C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
C22B34/00—Obtaining refractory metals
C22B34/30—Obtaining chromium, molybdenum or tungsten
C22B34/32—Obtaining chromium
B—PERFORMING OPERATIONS; TRANSPORTING
B22—CASTING; POWDER METALLURGY
B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
B22F1/14—Treatment of metallic powder
B22F1/145—Chemical treatment, e.g. passivation or decarburisation
C—CHEMISTRY; METALLURGY
C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
C22C—ALLOYS
C22C1/00—Making non-ferrous alloys
C22C1/04—Making non-ferrous alloys by powder metallurgy