CPC technology class · C25
C25C — Processes FOR THE Electrolytic Production
Processes for the electrolytic production, recovery or refining of metals; apparatus therefor. 753 US utility patents granted 2015–2025, with the leading assignees and year-by-year filing trajectory.
- 753
- US patents granted
- C25
- Parent CPC class
- 20
- Active assignees
- +4%
- 5-yr velocity
CPC subclass C25C — PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR — covers 753 US utility patents granted between 2015 and 2025 according to USPTO PatentsView records. This subclass sits within the broader CPC class C25 (ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR), one of roughly 250 top-level technology categories in the Cooperative Patent Classification system jointly maintained by the USPTO and the European Patent Office. At the subclass level, four-character codes like C25C give the most practical resolution for tracking a specific technology domain without losing sight of adjacent filings. Every grant here has been classified by a USPTO examiner based on the technical disclosure in the patent specification.
The competitive landscape in C25C is shaped by 20 distinct companies actively filing in this space. FREEPORT MINERALS CORPORATION leads with 23 patents, followed by INDUSTRIE DE NORA S.P.A. at 49 grants and United Company RUSAL Engineering and Technology Centre LLC at 25. Concentration at the top of the leaderboard indicates whether this technology area is dominated by a handful of incumbents or fragmented across many filers — a useful signal for investors evaluating competitive moats and for product teams mapping freedom-to-operate risk.
Filing trajectory matters as much as static counts. The yearly series on this page plots grants from 2015 through 2025, highlighting whether innovation in C25C is accelerating, plateauing, or cooling. Technology areas with rising post-2020 activity often reflect emerging markets or new platform shifts, while declining filings can signal mature domains where incremental improvement has slowed. Researchers, licensing professionals, and competitive-intelligence teams use these patterns — together with the top-assignee distribution — to decide where to invest, where to license, and where to avoid entanglement. All counts on this page come directly from USPTO PatentsView and reflect US granted utility patents only.
Is C25C innovation accelerating?
US utility-patent grants per year in C25C, 2015–2025 — recent five years are up 4% versus 2015–2019.
Who leads C25C?
The 12 most active assignees in PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR — wider bars mean more grants
- Freeport Minerals 55
FREEPORT MINERALS CORPORATION
55 patents
- Industrie De Nora S P… 49
INDUSTRIE DE NORA S.P.A.
49 patents
- United Rusal Engineer… 25
United Company RUSAL Engineering and Technology Centre LLC
25 patents
- Rio Tinto Alcan Inter… 36
Rio Tinto Alcan International Limited
36 patents
- Alcoa Usa 34
ALCOA USA CORP.
34 patents
- Outotec (Finland) Oy
OUTOTEC (FINLAND) OY
174 patents
- Metalysis 12
METALYSIS LIMITED
12 patents
- Elysis Partnership 11
ELYSIS LIMITED PARTNERSHIP
11 patents
- Pultrusion Technique 16
PULTRUSION TECHNIQUE INC.
16 patents
- Mangrove Water 15
Mangrove Water Technologies LTD.
15 patents
- Aqua Metals 13
AQUA METALS INC.
13 patents
- Shenzhen Sunxing Ligh… 18
SHENZHEN SUNXING LIGHT ALLOYS MATERIALS CO., LTD.
18 patents
What this shows Freeport Minerals is the most active filer in C25C, holding 23 of the 753 patents in this class. Concentration at the top signals how contestable this technology area is for new entrants.
View data table
| Rank | Company | Patents in C25C |
|---|---|---|
| #1 | FREEPORT MINERALS CORPORATION | 55 |
| #2 | INDUSTRIE DE NORA S.P.A. | 49 |
| #3 | United Company RUSAL Engineering and Technology Centre LLC | 25 |
| #4 | Rio Tinto Alcan International Limited | 36 |
| #5 | ALCOA USA CORP. | 34 |
| #6 | OUTOTEC (FINLAND) OY | 174 |
| #7 | METALYSIS LIMITED | 12 |
| #8 | ELYSIS LIMITED PARTNERSHIP | 11 |
| #9 | PULTRUSION TECHNIQUE INC. | 16 |
| #10 | Mangrove Water Technologies LTD. | 15 |
| #11 | AQUA METALS INC. | 13 |
| #12 | SHENZHEN SUNXING LIGHT ALLOYS MATERIALS CO., LTD. | 18 |
| #13 | GE-Hitachi Nuclear Energy Americas LLC | 215 |
| #14 | Consolidated Nuclear Security, LLC | 81 |
| #15 | ALCOA INC. | 52 |
| #16 | Enlighten Innovations Inc. | 15 |
| #17 | NORSK HYDRO ASA | 25 |
| #18 | Korea Institute Of Geoscience And Mineral Resources | 153 |
| #19 | Outotec Oyj | 54 |
| #20 | OBSHCHESTVO S OGRANICHENNOY OTVETSTVENNOST'YU “OBEDINENNAYA KOMPANIYA RUSAL INZHENERNO-TEKHNOLOGICHESKIY TSENTR” | 13 |
About This Class
CPC subclass C25C belongs to class C25.
753 patents were granted in this class between 2015 and 2025.
20 companies actively patent in this space.
Classification System
Cooperative Patent Classification (CPC) is a hierarchical patent classification system used by the USPTO and EPO.
Frequently Asked Questions
What is CPC class C25C?
How many patents have been filed in C25C?
Which company holds the most patents in C25C?
How is patent data for C25C collected?
What is the difference between CPC class and subclass?
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Explore the patent dataset
Read our methodology — how this data is sourced, computed, and verified.