Bioleaching of acid-consuming low-grade nickel ore with elemental sulfur addition and subsequent acid generation
✍ Scribed by Virpi LA Salo-Zieman; Päivi H-M Kinnunen; Jaakko A Puhakka
- Publisher
- Wiley (John Wiley & Sons)
- Year
- 2005
- Tongue
- English
- Weight
- 165 KB
- Volume
- 81
- Category
- Article
- ISSN
- 0268-2575
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✦ Synopsis
Abstract
The bioleaching of a nickel concentrate and an acid‐consuming nickel ore was studied using a co‐culture of Acidithiobacillus ferrooxidans and A. thiooxidans, as well as a thermophilic enrichment culture, VS2. The VS2 was dominated by a Sulfolobus species related to Sulfolobus metallicus. Nickel concentrate was readily solubilized with A. ferrooxidans and the VS2, resulting in nickel yields of 56% and 100%, respectively. Low‐grade nickel ore required 350 g H~2~SO~4~ kg^−1^ ore for maintaining the pH of the leaching solution below 3. To overcome the high acid demand, biological elemental sulfur oxidation was combined with the ore leaching. Leaching of a 2% (wt/vol) nickel ore with a co‐culture of A. thiooxidans and A. ferrooxidans resulted in nickel yield of up to 86% with acid supplementation of 290 g H~2~SO~4~ kg^−1^ ore. When coupled with biological sulfur oxidation, an 86% nickel recovery was achieved with 0.5% (wt/vol) ore concentration without further sulfuric acid addition. The VS2 oxidized sulfur at a rate of 0.063 g L^−1^ d^−1^ and the simultaneous nickel ore leaching resulted in 100% nickel yield. In summary, the potential of using elemental sulfur addition and subsequent biological acid generation to maintain the low pH during bioleaching of an acid‐consuming nickel ore was demonstrated. Copyright © 2005 Society of Chemical Industry