C21B 13/105
Rotary hearth-type furnaces
Official title: {Rotary hearth-type furnaces}
C21B13/105 (Rotary hearth-type furnaces) appears on 165 US grants and 154 published applications in this corpus.
Search patents in C21B- Granted patents
- 165
- Published applications
- 154
- Assignees
- 59
- Inventors
- 269
- Latest grant
- 12 May 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 1 | 0 |
| 1977 | 1 | 0 |
| 1978 | 0 | 0 |
| 1979 | 0 | 0 |
| 1980 | 1 | 0 |
| 1981 | 0 | 0 |
| 1982 | 0 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 2 | 0 |
| 1987 | 3 | 0 |
| 1988 | 1 | 0 |
| 1989 | 0 | 0 |
| 1990 | 0 | 0 |
| 1991 | 0 | 0 |
| 1992 | 0 | 0 |
| 1993 | 1 | 0 |
| 1994 | 0 | 0 |
| 1995 | 0 | 0 |
| 1996 | 2 | 0 |
| 1997 | 2 | 0 |
| 1998 | 2 | 0 |
| 1999 | 7 | 0 |
| 2000 | 12 | 0 |
| 2001 | 18 | 9 |
| 2002 | 13 | 11 |
| 2003 | 16 | 11 |
| 2004 | 8 | 12 |
| 2005 | 3 | 5 |
| 2006 | 4 | 13 |
| 2007 | 3 | 8 |
| 2008 | 4 | 3 |
| 2009 | 3 | 11 |
| 2010 | 9 | 14 |
| 2011 | 8 | 10 |
| 2012 | 11 | 12 |
| 2013 | 8 | 7 |
| 2014 | 3 | 2 |
| 2015 | 3 | 7 |
| 2016 | 2 | 1 |
| 2017 | 1 | 3 |
| 2018 | 3 | 1 |
| 2019 | 2 | 3 |
| 2020 | 2 | 2 |
| 2021 | 0 | 0 |
| 2022 | 3 | 0 |
| 2023 | 1 | 0 |
| 2024 | 0 | 5 |
| 2025 | 0 | 0 |
| 2026 | 1 | 4 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Recent patents
- Process and system for the production of iron nuggets12 May 2026US 12,624,406 B2Carbontec Energy Corporation
- Oxide ore smelting method21 Mar 2023US 11,608,543 B2Sumitomo Metal Mining Co., Ltd.
- Method for smelting oxide ore25 Oct 2022US 11,479,832 B2Sumitomo Metal Mining Co., Ltd.
- Rotary hearth furnace, and method for producing reduced iron using rotary hearth furnace30 Aug 2022US 11,428,468 B2Kobe Steel, Ltd.
- Reduced iron production method5 Apr 2022US 11,293,068 B2Kobe Steel, Ltd.
- Method for producing metallic iron25 Jun 2026US 2026/0176707 A1Jef Steel Corporation
- A method for manufacturing pig iron in an electrical smelting furnace and associated furnace25 Jun 2026US 2026/0176708 A1
- Non-fired pellets for reduction and method for producing same12 Feb 2026US 2026/0043102 A1Jfe Steel Corporation
- Fired pellets for reduction and method for producing same29 Jan 2026US 2026/0028688 A1Jfe Steel Corporation
- Direct bath smelting process with fast quench of molten material in hot offgas22 Aug 2024US 2024/0279757 A1Nucor Corporation
Most cited
By later US patents
- Method of producing iron using rotary hearth and apparatus73US 4,701,214 AMidrex International B.V. Rotterdam · 1987
- Method of producing a reduced metal, and traveling hearth furnace for producing same73US 6,126,718 AKawasaki Steel Corporation · 2000
- Method of direct iron-making / steel-making via gas or coal-based direct reduction and apparatus61US 6,648,942 B2Midrex International B.V. Rotterdam, Zurich Branch · 2003
- Direct reduction process in a rotary hearth furnace56US 5,186,741 AZia Patent Company · 1993
- Method for rapid reduction of iron oxide in a rotary hearth furnace53US 5,730,775 AMidrex International B.V. Rotterdam, Zurich Branch · 1998