Numerical Simulation And Optimization Of Cavitation Reactor For High-sulfur Slag Dissociation

The oxygen pressure leaching process of zinc smelting produces a large amount of high-sulfur slag,in which the sulfur content is as high as 46.21 %,and also contains a large amount of toxic elements such as arsenic and mercury.It is of great significance to realize the harmless treatment and comprehensive utilization of high-sulfur slag.In view of the low yield of elemental sulfur in the current treatment process of high sulfur slag,the hydraulic cavitation technology was introduced to dissociate the high sulfur slag.In this study,the Cavitation Reactor for High-sulfur Slag Dissociation has been designed,and the characteristics of fluid and particle motion in the reactor are studied in depth.The main research contents and conclusions are as follows:(1)In this study,a numerical simulation model of the Cavitation Reactor for High-sulfur Slag Dissociation was established,and the structure of the reactor and process conditions were optimized.The results show that,when the diameter of the inlet pipe is 200 mm,the inclination Angle of the contraction pipe is 60°,the length of the throat pipe is 50 mm,the diameter of the throat pipe is 60 mm,the inclination Angle of the expansion pipe is 40°,the diameter of the outlet pipe is 200 mm,and the flow rate of the inlet pipe is 10 m/s,the reactor has better operability and economy.In addition,the average gas volume fraction and the average turbulent kinetic energy of the flow field in the reactor are maintained at a high level,which makes it easier for the monomer to dissociate from the high-sulfur slag.(2)In this study,the flow behavior of the Cavitation Reactor for High-sulfur Slag Dissociation under the optimal structure and technological conditions was analyzed and discussed.The formation,accumulation and collapse of cavitation bubbles and their agitation behavior on liquid were analyzed from the pressure distribution,gas volume fraction distribution,velocity distribution and turbulent kinetic energy distribution of flow field.It was found that the greatest flow rate and lowest pressure were found at the center of the throat pipe.The formation of cavitation bubbles is directly related to the pressure value.Cavitation bubbles mainly concentrated near the wall of the throat pipe,expansion pipe and outlet pipe.The turbulent kinetic energy is related to the vapor-liquid phase change.The maximum turbulent kinetic energy is located at the gas-liquid interface in the outlet pipe.(3)Based on the EDEM-Fluent coupling algorithm,a bidirectional coupling transient calculation model was established to simulate the movement and dissociation process of the "mushroom-shaped" high-sulfur slag particles in the reactor.The results showed that,when the high-sulfur slag particles moved to the contraction pipe of the venturi tube.Due to the gradient changes of pressure and velocity in the flow field,the fluid force on the whole particle increases and the external pressure decreases.This is not conducive to the stability of the internal structure of particles.The particle begins to crack and dissociate.