Oxygen solubility modelling in ammoniacal leaching solutions: Leaching of sulphide concentrates

Oxygen solubility in ammoniacal solutions of the type used for pressure lea ching of sulphide concentrates has been modelled as a function of oxygen pa rtial pressure, temperature and the conjoint presence of several inorganic solutes. This was achieved by combining oxygen solubility models for pure w ater and single solute solutions with published experimental data for singl e solutes of relevance to sulphide leaching. Differences between the oxygen solubility effects of dissolved molecular ammonia and ammonium salts were noted and analysed. Justification was made for assuming no distinction betw een effects of ammine cations and normal aqueous (solvated) cations on oxyg en solubility. Applications of the model to industrial solutions are discus sed, including estimation of oxygen concentrations and optimum process temp eratures for mass transport of dissolved oxygen. (C) 2000 published by Else vier Science Ltd. All rights reserved.