Integrated chemical-looping combustion process with downstream CO2 mineralization to cementitious products

Chemical-looping combustion (CLC) has attracted serious industrial attention as a pathway to near-zero-cost CO2 capture, because the oxygen carrier — not post-combustion scrubbing — does the separations work. What has remained separate in both research literature and commercial deployments is the fate of the captured CO2 stream: it is typically compressed, piped, and either sequestered or sold into a thin merchant market. Meanwhile, the steel, aluminum, and cement industries are generating millions of tonnes per year of alkaline solid waste — blast-furnace slag, basic-oxygen-furnace slag, electric-arc-furnace slag, cement-kiln dust, Class C and F fly ash, red mud, lithium-recovery tailings — that carry latent reactivity with CO2 and could, in principle, become supplementary cementitious materials (SCMs) if mineralized. These two industrial challenges have historically been addressed by separate unit operations: an amine or oxyfuel capture train on one side, and a standalone mineral-carbonation or slag-activation plant on the other. This patent asset covers an integrated process that eliminates that architectural gap. The CO2-bearing exhaust from the re-oxidation stage of a CLC loop is routed directly into a carbonation reactor charged with alkaline solid waste, producing a cementitious product without requiring a standalone capture plant, CO2 compression, or a separate SCM processing facility. The timing is commercially compelling for a structural reason: carbon-border-adjustment mechanisms, embodied-carbon procurement specifications in large construction contracts, and SEC/IFRS climate-disclosure rules are simultaneously tightening the business case for both lower-emission cement substitutes and for industrial CO2 capture at steel and aluminum sites. Regulators are not coordinating these pressures on the same timeline, but they converge on the same industrial sites — integrated steel mills and cement plants that operate both combustion units and generate the precise alkaline byproducts this process consumes. A buyer licensing this process patent does not need to build a carbon-capture business and a supplementary-cementitious-materials business separately; the integration is the value proposition. This asset is the load-bearing process claim within the broader doped brownmillerite chemical-looping oxygen carrier family covered by the catalysts and energy-conversion materials portfolio. It is explicitly a system-level process claim rather than a composition claim — the novelty lies in the coupled inter-stage operating windows and the cementitious endpoint, not in the mere co-location of two known unit operations, which is expressly disclaimed.

The process operates in three thermally coupled stages. In the fuel reactor, a doped brownmillerite oxygen carrier is reduced by methane or syngas at 800–920 °C, releasing a concentrated CO2 and water vapor exhaust. Optionally, a steam or CO2 oxidation step can be inserted to produce hydrogen or additional syngas — a flexibility that makes the process relevant both to power generation and to chemical-industry hydrogen production. The carrier is then re-oxidized in air at 850–940 °C, and the resulting hot CO2-enriched exhaust stream — already separated from nitrogen by the intrinsic virtue of chemical looping — is directed to a downstream carbonation vessel. The inter-stage temperature windows are not arbitrary; they are specified with enough precision to be load-bearing claim elements, and they are tightly coupled to the thermodynamic and kinetic requirements of both the carrier redox cycle and the subsequent carbonate mineralization. The carbonation stage accepts a broad class of alkaline solid wastes: basic-oxygen-furnace and electric-arc-furnace slags, blast-furnace slag, Class C and Class F fly ash, cement-kiln dust, red mud from alumina refining, and lithium-recovery tailings. These wastes share calcium and magnesium silicate phases whose alkalinity drives CO2 uptake, but their phase compositions differ substantially — the process claims accommodate all of them. The output is characterized as a supplementary cementitious material, meaning it must demonstrate latent hydraulic reactivity sufficient for use as a Portland cement partial replacement. The performance bar embedded in the claims is cycle retention of at least 80% over at minimum 50 cycles, with higher cycle targets at 100 and 500 cycles, ensuring the process is not merely a laboratory curiosity but a commercially durable cycling operation. Computational validation for this asset reflects its nature as a process claim rather than a crystal-structure composition claim. The applicable simulation is a Pourbaix operating-temperature screen (referenced as simulation 0231 in the computational record), which maps the thermodynamic stability of the oxygen carrier under the coupled redox and carbonation conditions across the specified temperature windows. This type of analysis establishes whether the carrier phases remain within a thermodynamically coherent operating envelope — avoiding parasitic phase transitions, runaway oxidation states, or corrosive degradation products — across the range of waste-stream chemistries the process is designed to accept. Because the asset is a process rather than a specific crystal composition, the multi-potential phonon stability workflow (MACE, CHGNet, MatterSim, ORB consensus) is not the primary validation route; that workflow is applied to the oxygen-carrier compositions claimed in the companion composition patents within the same family. The integration between carrier-level atomistic validation and process-level thermodynamic screening is what makes the family coherent as a portfolio. The two open validation gates are honest and material. First, a pilot integrated-loop demonstration — running the fuel reactor, optional syngas stage, air reactor, and carbonation vessel in a coupled configuration rather than as individually optimized standalone units — has not yet been reported in the computational or experimental record. The coupling introduces heat-integration constraints and residence-time dependencies that bench-scale batch experiments do not fully capture. Second, the carbonate product must be characterized for compressive-strength development and measured CO2 uptake under standardized cementitious test protocols (ASTM C989 or equivalent) to confirm it qualifies as an SCM rather than merely an inert filler. These are the two gates a licensee would need to fund before commercial-scale deployment.

The addressable market for this process patent sits at the intersection of two large industrial sectors that are both under structural decarbonization pressure. The global supplementary cementitious materials market is estimated to be in the range of $20–30 billion annually, with blast-furnace slag and fly ash commanding the bulk of volume; however, regulatory pressure on coal-fired power (which generates fly ash) is tightening supply just as demand for lower-embodied-carbon concrete is rising, creating a supply-demand imbalance that favors new SCM sources. The CLC-integrated mineralization process is a credible pathway to produce SCMs at industrial scale from the alkaline wastes that steel mills generate regardless of energy-transition trajectory. This is a commercially disciplined estimate: the actual process-level licensing opportunity is a subset of the SCM market — the fraction addressable by a new continuous-production process integrated with CLC at existing steel or industrial sites, estimated at $1–5 billion in addressable licensing and process-value terms. Buyers in this market are primarily integrated steel producers (who generate BOF/EAF/BF slag and who increasingly face carbon-pricing pressure on their combustion operations), cement producers looking to secure SCM supply chains under tightening fly-ash availability, and CCS project integrators building industrial decarbonization packages for refinery, chemicals, or power sites. The licensing logic is straightforward: a process patent of this kind commands a royalty on either the CO2 captured or the SCM produced per tonne, or both. At typical industrial carbon-capture project economics — where a tonne of CO2 avoided is valued at $50–150 depending on jurisdiction and policy mechanism — a process that avoids both the compression-and-sequestration cost and the standalone SCM production cost has compounding value per tonne that makes a royalty of $5–15 per tonne of CO2 processed commercially rational. Hydrogen production optionality from the steam-oxidation step adds a third revenue lever for licensees, broadening the market aperture beyond carbon capture alone.

single integrated loop replaces separate capture + SCM operations

coupled inter-stage operating windows + cementitious endpoint; generic process claims not pursued

The primary strategic acquirers or licensees are integrated steel producers — particularly those operating basic-oxygen or electric-arc furnace routes who generate the alkaline slag feedstocks the process requires and who face simultaneous carbon-pricing pressure on their combustion operations. ArcelorMittal, POSCO, Nippon Steel, Tata Steel, and the major Chinese state steel groups are all running active decarbonization programs that include both CCS evaluation and SCM valorization, making this process patent directly relevant to their capital planning. A secondary tier of buyers is cement majors — Holcim, CEMEX, HeidelbergMaterials, CRH — who are actively acquiring SCM supply-chain optionality as fly-ash availability tightens under coal-plant retirements and who would benefit from a licensed process that turns their industrial neighbor's slag into a qualifying cement substitute. CCS project developers and engineering contractors (Aker Carbon Capture, MHI, Fluor, SLB) represent a third buyer profile: firms that package integrated industrial decarbonization solutions and would embed this process as a differentiated module in an overall plant-decarbonization offering rather than operating it as a materials producer. For these buyers, the value is in the architecture — a single-loop solution they can license and deploy — rather than in the SCM product per se. Licensing terms structured as a per-tonne-CO2-processed royalty would suit all three buyer types and would scale naturally with production volume without requiring the licensor to take operational risk.

The primary technical risk is the pilot integration gap. Each stage of the process — CLC fuel reduction, optional syngas production, air-reactor re-oxidation, carbonation of alkaline waste — has been demonstrated independently at bench or pilot scale by various groups globally, but the coupled integrated system has not been demonstrated in the configuration claimed here. Heat-integration mismatches, CO2 partial-pressure misalignment between the air-reactor exhaust and the carbonation kinetics, and feed-preparation variability across the eight waste-stream categories could each require design iteration before the process meets its claimed cycle-retention performance at scale. This is a real engineering-execution risk, and a licensee should budget for a meaningful pilot campaign before committing to commercial-scale capital expenditure. The second risk is FTO scope: the narrow FTO rating means a licensee must conduct its own clearance for upstream CLC operations, and changes in the CLC patent landscape — particularly grant of pending claims by NETL or major industrial players — could constrain freedom of operation in the fuel and air reactor stages independently of the protection this asset provides. The roadmap to de-risk both gaps is well-defined. On the technical side, a 12–24 month pilot campaign at a steel-site host with existing CLC infrastructure would address the integration and product-quality gates simultaneously. On the FTO side, the expressly narrow claim strategy already provides a defensible perimeter around the integration, and continued prosecution of divisional claims targeting specific waste-stream combinations or specific temperature-window sub-ranges can incrementally expand the protected perimeter as the prior-art landscape clarifies. This is a supporting process asset in a broader family — its value is amplified by the companion composition patents and is best monetized as a package rather than in isolation.