Abstract
A two-step process, which involved ferric leaching with biologically generated solution and subsequent biooxidation with the microbial community, has been previously proposed for the processing of low-grade zinc sulfide concentrates. In this study, we carried out the process of complete biological oxidation of the product of ferric leaching of the zinc concentrate, which contained 9% of sphalerite, 5% of chalcopyrite, and 29.7% of elemental sulfur. After 21 days of biooxidation at 40 °C, sphalerite and chalcopyrite oxidation reached 99 and 69%, respectively, while the level of elemental sulfur oxidation was 97%. The biooxidation residue could be considered a waste product that is inert under aerobic conditions. The results of this study showed that zinc sulfide concentrate processing using a two-step treatment is efficient and promising. The microbial community, which developed during biooxidation, was dominated by Acidithiobacillus caldus, Leptospirillum ferriphilum, Ferroplasma acidiphilum, Sulfobacillus thermotolerans, S. thermosulfidooxidans, and Cuniculiplasma sp. At the same time, F. acidiphilum and A. caldus played crucial roles in the oxidation of sulfide minerals and elemental sulfur, respectively. The addition of L. ferriphilum to A. caldus during biooxidation of the ferric leach product proved to inhibit elemental sulfur oxidation.
Highlights
At present, zinc is one of the main non-ferrous metals and is currently the fourth most widely consumed metal after iron, aluminum, and copper [1]
We proposed biooxidation of these leach products by a community of acidophilic chemolithotrophic microorganisms to increase the level of metal recovery from the concentrate and to produce relatively inert waste with a minimum content of toxic elements
The final oxidation levels of sphalerite and chalcopyrite were 99 and 69%, respectively, which indicates the effectiveness of a two-step process for processing low-grade zinc concentrates;
Summary
Zinc is one of the main non-ferrous metals and is currently the fourth most widely consumed metal after iron, aluminum, and copper [1]. Zinc sulfide ores are the main source of zinc metal production and more than 85% of the world’s zinc is produced from zinc sulfide concentrates using the roast–leach–electrowinning process [1,4]. Low-grade monometallic sulfide concentrates (zinc concentrates with relatively high copper content and copper concentrates with relatively high zinc content) are produced at numerous concentrators. This results in the losses of non-ferrous metals in slag during the pyrometallurgical processing of sulfide concentrates and creates technological difficulties at various stages of the metal production process. Technologies based on biooxidation of sulfides may be promising for the processing of the low-grade concentrates of non-ferrous metals, including polymetallic ones
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
