Utilisation of steel slags as neutralising agents in biooxidation of a refractory gold concentrate and their influence on the subsequent cyanidation

► Steel slags utilised for neutralisation in biooxidation of refractory gold concentrates. ► Good microbial sulphide oxidation irrespective of neutralising agent used. ► High Au recovery from bioresidues with all neutralising agents. ► NaCN consumption was 2-3 times higher for steel slags compared with Ca(OH)2. ► Ladle slag is a possible substitute for limestone in biooxidation processes.