Bottom Ash Recycling Patents: Top Companies & Filing Trends 2026
- 81.1% of all 37 records sit with just five assignees, while the ranked leaders' list of 12 companies accounts for every record in scope — a field with almost no unranked long tail.
- Filings grew 50% from 2021 to 2024, the last complete filing year, after peaking at 18 records in 2022 — the field is still active, not winding down.
- C04B and B09B dominate covering 67.6% and 59.5% of records respectively, while wet separation (B03B) and roads (E01C) each sit near 11-14% — a sign of where claim space is thinner.
Filing growth compares 2021 (2 records) with 2024 (3) — 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 37 records in scope (CR5), not by the ranked leaders only.
What the bottom ash recycling patent record actually shows
Incineration bottom ash (IBA) recycling patents cluster around three practical problems: getting metals out of the ash, turning the residue into a usable aggregate, and controlling how much leaches once that aggregate is in the ground or in concrete. The search scope here pulls together metal recovery, aggregate substitution, weathering treatment, leaching test, chloride washing and construction application claims, which is why cement and construction-materials classifications outweigh pure waste-processing ones in the class breakdown below.
With only 37 published records in scope, this is a compact field rather than a crowded one. That makes the concentration at the top more informative than in a larger dataset: a small number of assignees have effectively defined the claim space, and the filing offices in scope skew toward the United States, Singapore and PCT routes rather than a single dominant jurisdiction.
Filing trend and technology composition
Publication lags filing by roughly 18 months, so 2025 and 2026 figures in the trend chart understate real activity; treat the 2024 figure as the last complete year.
A decade of uneven but rising activity
Filings began at 1 record in 2017, built steadily, and peaked at 18 records in 2022. The 2021-to-2024 span shows a 50% increase, from 2 to 3 records, confirming the field kept expanding into its most recent complete year rather than plateauing.
Cement and waste-disposal classes carry the weight
C04B (ceramics, cement and refractories) appears in 67.6% of the 37 records and B09B (solid waste disposal) in 59.5%, confirming that most patent activity treats bottom ash as a construction-material feedstock first and a waste stream second. B28C (mortar and concrete mixing) at 32.4% reinforces that pattern, while B01J, A62D, C08L, E01C and B03B each sit under 19%, marking narrower but still active sub-routes.
Shares are the percentage of the 37 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Bottom Ash Recycling with Eureka
This page is one run against one query. Ask Eureka your own question about bottom ash recycling and every answer comes back with the patent numbers behind it.
Try EurekaThe records shaping this field
WO2026049677A1 — Method of inhibiting metal leaching from incineration bottom ash
The invention provides a method of inhibiting metal leaching from incineration bottom ash (IBA), the method comprising providing a carbonated IBA, and subjecting the carbonated IBA to one or more solidification reactions comprising adding a binder to the carbonated IBA. The carbonated IBA may be provided by a process comprising mixing an aqueous solution comprising a carbonation agent with the IBA for a period of time to obtain a carbonated IBA mixture and filtering the carbonated IBA mixture to obtain the carbonated IBA and a filtrate. The invention also provides a method of regenerating a carbonation agent from that filtrate through a carbon-based recovery step.Filed by Agency for Science, this 2026 filing sits at the newest edge of the dataset and illustrates the carbonation-plus-solidification route now being claimed around leaching control.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US20110251449A1 | Treatment of fly ash | 17 |
| 2 | US20170370050A1 | Waste to energy ash and engineered aggregate in road construction | 15 |
| 3 | US8349282B2 | Treatment of fly ash | 10 |
| 4 | WO2019212418A1 | A method and system for heavy metal immobilization | 6 |
| 5 | US20230033496A1 | Waste to energy ash and engineered aggregate in road construction | 4 |
| 6 | WO2024242625A1 | Green leaching of sewage sludge ash | 1 |
| 7 | US20240208861A1 | Low-cost four-element system cementitious material, preparation method and application thereof | 1 |
| 8 | WO2024112673A1 | A novel process and flotation chemistry for valuable metal recovery from municipal solid waste incineration (… | 1 |
Citation counts favour older filings inside a searched corpus; read them as a signal of influence on later filers, not as a ranking of current importance.
Publication numbers are shown where the record carries one (8 of 8 rows); clicking a row searches Eureka by that number.
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Browse MCP servers →What the data means for a filing decision
Three patterns are worth acting on before drafting new claims in this space.
The field is small and already claimed by a handful of players
With the top 5 of the ranked 12 assignees holding 81.1% of all 37 records, and the top 10 accounting for 100.0%, there is effectively no unranked long tail in this dataset. Any new entrant is filing directly against a known, short list of holders rather than into open space.
Activity is still rising, not cooling
The peak year so far is 2022 at 18 records, and the 2021-to-2024 window still shows growth of 50%. Because publication lags filing by about 18 months, the apparent dip after 2024 reflects incomplete data, not declining interest.
Construction-material framing dominates over pure waste processing
Cement and refractories claims (C04B) and solid-waste-disposal claims (B09B) both cover more than half the dataset, and B28C mortar/concrete claims add another 32.4%. Metal recovery and detox-focused classes (B01J, A62D) sit well below 20%, suggesting the aggregate-substitution route is more heavily claimed than the metal-extraction route.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to bottom ash recycling, with the prior art for and against each one.
Who holds the claim space, and where it thins out
The ranked list covers all 12 assignees the data endpoint returns for this scope — there is no larger unranked pool behind it.
One assignee well ahead of the rest
The leading assignee holds 15 of the 37 records in scope, more than the next several ranked assignees combined, and anchors the top-5 concentration figure of 81.1%.
A sharp drop after the leader
Filing counts fall away quickly outside the leading position, with fifth place holding only 2 records and tenth place holding 1 — a steep gradient rather than a gradual one.
Co-filing is rare and concentrated
The strongest co-assignee link in the dataset is a two-record pairing between Virginia Tech Intellectual Properties and Phinix LLC, pointing to a university-industry metal-recovery collaboration rather than a broader partnering pattern.
| Assignee | Recent year | YoY |
|---|---|---|
| Engro Corporation | 0 | — |
| University of Florida Research Foundation, Inc. | 0 | — |
| National University of Singapore | 0 | — |
| ZeroWaste Asia Pte Ltd | 0 | — |
| Virginia Tech Intellectual Properties, Inc. | 0 | — |
| PHINIX LLC | 0 | — |
| GREEN CONVERSION SYSTEMS INC | 0 | — |
| Agency for Science, Technology and Research (A*STAR) | 0 | -100% |
Where to take this analysis
The dataset points to specific next steps depending on whether the goal is defensive clearance or offensive filing.
Check freedom-to-operate against the leader
Given one assignee holds 15 of 37 records, any new metal-recovery or aggregate-substitution filing should be checked against that portfolio first, not against the field average.
Run a freedom-to-operate searchDraft into the thinner classes
B03B wet separation and E01C road-application claims each cover under 15% of records, leaving more room for a narrowly drafted first claim than in C04B or B09B.
Explore white space in EurekaTrack the 2025-2026 filings as they publish
Because publication lags filing by roughly 18 months, the current 2025-2026 figures will keep rising; revisit the trend once those years are more complete.
Set an alert for new filingsCommon questions on bottom ash recycling patents
This dataset scopes 37 published records combining incineration bottom ash treatment with metal recovery, aggregate substitution, weathering treatment, leaching test, chloride washing or construction application claims between 2015 and 2026. That is a compact field rather than a crowded one, and the ranked assignee list covers only 12 companies. Because publication lags filing by roughly 18 months, the true count for 2025-2026 filings will rise as they publish.
One assignee leads with 15 of the 37 records in scope, well ahead of the rest of the field; the fifth-ranked assignee holds only 2 records and the tenth holds 1. Together the top 5 assignees account for 81.1% of all records, and the top 10 account for 100.0%, meaning there is essentially no long tail of minor filers beyond the ranked list. This concentration makes it practical to check any new filing against a short, known set of portfolios.
Cement and refractories claims (IPC class C04B) appear in 67.6% of the 37 records and solid-waste-disposal claims (B09B) in 59.5%, showing that most filings treat bottom ash primarily as a construction-material feedstock. Mortar and concrete mixing (B28C) adds another 32.4%. Metal-recovery-adjacent classes such as B01J and detox-focused A62D each sit under 19%, indicating the aggregate-substitution route is more heavily claimed than pure metal extraction.
Filing activity grew 50% from 2021 to 2024, the last year that can be treated as complete, after peaking at 18 records in 2022. Any apparent drop in 2025 or 2026 reflects publication lag, which typically runs about 18 months behind actual filing, rather than a real slowdown. Readers should treat the most recent one to two years in any bottom ash trend chart as understated.
The thinner IPC classes in this dataset are B03B wet separation of solids (10.8% of records), E01C roads and pavements (13.5%), and C08L polymer compositions (13.5%), compared with over 59% coverage for the two leading classes. These narrower branches, along with chloride-washing pretreatment and carbonation-based solidification, carry lower filing density and more room for a well-drafted first claim than the dominant cement and waste-disposal categories.
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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.