China Nonferrous Metallurgy

In order to explore the characteristics and influence of the flow field of autoclave in the pressure leaching process, the operating pressure is set at 10MPa and standard -k-ε- turbulence model and the multiple reference frame method are adopted to numerically simulate the fluid dynamics of the pressure leaching process based on CFD method. The influence of different impeller heights and blade inclination angles on the flow field and flow pattern and the relationship between stirring speed and flow field distribution, turbulent kinetic energy and turbulent dissipation rate are analyzed. The reliability of the model is verified through PIV test. The results show that the flow pattern has a double-loop structure when using the paddle agitator, the height of the agitator distance from the bottom of the autoclave has a great influence on the flow pattern and vortex position. The stirring power decreases with the increase of blade inclination angle, and the main flow in the autoclave transfers to the axial flow, the circulation effect in the autoclave is better when the blade inclination angle is 45°. When the speed is increased, the stirring power rises exponentially, when the stirring speed is 600r/min, the range of the dead zone is the smallest and then further increasing the stirring speed cannot effectively improve the circulating mixing capacity in the autoclave. The turbulent kinetic energy of the flow field rises with the increase of the stirring speed, and peaks in the blade region and rapidly declines in the upper part of the autoclave. The turbulent dissipation is mainly concentrated in the blade vortex region and grows exponentially with the increase of the stirring speed.