Progress in green and efficient enrichment of rare earth from the leaching liquor of ion adsorption type rare earth ores

Progress in green and efficient enrichment of rare earth from leaching liquor of ion adsorption type rare earth ores

Recovery of rare earth elements from CaCl2 and MgSO4 leach solutions of ion-adsorbed rare earth deposits

LiFePO4/FePO4 material was chosen as ion-sieve for selectively extracting Li from high Mg/Li mass ratio brine.Thermodynamic analysis was conducted about selectivity of adsorption of Na+,K+,Mg2+ and Li+ by FePO4 ion-sieve.The corresponding -pH diagrams of Me(Li,Na,K,Mg)-Fe-P-H2O system at 298.15K were plotted and analyzed.The results show that,under the condition of ion concentration 0.1 mol/L,the redox potential of Me(Li,Na,K,Mg)-Fe-P-H2O system is controlled not higher than 0.36V(vs SCE),Fe3+ in FePO4 is reduced to Fe2+,and,Li+ is inserted into FePO4 crystal lattice to form LiFePO4 synchronously.KFePO4 and NaFePO4 will not be obtained until the potential of the system is reduced to 0.132 V and 0.073 V,respectively.Li+ is absorbed preferentially compared with Na+ and K+ by FePO4 ion-sieve.Mg0.5FePO4 can't exist steadily in the studied range,which means that Mg2+ can't be absorbed by the material.Therefore,the FePO4 ion-sieve can be used to selectively extract Li+ when the redox potential being set within 0.173～0.33 V.After extraction,Li can be de-intercalated from LiFePO4 by setting the potential of system above 0.33 V.

Thermodynamics analysis of Li-extraction from brine using FePO_4 ion-sieve

The use of calcium oxide as a precipitant can achieve a nonammonia enrichment of a rare earth leaching liquor. However, an alkaline rare earth sulfate forms during the precipitation process, thus r...

Anbang Lai

Papers

Non-ammonia enrichment of rare earth elements from rare earth leaching liquor in a magnesium salt system I: Precipitation by calcium oxide

Removal of Sulfate Ions from Calcium Oxide Precipitation Enrichment of a Rare Earth Leaching Liquor by Stirring Washing with Sodium Hydroxide.