Thermal treatment for the separation of phosphate and recovery of rare earth metals (REMs) from Korean monazite

Abstract

Systematic study for thermal decomposition of monazite to remove phosphate as a valuable product using Na2CO3 and NaOH roasting processes to validate the TG/DTA studies is reported here. Monazite in 1:1 wt. ratio with Na2CO3 and NaOH requires a temperature of 900 8C and 400 8C, respectively, for 120 min in order to achieve complete conversion of rare earth phosphate into its oxides. The roasted mass was washed, dried and leached in 6 M HCl for 2 h, pulp density 30 g/L at 80 8C which results in >90% REMs recovery. Leach liquor generated will be further processed by solvent extraction and precipitation processes.