Biotechnological Approaches to Facilitate Gold Recovery from Double Refractory Gold Ores

Keiko Sasaki and Kojo T. Konadu

A chapter in Heavy Metals - Their Environmental Impacts and Mitigation from IntechOpen

Abstract: Double refractory gold ore (DRGO) not only include ppt levels of gold grains locked in sulfide minerals but also a problematic amount of carbonaceous matter. This causes a significant recovery loss of gold during cyanidation because of the strong affinity of the Au(CN)2- with the carbonaceous matter. Combustion decreases the carbonaceous matter content, but also emits pollutant gases like CO2, SO2 and As2O3. Therefore, environmentally-friendly solutions have been explored by using biotechnology. Due to the very small amount of the above targets in the ore, it is challenging to show evidential changes in solid-phase before and after the biomineral processing of DRGO. This chapter introduces the mineralogical and chemical changes in the various solid residues produced during a sequential biotreatment, consisting of the liberation of gold from sulfides by an iron-oxidizer and decomposition of carbonaceous matter by lignin-degrading enzymes (lignin peroxidase, manganese peroxidase, laccase) secreted from a white rot-fungus, which successfully improved of gold recovery to over 90%. In addition, further development of biotechnology in the recovery of gold from DRGO is addressed.

Keywords: double refractory gold ore; carbonaceous matter; enzyme reaction; QEMSCAN map; biooxidation of sulfides (search for similar items in EconPapers)
JEL-codes: Q55 (search for similar items in EconPapers)
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Persistent link: https://EconPapers.repec.org/RePEc:ito:pchaps:218327

DOI: 10.5772/intechopen.94334

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