Numerical Simulation And Experimental Study On The Process Intensification Of Steam Injection And Mechanical Stirring In Hydrometallurg

Mechanical mixing is a common technique for mixing in a variety of industrial processes.However,in some cases,more intensive and intense mixing is required to achieve the desired level of homogeneity and efficiency.Therefore,this study investigates the flow field characteristics of the compound mechanical stirring action of steam injection,which is using numerical calculations and experimental methods in zinc refining processes.The steam phase change properties are used to apply gas blowing to the wet metallurgical process to achieve enhanced mixing in the purification of solid waste containing zinc.The study investigates the mixing effect from three perspectives:the selection of a single mechanical stirring paddle,the effect of plume morphology and stirring during direct steam contact condensation,and the effect of combined mechanical stirring with steam blowing on the flow field structure in the stirred tank,and uses a step-by-step approach to explore the potential of combined mechanical stirring with steam blowing to enhance the mixing process.After optimisation of the paddle type selection,the multi-bladed combined paddle stirring system has a larger mixing range,generating a faster response to the mixing zone and a wider range of fluid viscosities.Under the same operating conditions,the multibladed combined paddle stirring system is able to rapidly break up the large scale periodic simulation structure of the fluid.The mixing isolation zone in the macroscopic flow pattern of the flow field gradually dissipates,which in turn causes convection in the stirred tank,creating an axial momentum enhancement effect.The enhanced axial momentum leads to increased collisions between impurity particles and zinc powder particles,thereby increasing the speed of the displacement reaction.The paddle type achieves a maximum reduction of 344.242 J and a minimum reduction of 65.037 J per hour per unit of ion purification energy while meeting purification process standards with high efficiency,resulting in energy savings and consumption reductions.In the study of the coil-type steam transport pipeline,to achieve submerged spray direct contact condensation process,the condensation of steam in the mixing tank generates pressure oscillation,which helps to break the pseudo-uniformity of the local flow field mixing,separating bubble stirring and oscillating spray as two steam jet states,the local stirring range is expanded,which can effectively enhance the overall flow field mixing performance.The coiled steam injection arrangement breaks the fluid flow periodicity in multiple localised areas,triggering a non-tank mass transfer enhancement effect and inducing fluid convection.This steam injection method achieves an effective stirring range of 80%in the mixing tank while effectively mitigating the generation of low velocity regions and keeping them within 8.9%,achieving the goal of increasing efficiency without reducing velocity.In the application of a combination of both steam blowing and mechanical stirring to the mixing of fluids in the mixing tank,the direction of the main flow of steam is shifted with the direction of rotation of the stirring paddle.The steam enters the mixing tank in a wheezing pattern,creating vortices of varying size and number at the outlet of the lance,allowing for enhanced local mixing while triggering non-linear in-tank mass transfer.The steam content in the flow field under the action of the double layer four straight blade stirring paddle is 2.84 times that under the action of the combined blade stirring paddle,and under the synergistic effect of steam blowing,the number of mixing isolation zones is further reduced,and the area of mixing isolation zones is further reduced by 43.7%,effectively solving the problem of poor mass exchange and low mixing efficiency when mixing isolation zones exist.The steam injection compound mechanical mixing technology can effectively improve the mixing efficiency of mechanical stirring reactors and has a broad potential for scientific research and industrial practice.