Rare earth characterizations & processing for the metal La recovery

Abstract

This study presents characterization of Korean monazite and hydrometallurgical processing for metal (La) recovery. In Korea Monazite, there is 29.4% phosphate. Presence of phosphate decreases leaching efficiency of metals from monazite. Dephosphorization of Korean Monazite were carried out using NaOH roasting. At 400°C, more than 99% phosphate removed during 2 hr of NaOH roasting. Parameters were optimized for metal leaching after dephosphorisation of Korean Monazite. Leaching with 6M HCl at a pulp density of 30 g/L and 90°C resulted in the recovery of ~99.1% La in 120 min. Leach liquor of Monazite containing 0.65 g/L of La. Experiments were carried out using synthetic solution of 0.65g/L La (composition similar to the leach liquor) to optimize the condition for the metal recovery from the leach liquor of monazite. 5% DEHPA as extractant, 1% isodecanol as phase modifier and kerosene as diluents extracted about 99.9 % La from synthetic solution at equilibrium pH 3.2, O/A ratio 1:1 within 5 min of contact time. 5% Hydrochloric acid is used for stripping of metal loaded organic. Salt of metal could be prepared from pure solution using evaporation or crystallization.