Mechanism and Primitive Description

The End-of-Life Carbon Recovery primitive (Provisional 64/050,895, carbon-substrate-flow) defines a sequence of unit operations that intercept structural elements at the conclusion of their service life and route the embedded graphene fraction back into the upstream fabrication pipeline rather than to landfill, crushing, or atmospheric release. Inputs to the primitive include demolition rubble from decommissioned buildings, retired structural blocks from infrastructure replacement programs, and end-of-service panels from prefabricated assemblies. Each input class shares a common physical characteristic: a graphene fraction is dispersed within or bonded to a cementitious matrix at mass loadings established during the original fabrication step and recorded in the credentialed lineage chain.

Recovery proceeds in two stages. The first stage is mechanical separation. Comminution, classification, and density-based or electrostatic sorting separate the cementitious matrix from the carbon-rich fraction. The cementitious fraction may be diverted to conventional aggregate reuse; the carbon-rich fraction proceeds to the second stage. The second stage is carbonization re-treatment by FJH or an analogous high-current pulsed-discharge process that subjects the carbon-rich fraction to brief, high-temperature transients sufficient to re-graphenize disordered or partially oxidized carbon recovered from the matrix. The output of the second stage is graphene of fabrication-grade quality, returned to the upstream pipeline for incorporation into the next generation of structural elements.

The recovery efficiency, defined as the ratio of carbon mass recovered as fabrication-grade graphene at the FJH outlet to the originally-incorporated carbon mass recorded in the lineage chain, is disclosed as 70 to 95 percent. Losses comprise two principal terms: mechanical-separation residual, in which carbon remains physically bound to or entrained within the rejected cementitious fraction and exits the recovery loop as a contaminant of the aggregate stream; and process-stream volatilization, in which a portion of the carbon mass is converted to gaseous species (CO, CO2, light hydrocarbons) during the FJH transient and either captured for downstream sequestration or vented depending on the equipment configuration. The recovery efficiency for each batch is recorded in the credentialed lineage chain alongside the originating element identifier, enabling cradle-to-cradle accounting at the structural-element level.

Operating Parameters and Engineering Envelope

The mechanical-separation stage operates over a comminution range that reduces input rubble to a particle size distribution suitable for downstream sorting, typically with a target top size between 5 mm and 25 mm depending on the original element geometry and the degree of carbon-matrix bonding. Sorting may employ density-based separation (gravimetric tables, dense-media cyclones) where the bulk-density contrast between the carbon-rich fraction and the cementitious fraction is sufficient, or electrostatic and triboelectric separation where the particle conductivity contrast dominates. Separation efficiency at this stage governs the mechanical-separation residual loss term and is the dominant determinant of the lower bound of the disclosed 70 to 95 percent envelope.

The FJH re-treatment stage operates at peak temperatures in the range commonly disclosed for graphenization, typically 2500 K to 3000 K achieved over millisecond-scale current pulses. Pulse energy, electrode geometry, and feedstock packing density are tuned to balance two competing requirements: sufficient thermal budget to re-graphenize partially oxidized or disordered carbon, and sufficient confinement to limit volatilization losses. The volatilization fraction increases monotonically with pulse energy beyond the graphenization threshold, defining an efficiency-quality trade-off that the operator selects based on the downstream graphene-grade specification recorded in the lineage chain.

Throughput envelope for a fabrication-scale recovery line is established by the pulse-repetition rate of the FJH stage and the upstream comminution-and-sorting throughput. Batch identifiers are propagated from the input structural-element identifier through both stages, so that the recovered graphene exiting the FJH stage carries a verifiable provenance trace back to its originating element. The credentialed lineage chain records: input element identifier and original carbon mass; mechanical-separation residual mass and disposition; FJH energy delivered and volatilization fraction; output graphene mass and grade; and the resulting recovery efficiency. These records are the auditable basis for carbon-accounting credit assigned to subsequent structural elements that incorporate the recovered graphene.

Alternative Embodiments

Several alternative embodiments fall within the disclosed scope. In a first alternative, the carbonization re-treatment stage is implemented by an analogous high-temperature carbonization process other than FJH, including but not limited to inductive plasma processing, microwave-driven carbonization, or arc-discharge graphenization, where the analogous process delivers a comparable thermal transient sufficient to re-graphenize the recovered carbon fraction. The choice of carbonization technology may be driven by feedstock characteristics, energy-source availability, or capital-cost considerations at the recovery facility.

In a second alternative, the mechanical-separation stage is supplemented or replaced by a chemical-leaching stage in which the cementitious matrix is dissolved by a controlled-pH leachate, leaving the carbon fraction as an insoluble residue. This embodiment increases recovery efficiency at the upper end of the disclosed envelope at the cost of additional reagent handling and effluent treatment, and may be preferred for high-value structural elements where lineage continuity outweighs reagent cost.

In a third alternative, the recovered graphene is returned not to the original fabrication pipeline but to a parallel pipeline producing a different structural-element class, where the cross-pipeline transfer is recorded in the lineage chain as a fungibility event. In a fourth alternative, the volatilized carbon fraction is captured by a downstream gas-handling stage and routed to a separate sequestration or feedstock-conversion pipeline, raising the system-level recovery efficiency above the per-element envelope.

Composition with Adjacent Primitives

The End-of-Life Carbon Recovery primitive composes with several adjacent primitives in the carbon-substrate-flow family. Upstream, it composes with the original fabrication primitive that incorporated the graphene into the structural element: the original carbon mass and lineage identifier produced at fabrication are the inputs against which recovery efficiency is computed. The lineage chain links the two events directly, so that recovered graphene re-entering the fabrication pipeline carries forward the cumulative provenance of all prior incorporations and recoveries.

Laterally, the primitive composes with the credentialed-accounting primitive that maintains the lineage chain and issues carbon-accounting credits. Recovery efficiency, mechanical-separation residual disposition, and volatilization fraction are the principal data fields written by this primitive into the accounting layer. Downstream, the recovered graphene composes with whichever fabrication primitive consumes it next; the recovery primitive is intentionally agnostic to the downstream consumer, admitting flexible routing based on grade and demand.

The primitive also composes vertically with monitoring and verification primitives that sample the FJH output for grade confirmation, and with energy-sourcing primitives that supply the FJH pulse energy from grid, on-site renewable, or stored sources. The choice of energy source affects the net carbon balance of the recovery operation itself, which is recorded as a separate accounting field distinct from the recovery efficiency.

Prior-Art Distinctions

The disclosed primitive is distinguished from conventional demolition practice in three principal respects. First, conventional demolition treats end-of-life structural elements as a waste stream: the embodied and sequestered carbon is released either to landfill (where eventual microbial or oxidative degradation returns the carbon to the atmosphere over decadal timescales) or to crushing for aggregate reuse (where the carbon remains nominally locked but is no longer accounted, traced, or available as feedstock). Neither pathway recovers the carbon as a fabrication-grade input; both pathways terminate the lineage chain.

Second, the disclosed primitive is distinguished from prior carbon-capture and utilization schemes that operate on dilute atmospheric or flue-gas streams. Those schemes incur a thermodynamic penalty associated with separating dilute CO2 from a carrier gas. The present primitive operates on concentrated, solid-phase carbon already separated and sequestered within a structural matrix, avoiding that penalty entirely.

Third, the primitive is distinguished from prior recycling schemes for carbon-containing composites (e.g., carbon-fiber-reinforced polymer recycling) that recover the carbon as low-grade or chopped feedstock unsuitable for the original application. The FJH or analogous re-treatment stage in the present primitive returns the carbon as fabrication-grade graphene, suitable for re-incorporation at the original loading and grade. The credentialed lineage chain renders this re-incorporation auditable in a way that prior recycling schemes do not support.

Disclosure Scope

The disclosure scope encompasses the full recovery pipeline from end-of-life structural-element input through fabrication-grade graphene output, including the mechanical-separation stage, the carbonization re-treatment stage, and the lineage-chain accounting layer that binds them. The scope is independent of the specific structural-element form factor (block, panel, beam, slab) and of the specific cementitious binder chemistry, so long as a graphene fraction is recoverable from the matrix.

The scope encompasses recovery efficiencies across the disclosed 70 to 95 percent envelope, with the understanding that the lower bound reflects coarse mechanical-separation embodiments and the upper bound reflects chemical-leaching or hybrid-separation embodiments. Operating outside the envelope is contemplated where alternative separation or carbonization technologies extend the achievable efficiency, and such operation falls within the scope so long as the recovery is recorded in a credentialed lineage chain that supports cradle-to-cradle accounting.

The scope expressly contemplates analogous carbonization processes beyond FJH, including inductive, microwave, plasma, and arc-discharge variants, and expressly contemplates the capture and downstream utilization of volatilized carbon as a separate accounted stream. The scope does not extend to demolition-and-disposal pathways that terminate the lineage chain without recovery, nor to recycling pathways that return carbon at a grade insufficient for re-incorporation into structural fabrication.