Significance of acid washing after biooxidation of sulfides in sequential biotreatment of double refractory gold ore from the syama mine, mali

Cindy, Ryotaro Sakai, Diego M. Mendoza, Kojo T. Konadu, Keiko Sasaki

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1 Citation (Scopus)

Abstract

Environmentally friendly pretreatment of double refractory gold ores (DRGO) to improve gold recovery without emitting pollutant gas is challenging. Sequential biotreatment, including iron‐oxidizing microorganisms to decompose sulfides, followed by the enzymatic decomposition of carbonaceous matter, was recently developed. The effect of acid washing by 1 M HCl for 24 h between two bioprocesses was evaluated using a real double refractory gold ore from the Syama mines, Mali, which includes 24 g/t of Au and 5.27 wt % of carbon with a relatively higher graphitic degree. The addition of the acid washing process significantly improved gold recovery by cyanida-tion to yield to 84.9 ± 0.7% from 64.4 ± 9.2% (n = 2). The positive effects of acid washing can be explained by chemical alteration of carbonaceous matter to facilitate the accessibility for lignin pe-roxidase (LiP) and manganese peroxidase (MnP) in cell‐free spent medium (CFSM), although the agglomeration was enhanced by an acid attack to structural Fe(III) in clay minerals. Sequential treatment of DRGO basically consists of the oxidative dissolution of sulfides and the degradation of carbonaceous matter prior to the extraction of gold; however, the details should be modified de-pending on the elemental and mineralogical compositions and the graphitic degree of carbonaceous matter.

Original languageEnglish
Article number1316
JournalMinerals
Volume11
Issue number12
DOIs
Publication statusPublished - Dec 2021

All Science Journal Classification (ASJC) codes

  • Geotechnical Engineering and Engineering Geology
  • Geology

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