Simulation of a continuous stirred tank reactor under pressure leaching conditions

Abstract

Pressure oxidation of sulphide materials is exothermic in nature hence heat balance consideration is very important for such operations. A model has been developed for sphalerite pressure oxidation in ammonia solution considering feed particle size distribution, residence time distribution in the continuous leaching reactor i.e. continuous stirred tank reactor (CSTR) and heat balance. The required kinetic rate equations and other parameters were taken from the laboratory scale studies on mono-size particles. Adiabatic operation of the single stage CSTR was simulated by simultaneously solving mass balance and heat balance equations. Simulation results for adiabatic CSTR are shown for 5 and 10 wt% slurry densities varying retention times and feed temperatures in order to scan stable operating temperature. For low slurry density (5 wt%) stable operating temperature of 145 degrees C is achieved with 50 degrees C slurry preheating and 2 hour retention time leading to Zn recovery - 80%.