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Evaluation of oxidic by-products as Neutralizing agents in Biooxidation of a Refractory Gold concentrate and their influence on Gold extraction through Cyanidation

Author Affiliations

  • 1 Minerals and Metals Research Laboratory, MiMeR, Division of Sustainable Process Engineering, Luleå University of Technology, SE-971 87 Luleå, SWEDEN
  • 2Boliden Mineral AB, SE-936 81, Boliden, SWEDEN
  • 3 Department of Mining Engineering, Mineral Processing Division (Mineral-Metal Recovery and Recycling Research Group), Suleyman Demirel University, TR32260, Isparta, TURKEY

Res. J. Recent Sci., Volume 2, Issue (11), Pages 29-34, November,2 (2013)


The neutralization cost in bioleaching operations is one of the biggest operation costs and therefore the aim of the present study has been to replace the generally used lime/limestone with industrial oxidic by-products. A comparative study on the potential use of some selected industrial by-products as neutralizing agents during biooxidation and their influence on subsequent gold recovery was carried out with reference to a commercial grade Ca(OH)2. The by-products used comprised of an electric arc furnace slag (EAF slag), and a slag from ladle refining (Ladle slag) both from scrap based steel production, an EAF dust and a lime sludge from paper and pulp industry (Mesa lime). Continuous biooxidation of a refractory gold concentrate was performed in single stage reactor at a retention time of 56 h with a mixed mesophilic culture. Biooxidation results as well as gold recoveries were good for all by-products investigated and similar to the results obtained with the slaked lime reference. However, cyanide consumption was elevated in the experiments with steel slags and the EAF dust partly because of a higher content of S° in the bioresidues in these experiments. It is however expected, that in a bioleaching operation with several reactors in series, that sulfur oxidation would be more complete, thereby possibly decreasing cyanide consumption.


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