METHOD FOR PREPARING CERIUM HYDROXIDE FROM BASTNASITE

摘要

PURPOSE: A method for preparing cerium hydroxide from bastnasite is provided, in which cerium compound is separated through roasting and sulfuric acid leaching of the bastnasite and remove fluorine contained in the cerium compound by using metal salts. CONSTITUTION: In a method for preparing high purity cerium hydroxide from bastnasite, the method comprises the steps of drying and crushing bastnasite; roasting bastnasite, followed by leaching out cerium from the roasted bastnasite with sulfuric acid; separating and recovering cerium by adding sodium sulfate to the sulfuric acid leachate; precipitating cerium sodium sulfate and removing fluorine by adding sodium sulfate and aluminum sulfate to the separated and recovered solution containing cerium fluoride negative ions; and adding a sodium hydroxide aqueous solution to cerium sodium sulfate, wherein quadrivalent cerium ions as well as trivalent rare earth elements are selectively reacted with sodium sulfate in the step of separating and recovering cerium by adding sodium sulfate to the sulfuric acid leachate, TREO (total rare earth oxides) concentration of the leachate is 50 to 100 g/L, addition amount of sodium sulfate is 1.5 to 2.5 equivalents, and reaction temperature is 30 to 60 deg.C, and wherein purity of cerium hydroxide is 99% or more in the step of adding a sodium hydroxide aqueous solution to cerium sodium sulfate.