Copper Converting Patents: Who Leads, Where the Gaps Are 2026
- 37.4% of the field sits with five assignees. Top 5 combined account for 82 of 219 records in scope, while a long tail of 77 ranked companies files one or two records each.
- Filing peaked in 2023 at 14 records. With publication lag of roughly 18 months, 2025-2026 counts will fill in later and should not be read as a slowdown yet.
- Australia, Canada and the US lead receiving offices. 33, 31 and 30 filings respectively, ahead of the EPO at 26 — a filing footprint shaped by where copper smelting capacity actually sits.
Top-5 share is the combined record count of the five largest assignees divided by all 219 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Copper converting and fire refining is the pyrometallurgical stage between matte production and anode casting: oxidizing sulfur and iron out of copper matte to yield blister copper, then refining that blister to anode-grade copper before casting. This landscape covers 219 published records filed between 2015 and mid-2026, indexed against terms spanning Peirce-Smith converters, tuyere punching, slag skimming, anode casting wheels and fugitive gas capture.
The dataset is dominated by core metallurgical extraction claims, with secondary clusters in furnace hardware and gas or slag analysis instrumentation. Filing is concentrated among a small number of established smelting equipment and mining technology firms, with a long tail of single- or double-filing entrants including universities and national research organisations.
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Filing trend and technology composition
Two views of the same 219 records: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend, 2015-2026
Filing peaked at 14 records in 2023. The most recent years are undercounted because publication typically lags filing by around 18 months, so 2025 and 2026 figures will continue to rise as later filings publish.
IPC subclass composition
C22B (metal extraction and refining) covers 96.3% of the 219 records, confirming this is a tightly bounded metallurgical process area. Secondary classes — C21C steelmaking, furnace hardware under F27B/F27D, and analytical classes G01J/G01N — each sit in single digits, marking smaller but distinct claim clusters around furnace design and process monitoring rather than the core conversion chemistry.
Shares are the percentage of the 219 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Copper Converting and Fire Refining with Eureka
This page is one run against one query. Ask Eureka your own question about copper converting and fire refining and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records in this landscape
Process and apparatus for the continuous refining of blister copper
Copper matte is processed to anode copper without oxidizing blister copper in an anode furnace. Copper matte, in either molten or solid form, is fed to a continuous copper converting furnace in which it is converted to blister copper and slag. The blister copper and slag collect in the settler region and separate into two phases, with the interface actively stirred so that sulfur content in the blister copper phase and copper content in the slag phase are both reduced.Filed by Kennecott Utah Copper LLC, published 2001-04-03.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4657586A | Submerged combustion in molten materials | 82 |
| 2 | US5449395A | Apparatus and process for the production of fire-refined blister copper | 48 |
| 3 | US5888270A | Copper converting | 45 |
| 4 | US6231641B1 | Enhanced phase interaction at the interface of molten slag and blister copper, and an apparatus for promoting… | 36 |
| 5 | US4830667A | Pyrometallurgical copper refining | 31 |
| 6 | US4470845A | Continuous process for copper smelting and converting in a single furnace by oxygen injection | 30 |
| 7 | US4416690A | Solid matte-oxygen converting process | 29 |
| 8 | WO2015081385A1 | Copper processing method | 26 |
| 9 | US20160304988A1 | Copper processing method | 25 |
| 10 | US4572482A | Fluid-cooled metallurgical tuyere | 24 |
Citation counts are drawn from within the searched corpus and favour older filings; they signal influence on subsequent claims, not current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Three findings that shape where to file and where to watch.
Filing is concentrated but not locked up
The top 5 assignees combined hold 82 of 219 records (37.4%), and the top 10 extend that to 66.2%. That still leaves a third of the field spread across a long tail of 77 ranked companies, many filing only once or twice.
Core conversion chemistry dominates the claim space
Almost all records sit in C22B metal extraction and refining, with much smaller secondary clusters in furnace hardware (F27B/F27D) and gas or material analysis (G01J/G01N). These secondary classes mark where instrumentation and monitoring claims are being layered onto established conversion processes.
Activity has not shown a sustained multi-year climb
The trend peaks at 14 records in 2023, without enough complete years post-lag to support a growth-rate claim. Recent-year counts for individual assignees, including the most active ones, show no new filings in the latest year on record — read cautiously given the ~18-month publication lag.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to copper converting and fire refining, with the prior art for and against each one.
Who is filing, and where the field is still open
The leader holds 21 records; fifth place holds 13. Co-assignee pairs point to a small number of recurring research partnerships between mining companies, universities and national labs, most visibly around Chile-based collaborations.
A single leader well ahead of fifth place
The top-ranked assignee holds 21 records against 13 for fifth place, a real but not overwhelming gap — enough to indicate a company setting the pace on core conversion and refining hardware without shutting out challengers.
A wide base of single- and double-filers
Beyond the top 10 (66.2% of records), the ranking runs to 77 companies total, many represented by only one or two filings. This is typical of a mature process area where incremental improvements come from equipment vendors and research institutes rather than a handful of majors.
Research partnerships cluster around specific pairs
Ten co-assignee pairs appear in the data, with the strongest pairs each sharing 13 records — including university and national-mining-research combinations. These recurring pairings suggest joint R&D programmes rather than one-off collaborations.
| Assignee | Recent year | YoY |
|---|---|---|
| Kennecott Copper Corp | 0 | — |
| University of Chile | 0 | — |
| Outotec Oyj | 0 | — |
| Mitsubishi Materials Corp | 0 | — |
| Isasmelt Mining Ltd | 0 | — |
| Commonwealth Scientific and Industrial Research Organisation (CSIRO) | 0 | — |
| Glencore Technology Pty Ltd | 0 | — |
| RHI NON FERROUS METALS ENG | 0 | — |
Where to take this
The dataset points to specific next steps depending on whether you are scoping freedom-to-operate or deciding where to file.
Check the under-claimed branches first
Instrumentation and monitoring claims (G01J, G01N) sit far below the core C22B density, and fugitive gas capture and casting wheel process control show light coverage relative to the core conversion chemistry.
Explore white space in EurekaTrack the leading assignees' filing behaviour
With the top 5 holding 37.4% of records and recent-year momentum flat across the most active filers, a shift in any one company's filing pace is a meaningful early signal.
Set up assignee monitoring in EurekaRead the most-cited records before drafting claims
The five highest-cited records anchor much of the surrounding claim language on blister copper production and phase interaction; understanding what they actually cover narrows the search fast.
Review cited records in EurekaCommon questions on copper converting patents
The dataset's leading assignee holds 21 of the 219 records in scope, with fifth place at 13. The top 5 assignees together account for 82 records, or 37.4% of the field, while the top 10 extend to 66.2%. Beyond that, the ranking runs to 77 companies total, most filing only one or two records, so the field is concentrated at the top but not closed to new entrants.
Almost all records, 96.3% of the 219 in scope, classify under IPC subclass C22B, metal extraction and refining, confirming this is a tightly bounded process area. Smaller clusters appear in furnace hardware (F27B, F27D), steelmaking-adjacent processes (C21C), and analytical instrumentation (G01J for radiation measurement, G01N for material testing), each covering under 10% of records and marking distinct secondary claim spaces around monitoring and furnace design.
Filing activity peaked at 14 records in 2023, but there are not enough complete years after accounting for publication lag to state a reliable growth rate. Publication typically lags filing by around 18 months, so the most recent one to two years in any trend chart will understate true filing activity. Recent-year momentum figures for the most active assignees show no new filings in the latest year, but this should be read as a data-lag artefact rather than a confirmed slowdown.
Australia leads receiving offices with 33 filings, followed by Canada at 31, the United States at 30, the European Patent Office at 26, Finland at 20, and the WIPO PCT route at 15. This spread reflects where major copper smelting operations and equipment suppliers are based rather than any single dominant jurisdiction, so a freedom-to-operate review should not assume US-only coverage is sufficient.
US6210463B1, filed by Kennecott Utah Copper LLC, covers a continuous copper converting furnace process where copper matte is converted to blister copper and slag without oxidizing the blister copper in a separate anode furnace, using active stirring at the blister-slag interface to reduce sulfur and copper losses. It is a specific apparatus-and-process claim tied to continuous, single-furnace conversion with interface agitation, not a blanket claim over converting or fire refining generally. Anyone working on batch Peirce-Smith conversion, alternative interface designs, or separate anode-furnace refining sits outside its core claim scope, though a detailed claim-by-claim comparison is still warranted before filing nearby.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.