SEPARATION OF CERIUM FROM OTHER RARE EARTHS BY IGNITION OF THE NITRATES

Cerium was separated from the light rare earths by ignition of the nitrates whereby the cerous nitrate was decomposed to ceric oxide. Small scale investigations were made using sodium nitrate and magnesium nitrate hexahydrate as fluxes. A cost estimate based on data from the small scale investigations showed the sodium nitrate ignition to be more economical; therefore, bench scale investigations were made using sodium nitrate. With a weight ratio of sodium nitrate to rare earth nitrate hexahydrate of 1:2 and a temperatare of approximately 295 C for 12 to 16 hours, a nearly quantitative conversion of cerous nitrate to ceric oxide was obtained. The ceric oxide obtained upon dissolving the soluble sodium nitrate and undecomposed rare earth nitrates and filtering, using Celite filtering aid as a precoat, was found to be quite pure. Indications are that an even purer ceric oxide could posibly be obtained if a lower temperature for a longer length of time had been used. (auth)