Vacuum carbon reduction of tungstic oxide

Claim 1

IN THE ART OF PRODUCING POWDERED TUNGSTEN METAL BY THE CARBON REDUCTION OF OXIDIC TUNGSTEN AT SUB-ATMOSPHERIC PRESSURES, WHEREIN A REACTION GAS PRODUCT OF CO IS FORMED, THE IMPROVEMENT OF EFFECTING TUNGSTEN PARTICLE SIZES BETWEEN 0.5 AND 10 MICRONS WITHOUT ENTRAINMENT IN SAID REACTION GAS PRODUCT, SAID IMPROVEMENT COMPRISING MIXING IN POWDER FROM CARBON AND OXIDES OF TUNGSTEN, HEATING SAID MIXTURE AT A PRESSURE BELOW 5 MM. OF MERCURY UP TO A REDUCING TEMPERATURE OF APPROXIMATELY 800* C., HEATING SAID MIXTURE UP TO APPROXIMATELY 1200* C. AT A HEATING RATE BETWEEN 15* C. PER HOUR AND 20* C. PER HOUR, TO FORM READILY DISINTEGRABLE AGGREGATES OF SUBSTANTIALLY PURE TUNGSTEN, AND COOLING SAID MIXTURE IN A NON-OXIDIZING ATMOSPHERE TO RETAIN SAID AGGREGATES IN THEIR ELEMENTAL FORM, WHEREBY SAID AGGREGATES MAY BE SUBSEQUENTLY DISINTEGRATED INTO A PULVERULENT MASS OF FINELY DIVIDED TUNGSTEN.