium slag (V-slag) is an important secondary V source, but other valuable elements are discarded in the tailings in industry. Herein, a green nitridation-corrosion process is proposed for the comprehensive recovery of valuable elements (V, Ti, Cr, Fe) from V-slag without producing hazardous waste. Thermodynamic results indicate that ammonia gas (NH₃) can selectively reduce Fe and nitride V, Cr, and Ti. The main phase composition of the nitrided V-slag included metallic Fe, nitrides, and diopside under optimal conditions, and their relative contents were 42.5, 26.2, and 31.3%, respectively, after roasting at 1000 °C for 6 h. The effects of the main parameters on corrosion test were investigated, and the highest weight-gain ratio attained was 19.6%. FeOOH crystallizes on the surface of the nitrided V-slag due to the oxidization of metallic Fe. The phase evolution during the entire process is spinel/olivine/diopside → Fe/nitrides/diopside → FeOOH/nitrides/diopside. Owing to finer particle sizes, most FeOOH is separated by wet sieving (<1400 mesh). The purity of the enriched nitrides attained was 43% after pickling to remove excess Fe. The total recovery rates of Fe, V, Ti, Cr were 87.76%, 95.92%, 92.92%, 92.11%, respectively. This paper provides a sustainable strategy for the comprehensive utilization of V-slag, and guides the cleaner treatment of other similar minerals.

Keywords: Ammonia gas; Corrosion of metallic iron; Enrichment of nitrides; Selective nitridation; Vanadium slag.