Process and apparatus for the production of finely divided powders

Claim 1

A CONTINUOUS PROCESS FOR PRODUCING FINELY DIVIDED REFRACTORY OXIDES COMPRISING THE STEPS OF: FEEDING A MIXTURE OF MINERAL OXIDE AND A REDUCING AGENT INTO AN ENCLOSED ELECTRIC ARC FURNACE COMPRISING ELECTRODES; PASSING A CURRENT BETWEEN THE ELECTRODES SO SA TO PRODUCE AN ARC, HEATING OF THE MIXTURE, AND AT LEAST PARTIAL REDUCTION OF SAID MINERAL OXIDE TO PRODUCE GASEOUS REDUCTION PRODUCTS; SUPPLYING AN INERT GAS TO THE FURNACE TO CONTINUOUSLY SWEEP THE REDUCTION PRODUCTS THEREFROM AND INTO A SEPARATE OXIDIZING ZONE; AUTOMATICALLY VARYING THE VOLUME OF THE INERT SWEEP GAS SUPPLIED TO THE FURNACE WITH VARIATION IN THE INTENSITY OF THE ARC CURRENT, WHEREBY THE INTENSITY OF THE CURRENT IS MAINTAINED SUBSTANTIALLY CONSTANT; COOLING SAID REDUCTION PRODUCTS UPON THEIR ENTRANCE INTO SAID ZONE; CONTACTING THE COOLED REDUCTION PRODUCTS IN SAID ZONE WITH A GASEOUS OXIDIZING MEDIUM TO OXIDIZE SAID REDUCTION PRODUCTS AND TO THEREBY PRODUCE THE REFRACTORY OXIDIZE IN A FINELY DIVIDED, SOLID STATE SUSPENDED IN COMBUSTION GASES, ANS SEPARATING THE FINELY DIVIDED OXIDE FROM THE COMBUSTION GASES.