Ion Exchange Model And Solute Transport Equation In Leaching Process Of Weathering Crust Leaching Rare Earth Ore

In order to determine the concentration of leaching agent solution reasonably,improve the recovery rate of resources and control the ammonia nitrogen pollution and pollutant migration in mines,the ion exchange process and solute transport law in the leaching process of weathering crust leaching rare earth ore are studied in this paper.The research results will have certain theoretical and practical guiding significance for the green and efficient extraction of rare earth resources and the protection of the environment.In this paper,the effects of leaching agent concentration on the leaching effect of rare earth ions are studied through the balanced leaching test of the same grade ore samples and the unbalanced leaching test of the same grade ore samples,and the ion exchange model and selectivity coefficient are determined.The unbalanced leaching process is analyzed,and the effect of leaching time on the leaching effect of rare earth ions is studied.Based on the balanced leaching process,the unbalanced leaching process is considered,Fick's law and Kerr's law are adopted.Based on the ion exchange and migration process,the dynamic model of column leaching,i.e.source and sink terms,was established and solved.The applicability of the model was verified by the penetration curve of ore samples.The main conclusions are as follows:(1)The effect of leaching agent concentration on the leaching efficiency of rare earth ions was studied through the equilibrium leaching test of the same size ore samples.The results show that when the concentration is less than 5.3 g/L,the leaching amount of rare earth ions increases with the increase of concentration,and tends to be stable when the concentration exceeds 5.3 g/L.Kerr model is selected as the ion exchange model of equilibrium leaching.(2)The non-equilibrium leaching process is analyzed,the diffusion process of ammonium and rare earth ions is described by Fick's law,the ion exchange process is described by Kerr model,and the leaching kinetics model is established.The non-equilibrium test results verify the applicability of the model,and the parameters related to the diffusion coefficient are obtained.(3)Longitudinal pillar is divided into several units,each of which "occurs" non-equilibrium leaching process.Based on the different ion concentration of ore samples at different locations and at different times,combined with leaching kinetics model,the source-sink term equation in the process of pillar leaching is established.(4)Establishing solute transport equation with source and sink terms.Compared with the measured penetration curve,the average relative error of the calculated penetration curve is less than 10%,which indicates that the solute transport equation can describe the law of solute transport in the process of leaching.