C01B 21/46
Purification
Official title: Purification; Separation {; Stabilisation (C01B21/40 takes precedence)}
C01B21/46 (Purification) appears on 39 US grants and 29 published applications in this corpus.
Search patents in C01B- Granted patents
- 39
- Published applications
- 29
- Assignees
- 43
- Inventors
- 120
- Latest grant
- 14 Oct 2025
Filings by year
| Year | Granted patents | Published applications |
|---|---|---|
| 1976 | 2 | 0 |
| 1977 | 1 | 0 |
| 1978 | 1 | 0 |
| 1979 | 1 | 0 |
| 1980 | 0 | 0 |
| 1981 | 1 | 0 |
| 1982 | 2 | 0 |
| 1983 | 0 | 0 |
| 1984 | 0 | 0 |
| 1985 | 1 | 0 |
| 1986 | 0 | 0 |
| 1987 | 0 | 0 |
| 1988 | 0 | 0 |
| 1989 | 0 | 0 |
| 1990 | 1 | 0 |
| 1991 | 1 | 0 |
| 1992 | 2 | 0 |
| 1993 | 2 | 0 |
| 1994 | 3 | 0 |
| 1995 | 0 | 0 |
| 1996 | 1 | 0 |
| 1997 | 2 | 0 |
| 1998 | 1 | 0 |
| 1999 | 0 | 0 |
| 2000 | 1 | 0 |
| 2001 | 1 | 0 |
| 2002 | 1 | 1 |
| 2003 | 1 | 1 |
| 2004 | 0 | 0 |
| 2005 | 0 | 1 |
| 2006 | 0 | 1 |
| 2007 | 1 | 0 |
| 2008 | 1 | 1 |
| 2009 | 0 | 0 |
| 2010 | 1 | 0 |
| 2011 | 0 | 0 |
| 2012 | 0 | 2 |
| 2013 | 0 | 1 |
| 2014 | 0 | 0 |
| 2015 | 1 | 0 |
| 2016 | 0 | 2 |
| 2017 | 1 | 0 |
| 2018 | 0 | 0 |
| 2019 | 0 | 0 |
| 2020 | 0 | 2 |
| 2021 | 0 | 1 |
| 2022 | 2 | 5 |
| 2023 | 1 | 4 |
| 2024 | 2 | 4 |
| 2025 | 3 | 3 |
By publication year. Applications have been published since 2001.
Recent patents
- Method of cleaning an apparatus used in the concentration of a mineral acid14 Oct 2025US 12,441,614 B2Covestro Deutschland AG
- Method for preparing electronic grade inorganic acids from waste acid solution19 Aug 2025US 12,391,549 B2Green Advanced Technology Ltd.
- Bleaching tower and method for nitric acid production18 Mar 2025US 12,252,399 B2Yara International Asa
- Plant for the production of nitric acid, a related process and method of revamping29 Oct 2024US 12,129,170 B2Casale SA
- Plant for the production of nitric acid, a related process and method of revamping11 Jun 2024US 12,006,211 B2Casale SA
- Catalyst support system for ammonia oxidation burners16 Oct 2025US 2025/0319450 A1Casale SA
- Mono pressure system for producing nitric acid and method of operating thereof20 Mar 2025US 2025/0091869 A1Yara International Asa
- Mono pressure system for producing nitric acid and method of operating thereof9 Jan 2025US 2025/0011171 A1Yara International Asa
- Dual pressure system for producing nitric acid and method of operating thereof17 Oct 2024US 2024/0343577 A1Yara International Asa
- Device and method for on-line continuous recovery of excess nitric acid in nitration reaction25 Jul 2024US 2024/0246820 A1Fudan University
Most cited
By later US patents
- Membrane solvent extraction82US 3,956,112 AAllied Chemical Corporation · 1976
- Apparatus and method for distilling waste liquids18US 6,508,915 B1Fujitsu Limited · 2003
- Acid recycling system16US 5,264,123 A1993
- Process for denitration of exhaust gas14US 4,110,183 AKobe Steel, Ltd. · 1978
- Point-of-use recycling of wafer cleaning substances14US 5,632,866 AFSI International, Inc. · 1997