Thermodynamic Modelling for Process Control at the Kalgoorlie Nickel Smelter

Abstract

WMC Ltd operates a flash furnace for the treatment of nickel concentrates at Kalgoorlie in Western Australia. A thermodynamically based model has been developed for the furnace to provide setpoints based on feed forward control with feed back correction. The model employs a non-stoichiometric method to predict the quantities of matte. slag and gas through a minimisation of the free energy of the system. It is designed to predict key process inputs such as total process oxygen, flux addition and process oil, to meet the process targets of matte grade, iron/silica ratio and slag temperature. The feed back is designed to trim the control through adjustment of the oxygen efficiency, heat loss from the reaction shaft and an iron/silica ratio offset. This paper provides an overview of the structure of the model and experience gained during its implementation.