C
CHEMISTRY; METALLURGY
C
CHEMISTRY; METALLURGY
C22
METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
C22
METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
C22B
PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
C22B
PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
11/00
Obtaining noble metals
11/00
Obtaining noble metals