Treatment of Rare-Earth Concentrate to Remove Phosphorus and Fluorine Compounds

It was suggested to purify poor lanthanide concentrate precipitated from the extraction orthophosphoric acid produced by the dihydrate process to remove phosphorus and fluorine compounds by heating a mixture of the concentrate with sulfuric acid in the presence of hydrated silica followed by water leaching of water-soluble sulfates and phosphates. The treatment conditions for the separation of the bulk of phosphorus( V) and the entire fluorine in the form of SiF(4) were determined, ensuring approximately 3.5-fold increase in lanthanide concentration.