OA22076A - Use of alkaline amino acid salt for carbonation of mineral matrix. - Google Patents

Abstract

Use of an alkali salt of a proteinogenic amino acid selected from alanine (Ala), arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine (Cys), glutamate (Glu), glutamine (Gln), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline (Pro), pyrrolysine (Pyl), selenocysteine (Sec), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr), and valine (Val), and their optical isomers, for the carbonation of an oxide, silicate, aluminate, phosphate, or chloride or of an alkaline earth metal sulfate or of a material containing an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal.

Description

DESCRIPTION

TITLE: USE OF ALKALINE AMINO ACID SALT FOR MINERAL MATRIX CARBONATION

The present invention relates to the use of an alkaline salt of an amino acid for the carbonation of a mineral matrix.

The manufacture of hydraulic binders, and in particular cements, essentially consists of calcining a mixture of carefully selected and measured raw materials, also known as "raw material." Firing this raw material produces an intermediate product, clinker, which, when ground with calcium sulfate and possibly added minerals, yields cement. The type of cement produced depends on the nature and proportions of the raw materials as well as the firing process. Several types of cement are distinguished: Portland cements (which represent the vast majority of cements produced worldwide), aluminous cements (or calcium aluminate cements), natural quick-setting cements, sulfoaluminate cements, sulfobelic cements, and other intermediate varieties.

The most common cements are Portland cements. Portland cements are obtained from Portland clinker, which is produced by clinkerizing a raw material rich in calcium carbonate in a kiln at a temperature of around 1450°C. The production of one tonne of Portland clinker is accompanied by the emission of significant quantities of CO₂ (approximately 0.8 to 0.9 tonnes of CO₂ per tonne of cement in the case of clinker).

However, in 2014, the quantity of cement sold worldwide was around 4.2 billion tons (source: French Cement Industry Association - SFIC). This figure, which is constantly increasing, has more than doubled in 15 years.

During the production of clinker, the main component of Portland cement, CO₂ emissions are linked to:

- up to 40% for heating the cement kiln, grinding and transport;

- up to 60% of CO? said chemical, or decarbonation.

Decarbonation is a chemical reaction that occurs when limestone, the main raw material for the manufacture of Portland cement, is heated to a high temperature. The limestone is then transformed into quicklime and CO₂ according to the following chemical reaction:

_CaCO3 → CaO + _CO2

To reduce CO2 emissions related to Portland cement production, several approaches have been considered so far:

- the adaptation or modernization of cement processes in order to maximize the efficiency of heat exchange;

- the development of new "low carbon" binders such as sulfo-aluminous cements prepared from raw materials less rich in limestone and at a lower firing temperature, which allows a reduction in CO2 emissions of approximately 35%;

- or even the (partial) substitution of clinker in cements by materials that limit _CO2 emissions.

Carbon capture and storage technologies have also been developed to limit _CO2 emissions from sources such as cement plants, blast furnace steel mills, and coal-fired power plants. Deep geological storage is a possibility but is severely limited by factors such as geological conditions. Therefore, other storage options and methods, such as mineralization, must be explored.

Among the various techniques for capturing and storing _CO2 , the so-called "integrated absorption mineralization" or "IAM" route has been the subject of numerous studies, such as those by Meishen Liu et al., "Integrated _CO2 Capture, Conversion, and Storage To Produce Calcium Carbonate Using an Amine Looping Strategy", Energy Fuels, 2019, 33, 1722–1733, and "Integrated _CO2 Capture and Removal via Carbon Mineralization with Inherent Regeneration of Aqueous Solvents", Energy Fuels, 2021, 35, 8051–8068.

This pathway can be summarized by the following reaction scheme:

X + CO2 _→ X-CO2 then

X-CO2 MO 4 MCO3 + X where X designates the CO2 sensor and M designates a mineral, in particular a mineral rich in calcium or magnesium.

The process primarily involves capturing CO₂ using a solvent and then contacting the resulting solution with a mineral acceptor such as CaO or MgO to carbonate it, thus obtaining a stable, insoluble carbonate. The process generally implemented is a closed-system, one-pot process in which the mineral acceptor is suspended in a CO₂ absorbent solution contained in a reactor under a constant pCO₂ atmosphere (pCO₂ = I atm). The pressure drop induced by CO₂ absorption is compensated by a constant supply of CO₂-containing gas. Once the reaction is complete, the solid (carbonate mineral acceptor) and liquid are separated by filtration, the solid is washed, and the liquid phases are recombined for reuse.

The CO₂ absorbers primarily used to date have been industrial amines, particularly monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), 2-amino-2-methylpropanol (AMP), piperazine, and 1,8-diazabicyclo[5.4.0]undec7-ene (DBU). However, in the IAM strategy, a crucial point for industrial development concerns the loss of the amine in the resulting mineral carbonate matrix. Indeed, this sequestration induces a double economic penalty for a potential process:

consumption of the absorbent during IAM cycles and necessary replenishment; and - reduction in the market value of the carbonate formed.

Furthermore, the eco-toxicity of the industrial amines used greatly reduces the possibilities of using the carbonate that is ultimately formed.

As a result, research has also focused on the use of an alkaline amino acid salt, sodium glycinate (NaGly), to capture CO₂, particularly because of its environmental safety.

Although sodium glycinate is more environmentally acceptable than the industrial amines used until now, the use of this amino acid has a number of disadvantages, particularly in terms of yield and reaction kinetics, but also in terms of regeneration rate, which limits the industrial application of the IAM process implementing this CO2 sensor.

It would therefore be interesting to identify new CO2 capture agents enabling the industrial implementation of the "IAM" pathway by improving the yield and kinetics of the reaction.

In “Efficient CO2 Sequestration by a Solid-Gas Reaction Enabled by Mechanochemical Engineering: The Case of L-Lysine,” ACS Sustainable Chem. Eng. 2020, 8, 13159–13166, El-Terkawi et al. describe the use of L-lysine for CO2 capture. However, this publication does not describe the use of this amino acid in an IAM-type process for the carbonation of an alkali-earth metal oxide or silicate. Furthermore, since a proteinogenic amino acid (and not an alkali salt thereof) is used, CO2 capture involves the formation of carbamates (and not carbonates) according to the following reaction:

2Lys + CO2 -> LysH ⁺ + LysCGh'.

However, the formation of carbamates makes the carbonation of metals difficult.

In “CO2 absorption into aqueous potassium salts of lysine and proline: Density, viscosity and solubility of CO2”, Fluid Phase Equilibria, 399 (2015) pages 40-49, Shen et al. describe the use of potassium salts of lysine or proline to capture CO2.

However, again, this publication does not describe the use of these amino acids in an IAM-type process for the carbonation of a non-earth alkali metal oxide or silicate.

However, it has now been found, quite surprisingly, that replacing glycine with other proteinogenic amino acids improves the yield and kinetics of the IAM reaction.

Thus, the present invention relates to the use of an alkali salt of a proteinogenic amino acid selected from alanine (Ala), arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine (Cys), glutamate (Glu), glutamine (Gin), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline (Pro), pyrrolysine (Pyl), selenocysteine (Sec), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr) and valine (Val), as well as their optical isomers, for the carbonation of an oxide, a silicate, an aluminate, of an alkaline earth metal phosphate, chloride or sulfate or of a material containing an alkaline earth metal oxide, silicate, aluminate, phosphate, chloride or sulfate.

The use of an alkaline salt of proteinogenic amino acid according to the invention instead of glycine improves the yield and kinetics of the IAM reaction.

Within the scope of the present invention:

- "Use for the carbonation of an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal or of a material containing an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal" means any use in a process for carbonated to produce an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal or a material containing an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal, in particular any use in an "IAM" type process involving a CO2 capture step and a carbonation step of an oxide or silicate of an alkaline earth metal; and

- The term "alkaline salt" refers to any addition salt obtained with a mineral or organic base by the action of such a base in an organic or aqueous solvent such as an alcohol, ^{ketone, ether, or chlorinated solvent. Examples of such salts include ammonium (NH₄⁺} ₎ , calcium ( ^Ca²⁺ ), iron(II) ( ^Fe²⁺ ) or (III) ( ^Fe³⁺ ), magnesium ( ^Mg²⁺ ), potassium ( ^K⁺ ), sodium ( ^Na⁺ ), and lithium ( ^Li⁺ ). Preferably, an "alkaline salt" refers to a potassium or sodium salt.

The present invention therefore relates to the use of an alkali salt of a proteinogenic amino acid for the carbonation of an oxide, silicate, aluminate, phosphate, chloride, or sulfate of an alkaline earth metal, or of a material containing an oxide, silicate, aluminate, phosphate, chloride, or sulfate of an alkaline earth metal. Preferably, the present invention has the following characteristics, taken alone or in combination:

The proteinogenic amino acid is chosen to be arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine (Cys), histidine (His), or lysine (Lys), as well as their optical isomers. Preferably, the proteinogenic amino acid is chosen to be arginine (Z-Arg), Z-asparagine (Z-Asn), Z-aspartate (Z-Asp), Z-cysteine (Z-Cys), or Z-lysine (Z-Lys). Most preferably, the amino acid is chosen to be L-lysine (Z-Lys);

the alkali salt of proteinogenic amino acid is used for the carbonation of an oxide or silicate of an alkaline earth metal or of a material containing an oxide or silicate of an alkaline earth metal;

the alkaline earth metal is chosen to be calcium (Ca) or magnesium (Mg); the alkaline earth metal oxide is chosen to be CaO or MgO; and/or the alkaline earth metal silicate is chosen to be CaSiOs or MgSiOj.

The alkaline earth metal carbonates obtained using proteinogenic amino acids according to the invention are insoluble and stable, thus enabling the long-term storage of CO2. Furthermore, they can be reused in various ways, for example as a filler in cement production, as a mineral filler in various products, or as a soil amendment.

The present invention can be illustrated in a non-limiting way by the following examples.

Example 1 - "IAM" process for the carbonation of alkaline earth metal oxide

1.1 — Procedure implemented

Preparation of amino acid-CO adducts?

1g of amino acid and an equivalent of KOH are dissolved in 6 ml of a mixture of distilled water and methanol with a ratio of 1:5. CO2 is introduced into the solution at 200 mg/min for 1 hour.

The formation of a white precipitate is observed.

At the end of the reaction the precipitate is filtered on sintered, cold washed with a water/methanol mixture with a ratio of 1:5 and dried under vacuum ramp for 12h.

Carbonation (dry grinding)

The carbonation of the alkaline earth metal oxide is then carried out with a metal oxide:CO2 molar ratio of approximately 1:1. The grindings are carried out in a 20 ml WC reactor with 60 balls of 5 mm diameter at 500 rpm for 30 minutes.

The solid obtained is recovered using 5 ml of distilled water, then centrifuged and washed twice more with 5 ml of distilled water.

The liquid and solid phases are separated and the liquid phases are combined.

The solids are then dried using a freeze dryer.

1.2 - Amino acids / alkaline earth metal oxide tested [Table 1]

Amino acid Alkaline earth metal oxide Molar ratio of metakCOi oxide GlyK CaO 1:0.98 LysK CaO 1:1.47 CysK CaO 1:1.08 GlyK MgO 1:0.94 LysK MgO 1:1.02 CysK MgO 1:0.94

Table 1 - Amino acids / alkaline earth metal oxide tested

1.3 - Results

Carbonation rate of alkaline earth metal oxide

The carbonation rate of the alkaline earth metal oxide (ratio of moles of CO2 fixed in the solid phase per mole of alkaline earth metal oxide) is determined:

by volumetric titration of the CO2 expelled during the acid digestion of the solid obtained (determination of the so-called "inorganic" carbonate) on a Chittick apparatus with a 3 ml burette: an aliquot of dry solid of approximately 10 mg is titrated with 1 ml of H2SO4 IM acid. The calibration of the apparatus is done beforehand with NaHCOs titrated with H2SO4 IM, thus obtaining a calibration curve of y=13.225 with R2=0.9943;

By elemental analysis of the carbon content (total carbon), after deducting the potential contribution of the trapped amine, the nitrogen content of the solid allows us to determine the amount of amine, and therefore the amount of carbon originating from the amine in the solid. Subtracting this from the total carbon content in the solid, we can deduce the amount of carbon originating from the fixed CO2.

These two measurements are confirmed by ql3C NMR on the liquid phases to confirm the quantity of amine: an aliquot of the liquid phase is analyzed by NMR in the presence of an internal reference to allow the quantification of the amine in solution.

The carbonation rate is calculated according to the following equations:

%C / 100 = g C in 1 g of solid sample (1)

Eq. (1) x exact mass of the sample = g C in the sample studied (2)

Eq.(2)/ 12.011 (atomic mass of carbon) = moles of C (3)

The number of moles of CO₂ in the solid phase is calculated by subtracting the number of moles of amino acid/amyl from the number of moles of carbon:

Moles of CO? — moles of C — (moles of amino acid/amine x #C in the amino acid/amine) (4)

To calculate the number of moles of amino acid/amine, we use the following equations 5 to 7: %N / 100 = g N in 1 g of solid sample (5)

Eq. (5) x exact mass of the sample = g N in the sample studied (6) Eq. (6) / 14.008 (atomic mass of nitrogen) = moles of N (7)

After obtaining the number of moles of N in the sample, the number of moles of amino acid/amine is obtained by dividing the number of moles of nitrogen by the number of nitrogen atoms present on the amine (e.g., 3 for DETA and 2 for lysine):

Moles of N (3) / #nitrogens present on the amino acid/amine = moles of amino acid/amine (8)

The carbonation rate (TR) is then calculated as follows:

TC (%) = moles of CO? / moles of CO? initial (9)

Results

[Table 2]

Amino acid Oxide Amount of CO2 captured by the amino acid Carbonation rate of alkaline earth metal oxide GlyK CaO 0.61 45% Lys K CaO 0.77 82% CysK CaO 0.52 52% GlyK MgO 0.61 8.9% LysK MgO 0.57 21% CysK MgO 0.61 16%

Table 2 — Carbonation rate of metal oxide and amino acid regeneration rate

In this table, the amount of CO2 captured by the amino acid corresponds to the ratio of moles of CO2 to moles of nitrogen.

1.4 - Conclusion

According to the experimental results obtained, the use of basic lysine or cysteine salts significantly improves the carbonation rate of alkaline earth metal oxides in the context of an IAM process compared to a basic glycine salt.

Improving the yield of the IAM reaction makes it possible to consider its use at industrial level 15.

Claims (9)

1. Use of an alkali salt of a proteinogenic amino acid selected from alanine (Ala), arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine (Cys), glutamate (Glu), glutamine (Gin), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline (Pro), pyrrolysine (Pyl), selenocysteine (Sec), serine (Ser), threonine (Thr), tryptophan (Trp), tyrosine (Tyr) and valine (Val), and their optical isomers, for the carbonation of an oxide, a silicate, an aluminate, a phosphate, of an alkaline earth metal chloride or sulfate or of a material containing an oxide, silicate, aluminate, phosphate, chloride or sulfate of an alkaline earth metal. 2. Use according to claim 1, characterized in that the alkali salt is a salt of ammonium (NHV), calcium (Ca ²⁺ ), iron (II) (Fe ²⁺ ) or (III) (Fe ³⁺ ), magnesium (Mg ²⁺ ), potassium (K ⁺ ), sodium (Na ⁺ ) or lithium (Li ⁺ ) 3. Use according to claim 1 or 2, characterized in that the proteinogenic amino acid is chosen to be arginine (Arg), asparagine (Asn), aspartate (Asp), cysteine (Cys), rhistidine (His) or lysine (Lys), as well as their optical isomers 4. Use according to claim 3, characterized in that the proteinogenic amino acid is chosen as L-arginine (L-Arg), Λ-asparagine (L-Asn), Σ-aspartate (A-Asp), L-cysteine (A-Cys), or A-lysine (A-Lys). 5. Use according to claim 4, characterized in that the amino acid is chosen as A-lysine (A-Lys). 6. Use according to any one of claims 1 to 5 for the carbonation of an oxide or silicate of an alkaline earth metal or of a material containing an oxide or silicate of an alkaline earth metal. 7. Use according to any one of claims 1 to 6, characterized in that the alkaline earth metal is chosen to be calcium (Ca) or magnesium (Mg). 8. Use according to any one of claims 1 to 7, characterized in that the alkaline earth metal oxide is chosen to be CaO or MgO. 9. Use according to any one of claims 1 to 7, characterized in that the alkaline earth metal silicate is chosen to be CaSiCh or MgSiCh.