Numerical Simulation Study On The Cavitation And Dissociation Of Sulfur From Zinc Leaching Residue

The zinc leaching residue has complex components and contains a variety of valuable components and toxic elements.It has the characteristics of wide particle size distribution,wrapped and embedded ore phase,small particle size and so on.At present,the commonly used method for the treatment of the leaching residue from zinc smelting is"flotation thermal filtration",but there are some disadvantages,such as low direct yield of elemental sulfur,poor synergistic extraction effect of valuable components,incomplete disposal of toxic elements and so on.There is an urgent need for technological innovation and upgrading.Therefore,in order to realize the collaborative extraction of valuable components and safe dissociation of toxic elements in zinc leaching residue,this study puts forward the treatment process of cavitation dissociation,and made visual research on each stage by using numerical simulation software,which provides theoretical basis and technical support for the resource treatment of zinc leaching residue.The main research results are as follows:（1）The engineering model of cavitation and dissociation reactor was designed,and the"gas-liquid"two-phase flow numerical model of cavitation and dissociation reactor was constructed,which revealed the distribution and movement law of gas-liquid two-phase in the reactor.The best models of two-phase flow,turbulence and interphase force were selected through PIV comparison test.The reactor design with convective inlet was proved to be more advantageous.At the same time,through the gas-phase distribution,two-phase velocity distribution and turbulence distribution,the area between the gas-liquid convection inlet and the ore inlet in the reactor was determined,creating a high-altitude dissolution separation reaction area.（2）Based on the theory of cavitation dissociation and the two-phase flow model,a gas-liquid-solid three-phase numerical model in the reactor was established.The accuracy of the three-phase numerical model of cavitation and dissociation was verified by comparing the experimental results with the numerical simulation.The effects of operating parameters,physical parameters and structural parameters of cavitation and dissociation reactor on the formation,movement,growth and collapse of cavitation bubbles were investigated in detail.The research showed that for the same boundary condition,the gas phase distribution and particle concentration were emphases the cavitation and dissociation of zinc leaching residue.The key to improving the cavitation and dissociation efficiency was to regulate the flow field conditions and avoid the formation of dissociation dead zone.Increasing the temperature in the reactor increaseed the maximum equivalent radius of the cavitation bubble and prolongs the cavitation pulsation period.Due to the influence of saturated steam pressure,the energy of the cavitation bubble reached the maximum at the reactor temperature of 80℃.（3）The cavitation and dissociation reaction process of laboratory grade was studied.Through the process optimization test,the cavitation and dissociation control technology of high sulfur slag monomer was formed.Reactor temperature could indirectly affect the distribution and diameter of cavitation bubbles required in the process of cavitation and dissociation,which was an important factor affecting the effect of cavitation and dissociation.The inlet gas flow affected the cavitation dissociation process by affecting the flow field distribution and gas volume fraction distribution.When the pulp concentration was too high,the cavitation dissociation process was incomplete.Reducing the pulp concentration could speed up the cavitation dissociation process.Ultrasonic physical field had a good effect on the dissociation of zinc leaching residue in the whole particle size range,but it had a poor effect on the extraction of valuable components.When the energy required for the dissociation of coarse particles of zinc leaching residue was basically the same as that of cavitation collapse,it could be considered that the dissociation effect was the best.The results showed that the reactor temperature of 80℃and 6×10^-5 kg·L^-1 gas flow,5 g·L^-1 slurry concentration and air as gas phase input meet this standard,that is,the best process conditions for cavitation and dissociation of zinc leaching residue.