Process flowsheet development for recovering antimony from Sb-bearing copper concentrates

• Published in: Minerals engineering 2013-08, Vol.49, p.45-53
• Main Authors: Awe, Samuel A., Sundkvist, Jan-Eric, Bolin, Nils-Johan, Sandström, Åke
• Format: Article
• Language: English
• Subjects: Alkaline sulphide electrolyte; Antimony; Antimony cathode; Cathodes; Concentrates; Copper; Current density; Current efficiency; Electrowinning; Leaching; Process flowsheet; Process Metallurgy; Processmetallurgi; Selective leaching; Sulfides; Tetrahedrite
• ISSN: 0892-6875; 1872-9444; 1872-9444
• DOI: 10.1016/j.mineng.2013.04.026

•A hydro-/electrometallurgical process flowsheet for recovering antimony from copper concentrates was developed.•Excessive sodium sulphide concentration facilitates antimony leaching but it is detrimental to the electrolytic process.•Increase in sodium hydroxide promotes antimony electrowinning.•Antimony content of the copper concentrate was reduced from 1.7% to less than 0.1%.•Increase in temperature enhances both leaching and electrolytic process. The technical feasibility, on laboratory scale, of hydro- and electrometallurgical processes of recovering metallic antimony from an antimony-bearing copper sulphide concentrate has been investigated. The influence of Na2S concentration, temperature and solid concentration was studied during the leaching test while the effect of current density, Na2S concentration, electrolyte temperature and NaOH concentration on antimony electrowinning from alkaline sulphide solutions was investigated. The leaching results showed that antimony dissolution is strongly dependent on the concentration of the leaching reagent as well as the leaching temperature. The antimony content in the concentrate was reduced from 1.7% to less than 0.1% Sb which is desirable for copper metallurgy. Cathode current efficiency is one of the important parameters to evaluate the performance of an electrolytic process. It is revealed in this study that current efficiency of antimony deposition from sulphide electrolytes is highly dependent on the concentration of sodium hydroxide and the current density used. The results illustrate that the combined effect of increasing anode current density (which was 10times higher than the cathode current density) and NaOH concentration enhanced the current efficiency of the electrolytic process. It was demonstrated that excess free sulphide ions impacts the current efficiency of the process detrimentally. An integrated hydro-/electrometallurgical process flowsheet for antimony removal and recovery from a sulphide copper concentrate was developed.