The study of process production of polishing powder based on cerium dioxide

Abstract Finely divided cerium dioxide powder is an excellent polishing agent for optical glass under intensive processing conditions. Cerium dioxide powder was produced from a mixture of rare earth carbonates by conversion to oxides, reacting with acid to separate a sediment of CeO(OH)2 from solution containing the trivalent rare earth ions, washing the sediment, and drying and annealing it to produce finely divided CeO2. Physical and chemical investigations of each stage of the processing were performed. A relation was established between the properties of CeO(OH)2 (such as degree of fineness and crystal structure) and the properties of the REE oxides that were used. It was shown that very fine REE oxides generate fine CeO(OH)2. It was also shown that to obtain CeO2 powder with high specific surface area and perfect crystal structure, the CeO(OH)2 must be annealed in two steps: (1) dehydration of intermediate CeO1.5(OH) to produce very fine powder, and (2) dehydration at 800–1050°C.