Dissolution of some rare earth element oxides with hydrochloric acid vapors

A procedure is suggested for the dissolution of high-grade rare earth element oxides with HCl vapors. The process is conducted in a closed system, owing to which contamination by impurities is limited and elevated temperatures (up to 230 degC) and pressures can be applied to make advantage of the aggressiveness of the acid, which in these circumstances disturbs crystal structures of solids. The working conditions are such that volatilization of the trace element in question is prevented. (P.A.). 3 tabs., 21 refs