Vapor phase process for the production of titanium dioxide

Claim 1

IN A PROCESS FOR PRODUCING A FINELY DIVIDED TITANIUM DIOXIDE PIGMENT, COMPRISING CONTINUOUSLY FLOWING INTO A REACTION ZONE AND ANHYDROUS GASEOUS REACTION MIXTURE OF VAPORIZED TITANIUM TETRACHLORIDE AND OXYGEN CONTAINING GAS, CONTINUOUSLY FLOWING THEREINTO AUXILIARY GASES INCLUDING SEPARATE STREAMS OF CARBON MONOXIDE AND OXYGEN CONTAINING GAS RESPECTIVELY SURROUNDING THE INFLOWING REACTION MIXTURE AND MAINTAINING AN AUXILIARY FLAME AROUND SAID MIXTUR IN SAID ZONE BY BURINING SAID CARBON MONOXIDE THEREIN, THEREBY REACTING SAID MIXTURE IN CONTACT WITH SAID FLAME TO FORM SAID PIGMENT, THE IMPROVEMENT WHICH COMPRISES SUPPLYING AS THE STREAM OF AUXILIARY GAS NEXT ADJACENT TO SAID INFLOWING MIXTURE A DRY GAS CONTAINING LESS THAN 0.05% OF MOISTURE BY VOLUME AND SO LITTLE MOISTURE AS TO PREVENT OXIDE INCRUSTATIONS ON THE REACTION MIXTURE INLET, YET MAINTAINING IN SAID AUXILIARY GASES A TOTAL MOISTURE EQUIVALENT OF AT LEAST 0.005% OF THEIR VOLUME TO KEEP SAID CARBON MONOXIDE FLAME BURNING, SAID TOTAL MOISTURE EQUIVALENT BEING MAINTAINED AT NOT MORE THAN 0.25% OF THE VOLUME OF SAID AUXILIARY GASES TO LIMIT TO A MINUTE AMOUNT THE HCL CONTENT OF THE REACTION PRODUCTS.