IPC Subgroup
C21B 3/04 Recovery of by-products, e.g. slag
Introduced: September 1968
Last revised: January 2006
Full Title
General features in the manufacture of pig-iron > Recovery of by-products, e.g. slag
Classification Context
- Section:
- CHEMISTRY; METALLURGY
- Class:
- METALLURGY OF IRON
- Subclass:
- MANUFACTURE OF IRON OR STEEL
Related Keywords
treatment of SLAG in iron production
1 direct subcode
Child Classifications
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- C21B 3/06 Treatment of liquid slag
Top Applicants
Top 10 applicants by patent filingsfor class C21, 2013–2023, worldwide · Source: EPO PATSTAT
- JFE STEEL JP 7,470
- POSCO (POHANG IRON AND STEEL COMPANY) KR 4,615
- JFE STEEL 4,538
- NIPPON STEEL CORPORATION JP 4,536
- ARCELORMITTAL LU 2,597
- NSSMC (NIPPON STEEL & SUMITOMO METAL) JP 2,241
- ANGANG STEEL COMPANY 2,126
- NSSMC (NIPPON STEEL & SUMITOMO METAL) 1,783
- BAOSHAN IRON & STEEL COMPANY 1,620
- HYUNDAI STEEL COMPANY KR 1,545