Column Flotation Patents: Who Leads, Where the Gaps Are 2026
- One assignee holds 158 of 231 records. the top 5 combined account for 90.9% of all filings in scope, leaving a thin tail below them.
- Filing has cooled from its 2018 peak of 98. the tracked 2021→2024 window shows a 22% decline, though 2025–2026 figures are still filling in under publication lag.
- B03D flotation classes cover 95.7% of records. but B01F mixing and stirring (29.0%) and C02F water treatment (12.6%) mark the adjacent claim space.
Filing growth compares 2021 (18 records) with 2024 (14) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 231 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
Column flotation and fine particle recovery patents span the mechanics of bubble-particle attachment, wash water distribution and froth crowding control that separate hydrophobic from hydrophilic particles at fine size fractions. The search set combines column flotation and fine particle flotation terminology with the specific operating controls — bias water rate, froth carrying capacity, axial mixing — that distinguish column technology claims from conventional mechanical cell flotation. This is a mature, narrowly-defined corner of mineral processing and water treatment IP rather than a broad flotation category.
231 published records sit in scope from 2015 through the 2026-07-31 cut-off. The dataset is small enough that a single dominant assignee shapes the entire competitive picture, and the receiving-office spread points to where enforcement and freedom-to-operate questions concentrate in practice.
Filing trend and technology composition
Two views of the same 231 records: how filing activity has moved year over year, and which IPC subclasses the claims actually sit in.
Filing trend, 2017–2026
Filings ran from 7 in 2017 to a peak of 98 in 2018, then eased through the following years. The tracked 2021 (18) to 2024 (14) window shows a 22% decline; 2025 and 2026 figures will keep revising upward as publication catches up to filing dates.
IPC subclass composition
B03D (Flotation) covers 95.7% of the 231 records, confirming this is a tightly-scoped flotation dataset. B01F (Mixing & stirring) at 29.0% and C22B (Metal extraction & refining) at 16.0% mark the two largest adjacent classes, with C02F (Water & wastewater treatment) at 12.6% showing a smaller but distinct cluster. Because records can carry multiple IPC codes, these shares sum to more than 100% of the record total.
Shares are the percentage of the 231 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Column Flotation and Fine Particle Recovery with Eureka
This page is one run against one query. Ask Eureka your own question about column flotation and fine particle recovery and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited patents in this space
US5814210A — Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column flotation
A method and apparatus are disclosed for the microbubble flotation separation of very fine and coarse particles, especially coal and minerals, so as to produce high purity and high recovery efficiency. This is accomplished through the use of a flotation column, microbubbles, recycling of the flotation pulp, and countercurrent wash water to gently wash the froth. Also disclosed are unique processes and apparatus for generating microbubbles for flotation in a highly efficient and inexpensive manner using either a porous tube or in-line static generators.Filed by Virginia Tech Intellectual Properties, granted 1998-09-29.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US4981582A | Process and apparatus for separating fine particles by microbubble flotation together with a process and appa… | 150 |
| 2 | US5167798A | Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column fl… | 123 |
| 3 | US5814210A | Apparatus and process for the separation of hydrophobic and hydrophilic particles using microbubble column fl… | 89 |
| 4 | US5397001A | Apparatus for the separation of hydrophobic and hydrophilic particles using microbubble column flotation toge… | 85 |
| 5 | WO1997045203A1 | Method and apparatus for controlling froth flotation machines | 67 |
| 6 | WO2008156795A1 | Process and apparatus for adsorptive bubble separation | 31 |
| 7 | US5746910A | Frothless flotation apparatus | 29 |
| 8 | US20100181234A1 | Process and apparatus for adsorptive bubble separation | 21 |
| 9 | US5122261A | Concentration of minerals | 20 |
| 10 | US5294003A | Process for concentration of minerals | 18 |
Citation counts favour older records and should be read as a signal of influence within this searched corpus, not as a measure of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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The concentration and citation patterns here are unusually sharp for a 231-record dataset, and that changes how a freedom-to-operate review should be scoped.
One assignee dominates the entire field
The leading assignee alone holds 158 of the 231 records in scope, and the top 5 combined reach 90.9% of all filings. A landscape this concentrated means most freedom-to-operate work reduces to a small number of families rather than a broad competitor map.
Recent activity is a single-company story
The leading assignee filed 12 records in the latest year against a near-zero prior year, while every other ranked assignee shows no recent-year activity. Momentum in this dataset is not distributed — it tracks one company's filing cadence.
Foundational microbubble patents anchor the field
The four most-cited records all describe microbubble column flotation apparatus and process, with citation counts running from 85 to 150. These early patents still frame how later claims are drafted around wash water and bubble generation.
Filing activity clusters around mining jurisdictions
Australia (43), EPO (34) and the United States (23) lead the receiving-office count, with Canada (19) and WIPO/PCT (19) close behind. That spread follows mineral-processing geography more than general industrial filing patterns.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to column flotation and fine particle recovery, with the prior art for and against each one.
Who holds the claim space
The assignee ranking covers 19 companies and is not a top-50 or top-100 cut — this is the entire ranked field the data endpoint returns for this search.
A single assignee dominates by scale
This assignee's filing volume is more than five times the combined total of the next four ranked companies, and its latest-year activity (+1100% YoY) suggests continued investment rather than a legacy filing position.
The tail thins out fast
Filing volume drops sharply outside the top few positions — fifth place holds 9 records and tenth place holds just 1. Most ranked assignees in this dataset are single- or few-filing entrants rather than sustained programmes.
Collaboration is limited and mostly corporate-internal
Only 10 co-assignee pairs appear across the dataset, and the strongest pairs link entities that are effectively the same corporate group under different naming, or successive corporate identities of the same company.
| Assignee | Recent year | YoY |
|---|---|---|
| Metso Outotec Finland Oy | 12 | +1100% |
| Outotec (Finland) Oy | 0 | — |
| Renewable Algal Energy LLC | 0 | — |
| Eriez Manufacturing Co | 0 | — |
| Eastman Chemical Company | 0 | — |
| Virginia Tech Intellectual Properties, Inc. | 0 | — |
| HOLLINGSWORTH CLINTON A | 0 | — |
| Baker Hughes Holdings LLC | 0 | — |
Where to take this landscape
The concentration at the top and the thin tail below it both suggest specific next steps depending on whether you are filing, licensing or watching the space.
Map the leader's claim boundaries precisely
With one assignee holding 158 of 231 records, a targeted claim-chart review of that portfolio will tell you more than a broad competitor scan.
Run a claim comparison in EurekaCheck the under-claimed branches before drafting
C12M, C12N and B03B overlaps carry single-digit record counts here — verify whether that reflects genuine white space or simply thin search coverage.
Explore adjacent classes in EurekaTrack the leader's momentum, not the aggregate trend
Aggregate filings look flat to declining, but that masks one assignee's +1100% YoY jump — set an alert on that entity specifically.
Set a monitoring alert in EurekaCommon questions on this landscape
One assignee holds 158 of the 231 records in this dataset, roughly five times the combined volume of the next four ranked companies. That single company also accounts for essentially all of the most recent year's filing activity, showing a +1100% year-over-year jump. Any freedom-to-operate review in this space should start by mapping that one portfolio in detail before looking at the rest of the ranked field.
Filing peaked in 2018 at 98 records and has since declined; the most recent complete comparison, 2021 (18) to 2024 (14), shows a 22% drop. Figures for 2025 and 2026 are still incomplete because publication typically lags filing by around 18 months, so those years will revise upward over time. Treat the recent apparent slowdown as partly a data-lag artifact rather than a confirmed trend.
US5814210A, assigned to Virginia Tech Intellectual Properties, claims apparatus and process for separating hydrophobic and hydrophilic particles using microbubble column flotation, including countercurrent wash water froth washing and specific microbubble generation methods using porous tubes or in-line static generators. It sits among the four most-cited records in this dataset, with citation counts from related family members ranging from 85 to 150. Anyone designing a microbubble-based column flotation system should review this family's claim scope closely before finalizing bubble generation or wash water mechanisms.
B03D (Flotation) covers 95.7% of the 231 records, but adjacent classes carry much lower density: C12M (bioreactors) and C12N (microorganisms) each sit at 2.6%, and B03B (wet separation of solids) at 1.3%. These lower counts suggest either genuine white space around bioprocessing-integrated flotation and hybrid wet separation, or simply narrower search coverage in those areas — worth verifying with a targeted search before assuming the gap is real.
Australia leads receiving offices with 43 filings, followed by the European Patent Office at 34 and the United States at 23; Canada and WIPO/PCT each show 19. This pattern tracks mineral-processing geography — Australia and Canada are major mining jurisdictions — more than it reflects general industrial patent filing trends. A company assessing enforcement risk should weight Australian and Canadian filings accordingly.
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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.