C21B 13/00
Making spongy iron or liquid steel, by direct processes
C21B13/00 (Making spongy iron or liquid steel, by direct processes) appears on 1,700 US grants and 1,110 published applications in this corpus.
Search patents in C21B- Granted patents
- 1,700
- Published applications
- 1,110
- Assignees
- 606
- Inventors
- 2,613
- Latest grant
- 6 Oct 2026
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 37 | 0 |
| 1977 | 44 | 0 |
| 1978 | 39 | 0 |
| 1979 | 32 | 0 |
| 1980 | 45 | 0 |
| 1981 | 39 | 0 |
| 1982 | 32 | 0 |
| 1983 | 44 | 0 |
| 1984 | 26 | 0 |
| 1985 | 27 | 0 |
| 1986 | 24 | 0 |
| 1987 | 31 | 0 |
| 1988 | 32 | 0 |
| 1989 | 34 | 0 |
| 1990 | 26 | 0 |
| 1991 | 28 | 0 |
| 1992 | 18 | 0 |
| 1993 | 22 | 0 |
| 1994 | 19 | 0 |
| 1995 | 39 | 0 |
| 1996 | 37 | 0 |
| 1997 | 30 | 0 |
| 1998 | 39 | 0 |
| 1999 | 61 | 0 |
| 2000 | 51 | 0 |
| 2001 | 99 | 21 |
| 2002 | 69 | 45 |
| 2003 | 55 | 26 |
| 2004 | 18 | 38 |
| 2005 | 12 | 21 |
| 2006 | 11 | 42 |
| 2007 | 15 | 27 |
| 2008 | 14 | 22 |
| 2009 | 27 | 42 |
| 2010 | 31 | 50 |
| 2011 | 31 | 40 |
| 2012 | 37 | 55 |
| 2013 | 44 | 35 |
| 2014 | 30 | 46 |
| 2015 | 37 | 41 |
| 2016 | 31 | 38 |
| 2017 | 25 | 26 |
| 2018 | 24 | 29 |
| 2019 | 28 | 21 |
| 2020 | 23 | 24 |
| 2021 | 19 | 44 |
| 2022 | 17 | 50 |
| 2023 | 24 | 66 |
| 2024 | 32 | 95 |
| 2025 | 54 | 87 |
| 2026 | 37 | 79 |
By publication year. Applications have been published since 2001. 2026 runs to 8 Oct.
Subgroups
Granted patents
- C21B 13/0006Obtaining iron or steel in a molten state417
- C21B 13/14Multi-stage processes processes carried out in different vessels or furnaces399
- C21B 13/0073Selection or treatment of the reducing gases273
- C21B 13/10In hearth-type furnaces239
- C21B 13/02In shaft furnaces233
- C21B 13/12In electric furnaces175
- C21B 13/0033In fluidised bed furnaces or apparatus containing a dispersion of the material155
- C21B 13/0046Making metallised agglomerates or iron oxide146
All 16 subgroupsShow fewer
- C21B 13/0086Conditioning, transformation of reduced iron ores139
- C21B 13/0066Preliminary conditioning of the solid carbonaceous reductant136
- C21B 13/08In rotary furnaces111
- C21B 13/006Starting from ores containing non ferrous metallic oxides89
- C21B 13/008Use of special additives or fluxing agents72
- C21B 13/004In a continuous way by reduction from ores49
- C21B 13/04In retorts28
- C21B 13/06In multi-storied furnaces20
Recent patents
- Method for manufacturing direct reduced iron and DRI manufacturing equipment6 Oct 2026US 12,753,452 B2ArcelorMittal
- Wire rod for 5000 MPa-grade diamond wire and production method therefor15 Sep 2026US 12,735,763 B2Institute of Research of Iron and Steel, Jiangsu Province/Sha-Steel, Co. Ltd (Cn)
- Zigzag flow reactor for heterogenous thermochemical reduction8 Sep 2026US 12,728,457 B2Arizona Board of Regents on behalf of Arizona State University
- High-carbon biogenic reagents and uses thereof1 Sep 2026US 12,723,211 B2Carbon Technology Holdings, LLC
- Method for producing liquid pig iron from a DRI product25 Aug 2026US 12,716,105 B2SMS group GmbH
- Reoxidation retardant and method for hindering reoxidation of direct reduced iron8 Oct 2026US 2026/0308704 A1
- Method of producing reduced iron8 Oct 2026US 2026/0308705 A1Jfe Steel Corporation
- Zigzag flow reactor for heterogenous thermochemical reduction1 Oct 2026US 2026/0295671 A1Arizona Board of Regents on behalf of Arizona State University
- Novel process for the smelting of a blend of hot and cold metalliferous feedstock material yielding reduced carbon emissions1 Oct 2026US 2026/0297695 A1Metix (Proprietary) Limited
- Cold water, wide range wet venturi scrubber for a direct reduction plant1 Oct 2026US 2026/0297696 A1Midrex Technologies, Inc.
Most cited
By later US patents
- Cryoplasty device and method384US 5,868,735 ASciMed Life Systems, Inc. · 1999
- Cryoplasty device and method227US 6,290,696 B1SciMed Life Systems, Inc. · 2001
- Cryoplasty device and method182US 6,648,878 B2SciMed Life Systems, Inc. · 2003
- Cryoplasty device and method170US 7,022,120 B2SciMed Life Systems, Inc. · 2006
- Method and system for energy-optimized and CO2 emission-optimized iron production101US 8,419,825 B2Siemens Vai Metals Technologies GmbH · 2013