MIXING OPTIMIZATION OF HIGH PRESSURE OXIDATION OF GOLD ORE SLURRIES

摘要

Mixing is a common unit operation in the mining industry. Mixers are often used in agitated leach, bio-oxidation, and pressure oxidation. In all of these cases it is important to understand the application and what it requires from a mixer in order to be optimized. In the mining industry, it is obviously important to suspend solids. However, the shear level of each of these three applications is very different. In acid leaching, the mixer needs to suspend solids and produce a good degree of blending. In pressure oxidation, the agitator must also disperse air or oxygen by creating fine bubbles. Because of the presence of microorganisms, bio-oxidation requires less shear than the other two processes, but the agitator must be able to suspend the solids, provide excellent blending/heat transfer and distribute the air. Thus, in the mining industry there is an application spectrum that requires different impellers to perform different jobs. Specifically, these jobs are blending, solids suspension, gas dispersion, mass transfer and heat transfer. It is important to determine whether the process is mass transfer or kinetic rate limited. Mixers affect a mass transfer limitation but have no affect on the kinetics.