Study on the Physical and Chemical Properties of LiF-NaF-KF and NaCl-KCl Molten Salt Systems for Electrolytic Recycling of Rare Earth Waste
Molten salt electrolysis is an important method for recycling NdFeB scrap.Fluoride and chloride are often used as electrolytic media in molten salt systems for recycling rare earth scrap.The physical properties of molten salt have an important impact on current efficiency,power consumption,recovery rate and form of recovered products.This article first discusses the thermodynamic behavior of Nd,Pr and Fe in LiF-NaF-KF and NaCl-KCl,and further uses the rotation method,Archimedes method and tube drawing method to study the molten salt systems with different proportions at different temperatures.Changes in viscosity,density and surface tension.The results show that in the LiF-NaF-KF system,Nd and Prspontaneously react with NaF and KF;The equilibrium solubility of Nd and Pr elements are 2.34 mg/g and 1.07 mg/g respectively,while Fe Elements are basically insoluble.For the NaCl-KCl system,the reactions of each component of NdFeB scrap not proceed spontaneously.Fe3+needs to be precipitated before electrolysis to avoid its preferential deposition during electrolysis.The viscosity,density and surface tension of the two molten salt systems all decrease with the increase of temperature.The change of density with temperature is more consistent with a linear relationship,and the linearity degree is greater than 0.95.As the amounts of NdF3 and AlCl3-Nd2O3 increase,the two systems,the viscosity,density and surface tension all increased,but the addition of electrolytic raw materials did not change the influence of temperature on the density of the system.
molten salt electrolysisphysical and chemical propertiesrare earthNdFeB scrap
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维普
