Clean antimony production from stibnite concentrate with goethite residue co-treatment for zinc, iron, sulfur conservation

Abstract

In view of the issues of low efficiency and environmental pollution existing in current antimony production, this work proposes an innovative and cleaner process to extract antimony from stibnite concentrate and co-treat goethite residues. The mechanisms of antimony extraction and zinc, iron, sulfur conservation was thermodynamically and experimentally investigated. The results show that iron- and zinc-bearing components in the goethite residue firstly reacted and releasing FexOy and ZnO, then stibnite (Sb2S3) quickly converted to senarmontite (Sb2O3) in the presence of FexOy and ZnO. Intermediate Sb2O3 was subsequently reduced to metallic Sb. Bench-scale experiments of antimony extraction from stibnite concentrate with goethite residue as sulfur-fixing agent validated that 85.7% of Sb was directly recovered as crude antimony bullion, only around 7.4% antimony volatilized to fume. Pb, As, Au, and Ag tended to also be co-enriched in the bullion. 97.4% of sulfur, 88.8% of zinc and 86.1% of iron were recovered and fixed simultaneously. Sulfur in Sb2S3, iron and zinc contained in goethite residues was conserved in matte as marketable Fe2Zn3S5, FeS, and ZnS, instead of forming gaseous SO2. This novel process is a promising recycling and co-treatment alternative for various secondary iron- and zinc-containing materials.