Chlorine plasmas

Solid, finely divided metal oxide is produced by the vapour phase oxidation of the corresponding metal chloride, by passing chlorine into a reaction zone wherein the metal chloride is reacted with a free-oxygen containing oxidizing gas, the chlorine being heated in the reaction zone or prior to entering by passage through an electrically produced hot plasma. The oxidizing gas or oxidizing gas and metal chloride may also be passed through the plasma, which may be produced by an arc between electrodes, by induction means or by capacitative means. The chlorine used to form the plasma remains unchanged and may be recycled.