Method of recovering metallic oxides

Claim 1

IN THE PRODUCTION OF TITANIUM DIOXIDE PIGMENTS BY THE DECOMPOSITION AND OXIDATION OF TITANIUM TETRACHLORIDE IN THE PRESENCE OF AN EXCESS OF OXYGEN AT TEMPERATURES ABOVE 800* C. WHEREBY A CHLORINE AND OXYGEN CONTAINING HOT GASEOUS SUSPENSION OF TITANIUM DIOXIDE IS FORMED, THE PROCESS WHICH COMPRISES FIRST RAPIDLY COOLING SAID SUSPENSION TO A TEMPERATURE NOT EXCEEDING 600* C. BY MIXING WITH SAID SUSPENSION A COOLED GASEOUS PRODUCTION PREVIOUSLY FORMED BY SUCH DECOMPOSITION AND OXIDATION AND SUBSTANTIALLY FREED OF TIANIUM DIOXIDE, THEN FURTHER COOLING SAID SUSPENSION IN AT LEAST ONE COOLING ZONE BY ABSTRACTING HEAT FROM IT THEREIN THROUGH EXTERNALLY COOLED GAS IMPERVIOUS ZONE BOUNDING WALLS COMPOSED PREDOMINANTLY OF METALLIC ALUMINUM AND BEARING A THIN INTEGRAL FILM OF ALUMINUM OXIDE OVER THEIR INTERNAL SURFACES, AND THEN FINALLY COOLING SAID SUSPENSION AND PRECIPITATING TITANIUM DIOXIDE FROM IT IN A PRECIPITATING ZONE BOUNDED BY EXTERNALLY COOLED GAS IMPREVIOUS WALLS COMPOSED PREDOMINANTLY OF METALLIC ALUMINUM AND BEARING A THIN INTEGRAL FILM OF ALUMINUM OXIDE OVER THEIR INTERNAL SURFACES.