Microwave-assisted Carbochlorination Recovery Of Indium Process Of Dynamic Simulation Based On Multi-field Coupling

At present,annual indium is mostly used to produce the liquid crystal display(LCD)worldwide.With a large number of LCD scrapped,it's becoming mounting important to recycle indium form LCD.Our study shows that HCl gas generated from PVC pyrolysing can be used as a chlorination agent,react with LCD powder and recycle indium with microwave carbon thermal method.In this process two wastes recycle and disposal together is realized.But less fundamental researches about microwave chloride metallurgy have been done,let alone use for recycling indium.Therefore,it's necessary to design and optimize the microwave reactor for microwave-assisted carbochlorination recovery of indium process as well as its experimental design.Base on the COMSOL Multiphysics simulator software and numerical analysis method,the microwave reactor in lab and microwave-assisted carbochlorination process has been studied,thus providing a basis for the practical use.Firstly,according to the real reaction,the coupling relationship and governing equationamongradio frequency,temperature field,flow field and chemical reaction are confirmed,the simulation model is established,the relevant parameters and boundary conditions are set.Then,the change rules of electric field distribution,temperature rise of the sample and product concentration is investigated under the steady state flow field.In addition,a series of single factor experiments,including microwave input power and flow rate,are carried out under coupling multiphysis.Finally,this paper explores the effect of sample location on the reaction and optimizes the structure in the microwave cavity.Under the steady state flow filed,the sample temperature rise can be divided into two phases,including a linear increase and a non-linear increase.This shows that the dielectric constant of the sample changes with temperature and has a critical value.When sample temperature exceeds the value,the chemical reaction rate increases.In certain concentration scope,higher concentration of HCl gas can improve the reaction,but it shows low impact on product concentration increase.Under the multi-field coupling,the flow will reduce the heating rate,the temperature critical value will change as well.The heating rate has a positive relationship with microwave input power.Product concentration also increases with input power.The HCl flow rate has effect on both mass transfer and heat transfer.When flow rate value between 100 ml/min and 200 ml/min,sample temperature increases with the increasing flow rate,and the fitting equation conforms to the quadratic function and satisfies the increasing trend.208.18 ml/min is the position of monotonic change.We can deduce excessive flow rate will lead to decrease of sample temperature.But when flow rate value is under 100 ml/min,lower flow rate can lead to higher sample temperature.A reasonable placement of sample can improve electric field intensity without inputting higher microwave power.Base on the distribution of electric field,more reaction tubes are set in the cavity.Results show that 3 positions meet the requirements.After adjusting model structure,3 tubes are set in the cavity and sample temperatures meet the needs of actual reactions and influent each other.In this paper,base on the numerical simulation method,this paper realizes the analysis of microwave-assisted carbochlorination recovery process of indium and optimize a degree of the microwave reactor.