Heterocyclic compounds

Introduced: January 1990

Last revised: January 2006

Full Title

Extraction of metal compounds from ores or concentrates by wet processes > Treatment or purification of solutions, e.g. obtained by leaching > by liquid-liquid extraction using organic compounds > Heterocyclic compounds

Classification Context

Section:: CHEMISTRY; METALLURGY
Class:: METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
Subclass:: PRODUCTION OR REFINING OF METALS; PRETREATMENT OF RAW MATERIALS

Top Applicants

Top 10 applicants by patent filingsfor class C22, 2013–2023, worldwide · Source: EPO PATSTAT

JFE STEEL JP 7,152
NIPPON STEEL CORPORATION JP 5,416
POSCO (POHANG IRON AND STEEL COMPANY) KR 4,530
JFE STEEL 3,986
CENTRAL SOUTH UNIVERSITY 3,086
NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 2,843
CHINESE ACADEMY OF SCIENCES 2,702
ARCELORMITTAL LU 2,124
NSSMC (NIPPON STEEL & SUMITOMO METAL) 2,075
KOBE STEEL JP 1,891