WO2018081308A1 - Produit en béton recyclé co2-négatif destiné à être utilisé dans la construction - Google Patents

Produit en béton recyclé co2-négatif destiné à être utilisé dans la construction Download PDF

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Publication number
WO2018081308A1
WO2018081308A1 PCT/US2017/058357 US2017058357W WO2018081308A1 WO 2018081308 A1 WO2018081308 A1 WO 2018081308A1 US 2017058357 W US2017058357 W US 2017058357W WO 2018081308 A1 WO2018081308 A1 WO 2018081308A1
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fly ash
manufacturing process
concrete product
calcium
carbonation
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PCT/US2017/058357
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English (en)
Inventor
Bu WANG
Laurent G. Pilon
Narayanan NEITHALATH
Gaurav SANT
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The Regents Of The University Of California
Arizona Board Of Regents On Behalf Of Arizona State University
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Publication of WO2018081308A1 publication Critical patent/WO2018081308A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/02—Oxides or hydroxides
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
    • C04B28/021—Ash cements, e.g. fly ash cements ; Cements based on incineration residues, e.g. alkali-activated slags from waste incineration ; Kiln dust cements
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00034—Physico-chemical characteristics of the mixtures
    • C04B2111/00181—Mixtures specially adapted for three-dimensional printing (3DP), stereo-lithography or prototyping
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P40/00—Technologies relating to the processing of minerals
    • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
    • Y02P40/18—Carbon capture and storage [CCS]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Definitions

  • This disclosure generally relates to concrete products and manufacturing processes of concrete products.
  • CCS Carbon capture and storage
  • a manufacturing process of a concrete product includes: (1) extracting calcium from reclaimed solids as portlandite; (2) forming a cementitious slurry including the portlandite; (3) shaping the cementitious slurry into a structural component; and (4) exposing the structural component to carbon dioxide, wherein the portlandite included in the structural component is converted to limestone, thereby forming the concrete product.
  • the reclaimed solids include at least one of iron slag or steel slag.
  • extracting the calcium includes exposing the reclaimed solids to a leaching solution.
  • the calcium is extracted as calcium ions, and extracting the calcium further includes concentrating the calcium ions by capacitive concentration.
  • extracting the calcium further includes inducing precipitation of the calcium ions as the portlandite.
  • inducing the precipitation of the calcium ions includes heating to a temperature above about 20 °C.
  • heating includes applying heat that is sourced from a flue gas stream.
  • forming the cementitious slurry includes combining fly ash with the portlandite.
  • shaping the cementitious slurry includes casting, extruding, molding, pressing, or 3D printing of the cementitious slurry.
  • the carbon dioxide is sourced from a flue gas stream having a carbon dioxide content equal to or greater than about 3% (v/v).
  • exposing the structural component to the carbon dioxide includes heating to a temperature above about 20 °C. In some embodiments, heating includes applying heat that is sourced from a flue gas stream.
  • a concrete product is formed by the manufacturing process of any one of the foregoing embodiments. In some embodiments, the concrete product includes i) aggregates and ii) a binder including the limestone. In some embodiments, the concrete product further includes iii) leached slag granules.
  • a concrete product includes: (1) a binder including limestone; (2) aggregates dispersed in the binder; and (3) leached slag granules dispersed in the binder.
  • an amount of the limestone is at least about 5% by weight of the concrete product.
  • the concrete product has a flexural strength equal to or greater than about 2 MPa.
  • the concrete product further includes fly ash dispersed in the binder.
  • a manufacturing process of a concrete product includes: (1) forming a cementitious slurry including fly ash; (2) shaping the cementitious slurry into a structural component; and (3) exposing the structural component to carbon dioxide, thereby forming the concrete product.
  • forming the cementitious slurry includes combining water with the fly ash.
  • the fly ash includes calcium in the form of one or more calcium-bearing compounds (e.g., lime (CaO)) in an amount of at least about 15% by weight, at least about 18% by weight, at least about 20% by weight, at least about 23% by weight, or at least about 25% by weight, and up to about 27% by weight, up to about 28% by weight, or more, along with silica (Si0 2 ) and oxides of metals.
  • CaO calcium-bearing compounds
  • shaping the cementitious slurry includes casting, extruding, molding, pressing, or 3D printing of the cementitious slurry.
  • the carbon dioxide is sourced from a flue gas stream having a carbon dioxide content equal to or greater than about 3% (v/v).
  • exposing the structural component to the carbon dioxide includes heating to a temperature above about 20 °C. In some embodiments, heating includes applying heat that is sourced from a flue gas stream.
  • FIG. 1 An overview of an upcycled concrete manufacturing process spanning the stages of: (i) securing reclaimed solid reactants and their provision in suitably granulated fractions, (ii) calcium extraction (by leaching) from the reactants within a leaching reactor, (iii) concentration of a leaching solution by capacitive concentration followed by portlandite (Ca(OH) 2 ) precipitation in a precipitation reactor, (iv) formulation of a rheology- optimized cementitious slurry (e.g., a mixture including fine and coarse aggregates, water, leached slag, fly ash, Ca(OH) 2 particulates and rheology modifiers), (v) shape stabilization of the slurry into the form of a structural component (e.g., a beam, column, or other form), and (vi) contacting the structural component with flue-gas borne C0 2 within a carbonation chamber to yield a pre-manufactured upcycled concrete structural component.
  • Stages (iii), (v) and (vi) utilize low-grade heat sourced from the flue gas, prior to, and following desulfurization to optimize process kinetics, and reduce external energy demands while enhancing C0 2 uptake.
  • FIG. 1 A schematic of a carbonation reactor showing vapor streams, sample placement, and monitoring and control units (e.g., flow-meters, pressure regulators, temperature/relative humidity (T/RH) meters, and gas chromatograph (GC)).
  • monitoring and control units e.g., flow-meters, pressure regulators, temperature/relative humidity (T/RH) meters, and gas chromatograph (GC)).
  • Figure 3 The evolution of compressive strengths of: (a) Ca-rich and Ca-poor fly ash pastes following C0 2 exposure at about 75 °C, and the control samples (exposed to pure N 2 ) for comparison, as a function of (carbonation) time, (b) hydrated OPC pastes at different ages after curing in limewater at about 23 °C, as a function of w/s.
  • the dashed black line shows the compressive strength of a Ca-rich fly ash formulation following its exposure to C0 2 at about 75 °C for about 7 days, (c) Ca-rich fly ash pastes carbonated at different temperatures following exposure to about 99.5% C0 2 (v/v) and simulated flue gas (about 12% C0 2 , v/v), as a function of time, and, (d) Ca-enriched (with added Ca(OH) 2 , or dissolved Ca(N0 3 ) 2 ) Ca-poor (Class F) fly ash pastes following C0 2 exposure at about 75 °C, as a function of time.
  • the compressive strengths of the pristine Ca-poor fly ash with and without carbonation are also shown for comparison.
  • 1/2FH 3 Fe(OH) 3
  • 1/2AH 3 Al(OH) 3
  • C-S-H calcium silicate hydrate.
  • the solid phase balance is calculated until the pore solution is exhausted, or the fly ash reactant is completely consumed.
  • Figure 5 Representative X-ray diffraction (XRD) patterns of Ca-rich and Ca-poor fly ash formulations before and after exposure to C0 2 at about 75 °C for about 10 days.
  • the Ca-poor fly ash shows no noticeable change in the nature of compounds present following exposure to C0 2 .
  • FIG. 6 Representative scanning electron microscopy (SEM) micrographs of: (a) a Ca-rich fly ash formulation following exposure to N 2 at about 75 °C for about 10 days; a magnified image highlighting the surface of a fly ash particle is shown in (b), (c) a Ca-rich fly ash formulation following exposure to pure C0 2 at about 75 °C for about 10 days; a magnified image highlighting the surface of a carbonated fly ash particle wherein carbonation products in the form of calcite are visible on the particle surface is shown in (d), (e) a Ca-poor fly ash formulation following exposure to pure C0 2 at about 75 °C for about 10 days, and (f) Ca(OH) 2 -enriched Ca-poor fly ash formulation following exposure to pure C0 2 at about 75 °C for about 10 days wherein the somewhat increased formation of calcite is noted on particle surfaces.
  • SEM scanning electron microscopy
  • FIG. 7 (a) The C0 2 uptake (normalized by the mass of Ca-rich fly ash in the formulation) as a function of time for samples exposed to pure C0 2 at different isothermal temperatures. The amount of C0 2 uptake was estimated using the mass-based method, (b) The compressive strength of the Ca-rich and Ca-poor fly ash samples as a function of their C0 2 uptake following exposure to pure C0 2 at different temperatures for up to about 10 days. The data reveals a strength gain rate of about 3.2 MPa per unit mass of fly ash that has reacted (carbonated).
  • the amount of C0 2 uptake was estimated using the mass-based method, (c) The C0 2 uptake of a Ca-rich fly ash formulation as a function of depth.
  • the macroscopic sample is composed of a cube (about 50 mm ⁇ about 50 mm ⁇ about 50 mm) that was exposed to pure C0 2 at about 75 °C for about 10 days.
  • C0 2 uptake was assessed by thermal analysis (TGA).
  • Figure 8 Fits of an equation for a generalized reaction-diffusion model to experimental carbonation data taken from Figure 7a for different carbonation temperatures.
  • Embodiments of this disclosure are directed to an upcycled concrete product.
  • the use of limestone as a cementation agent is leveraged to result in a C0 2 -negative concrete product.
  • the upcycled concrete product leverages a process to secure calcium species for carbonate mineralization using industrial wastes as precursors or reactants, thereby eliminating the need for newly mined or produced materials.
  • a carbonation process can efficiently utilize both C0 2 and waste heat carried by flue gas in a coal-fired power plant. In such manner, the upcycled concrete product and process can significantly enhance a C0 2 capturing capacity of a limestone-cement-based concrete product, and thereby can establish a C0 2 -negative process that can mitigate C0 2 emission at large scales.
  • An upcycled concrete product is a transformative, C0 2 -negative construction material which provides a solution for C0 2 and industrial waste upcycling.
  • a process of forming an upcycled concrete product of some embodiments is accomplished as follows ( Figure 1). First, light metals for C0 2 mineralization are sourced from reservoirs (e.g., landfills) which include reclaimed solids in the form of either, or both, crystallized iron slags or steel slags rich in calcium (Ca) and magnesium (Mg).
  • the slags can be formed as by-products of iron and steel manufacturing, and can include calcium in the form of lime (CaO) in an amount of at least about 25% by weight, at least about 30% by weight, at least about 35% by weight, or at least about 40% by weight, and up to about 45% by weight, up to about 50%) by weight, or more, along with silica (Si0 2 ) and oxides of metals, such as magnesia, alumina, manganese oxide, and iron oxide.
  • the slags can be suitably granulated in the form of granules to facilitate subsequent processing, such as through greater surface area and associated interface effects.
  • the calcium present in the slags is leached or extracted by dissolution in, or exposure to, a leaching solution (e.g., an aqueous solution optionally including one or more leaching aids), and then, following a controlled concentration of the calcium (in the form of calcium ions) in the leaching solution by capacitive concentration, the calcium is precipitated as portlandite (Ca(OH) 2 ), which is a potent sink for C0 2 .
  • a leaching solution e.g., an aqueous solution optionally including one or more leaching aids
  • the leached slags can include calcium in the form of lime (CaO) in an amount of no greater than about 20% by weight, no greater than about 18%> by weight, no greater than about 15%) by weight, no greater than about 13%> by weight, no greater than about 10%> by weight, no greater than about 8%> by weight, no greater than about 5% by weight, or no greater than about 3% by weight.
  • capacitive concentration is performed by applying an electrical input to a pair of electrodes, such that calcium ions in the leaching solution are drawn towards the electrodes, and subsequently can be released by reversing the electrical input to yield a higher concentration of the calcium ions.
  • the portlandite thus extracted can be in a particulate form, and the extracted portlandite, along with leached slag granules, are combined with fine and coarse mineral aggregates, fly ash (or other coal combustion by-products) sourced from reservoirs (e.g., landfills and ash ponds), water and rheology modifiers to form a cementitious slurry that is suited for extrusion and shape stabilization.
  • suitable aggregates include sand, gravel, crushed stone, slag, recycled concrete, and so forth.
  • Shape stabilization can include, for example, casting, extruding, molding, pressing, or 3D printing, yielding structural components such as beams, columns, slabs, wall panels, cinder blocks, bricks, sidewalks, and so forth.
  • the structural components can be shaped with channels to facilitate permeation of C0 2 through the channels.
  • the stabilized structural components are then contacted with, or exposed to, flue gas borne C0 2 within a reactor, wherein limestone (or calcite or calcium carbonate (CaC0 3 )) forms, locking-in C0 2 , while also ensuring cementation.
  • limestone or calcite or calcium carbonate (CaC0 3 )
  • C0 2 mineralization Such mineralized CaC0 3 can provide desirable mechanical properties and durability, as well as cementation by forming limestone around and between aggregates to bind the aggregates to one another.
  • a resulting structural component includes an amount of limestone that is at least about 3% by weight, at least about 5% by weight, at least about 10% by weight, at least about 15% by weight, at least about 20% by weight, at least about 25% by weight, at least about 30% by weight, or at least about 35% by weight, and up to about 40% by weight, up to about 45% by weight, up to about 50% by weight, or more of the structural component.
  • Fly ash also can serve as a calcium source, and upon slight dissolution or leaching, fly ash surfaces can be activated at a relatively high pH (e.g., in portlandite-rich environments) to provide cohesion/cementation.
  • a composition of an upcycled concrete product can be adjusted to provide: (a) a specific extent of C0 2 uptake (e.g., at least about 0.05 g of C0 2 /g of solid reactants, at least about 0.1 g of C0 2 /g of solid reactants, at least about 0.2 g of C0 2 /g of solid reactants, or at least about 0.3 g of C0 2 /g of solid reactants, and up to about 0.5 g of C0 2 /g of solid reactants or more) and (b) target mechanical properties.
  • a specific extent of C0 2 uptake e.g., at least about 0.05 g of C0 2 /g of solid reactants, at least about 0.1 g of C0 2 /g of solid reactants, at least about 0.2 g of C0 2 /g of solid reactants, or at least about 0.3 g of C0 2 /g of solid reactants, and up to about 0.5 g of C0 2 /g of solid react
  • Such a pathway for C0 2 mineralization and cementation can yield mechanical properties (e.g., flexural strength equal to or greater than about 2 MPa, equal to or greater than about 3 MPa, equal to or greater than about 4 MPa, equal to or greater than about 5 MPa, equal to or greater than about 6 MPa, equal to or greater than about 7 MPa, or equal to or greater than about 8 MPa, and up to about 10 MPa or more, or up to about 12 MPa or more) that are comparable, if not superior to, traditional ordinary portland cement (OPC)-based concrete, which is a threshold condition to substitute OPC-based concrete as a construction material.
  • OPC portland cement
  • an upcycled concrete product can provide functionality, utility and costs that are similar to OPC-based concrete, thereby reducing both end-user and market inertia to its uptake, and allowing propagation of a C0 2 -negative substitute for OPC-based concrete.
  • a manufacturing process of an upcycled concrete product is designed to integrate as a bolt-on system to coal-fired power plants. Therefore, provision is made to secure flue gas, before desulfurization, as a heat transfer fluid, and post- desulfurization as a source of C0 2 (e.g., about 12% C0 2 , v/v).
  • heat provisioned by the flue gas is used to facilitate temperature-swing based Ca(OH) 2 precipitation in view of reduced solubility at higher temperatures (e.g., above about 20 °C, above about 25 °C, or above about 35 °C), and accelerate the carbonation kinetics (e.g., above about 20 °C, above about 25 °C, or above about 35 °C).
  • the C0 2 present in the flue gas is systematically consumed by mineralization.
  • OPC portland cement
  • clinkering reactions involve substantial energy in the form of heat, and also result in the release of C0 2 from both the de-carbonation of limestone and the combustion of fuel to provide heat.
  • this example demonstrates a route for clinkering-free cementation by carbonation of fly ash, which is a by-product of coal combustion. It is shown that in moist environments and at sub- boiling temperatures, Ca-rich fly ashes react readily with gas-phase C0 2 to produce robustly cemented solids.
  • OPC-concrete has been used as the primary material for the construction of buildings and other infrastructure.
  • the production of OPC is a highly energy - and C0 2 - intensive process.
  • OPC production accounts for about 3% of primary energy use and results in about 9% of anthropogenic C0 2 emissions, globally.
  • Such C0 2 release is attributed to factors including: (i) the combustion of fuel involved for clinkering the raw materials (limestone and clay) at about 1450 °C, and (ii) the release of C0 2 during the calcination of limestone in the cement kiln. As a result, about 0.9 tons of C0 2 are emitted per ton of OPC produced. Therefore, there is great demand to reduce the C0 2 footprint of cement, and secure alternative solutions for cementation for building and infrastructure construction.
  • coal or natural gas
  • coal power is associated with significant C0 2 emissions (about 30% of anthropogenic C0 2 emissions worldwide), and also results in the accumulation of significant quantities of solid wastes such as fly ash (about 600 million tons annually worldwide).
  • CCMs supplementary cementitious materials
  • fly ash the extent of such utilization remains constrained. For example, in the United States, about 45% of fly ash produced annually is beneficially utilized to replace OPC in the concrete.
  • C0 2 is sequestered by the chemical reaction of C0 2 streams with light-metal oxides to form thermodynamically stable carbonates; thus allowing permanent and safe storage of C0 2 .
  • different alkaline waste streams can be examined to render cementation solutions, the low production throughput, or severe operating conditions (high temperature and elevated C0 2 pressure) can render comparative solutions difficult to implement at a practical scale. Therefore, to synergize the utilization of two abundant by-products from coal-fired power plants (fly ash and C0 2 in flue gas), this example demonstrates clinkering-free cementation via fly ash carbonation. It is shown that Ca-rich fly ashes react readily with C0 2 under moist conditions, at atmospheric pressure and at sub-boiling temperatures. The influences of Ca availability in the fly ash, C0 2 concentration, and processing temperature on reaction kinetics and strength gain are discussed. Taken together, this example demonstrates routes for simultaneous valorization of solid wastes and C0 2 , in an integrated process.
  • Class C (Ca-rich) and Class F (Ca-poor) fly ashes compliant with ASTM C618 were used.
  • An ASTM CI 50 compliant Type I/II ordinary portland cement (OPC) was used as a cementation reference.
  • the bulk oxide compositions of the fly ashes and OPC as determined by X-ray fluorescence (XRF) are shown in Table 1.
  • the crystalline compositions of the Ca-rich and Ca-poor fly ashes as determined using X-ray diffraction (XRD) are shown in Table 2. It should be noted that these two fly ashes were used since they represent typical Ca-rich and Ca-poor variants in the United States, and since Ca content can strongly influence the extent of C0 2 uptake and strength development of carbonated fly ash formulations.
  • Table 1 The oxide composition of fly ashes and OPC as determined using X-ray fluorescence (XRF).
  • Table 2 The mineralogical composition of fly ashes and OPC as determined using quantitative X-ray diffraction (XRD) and Rietveld refinement.
  • PSD particle size distribution
  • SLS static light scattering
  • IP A isopropanol
  • the complex refractive index of OPC was taken as 1.70 + 0.10/.
  • the uncertainty in the PSD was about 6% based on six replicate measurements. From the PSD, the specific surface area (SSA, units of m 2 /kg) of OPC was calculated by factoring in its density of about 3150 kg/m 3 , whereas the SSAs of the fly ashes were determined by N 2 -BET measurements.
  • SSA specific surface area
  • the compressive strengths of the fly ash cubes were measured at about 1 day intervals following ASTM CI 09 for up to about 10 days. All strength data reported in this example are the average of three replicate specimens cast from the same mixing batch.
  • C0 2 uptake due to carbonation of the fly ashes was quantified by two methods: (i) a mass-gain method, and (ii) thermogravimetric analysis (TGA).
  • the mass-gain method was used to estimate the average C0 2 uptake of the bulk cubic specimen from the mass gain of three replicate cubes following C0 2 contact as given by Equation (1): where, w (g/g) is the C0 2 uptake of a given cube, m t (g) is the mass of the specimen following C0 2 contact over a period of time t (days), m t (g) is the initial mass of the specimen, and m a (g) is the mass of dry fly ash contained in the specimen (estimated from the mixture proportions).
  • w/ (g) is the final mass of a given cubical specimen following about 10 days of C0 2 exposure.
  • TGA was used to determine the extent of C0 2 uptake at different depths in the fly ash cubes, from the surface to the center in about 5 mm increments. To accomplish so, cubes were sectioned longitudinally using a hand saw. Then, samples were taken from the newly exposed surface along a mid-line using a drill at a sampling resolution of about ⁇ 1 mm. The dust and debris obtained during drilling, at defined locations along the center-line, were collected and pulverized for thermal analysis in a PerkinElmer STA 6000 simultaneous thermal analyzer (TGA/DTG/DTA) provided with a Pyris data acquisition interface.
  • TGA PerkinElmer STA 6000 simultaneous thermal analyzer
  • thermodynamic calculations were carried out using GEM-Selektor, version 2.3 (GEMS).
  • GEMS is a broad-purpose geochemical modeling code which uses Gibbs energy minimization criteria to compute equilibrium phase assemblages and ionic speciation in a complex chemical system from its total bulk elemental composition. Chemical interactions involving solid phases, solid solutions, and aqueous electrolyte(s) are considered simultaneously.
  • the thermodynamic properties of all the solid and the aqueous species were sourced from the GEMS-PSI database, with additional data for the cement hydrates sourced from elsewhere.
  • 3 ⁇ 4 ⁇ is the activity coefficient of j th ion (unitless); z, is the charge of ) th ion, a, is the ion- size parameter (effective hydrated diameter of ) th ion, A), A (kg 1/2 mol "1/2 ) and B (kg 1/2 mol " 1/2 m “1 ) are pressure, p- and T-dependent Debye-Hiickel electrostatic parameters, b is a semi- empirical parameter that describes short-range interactions between charged aqueous species in an electrolyte, / is the molal ionic strength of the solution (mol/kg), x jw is the molar quantity of water, and X w is the total molar amount of the aqueous phase.
  • this solution phase model is suitable for / ⁇ 2.0 mol/kg beyond which, its accuracy is reduced.
  • Ca-rich and Ca-poor fly ashes were reacted with water in the presence of a vapor phase composed of: (a) air (about 400 ppm C0 2 ), (b) about 12% C0 2 (about 88 % N 2 , v/v), and, (c) about 100% C0 2 (v/v).
  • the solid phase balance was calculated as a function of degree of reaction of the fly ash, until either the pore solution is exhausted (constraints on water availability) or the fly ash is fully reacted.
  • Figure 3(a) shows the compressive strength development as a function of time for Class C (Ca-rich) and Class F (Ca-poor) fly ash pastes carbonated in pure C0 2 at about 75 °C.
  • the Ca-rich fly ash formulations show rapid strength gain following exposure to C0 2 , particularly during the first 6 days. For example, after about 3 days of C0 2 exposure, the carbonated formulation achieves a strength of about 25 MPa, whereas a strength on the order of about 35 MPa is produced after about 7 days of C0 2 exposure.
  • FIG. 3(b) shows that the compressive strength of a Ca-rich fly ash formulation following exposure to C0 2 for about 7 days at about 75 °C - about 35 MPa - corresponds to that of an OPC formulation prepared at w/s of about 0.50 and cured in limewater at about 23 °C over the same time period. It is noted, however, that the fly ash formulations show a reduced rate of strength gain after about 7 days - likely due to the consumption of readily available species (Ca, Mg) that can form carbonate compounds.
  • Ca, Mg readily available species
  • OPC systems show a strength increase on the order of about 30%) from about 7 days to about 28 days (a common aging period that is noted in building codes) of maturation across all w/s.
  • Figure 3(a) also indicates that, unlike the "carbonation strengthening" seen in Ca-rich fly ash formulations, Ca-poor fly ash systems showed a strength of ⁇ about 7 MPa even after about 10 days of carbonation, a gain of ⁇ about 2 MPa following C0 2 exposure vis-a-vis a system cured in a N 2 atmosphere.
  • Ca-poor fly ashes feature reduced potential for C0 2 mineralization or strength gain following C0 2 exposure because the [Ca, Mg] available therein is either insufficient or not easily available for reaction (e.g., see Figure 5).
  • carbonation strengthening is dominantly on account of the presence of reactive, alkaline compounds, namely Ca- and Mg-bearing compounds (e.g., CaO, MgO, and so forth), and Ca present in the fly ash glass (see Tables 1-2), that can react with C0 2 .
  • Ca-rich fly ashes contain cementitious phases such as Ca 2 Si0 4 , Ca 2 Al 2 Si07, and Ca3Al 2 0 6 (see Table 2), which upon hydration (and carbonation) form cementitious compounds such as the calcium-silicate- hydrates (C-S-H), or in a C0 2 enriched atmosphere, calcite and hydrous silica (e.g., see Figures 4-5).
  • C-S-H calcium-silicate- hydrates
  • calcite and hydrous silica e.g., see Figures 4-5.
  • the reactive crystalline compounds e.g., CaO, Ca 3 Al 2 06, and so forth
  • the reactive crystalline compounds present in a Ca-rich fly ash are expected to rapidly dissolve in the first few minutes.
  • alkaline species including Na, K, and Ca can be released progressively from the glassy compounds. This can result in the development of a silica-rich rim on the surfaces of fly ash particles. Pending the presence of sufficient solubilized Ca, and in the presence of dissolved C0 2 , calcite can form rapidly on the surfaces of leached (and other) particles, thereby helping proximate particles to adhere to each other as the mechanism of carbonation strengthening (e.g., see Figures 4-6).
  • the enhancement in strength observed in the Ca-poor formulations is postulated to be on the account of both: (a) the pozzolanic reaction between the added Ca source and silica liberated from the fly ash resulting in the formation of calcium silicate hydrates (C-S- H), and, (b) the formation of calcite and (hydrous) silica gel by the carbonation- decomposition of C-S-H, and by direct reaction of solubilized Ca with aqueous carbonate species.
  • the carbonation of C-S-H can result in the release of free water and the formation of a silica gel with reduced water content, as is also predicted by simulations (see Figure 4).
  • Figure 6 the electron micrographs shown in Figure 6 provide additional insights into morphology and microstructure development in Ca-rich fly ash formulations following exposure to N 2 and C0 2 at about 75 °C for about 10 days.
  • the un-carbonated fly ash formulations show a loosely packed microstructure with substantial porosity (Figure 6(a)). Close examination of a fly ash particle shows a "smooth" surface (e.g., see Figure 6(b)), although alkaline species might have been leached from the particle's surface.
  • Figures 6(c-d) reveal the formation of a range of crystals that resemble "blocks and peanut-like aggregates" on the surfaces of Ca-rich fly ash particles - post- carbonation.
  • Figure 7(a) shows C0 2 uptake by the Ca-rich fly ash formulation as determined by thermal analysis (by tracking the decomposition of CaC0 3 ) as a function of time across a range of curing temperatures. Both the rate and extent of C0 2 uptake, at a given time, increase with temperature. Although the terminal C0 2 uptake (which is a function of chemical composition) might be proposed to be similar across all conditions, this was not observed over the course of these experiments - likely due to kinetic constraints on dissolution, and the subsequent carbonation of the fly ash solids.
  • mineral carbonation typically takes the form of irreversible heterogeneous solid-liquid-gas reactions.
  • Ca-rich fly ashes it includes the processes of dissolution and hydration of the Ca-rich compounds including P-Ca 2 Si0 4 , Ca-rich glasses, CaO, Mg(OH) 2 , Ca(OH) 2 , and so forth, and the subsequent precipitation of CaC0 3 and MgC0 3 from aqueous solution, with reference to, for example, Table 2, Figure 4, and the following reactions:
  • vapor phase C0 2 will dissolve in water, as dictated by its equilibrium solubility (as described by Henry's law) at the relevant pH and temperature.
  • equilibrium solubility as described by Henry's law
  • ionized species from the reactants and dissolved C0 2 accumulate in the liquid phase, up to achieving supersaturation - described by the ratio of the ion activity product to the solubility product for a given compound, such as calcite - precipitation occurs thereby reducing the supersaturation level.
  • Ca- or Mg-bearing compounds in the fly ash would continue to dissolve as the solution remains under-saturated with respect to these phases due to the precipitation of carbonates, ensuring calcite and/or magnesite formation until the readily available quantity of these reactant compounds is exhausted and the system reaches equilibrium. It should be noted that in fly ash mixtures, wherein the abundance of alkaline compounds is substantial, where a large Ca/alkaline-buffer exists, the dissolution of gas-phase C0 2 which would otherwise acidify the pore solution has little impact on altering the solution pH.
  • Equation (9) reduces to Jander's model for diffusion-controlled reactions, wherein the reaction rate is determined by the transport of reactants through the product layer to the reaction interface.
  • Figure 8 shows fits of Equation (9) to the experimental carbonation data taken from Figure 7(a) for different carbonation temperatures.
  • a clear change in slope is noted just prior to a reaction interval of about 2 days.
  • Results set forth in this example demonstrate that exposure to concentrations of C0 2 in moist environments, at ambient pressure, and at sub-boiling temperatures can produce cemented solids whose properties are sufficient for use in structural construction. Indeed, Ca-rich fly ash solids, following C0 2 exposure achieve a strength of about 35 MPa after about 7 days or so, and take-up about 9% C0 2 by mass of reactants. Detailed results from thermodynamic modeling, XRD analyses, and SEM observations indicate that fly ash carbonation results in the formation of a range of reaction products, namely calcite, hydrous silica, and potentially some C-S-H which collectively bond proximate particles into a cemented solid.
  • Such underutilization stems from the presence of impurities in the fly ash including unburnt carbon and calcium sulfate that forms due to the sulfation of lime that is injected for air pollution control (APC), compromising the durability of traditional concrete.
  • the materials examined herein, namely fly ashes that are cemented by carbonation, should not be affected by the presence of such impurities - as a result, a wide range of Ca-rich fly ash sources - including those containing impurities, and mined from historical reservoirs ("ash ponds”) can be usable for carbonation-based fly ash cementation.
  • fly ash carbonation can be effected at sub-boiling temperatures using dilute, untreated (flue-gas) C0 2 streams
  • the outcomes of this example create a pathway for the simultaneous utilization of both solid- and vapor-borne wastes created during coal combustion.
  • Such routes for waste, and especially C0 2 valorization create value-addition pathways that can be achieved without a need for carbon capture (or C0 2 concentration enhancement).
  • the streamlined nature of this carbonation process ensures that it well-suited for co-location ("bolt-on, stack-tap" integration) with large point-source C0 2 emission sites including petrochemical facilities, coal/natural gas fired power plants, and cement plants.
  • emitted flue gas can be used to provide both waste heat to hasten chemical reactions, and C0 2 to ensure mineralization without imposing additional criteria for emissions control.
  • the proposed approach is significant since - within a lifecycle analysis (LCA) framework wherein there is no embodied C0 2 impact associated with reactants such as coal combustion wastes or emitted C0 2 , and wherein processing energy (heat) is secured from the flue gas stream - fly ash carbonation, by virtue of active C0 2 uptake, and C0 2 avoidance (by diminishing the production and use of OPC) has the potential to yield C0 2 negative pathways for cementation, and hence construction.
  • LCA lifecycle analysis
  • connection refers to an operational coupling or linking.
  • Connected objects can be directly coupled to one another or can be indirectly coupled to one another, such as via one or more other objects.
  • the terms “substantially” and “about” are used to describe and account for small variations.
  • the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation.
  • the terms can refer to a range of variation of less than or equal to ⁇ 10% of that numerical value, such as less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3%, less than or equal to ⁇ 2%, less than or equal to ⁇ 1%), less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1%, or less than or equal to ⁇ 0.05%).
  • a first numerical value can be "substantially” or “about” the same as a second numerical value if the first numerical value is within a range of variation of less than or equal to ⁇ 10% of the second numerical value, such as less than or equal to ⁇ 5%, less than or equal to ⁇ 4%, less than or equal to ⁇ 3%, less than or equal to ⁇ 2%, less than or equal to ⁇ 1%), less than or equal to ⁇ 0.5%, less than or equal to ⁇ 0.1%, or less than or equal to ⁇ 0.05%.
  • range format is used for convenience and brevity and should be understood flexibly to include numerical values explicitly specified as limits of a range, but also to include all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified.
  • a range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual values such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and so forth.

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Abstract

Un procédé de fabrication d'un produit en béton comprend : (1) l'extraction de calcium à partir de solides récupérés en tant que portlandite; (2) la formation d'une suspension cimentaire comprenant la portlandite; (3) la mise en forme de la suspension cimentaire en un composant structurel; et (4) l'exposition du composant structural au dioxyde de carbone, la portlandite incluse dans le composant structural étant convertie en calcaire, ce qui permet de former le produit en béton.
PCT/US2017/058357 2016-10-26 2017-10-25 Produit en béton recyclé co2-négatif destiné à être utilisé dans la construction WO2018081308A1 (fr)

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CN112062514A (zh) * 2020-07-29 2020-12-11 同济大学 一种废弃3d打印混凝土制备3d打印油墨的方法
WO2021255340A1 (fr) * 2020-06-15 2021-12-23 Teknologian Tutkimuskeskus Vtt Oy Régulation de carbonatation
CN113999049A (zh) * 2021-11-30 2022-02-01 大连理工大学 用于混凝土预制构件保护的碳酸盐覆层的制备方法
US11384029B2 (en) * 2019-03-18 2022-07-12 The Regents Of The University Of California Formulations and processing of cementitious components to meet target strength and CO2 uptake criteria
CN114920538A (zh) * 2022-05-06 2022-08-19 山东大学 一种混凝土再生粉体碳化砖及其制备方法
CN115340311A (zh) * 2022-09-13 2022-11-15 安徽理工大学 一种活化混凝土混合粉料、蒸养砖及其制备方法与应用
US11746049B2 (en) 2016-10-26 2023-09-05 The Regents Of The University Of California Efficient integration of manufacturing of upcycled concrete product into power plants
US11820710B2 (en) 2017-08-14 2023-11-21 The Regents Of The University Of California Mitigation of alkali-silica reaction in concrete using readily-soluble chemical additives
US11919775B2 (en) 2017-06-30 2024-03-05 The Regents Of The University Of California CO 2 mineralization in produced and industrial effluent water by pH-swing carbonation

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WO2013147608A1 (fr) * 2012-03-30 2013-10-03 Van Nieuwpoort Beheer B.V. Composition de liant comprenant de la cendre volante de lignite
WO2014005227A1 (fr) * 2012-07-03 2014-01-09 Co2 Solutions Inc. Stabilisation de laitier à l'aide de dioxyde de carbone capturé
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Publication number Priority date Publication date Assignee Title
US11746049B2 (en) 2016-10-26 2023-09-05 The Regents Of The University Of California Efficient integration of manufacturing of upcycled concrete product into power plants
US11919775B2 (en) 2017-06-30 2024-03-05 The Regents Of The University Of California CO 2 mineralization in produced and industrial effluent water by pH-swing carbonation
US11820710B2 (en) 2017-08-14 2023-11-21 The Regents Of The University Of California Mitigation of alkali-silica reaction in concrete using readily-soluble chemical additives
US11384029B2 (en) * 2019-03-18 2022-07-12 The Regents Of The University Of California Formulations and processing of cementitious components to meet target strength and CO2 uptake criteria
US11858865B2 (en) 2019-03-18 2024-01-02 The Regents Of The University Of California Formulations and processing of cementitious components to meet target strength and CO2 uptake criteria
WO2021255340A1 (fr) * 2020-06-15 2021-12-23 Teknologian Tutkimuskeskus Vtt Oy Régulation de carbonatation
CN112062514A (zh) * 2020-07-29 2020-12-11 同济大学 一种废弃3d打印混凝土制备3d打印油墨的方法
CN113999049A (zh) * 2021-11-30 2022-02-01 大连理工大学 用于混凝土预制构件保护的碳酸盐覆层的制备方法
CN114920538A (zh) * 2022-05-06 2022-08-19 山东大学 一种混凝土再生粉体碳化砖及其制备方法
CN115340311A (zh) * 2022-09-13 2022-11-15 安徽理工大学 一种活化混凝土混合粉料、蒸养砖及其制备方法与应用
CN115340311B (zh) * 2022-09-13 2023-09-05 安徽理工大学 一种活化混凝土混合粉料、蒸养砖及其制备方法与应用

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