Preparing Crystalline Rare Earth Carbonate by Carbonation with Carbon Dioxide

Abstract

As an important precursor for the production of rare earth oxides，rare earth carbonate is an important intermediate raw material in the intensive processing and material preparation of rare earth elements. The current preparation methods of rare earth carbonate include ammonium bicarbonate precipitation method，magnesium bicarbonate precipitation method and sodium carbonate precipitation method，etc，which exist the problems such as ammonia nitrogen pollution，poor crystallization performance，and unfavorable industrial production；this article introduces carbon dioxide carbonization method to crystalline rare earth carbonate，in order to develop a green and easy-to-industrial rare earth carbonate precipitation crystallization technology. The experiment used lanthanum chloride as the raw material to study the effects of carbonization system，carbonization temperature and carbonization time on the crystallization properties of the product；the results show that carbonization at 20 ℃ and pH=5.0 for 60 min can obtain La（2 CO3）3·8H2O in crystalline form with D50=21.4 μm and（D90D10）/2D50=0.745. In addition，this article also used cerium chloride and yttrium chloride as raw materials to discuss the adaptability of carbon dioxide carbonization. The crystal forms of Ce（2 CO3）3·8H2O and Y（2 CO3）3·2H2O were obtained by carbonization at 20 and 40 ℃. In this article，carbon dioxide carbonization method was applied to the preparation process of crystalline rare earth carbonate，which has the advantages of easy industrialization，easy operation，and reduced carbon emissions. It also provides theoretical and technological guidance for the preparation of crystalline rare earth carbonate by carbonization.