Vapor phase process for producing metal oxides

Claim 1

IN THE PROCESS FOR PRODUCING TITANIUM DIOXIDE BY REACTING IN THE VAPOR PHASE TITANAIUM TETRACHLORIDE AND AN OXIDIZING GAS IN AN OXIDATION ZONE COMPRISING A BED OF SOLID TITATNIUM DIOXIDE PARTICLES OF PREDETERMINED SIZE MAINTAINED IN A FLUIDIZED CONDITION AT A TEMPERATURE WITHIN THE RANGE OF 750*C. TO 1500*C. WHEREIN A PORTION OF THE TITANIUM DIOXIDE PRODUCED IS CARRIED AWAY IN THE GAS STREAM LEAVING THE OXIDATION ZONE IN THE DESIRED FINELY DIVIDED FORM AND ANOTHER PORTION REMAINS IN THE BED AS A DEPOSIT FORMING LARGE PARTICLES IN THE BED, THE IMPROVEMENTS WHICH COMPRISE CONTINUOUSLY CONTROLLING THE SIZE DISTRIBUTION OF THE PARTICLES FORMING THE BED AND CONVERTING SUBSTANTIALLY ALL OF THE TITANIUM TETRACHLORIDE VAPOR INTO TITANIUM DIOXIDE OF THE DESIRED FINELY DIVIDED FORM BY: (1) CONTINUOUSLY WITHDRAWING A PORTION OF THE LARGE PARTICLES FROM THE BED, (2) CONTINOUSLY REACTING THE WITHDRAWN PARTICLES IN A CHLORINATION ZONE WITH A GASEOUS CHLORINATING AGENT AND A GASEOUS REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF CARBONYL CHLORIDE AND A MIXTURE OF CHLORINE AND CARBON MONOXIDE IN AMOUNTS SUFFICIENT TO REDUCE THE SIZE OF THE PARTICLES AND RELEASE TITANIUM TETRACHLORIDE THEREFROM, AND (3) CONTINUOUSLY RETURNING THE PARTICLES OF REDUCED SIZE AND SAID RELEASED TITANIUM TETRACHLORIDE VAPOR FROM THE CHLORINATION ZONE TO THE BED IN THE OXIDATION ZONE TO AGAIN UNDERGO REACTION TO FORM SAID DESIRED FINELY DIVIDED TITANIUM DIOXIDE PARTICLES AND UTILIZE IN SAID OXIDATION ZONE SUBSTANTIALLY ALL OF THE TITANIUM TATRACHLORIDE ORIGINALLY INTRODUCED.