CA3177657A1 - Carbon dioxide-adsorbing artificial stone compositions - Google Patents

Abstract

The present disclosure relates to carbon dioxide-adsorbing artificial stone compositions. In some embodiments, the artificial stone can be formed from an uncured mixture of: between 25 wt% and 40 wt% binder; between 20 wt% and 25 wt% filler a polycarboxylate-based admixture, and a diluent. At least a portion of the filler comprises a component capable of mineral carbonation, which can be a metal oxide, such as calcium oxide, a silicon oxide, a magnesium oxide, an iron oxide, a magnesium iron silicate, a nickel oxide, and a manganese oxide. In some embodiments, at least a portion of the filler is olivine. When the artificial stone is exposed to CO2 and water, such as typical environmental conditions, the artificial stone adsorbs atmospheric CO2, thus sequestering or adsorbing the carbon in the artificial stone.

Description

CARBON DIOXIDE-ADSORBING ARTIFICIAL STONE COMPOSITIONS
TECHNICAL FIELD
The technical field generally relates to artificial stone products. More specifically, the present disclosure relates to carbon dioxide-adsorbing artificial stone compositions.
BACKGROUND
One of the major contributing factors to global warming and ocean acidification is atmospheric carbon dioxide (CO2) emissions. One targeted strategy for reducing the impacts of global warming and ocean acidification is carbon sequestration to reduce the CO2 levels in the atmosphere.
One carbon sequestration technique is in situ carbonation in building materials, such as cement bricks. This includes a carbonation step in a wet mixture or through already carbonated aggregates. For example, one conventional concrete composition included a mixture of cement, steel slag, and aggregates that undergoes a carbonation curing step to expose the mixture to a CO2 environment to accelerate the carbonation reaction. However, this convention technique only results in an uptake of about 10% CO2 based on the weight of the slag.
SUMMARY
According to one aspect, there is provided an artificial stone formed from an uncured mixture comprising: between 25 wt% and 40 wt% binder; between 20%
and 35% filler; between 1.5 wt% and 2 wt% polycarboxylate-based admixture;
and a diluent; wherein at least a portion of the filler comprises a component capable of mineral carbonization.
In some embodiments, the binder comprises cement.
In some embodiments, the component capable of mineral carbonization comprises a metal oxide.
In some embodiments, the component capable of mineral carbonation comprises at least one of a calcium oxide, a silicon oxide, a magnesium oxide, an iron oxide, a magnesium iron silicate, a nickel oxide, and a manganese oxide.
In some embodiments, at least a portion of the filler is olivine.
Date Regue/Date Received 2022-09-29

2 In some embodiments, the component capable of mineral carbonation comprises at least one of forsterite, fayalite, monticellite, kirschsteinite, and tephroite.
In some embodiments, the filler is a powder or an aggregate.
In some embodiments, the filler is less than 2 cm in diameter.
In some embodiments, the artificial stone adsorbs at least 10 kg/m3 of carbon.
In some embodiments, the cured mixture further comprises a pigment.
In some embodiments, the pigment is derived from stones.
In some embodiments, the cured mixture further comprising an air entrainer admixture.
In some embodiments, the air entrainer admixture is about 0.5 wt% to about 2 wt% of the cured mixture.
According to another embodiment, there is provided an artificial stone comprising cement and olivine, wherein the artificial stone is configured to adsorb a weight of carbon that is at least equivalent to a weight of the olivine.
In some embodiments, the uncured mixture comprises between 20 wt% and 35 wt% olivine.
According to another embodiment, there is provided an artificial stone formed from an uncured mixture comprising between 25 wt% and 40 wt% cement and between 20 wt% and 35 wt% olivine.
According to another embodiment, there is provided an artificial stone comprising an inner layer and an outer layer, wherein the inner layer and the outer layer are formed from an uncured mixture comprising between 25 wt% and 40 wt% binder, between 20 wt% and 25 wt% filler, between 1.5 wt% and 2 wt% polycarboxylate-based admixture, wherein the filler in the outer layer comprises a component capable of carbon mineralization.
Date Regue/Date Received 2022-09-29

3 In some embodiments, the binder comprises cement.
In some embodiments, the component capable of mineral carbonation comprises a metal oxide.
In some embodiments, the component capable of mineral carbonation comprises at least one of a calcium oxide, a silicon oxide, a magnesium oxide, an iron oxide, a magnesium iron silicate, a nickel oxide, and a manganese oxide.
In some embodiments, the component capable of mineral carbonation comprises an olivine mineral.
In some embodiments, the component capable of mineral carbonation comprises .. at least one of forsterite, fayalite, monticellite, kirschsteinite, and tephroite.
In some embodiments, the filler is a powder or an aggregate.
In some embodiments, the filler is less than 2 cm in diameter.
In some embodiments, the artificial stone has a carbon adsorption rate of at least 10 kg/m3.
.. In some embodiments, the outer layer is about 1/3 of a volume of the artificial stone.
In accordance with another aspect, there is provided a method of producing an artificial stone as defined herein, the method comprising: mixing the binder, the filler, the diluent, and the polycarboxylate-based admixture to produce a homogenous or near-homogenous uncured mixture; and allowing the uncured mixture to cure in a mold.
In some embodiments, the method further comprises mixing a pigment with the uncured mixture.
In some embodiments, the method further comprises mixing an air entrainer admixture with the uncured mixture.
Date Regue/Date Received 2022-09-29

4 In some embodiments, the air entrainer admixture comprises between about 0.5 wt% and about 2 wt% of the cement.
In accordance with another aspect, there is provided a method of producing an artificial stone as defined herein, the method comprising mixing the binder, the .. filler including the component capable of mineral carbonation, the diluent, and the polycarboxylate-based admixture to produce a homogenous or near-homogenous uncured outer layer mixture; providing the uncured outer layer mixture in a mold; mixing the binder, the filler, the diluent, and the polycarboxylate-based admixture to produce a homogenous or near-homogenous uncured inner layer mixture; providing the uncured inner layer mixture in the mold; and allowing the inner layer and the outer layer to cure in the mold.
In some embodiments, the method further comprises mixing a pigment with at least one of: the uncured outer layer mixture and the uncured inner layer mixture.
.. In some embodiments, the method further comprises mixing an air entrainer admixture with at least one of: the uncured outer layer mixture and the uncured inner layer mixture.
In some embodiments, the air entrainer admixture comprises between about 0.5 wt% and about 2 wt% of the binder.
In some embodiments, the outer layer is provided to the mold prior to the inner layer being provided to the mold.
In some embodiments, the inner layer is provided to the mold prior to the outer layer being provided to the mold.
In accordance with some aspects, there is provided an artificial stone comprising .. a cement material, wherein an outer layer of the artificial stone that is configured to be exposed to the atmosphere comprises between about 20 wt% and about 35 wt% olivine.
Date Regue/Date Received 2022-09-29

5 DETAILED DESCRIPTION
The present disclosure relates to artificial stone products that have an enhanced carbon dioxide (CO2) adsorbing capability. Also disclosed is an artificial stone product comprising a binder, a filler comprising a component capable of mineral carbonation, a diluent, and a polycarboxylate-based admixture. In some embodiments, the artificial stone product comprises entrained air and/or a pigment.
Mineral carbonation is the result of a reaction between CO2 with a metal oxide containing material to form insoluble carbonates. In some embodiments, the metal element can be magnesium (Mg), iron (Fe), calcium (Ca), manganese (Mn) and/or nickel (Ni). When this reaction occurs naturally in the environment, the phenomenon is referred to as silicate weathering, which consumes atmospheric CO2. This natural occurring reaction can be utilized to create artificial stones that capture atmospheric CO2 in the stone throughout its the lifetime.
Artificial stones can be used for a variety of purposes, such as cladding for a building, floor tile, countertops, paving stones, landscaping tile, steps, edges or corner pieces, wall caps, window frames, cornices, columns, terrazzo stone, etc.
By including a filler that includes a component capable of mineral carbonation, the artificial stones can be used to sequester atmospheric carbon, thus creating an artificial stone product that can help reduce the overall CO2 levels in the atmospheric and help combat climate change.
One promising filler that includes a component capable of mineral carbonation is olivine. Olivine is a group of silicate minerals that have a composition of A2SiO4.
"A" is often magnesium (Mg) or iron (Fe) but can also be calcium (Ca), manganese (Mn) and/or nickel (Ni). Common compositions of olivine include forsterite (Mg2SiO4), fayalite (Fe2SiO4), monticellite (CaMgSiO4), kirschsteinite (CaFeSiO4), and tephroite (Mn2SiO4). When exposed to the atmosphere, olivine reacts quickly with CO2 and water to create an innocuous carbonate solution, such as bicarbonate, embedded within the artificial stone, thus removing the from the atmosphere. For example, when used in a moderately humid climate, forsterite reacts with CO2 and water to form magnesium, bicarbonate, and silicic acid according to the following formula:
Mg2SiO4 +4 CO2 + H20 4 2 MG2+ +4 HCO3- + H4SiO4 In drier climates, forsterite can react with CO2 and water to form magnesium carbonate and chrysotile according to the following formula:
2 Mg2SiO4 + CO2 +2 H20 4 MgCO3 + Mg3Si205(OH)4 Date Regue/Date Received 2022-09-29

6 Accordingly, the climate-dependent weather reaction results in the sustainable capture of CO2, regardless of the humidity level.
Olivine has a hardness of between 6.5 and 7 oh the Mohs hardness scale, which is almost as hard as quartz. However, olivine is significantly heavier than quartz, making it more resistant to erosion.
In some cases, the olivine can be self-cementing, such as when olivine is used with marine constructions in shallow seawater. Shallow seawaters is often slightly supersaturated with calcium carbonate (CaCO3). When the seawater fills pores created in the artificial stone (for example, via air entraining or through use of pumice aggregate as a filler), the pH of the olivine grains will increase due to the reaction with the sea water. This pH rise, through its effect on the carbonate equilibria will strongly increase the calcite supersaturation and calcite will begin to precipitate between the olivine grains, thus cementing them into a solid structure.
Thus, artificial stones using olivine as a filler can be used in marine constructions, such as seawalls, piers, etc.
In some embodiments, pumice aggregate can be used as a filler to increase the porosity in the artificial stone and increase the overall surface area within the artificial stone for the component capable of mineral carbonation to react with the atmospheric CO2.
Other types of fillers can also be used, such as metal oxides that are capable of mineral carbonation or carbon adsorption. By using the unique properties of fillers that include components capable of mineral carbonation, such as olivine or other metal oxide containing minerals, the artificial stone can be capable of adsorbing carbon at a significantly higher rate than that of compositions that include only cement and aggregate. In some embodiments, the artificial stone can adsorb at least about 10 kg/m3, at least about 20 kg/m3 or at least about 30 kg/m3.
Artificial Stone Compositions The artificial stone with an enhanced CO2 adsorbing capability can be formed from an uncured mixture comprising a binder, a filler, a diluent, and a polycarboxylate-based admixture. At least a portion of the filler includes a component capable of mineral carbonation. In some embodiments, the artificial stone product comprises entrained air and/or a pigment.
The binder can be cement, such as white cement, grey cement, or Portland cement. The total percentage of binder can depend on the amount of tricalcium silicate (Ca3Si05) or alite in the binder. In some embodiments, the uncured Date Regue/Date Received 2022-09-29

7 composition forming the artificial stone comprises between about 25 wt% and about 40 wt% binder.
The diluent can be any suitable solvent that acts to decrease the density of the binder and the filler. In some embodiments, the diluent is distilled water, water, process water, etc.; however, other diluents suitable for use with cement are also contemplated. In some embodiments, the diluent is mixed with the polycarboxylate-based admixture prior to being mixed with the binder.
The polycarboxylate-based admixture can be polycarboxylate ethers (PCE), or other suitable superplasticizers. In some embodiments, the uncured mixture comprises between about 1.5 wt% and 2 wt% polycarboxylate-based admixture.
The filler can comprise any suitable cement filler, such as quartz, sand, clay, silica fume, olivine, crushed stone, sawdust, small gravel, limestone, pumice aggregate, etc. The filler can be a powder or an aggregate. At least a portion of the filler comprises a compound capable of mineral carbonation. The compound capable of mineral carbonation can be compounds that comprise a metal oxide, such as calcium oxides, silicon oxides, magnesium oxides, iron oxides, magnesium iron silicate, nickel oxides, manganese oxides, etc. (for example, clay, sand, silica fume, olivine). In some embodiments, the filler is olivine, which includes compounds capable of mineral carbonation (Le., compounds that adsorb carbon), particularly in humid environments. In some embodiments, the filler is a combination of natural sand with a purity above 70%, silica fume, and magnesium, and thus at least a portion of the compound capable of mineral carbonation is silicon dioxide.
The filler can be any size under about 2 cm in diameter. The filler can be a light filler having a particle size of between about 50 pm and about 200 pm and/or a heavy filler having a particle size of between about 200 pm and about 2 cm. In some embodiments, the filler is pulverized to a size less than 50 pm.
The particle size of the filler capable of mineral carbonation can impact the artificial stone's rate of carbon adsorption. Smaller particle size have a higher surface to volume ratio, which can provide more area for the filler to react with atmospheric CO2, thus potentially increasing the artificial stone's rate of carbon adsorption. Furthermore, the total amount of binder required to form the artificial stone can depend on the particle size of the filler. For example, when the individual particles of the filler have a higher volume, the amount of binder required to form the artificial stone can be reduced.
In some embodiments, the artificial stone can comprise multiple layers having different compositions. For example, as the carbon adsorption reaction with the Date Regue/Date Received 2022-09-29

8 filler capable of mineral carbonation is dependent on exposure to CO2 and water, the artificial stone can comprise an outer layer (or façade layer) that comprises a filler capable of mineral carbonation and an inner layer that comprises any suitable filler, regardless of the filler's capacity to adsorb carbon.
According, during use, the outer layer would be outwardly facing to the environment. For example, an artificial stone configured for use as building cladding would have an inner layer intended to face the outer wall of the building it is installed on, and the outer layer would be exposed to the outer environment, thus exposing the outer layer to atmospheric CO2 and water from humidity and/or precipitation.
In some embodiments, the outer layer is formed from an uncured mixture comprising a binder, a filler that includes a component capable of mineral carbonation, a diluent, and a polycarboxylate-based admixture and the inner layer is formed from an uncured mixture comprising a binder, a filler, a diluent, and a polycarboxylate-based admixture. Olivine has a hardness of between 6.5 and 7 on the Mohs hardness scale, which is almost as hard as quartz, making it a suitable material to be used as the filler that includes a component capable of mineral carbonation in the outer layer of the artificial stone. However, use of other components capable of mineral carbonation in the outer layer is also contemplated.
In some embodiments, the outer layer is formed from an uncured mixture comprising between about 25 wt% and about 40 wt% binder, between about 20 wt% to about 25 wt% filler, between about 1.5 wt% to about 2 wt%
polycarboxylate-based admixture, and a remainder of diluent. The filler can comprise between about 1% and about 100% olivine.
The addition of the filler capable of carbon mineralization significantly increases the carbon adsorption rate of the artificial stone, in some cases, by a rate of at least tenfold that of composition that include only cement and aggregate. The optimal temperature for the carbon adsorption reaction occurring within the artificial stone has been found to be around 40 C under 1 atmospheric pressure (Le., normal atmospheric pressure). The carbon adsorption rate can vary depending on the type of water the artificial stone is exposed to (ex., alkaline water, distilled water, rain water, etc.) and the amount of air contact. In some embodiments, when the filler capable of mineral carbonation is olivine, the artificial stone can sequester carbon at a rate of 1 1/2 times the weight of olivine over the lifetime of the artificial stone. In some embodiments, the natural reaction time of olivine to undergo complete mineral carbonation (Le., all or substantially all of the olivine has undergone the carbon adsorption reaction) is approximately 15 to 20 years. For example, 1 kg of olivine has the potential the sequester 1.5 kg of carbon over 15 to 20 years. Accordingly, an artificial stone comprising Date Regue/Date Received 2022-09-29

9 wt% olivine could be capable of adsorbing up to 37.5% of the stone's weight in carbon, if the entire content of olivine undergoes the carbonation reaction.
Manufacturing The method of manufacturing an artificial stone includes mixing between 25 wt%
and 40 wt% binder, between 20% to 35% filler, between 1.5 wt% to 2 wt%
polycarboxylate-based admixture and a remainder of diluent to form a homologous uncured mixture. The filler can comprise any suitable type of filler, with between 1% and 100% being a filler that includes a component capable of mineral carbonation. The uncured mixture is poured into a mold, such as a silicon mold, that has been sprayed or otherwise treated to receive the uncured mixture.
The uncured mixture is then allowed to dry (cure) before being removed from the mold. The mold can be any desired shape, including in brick form, corner pieces, cornices, statues, etc. In some embodiments, the forms are about 1 cm to about 4 cm thick.
In some embodiments, the artificial stone can be formed in multiple layers having different compositions. For example, the artificial stone can include an outer layer and an inner layer each formed from an uncured mixture comprising between 20 wt% and 40 wt% binder, between 20% to 35% filler, between 1.5 wt% to 2 wt%
polycarboxylate-based admixture and a remainder of diluent. However, the filler used in the outer layer (Le., the layer that is configured to be exposed to the atmosphere/environment) can include a higher percentage of a component capable of mineral carbonation than the inner layer.
In some embodiments, the outer layer is about 1 cm thick, which provides a layer with a high surface area to volume ratio to allow a faster reaction time of the filler capable of mineral carbonation with atmospheric CO2. In such embodiments, the artificial stone is produced by providing the uncured mixture of the outer layer, which comprises a higher concentration of filler capable of mineral carbonation, in a mold. The uncured mixture of the inner layer, which may or may not include a filler capable of mineral carbonation, is also provided in the mold. The inner and outer layers are then allowed to dry (cure) before being removed from the mold.
In some embodiments, the outer layer is provided in the mold before the inner layer. Alternatively, in some embodiments, the inner layer is provided in the mold before the outer layer. A small amount of mixing can occur between the inner and outer layer, or in some embodiments, between all the layers, such that the artificial stone appears as a homologous product despite the difference between the type of filler used in the different layers.
Date Regue/Date Received 2022-09-29

10 To facilitate a specific aesthetic, a pigment can be added to the mixture prior to being poured into the mold. The pigment can be any suitable pigment, such as concrete pigments. In some embodiments, the pigment is derived from natural stones to provide a natural color. In some embodiments, the surface of the artificial stone can undergo a finishing step to provide a suitable façade for the stone's purpose. For example, the finishing step can include polishing, adding texture, etc. In some embodiments, the method can include a step of restoration after the cured artificial stone is removed from the mold and/or before a surface finishing step.
In some embodiments, an air entraining admixture can be added to the diluent, filler, polycarboxylate-based admixture, or the uncured mixture prior to being poured into the mold. Air entraining admixtures produce interconnected air void structures with varying internal size, although they are often less than 1 mm in diameter. Including an entrained air admixture in the uncured mixture can increase the carbon adsorption rate of the artificial stone by increasing the surface of contact between the adsorbent (Le., the filler capable of mineral carbonation, and to a certain extent, the binder) and the absorbate (atmospheric CO2). The adsorption rate of atmospheric CO2 can also be referred to as the carbon sequestration rate.
The amount of air entrainer admixture included in the uncured mixture can be between about 0.5 wt% and about 2 wt% of the binder, which can entrain between about 1.5% and 6% air in the artificial stone. In some embodiments, the air entrainer admixture can be included in the uncured mixture at a rate of about 16 mL to 195 m L per 100 kg of binder to entrain between 4% and 6% air. In some embodiments, the air entrainer is Sika0 AIR. Consideration for the specific use for the manufactured artificial stone should be given when determining the amount of air entrainer admixture to include in the uncured mixture. For example, for a non-structural/non-weight bearing purpose, such as cladding, the overall amount of air entrainer admixture can be increased to increase the amount of entrained air, thus increasing the overall available surface area for the carbon adsorption reaction to take place. For structural/weight bearing purposes, such as floor tile, less entrained air may be desirable to retain a higher overall strength of the artificial stone.
Experimental Data The carbon adsorption capacity of an artificial stone product was conducted in a carbonation chamber using a sensitive digital balance scale to determine the weight difference over a period of time. The samples were enclosed in a carbonation chamber box made of plexiglass that measured 30 cm by 50 cm by Date Regue/Date Received 2022-09-29

11 50 cm. The carbonation chamber included an emergency outlet, an inlet coupled to a CO2 tank, and a pressure gauge. The pressure in the carbonation chamber was between 10 bar and 50 bar to mimic the artificial stone being exposure to atmospheric CO2 over several years. The carbonation chamber was placed on a sensitive digital balance and the artificial stones were weighed before being exposed to CO2, and after being in the carbonation chamber for 1 week, 1 month, and 3 months. The increase in weight over time can be attributed to the weight of the carbon adsorbed or sequestered in the artificial stone product.
Table 1 Percentage of Weight Size (Lx Starting Increase (%) Surface Area No. H x W in Weight (cm ) cm) (kg) After 1 After 1 After 3 week month month 1 20 x 3 x 10 1.28 580 0.01 0.02 0.04 2 30 x 3 x 20 4.5 1,500 0.01 0.025 0.05 3 20 x 3 x 10 1.28 580 0.02 0.035 1 4 30 x 3 x 20 4.5 1,500 0.02 0.04 1.2 5 20 x 3 x 10 0.77 580 0.02 0.03 1 6 30 x 3 x 20 2.7 1,500 0.02 0.03 1.2 Powder 7 1.28 -- 0.03 0.08 1.8 (<50 pm) Powder 8 4.5 -- 0.03 0.085 2.1 (<50 pm) Table 2 -Carbon Adsorption Est. Weight of Carbon Adsorption No Sequestered Carbon Volume (kg/m3) .
After 3 Months (g) (cm3) 1 0.512 600 0.85 2 2.25 1,800 1.25 3 12.8 600 20.83 Date Recue/Date Received 2022-09-29

12 4 54 1,800 30 7.7 600 12.83 6 32.4 1,800 18 7 23.04 --8 94.5 --Stones 1 and 2 were used as a control and comprised a cured product formed from an uncured mixture of cement, crushed stone, sand, water, and a polycarboxylate-based admixture. The cement component included about 0.5 5 .. wt% air entrainer admixture to produce about 1% entrained air. The entrained air increases the porosity in the artificial stone by creating internal voids and increasing the interconnected pores in the artificial stone.
Stones 3 and 4 comprised a 2 cm thick inner layer and a 1 cm thick outer layer.
The inner layer and the outer layer comprised a cured product formed from an uncured mixture of cement, 25 wt% filler, water, and polycarboxylate-based admixture. The cement component of both layers included about 0.5% air entrainer admixture to produce about 1% entrained air. The 25 wt% filler in the outer layer was comprised entirely of olivine sourced from recycled olivine extracted from nickel mines. Due to the high density of olivine, the outer layer weighs about 25% of the total weight of the artificial stone. The 25 wt%
filler in the inner layer was crushed stone and sand.
Stones 5 and 6 also comprised a 2 cm thick inner layer and a 1 cm thick outer layer. The inner layer and the outer layer comprised a cured product formed from an uncured mixture of cement, 25 wt% filler, water, and polycarboxylate-based admixture. The 25 wt% filler in the outer layer was comprised entirely of olivine recycled from nickel mines. The 25 wt% filler in the inner layer was crushed stone and pumice aggregate, which is a volcanic ash constituent. An air entrainer admixture was not used for Stones 5 and 6, as the pumice aggregate contains air porosity (small voids filled with air) that acts to entrains air in the artificial stone .. without the addition use of an air entrainer admixture. While the outer layer containing olivine of Stones 5 and 6 did not contain pumice aggregate as a filler component, use of pumice aggregate in the outer layer in addition to olivine or another compound capable of mineral carbonation can increase the porosity of the artificial stone, which can increase the overall rate of carbon adsorption. In some embodiments, use of pumice aggregate in both the inner and outer layers can also increase the homogeny between the two layers.
Date Regue/Date Received 2022-09-29

13 Stones 3 and 4 and Stones 5 and 6 each have the same composition but vary in their size. Stones 3 and 5 are smaller artificial stones, having a size of 20 cm x 3 cm x 10 cm, and Stones 4 and 6 are larger artificial stones, having a size of cm x 3 cm x 20 cm.
Compounds 7 and 8 were powders comprising a pulverized or crushed mixture of an artificial stone having the same composition as Stones 3 and 4 (Le., olivine, cement, crushed stone, sand, water, and a polycarboxylate-based admixture).
Compounds 7 and 8 were tested to determine the impact of increasing the surface of contact (Le., the overall surface area).
As shown in Tables 1 and 2, after 3 months control Stones 1 and 2 showed a 0.04% and 0.05% weight increase, respectively, equating to adsorbing 0.85 and 1.25 kg/m3 of carbon, respectively. The carbon adsorption of Stones 1 and 2, which do not contain olivine, show a baseline of carbon adsorption by the cement component, which includes active carbonization elements that can also react naturally with the atmospheric CO2, albeit at a significantly lower rate.
On the other hand, the artificial stones that included an outer layer with 25 wt%
olivine (Stones 3 to 6) showed a 1% to 1.2% weight increase, which equated to adsorbing between 12.83 and 30 kg/m3 of carbon. As can be seen, Stones 3 and 4 adsorbed more carbon than their respectively sized counterparts that used pumice aggregate instead of sand in the inner layer (Stones 5 and 6). Also shown is that the small artificial stones (Stones 3 and 5) adsorbed less carbon than the large artificial stones having the same composition (Stones 4 and 6, respectively).
After 3 months, Compounds 7 and 8 showed a higher total amount of adsorbed carbon, which was almost double that of Stones 3 and 4, which comprised the same compounds in the same weight. Accordingly, this significant increase in adsorption rate can likely be attributed to the increase in surface area.
Thus, it is contemplated that the total carbon adsorption capacity of the artificial stones (in this case, Stones 3 to 6), for example over 15 to 20 years, will be higher than the adsorption observed after 3 months at 10 to 50 bar.
The larger artificial stones (Stones 2, 4, and 6) have a slightly lower surface area to volume ratio than the smaller artificial stones (Stones 1, 3, and 5).
Having a high surface area to volume ratio allow materials, such as atmospheric CO2, to diffuse into the pores of the material (Le., react with the component capable of carbon adsorption in the middle of the artificial stone). Accordingly, it would be expected that the smaller artificial stones would have a higher carbon adsorption rate; however, the opposite was observed. As noted above, Stones 1, 3, and 5 Date Recue/Date Received 2022-09-29

14 have the same composition as Stones 2, 4, and 6, respectively, and differ only in their size. In each case, the carbon adsorption of Stones 2, 4, and 6 were significantly higher than the carbon adsorption rate of Stones 1, 3, and 5, respectively. This significant increase in carbon adsorption for artificial stones having a lower surface area to volume ratio could be attributed to the increased amount of cement and/or different air entrainer ratios causing higher overall surface area when the surface area of the internal pores created by entrained air are accounted for.
Date Recue/Date Received 2022-09-29

Claims (37)

15

1. An artificial stone formed from an uncured mixture comprising:
- between 25 wt% and 40 wt% binder;
- between 20% and 35% filler;
- between 1.5 wt% and 2 wt% polycarboxylate-based admixture; and - a diluent;
wherein at least a portion of the filler comprises a component capable of mineral carbonization.

lo 2. The artificial stone of claim 1, wherein the binder comprises cement.

3. The artificial stone of claim 1 or 2, wherein the component capable of mineral carbonization comprises a metal oxide.

4. The artificial stone of any one of claims 1 to 3, wherein the component capable of mineral carbonation comprises at least one of a calcium oxide, a silicon oxide, a magnesium oxide, an iron oxide, a magnesium iron silicate, a nickel oxide, and a manganese oxide.

5. The artificial stone of any one of claims 1 to 3, wherein at least a portion of the filler is olivine.

6. The artificial stone of claim 5, wherein the component capable of mineral carbonation comprises at least one of forsterite, fayalite, monticellite, kirschsteinite, and tephroite.

7. The artificial stone of any one of claims 1 to 6, wherein the filler is a powder or an aggregate.

8. The artificial stone of any one of claims 1 to 6, wherein the filler is less than 2 cm in diameter.

9. The artificial stone of any one of claims 1 to 8, wherein the artificial stone adsorbs at least 10 kg/m3 of carbon.

10.The artificial stone of any one of claims 1 to 9, wherein the cured mixture further comprises a pigment.

11.The artificial stone of claim 10, wherein the pigment is derived from stones.

12.The artificial stone of any one of claims 1 to 11, wherein the cured mixture further comprising an air entrainer admixture.

13.The artificial stone of claim 12, wherein the air entrainer admixture is about 0.5 wt% to about 2 wt% of the cured mixture.

14.An artificial stone comprising cement and olivine, wherein the artificial stone is configured to adsorb a weight of carbon that is at least equivalent to a weight of the olivine.

15.The artificial stone of claim 14, wherein the uncured mixture comprises between 20 wt% and 35 wt% olivine.

16.An artificial stone formed from an uncured mixture comprising between 25 wt% and 40 wt% cement and between 20 wt% and 35 wt% olivine.

17.An artificial stone comprising an inner layer and an outer layer, wherein the inner layer and the outer layer are formed from an uncured mixture Date Regue/Date Received 2022-09-29 comprising between 25 wt% and 40 wt% binder, between 20 wt% and 25 wt% filler, between 1.5 wt% and 2 wt% polycarboxylate-based admixture, wherein the filler in the outer layer comprises a component capable of carbon mineralization.

18.The artificial stone of claim 17, wherein the binder comprises cement.

19.The artificial stone of claim 17 or 18, wherein the component capable of mineral carbonation comprises a metal oxide.

20.The artificial stone of any one of claims 17 to 19, wherein the component capable of mineral carbonation comprises at least one of a calcium oxide, a silicon oxide, a magnesium oxide, an iron oxide, a magnesium iron silicate, a nickel oxide, and a manganese oxide.

21.The artificial stone of any one of claims 17 to 19, wherein the component capable of mineral carbonation comprises an olivine mineral.

22.The artificial stone of claim 21, wherein the component capable of mineral carbonation comprises at least one of forsterite, fayalite, monticellite, kirschsteinite, and tephroite.

23.The artificial stone of any one of claims 17 to 22, wherein the filler is a powder or an aggregate.

24.The artificial stone of any one of claims 17 to 22, wherein the filler is less than 2 cm in diameter.

25.The artificial stone of any one of claims 17 to 24, wherein the artificial stone has a carbon adsorption rate of at least 10 kg/m3.

26.The artificial stone of any one of claims 15 to 23, wherein the outer layer is about 1/3 of a volume of the artificial stone.

27.A method of producing an artificial stone as defined in any one of claims 1 to 11, the method comprising:
- mixing the binder, the filler, the diluent, and the polycarboxylate-based admixture to produce a homogenous or near-homogenous uncured mixture; and - allowing the uncured mixture to cure in a mold.

28.The method of claim 27, further comprising mixing a pigment with the uncured mixture.

29.The method of claim 27 or 28, further comprising mixing an air entrainer admixture with the uncured mixture.

30.The method of claim 29, wherein the air entrainer admixture comprises between about 0.5 wt% and about 2 wt% of the cement.

31.A method of producing an artificial stone as defined in any one of claims 17 to 26, the method comprising - mixing the binder, the filler including the component capable of mineral carbonation, the diluent, and the polycarboxylate-based admixture to produce a homogenous or near-homogenous uncured outer layer mixture;
- providing the uncured outer layer mixture in a mold;
Date Regue/Date Received 2022-09-29 - mixing the binder, the filler, the diluent, and the polycarboxylate-based admixture to produce a homogenous or near-homogenous uncured inner layer mixture;
- providing the uncured inner layer mixture in the mold; and - allowing the inner layer and the outer layer to cure in the mold.

32.The method of claim 31, further comprising mixing a pigment with at least one of: the uncured outer layer mixture and the uncured inner layer mixture.

33.The method of claim 31, further comprising mixing an air entrainer admixture with at least one of: the uncured outer layer mixture and the uncured inner layer mixture.

34.The method of claim 33, wherein the air entrainer admixture comprises between about 0.5 wt% and about 2 wt% of the binder.

35.The method of any one of claims 31 to 34, wherein the outer layer is provided to the mold prior to the inner layer being provided to the mold.

36.The method of any one of claims 31 to 34, wherein the inner layer is provided to the mold prior to the outer layer being provided to the mold.

37.An artificial stone comprising a cement material, wherein an outer layer of the artificial stone that is configured to be exposed to the atmosphere comprises between about 20 wt% and about 35 wt% olivine.
Date Regue/Date Received 2022-09-29