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.

Compiled byPlainPatent Editorial, US Patent Intelligence Editorial Team · May 15, 2026

753
US patents granted: C25
Parent CPC class: 20
Active assignees: +4%
5-yr velocity

The verdict

Processes FOR THE Electrolytic Production ranks #489 of 670 CPC technology areas - 753 US patents granted since 2015, with filing up 4% over five years.

#489
of 670 CPC technology areas: 753
US patents granted, 2015–2025: Freeport Minerals
leading assignee (23): +4%
filing velocity, last 5 yrs

Top assignee: Freeport Minerals Corporation (23 patents)

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, within the broader CPC class C25 (ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR). See our CPC classification guide for how the system works.

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 18 grants and United Company Rusal Engineering And Technology Centre Llc at 17.

Filing activity in C25C is up 4% over the past five years versus 2015-2019, a relatively steady filing pace. All counts 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.

Freeport Minerals

23
Industrie De Nora S P…

18
United Rusal Engineer…

17
Rio Tinto Alcan Inter…

13
Alcoa Usa

13
Outotec (Finland) Oy

12
Metalysis

12
Elysis Partnership

11
Pultrusion Technique

10
Mangrove Water

10
Aqua Metals

10
Shenzhen Sunxing Ligh…

8

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

Top patent holders in CPC subclass C25C
Rank	Company	Patents in C25C
#1	Freeport Minerals Corporation	23
#2	Industrie DE NORA S.p.a.	18
#3	United Company Rusal Engineering And Technology Centre Llc	17
#4	Rio Tinto Alcan International Limited	13
#5	Alcoa USA Corp.	13
#6	Outotec (finland) OY	12
#7	Metalysis Limited	12
#8	Elysis Limited Partnership	11
#9	Pultrusion Technique Inc.	10
#10	Mangrove Water Technologies Ltd.	10
#11	AQUA Metals Inc.	10
#12	Shenzhen Sunxing Light Alloys Materials Co., Ltd.	8
#13	Ge-hitachi Nuclear Energy Americas Llc	7
#14	Consolidated Nuclear Security, Llc	7
#15	Alcoa Inc.	7
#16	Enlighten Innovations Inc.	7
#17	Norsk Hydro ASA	6
#18	Korea Institute Of Geoscience And Mineral Resources	5
#19	Outotec Oyj	5
#20	Obshchestvo S Ogranichennoy Otvetstvennost'yu “obedinennaya Kompaniya Rusal Inzhenerno-tekhnologicheskiy Tsentr”	5

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.

← All Technology Classes Technology Rankings →

Footprint here vs. claim strategy

Each dot is a leading C25C assignee, placed by how many patents it holds in this class (horizontal) against its company-wide average claims per patent (vertical) - a read on whether the class is led by broad-but-shallow filers or focused deep-claim players.

Top 14 C25C assignees by class footprint. Bubble size = patents in C25C. Source: USPTO PatentsView (claim depth is company-wide across all classes).

Frequently Asked Questions

What is CPC class C25C?

CPC subclass C25C covers PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR. It belongs to CPC class C25 (ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR), with 753 US utility patents granted since 2015.

How many patents have been filed in C25C?

753 US utility patents were granted in CPC subclass C25C between 2015 and 2025, based on USPTO PatentsView data.

Which company holds the most patents in C25C?

Freeport Minerals Corporation leads C25C with 23 patents, making it the most active assignee in this technology area.

How is patent data for C25C collected?

Patent data comes from USPTO PatentsView, a public research dataset maintained by the United States Patent and Trademark Office. It covers all US granted utility patents and assigns CPC codes based on the technology described in each patent.

What is the difference between CPC class and subclass?

A CPC class (e.g., C25) is a broad technology category. Subclasses like C25C provide finer granularity within that category. PlainPatent organizes data at the subclass level (4-character codes) for the most useful view of technology domains.

Read our methodology - how this data is sourced, computed, and verified.

Data sourced from USPTO PatentsView - official U.S. government patent data. See our methodology for computation details. Retrieved and formatted by PlainPatent Editorial

Every figure on PlainPatent is rendered directly from USPTO source data, no number is typed in by an editor. This page draws directly on USPTO source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.