Abstract: A process for the thermal decomposition and conversion of metal chlorides to metal oxides in a fluidized bed wherein the fluidizing gas contains oxygen and the reaction temperature is maintained above the thermal decomposition temperature of the metal chloride but below the sintering temperature of the metal oxide thus produced. The gas velocity is determined by the critical relationship 0.34.rho..sup.0.9 .ltoreq. W.sub.G .ltoreq. 0.56.rho..sup.0.9 where W.sub.G is the approximate gas velocity through the fluidized bed chamber in the absence of the bed and .rho. is the density of the pure fluidized-bedmaterial (metal oxide). The height of the bed is also critical and should be that at which a critical pressure drop of 1200 to 2400 mm (water column) is obtained but at least 350 mm, measuring with the static or settled bed (nonfluidized).