Process for heavy metal removal from iron- and steelmaking flue dust
US-2026043110-A1 · Feb 12, 2026 · US
Recovery of by-products, e.g. slag
Recovery of by-products, e.g. slag · Cooperative Patent Classification (CPC)
Chemical and metallurgical processes, compounds, and materials.
Related technology areas
Mapped technology topics for this CPC code.
| Metric | Value |
|---|---|
| CPC code | C21B3/04 |
| Official title | Recovery of by-products, e.g. slag |
| Display label | Recovery of by-products, e.g. slag |
| Total patents | 33 |
Filing trend
Year-over-year patent counts classified under this CPC code.
Filing activity over the last five years is growing.
| Year | Patents |
|---|---|
| 2015 | 2 |
| 2016 | 3 |
| 2017 | 2 |
| 2018 | 4 |
| 2019 | 2 |
| 2020 | 6 |
| 2021 | 1 |
| 2022 | 3 |
| 2023 | 2 |
| 2024 | 3 |
| 2025 | 2 |
| 2026 | 3 |
Representative patents
Representative publications under this CPC code from precomputed stats, or recent filings when stats are unavailable.
A method for producing molten pig iron into an electrical smelting unit
US-2026022430-A1 · Jan 22, 2026 · US
A method of manufacturing molten pig iron into an electrical smelting unit
US-2026009095-A1 · Jan 8, 2026 · US
Methods for recovering a target metal from iron or steel slag using at least one of a carbothermic reduction process and a pyro-hydrometallurgical process
US-2025305086-A1 · Oct 2, 2025 · US
Methods for recovering a target metal from iron or steel slag using at least one of a carbothermic reduction process and a pyro-hydrometallurgical process
US-12305260-B2 · May 20, 2025 · US
Processing method
US-12168814-B2 · Dec 17, 2024 · US
Demetallized slag for abrasives and/or roofing granules and related methods
US-2024400873-A1 · Dec 5, 2024 · US
Demetallized slag for abrasives and/or roofing granules and related methods
US-12091605-B2 · Sep 17, 2024 · US
Porous material and method for preparing the same
US-11767271-B2 · Sep 26, 2023 · US
Process for modifying steel slag through acidification and carbonization coupling
US-11572307-B1 · Feb 7, 2023 · US
Methods for recovering a target metal from iron or steel slag using at least one of a carbothermic reduction process and a pyro-hydrometallurgical process
US-2022364200-A1 · Nov 17, 2022 · US
Demetallized slag for abrasives and/or roofing granules and related methods
US-2022332994-A1 · Oct 20, 2022 · US
Method of introducing a metalliferous feed in an ironmaking process
US-2022316017-A1 · Oct 6, 2022 · US
Porous material and method for preparing the same
US-2021221746-A1 · Jul 22, 2021 · US
Slag volume evaluation method for molten metal surface
US-10845352-B2 · Nov 24, 2020 · US
Processing method
US-2020354811-A1 · Nov 12, 2020 · US
Method for eluting calcium from steelmaking slag, and method for collecting calcium from steelmaking slag
US-2020318209-A1 · Oct 8, 2020 · US
Combined system for producing steel and method for operating the combined system
US-10604816-B2 · Mar 31, 2020 · US
Slag volume evaluation method for molten metal surface
US-2020064326-A1 · Feb 27, 2020 · US
Method and system for forming carbonate from steel slag
US-10526669-B2 · Jan 7, 2020 · US
Frequently asked questions
Answers are generated from the same data shown on this page.
- What is CPC C21B3/04?
- CPC C21B3/04 is the Cooperative Patent Classification code for “Recovery of by-products, e.g. slag.”
- How many patents are filed under CPC C21B3/04 (Recovery of by-products, e.g. slag)?
- Our database includes 33 publications tagged with this CPC code.
- Is patent activity under CPC C21B3/04 growing?
- Publication counts under this code: 3 in 2024 vs 2 in 2025 (latest complete years).