CN116282997A - Calcium carbonate cement, calcium carbonate cement hardened body and application thereof - Google Patents

Calcium carbonate cement, calcium carbonate cement hardened body and application thereof Download PDF

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CN116282997A
CN116282997A CN202310182489.8A CN202310182489A CN116282997A CN 116282997 A CN116282997 A CN 116282997A CN 202310182489 A CN202310182489 A CN 202310182489A CN 116282997 A CN116282997 A CN 116282997A
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calcium carbonate
carbonate cement
cement
aragonite
vaterite
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袁波
金点石
陈伟
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Wuhan University of Technology WUT
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Wuhan University of Technology WUT
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    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B12/00Cements not provided for in groups C04B7/00 - C04B11/00
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02WCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00Technologies for solid waste management
    • Y02W30/50Reuse, recycling or recovery technologies
    • Y02W30/91Use of waste materials as fillers for mortars or concrete

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

Abstract

The invention discloses calcium carbonate cement, a calcium carbonate cement hardening body and application thereof, wherein the calcium carbonate cement comprises the following solid raw materials in parts by mass: 30-100 parts of calcium carbonate cement precursor and 5-80 parts of crystal form regulator; the calcium carbonate cement precursor is vaterite, or vaterite and amorphous calcium carbonate; the crystal form regulator comprises at least one of aragonite whisker, coral sand or shell powder. The invention uses the aragonite mineral materials such as aragonite whisker, coral sand or shell powder as the crystal form regulator to control the conversion of the calcium carbonate cement precursor to the target mineral aragonite, the aragonite can be lapped in a three-dimensional space to form a hardened structure, and the compressive strength is improved.

Description

Calcium carbonate cement, calcium carbonate cement hardened body and application thereof
Technical Field
The invention belongs to the field of inorganic nonmetallic materials, and particularly relates to calcium carbonate cement, a calcium carbonate cement hardened body and application thereof.
Background
With the advancement of the national double carbon strategy, the production and use responsibility of Portland cement which occupies about 13.5% of the national industrial annual carbon emission is significant. And each ton of silicate cement is produced, the carbon emission caused by the self decomposition of the calcareous raw material is about 500-550 kg/t, and the carbon emission is more than 58% of the total emission of the silicate cement. Cement low-carbonization production is an important direction in the world and the inside and outside of the industry.
Calcium carbonate has its own "carbon cycle" characteristics in nature: namely, calcium carbonate is decomposed to generate CaO and discharge CO 2 And then regenerating the calcium carbonate under the environmental and chemical actions. The development of a novel cementing material design and preparation technology using calcium carbonate as a cementing component is one of the important ways for solving the carbon emission dilemma in the current cement industry. Calcium carbonate is a mineral widely existing in nature and has various crystal forms. The crystal forms involved in the calcium carbonate cement system are mainly amorphous calcium carbonate, vaterite, aragonite and calcite, and the thermodynamic stability is sequentially enhanced. The hardened body formed by calcium carbonate crystals through grain boundary, intermolecular action and other modes under the action of pressure, temperature or organic matter induction template has certain mechanical properties, and organisms mineralize partial tissues by using a mineralization strategy to form internal bones or external armor with excellent hardness and toughness.
The key point of the calcium carbonate cement is to regulate and control the calcium carbonate phase, and the current regulation and control mode of the calcium carbonate phase is mainly to add inorganic or organic additives to affect the crystal lattice or crystal face of the calcium carbonate, control the nucleation growth and regulate and control the phase and morphology of the calcium carbonate.
At present, inorganic ions are mainly used as a crystal form regulator in the preparation process of calcium carbonate cement, and Mg is added 2+ Setting and hardening as crystal form regulator for two hr to reach 6MPa, and adding Sr 2+ And is prepared by a compression molding mode, and curing is carried out for 3-7 days to generate coagulation hardening. It can be seen that the current regulation and control mode is single, the preparation mode is limited, and there is still room for improvement.
Disclosure of Invention
In order to overcome the problems of the prior art, it is an object of the present invention to provide a calcium carbonate cement which can be rapidly hardened and has a high compressive strength.
Another object of the present invention is to provide a hardened calcium carbonate cement product comprising the calcium carbonate cement.
The third object of the present invention is to provide a method for producing the calcium carbonate cement hardened body.
The fourth object of the present invention is to provide the use of the above calcium carbonate cement and a hardened calcium carbonate cement.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the first aspect of the invention provides calcium carbonate cement, which comprises the following solid raw materials in parts by weight: 30-100 parts of calcium carbonate cement precursor and 5-80 parts of crystal form regulator; the calcium carbonate cement precursor is vaterite, or vaterite and amorphous calcium carbonate; the crystal form regulator comprises at least one of aragonite whisker, coral sand or shell powder.
There are various methods for preparing amorphous calcium carbonate, such as decomposition of ammonium carbonate to produce CO 2 Amorphous calcium carbonate is obtained from various sources, such as amorphous calcium carbonate, precipitation (also called double decomposition), carbonization, and the like.
Wherein the carbonization method of amorphous calcium carbonate is to make gas CO 2 Method for preparing amorphous calcium carbonate by diffusing into calcium ion solution such as calcium salt or calcium hydroxide solution, wherein calcium source can be derived from calcium-containing waste resource such as carbide slag, phosphogypsum, construction solid waste, etc., and is not limited to chemical agent, CO 2 From industrial waste gas, can realize resource recycling, reduce carbon emission, and has the advantages of simple operation, abundant raw materials, easy industrial production and the like.
In a preferred embodiment of the present invention, amorphous calcium carbonate is prepared by carbonization.
Preferably, in the calcium carbonate cement, the amorphous calcium carbonate consists of CO 2 And calcium ion solution.
Preferably, in the calcium carbonate cement, the amorphous calcium carbonate is prepared by a method comprising the steps of: CO is processed by 2 Introducing calcium ion solution, adding stabilizer, carbonizing until pH of the solution is 7-9, separating and drying precipitate generated by the reaction to obtain the final productAmorphous calcium carbonate.
Preferably, the CO 2 The flow rate of the water is 400-600 mL/min; further preferably, the CO 2 The flow rate of the water is 450-550 mL/min; still more preferably, the CO 2 The flow rate of (C) was 500mL/min.
Preferably, the calcium ion solution comprises at least one of anhydrous calcium chloride, calcium chloride hydrate, anhydrous calcium nitrate, calcium nitrate hydrate, anhydrous calcium acetate, calcium acetate hydrate or calcium hydroxide; further preferably, the calcium ion solution includes at least one of calcium chloride hydrate, calcium nitrate hydrate, or calcium acetate hydrate; still more preferably, the calcium ion solution is selected from calcium chloride dihydrate.
Preferably, the concentration of the calcium ion solution is 0.8-1.2 mol/L; further preferably, the concentration of the calcium ion solution is 0.9-1.1 mol/L; preferably, the concentration of the calcium ion solution is 1mol/L.
Preferably, the stabilizer comprises at least one of magnesium ion, silicate ion, phosphate ion; further preferably, the stabilizer is selected from magnesium ions; still more preferably, the stabilizer is selected from anhydrous magnesium chloride.
Preferably, the concentration of the stabilizer is 0.08-0.12 mol/L; further preferably, the concentration of the stabilizer is 0.09 to 0.11mol/L; still more preferably, the concentration of the stabilizer is 0.1mol/L.
Preferably, the carbonization reaction is carried out until the pH of the solution is 7.2-8.8; further preferably, the carbonization reaction is carried out until the pH of the solution is 7.5 to 8.5; still more preferably, the carbonization reaction is carried out until the pH of the solution is 8.
In another preferred embodiment of the present invention, amorphous calcium carbonate is prepared by a precipitation method.
Preferably, in the calcium carbonate cement, amorphous calcium carbonate is prepared by reacting a calcium ion solution with a carbonate.
Preferably, in the calcium carbonate cement, the amorphous calcium carbonate is prepared by a method comprising the steps of: mixing 0.8-1.2 mol/L calcium ion solution with 0.08-0.12 mol/L carbonate according to the ratio of 1: mixing the volume ratios of (7-11), separating and drying the precipitate generated by the reaction to obtain the amorphous calcium carbonate.
Preferably, in the method for preparing amorphous calcium carbonate, the calcium ion solution comprises at least one of anhydrous calcium chloride, calcium chloride hydrate, anhydrous calcium nitrate, calcium nitrate hydrate, anhydrous calcium acetate, calcium acetate hydrate or calcium hydroxide; further preferably, in the method for preparing amorphous calcium carbonate, the calcium ion solution comprises at least one of anhydrous calcium chloride, anhydrous calcium nitrate or anhydrous calcium acetate; still more preferably, in the method for preparing amorphous calcium carbonate, the calcium ion solution is selected from anhydrous calcium chloride.
Preferably, in the method for preparing amorphous calcium carbonate, the carbonate comprises at least one of anhydrous sodium carbonate, a hydrate of sodium carbonate, anhydrous sodium bicarbonate, a hydrate of sodium bicarbonate, anhydrous potassium carbonate, a hydrate of potassium carbonate, anhydrous potassium bicarbonate, a hydrate of potassium bicarbonate, anhydrous ammonium carbonate, a hydrate of ammonium carbonate, anhydrous ammonium bicarbonate or a hydrate of ammonium bicarbonate; further preferably, in the method for preparing amorphous calcium carbonate, the carbonate comprises at least one of anhydrous sodium carbonate, anhydrous sodium bicarbonate, anhydrous potassium carbonate, anhydrous potassium bicarbonate, anhydrous ammonium carbonate or anhydrous ammonium bicarbonate; still more preferably, in the method for preparing amorphous calcium carbonate, the carbonate is selected from anhydrous sodium carbonate.
Preferably, in the preparation method of amorphous calcium carbonate, the concentration of the calcium ion solution is 0.85-1.15 mol/L; further preferably, in the method for preparing amorphous calcium carbonate, the concentration of the calcium ion solution is 0.9 to 1.1mol/L; still more preferably, in the method for preparing amorphous calcium carbonate, the concentration of the calcium ion solution is 0.95 to 1.05mol/L.
Preferably, in the preparation method of amorphous calcium carbonate, the concentration of carbonate is 0.085-0.115 mol/L; further preferably, in the method for preparing amorphous calcium carbonate, the concentration of carbonate is 0.09 to 0.11mol/L; still more preferably, in the method for producing amorphous calcium carbonate, the concentration of carbonate is 0.095 to 0.105mol/L.
Preferably, in the preparation method of amorphous calcium carbonate, the volume ratio of the calcium ion solution to the carbonate is 1: (7.5-10.5); further preferably, in the method for preparing amorphous calcium carbonate, the volume ratio of the calcium ion solution to the carbonate is 1: (8-10); still further preferably, in the method for preparing amorphous calcium carbonate, the volume ratio of the calcium ion solution to the carbonate is 1: (8.5-9.5).
Preferably, in the method for preparing amorphous calcium carbonate, the separation comprises at least one of filtration, suction filtration or centrifugation; further preferably, in the method for producing amorphous calcium carbonate, the separation includes at least one of filtration or suction filtration; still further preferably, in the method for preparing amorphous calcium carbonate, the separation is selected from suction filtration.
Preferably, in the preparation method of amorphous calcium carbonate, the drying temperature is 40-80 ℃; further preferably, in the method for preparing amorphous calcium carbonate, the drying temperature is 50-70 ℃; still more preferably, in the method for preparing amorphous calcium carbonate, the drying temperature is 55 to 65 ℃.
Preferably, in the method for preparing amorphous calcium carbonate, the drying time is 12-36 hours; further preferably, in the method for preparing amorphous calcium carbonate, the drying time is 18 to 30 hours; still more preferably, in the method for preparing amorphous calcium carbonate, the drying time is 22 to 26 hours.
Preferably, in the method for preparing amorphous calcium carbonate, the precipitate is further washed before being dried after being separated; further preferably, the solvent for washing includes at least one of water and an organic solvent; still more preferably, the solvent for washing is deionized water and absolute ethanol.
Preferably, in the calcium carbonate cement, the purity of the amorphous calcium carbonate is 90-100%; further preferably, in the calcium carbonate cement, the purity of amorphous calcium carbonate is 94-100%; still more preferably, in the calcium carbonate cement, the purity of amorphous calcium carbonate is 98 to 100%.
Vaterite also exists in a variety of preparation methods, such as thermal decomposition, precipitation, carbonization, etc., and it is seen that there are also many sources of vaterite available.
Wherein, the carbonization method of vaterite is similar to the carbonization method of amorphous calcium carbonate, and is to make gas CO 2 The calcium-containing solution can be derived from waste resources such as carbide slag, phosphogypsum, building solid waste and the like, and is not limited to chemical reagents and CO 2 The method can also come from industrial waste gas, can realize resource recycling, reduces carbon emission, and has the advantages of simple operation, abundant raw materials, easy industrial production and the like.
In a preferred embodiment of the present invention, vaterite is prepared using a carbonization process.
Preferably, in the calcium carbonate cement, vaterite is formed from CO 2 And ammonia water and calcium ion solution.
Preferably, in the calcium carbonate cement, vaterite is produced by a method comprising the steps of: adding ammonia water into the calcium ion solution, and introducing CO 2 And (3) until the pH value of the solution is 7-9, separating and drying the precipitate generated by the reaction to obtain the vaterite.
Preferably, the calcium ion solution comprises at least one of anhydrous calcium chloride, calcium chloride hydrate, anhydrous calcium nitrate, calcium nitrate hydrate, anhydrous calcium acetate, calcium acetate hydrate or calcium hydroxide; further preferably, the calcium ion solution comprises at least one of anhydrous calcium chloride, anhydrous calcium nitrate, or anhydrous calcium acetate; still more preferably, the calcium ion solution is selected from anhydrous calcium chloride.
Preferably, the concentration of the calcium ion solution is 0.1-0.2 mol/L; further preferably, the concentration of the calcium ion solution is 0.12-0.18 mol/L; preferably, the concentration of the calcium ion solution is 0.15mol/L.
Preferably, the concentration of the ammonia water is 25-28 wt%; further preferably, the concentration of the ammonia water is 26-27 wt%; still more preferably, the concentration of the aqueous ammonia is 26wt%.
Preferably, the addition amount of the ammonia water is 1-6% of the volume of the calcium ion solution; further preferably, the addition amount of the ammonia water is 2-5% of the volume of the calcium ion solution; still more preferably, the ammonia water is added in an amount of 3 to 4% by volume of the calcium ion solution.
Preferably, the CO 2 The flow rate of the water is 500-700 mL/min; further preferably, the CO 2 The flow rate of the water is 550-650 mL/min; still more preferably, the CO 2 The flow rate of (C) was 600mL/min.
Preferably, CO is introduced 2 The pH value of the solution is 7.2-8.8; further preferably, CO is introduced 2 The pH value of the solution is 7.5-8.5; more preferably, CO is introduced 2 To a pH of 8.
In another preferred embodiment of the present invention, vaterite is prepared using a precipitation process. Preferably, in the calcium carbonate cement, vaterite is produced by reacting a calcium ion solution with a carbonate.
Preferably, in the calcium carbonate cement, vaterite is produced by a method comprising the steps of: mixing 1.8-2.2 mol/L calcium ion solution and 1.8-2.2 mol/L carbonate according to an equal volume ratio, separating and drying a precipitate generated by the reaction, and obtaining the vaterite.
Preferably, in the method for preparing vaterite, the calcium ion solution comprises at least one of anhydrous calcium chloride, calcium chloride hydrate, anhydrous calcium nitrate, calcium nitrate hydrate, anhydrous calcium acetate, or calcium acetate hydrate; further preferably, in the method for producing vaterite, the calcium ion solution includes at least one of a hydrate of calcium chloride, a hydrate of calcium nitrate, or a hydrate of calcium acetate; still more preferably, in the method for producing vaterite, the calcium ion solution is selected from the group consisting of calcium chloride dihydrate.
Preferably, in the method for preparing vaterite, the carbonate comprises at least one of anhydrous sodium carbonate, a hydrate of sodium carbonate, anhydrous sodium bicarbonate, a hydrate of sodium bicarbonate, anhydrous potassium carbonate, a hydrate of potassium carbonate, anhydrous potassium bicarbonate, a hydrate of potassium bicarbonate, anhydrous ammonium carbonate, a hydrate of ammonium carbonate, anhydrous ammonium bicarbonate, or a hydrate of ammonium bicarbonate; further preferably, in the method for preparing vaterite, the carbonate comprises at least one of anhydrous sodium carbonate, anhydrous sodium bicarbonate, anhydrous potassium carbonate, anhydrous potassium bicarbonate, anhydrous ammonium carbonate, or anhydrous ammonium bicarbonate; still more preferably, in the method for producing vaterite, the carbonate is selected from anhydrous potassium carbonate.
Preferably, in the preparation method of vaterite, the concentration of the calcium ion solution is 1.85-2.15 mol/L; further preferably, in the method for producing vaterite, the concentration of the calcium ion solution is 1.9 to 2.1mol/L; still more preferably, in the method for producing vaterite, the concentration of the calcium ion solution is 1.95 to 2.05mol/L.
Preferably, in the preparation method of vaterite, the concentration of carbonate is 1.85-2.15 mol/L; further preferably, in the method for producing vaterite, the concentration of carbonate is 1.9 to 2.1mol/L; still more preferably, in the method for producing vaterite, the concentration of carbonate is 1.95 to 2.05mol/L.
Preferably, in the method for producing vaterite, the separating comprises at least one of filtering, suction filtering, or centrifuging; further preferably, in the method for producing vaterite, the separating comprises at least one of filtering or suction filtering; still further preferably, in the method of preparing vaterite, the isolating is selected from the group consisting of suction filtration.
Preferably, in the method for preparing vaterite, the drying temperature is 40-80 ℃; further preferably, in the method for preparing vaterite, the drying temperature is 50 to 70 ℃; still more preferably, in the method for producing vaterite, the drying temperature is 55 to 65 ℃.
Preferably, in the method for preparing vaterite, the drying time is 12 to 36 hours; further preferably, in the method for producing vaterite, the drying time is 18 to 30 hours; still more preferably, in the method for producing vaterite, the drying time is 22 to 26 hours.
Preferably, in the method for preparing vaterite, the precipitate is further washed before being dried after being separated; further preferably, the solvent for washing includes at least one of water and an organic solvent; still more preferably, the solvent for washing is deionized water and absolute ethanol.
Preferably, in the calcium carbonate cement, the purity of vaterite is 90-100%; further preferably, in the calcium carbonate cement, the vaterite has a purity of 92 to 100%; still more preferably, in the calcium carbonate cement, the vaterite has a purity of 95 to 100%.
Preferably, in the calcium carbonate cement, when the calcium carbonate cement precursor is vaterite and amorphous calcium carbonate, the mass ratio of amorphous calcium carbonate to vaterite is (0.25 to 1): 1, a step of; further preferably, in the calcium carbonate cement, when the calcium carbonate cement precursor is vaterite and amorphous calcium carbonate, the mass ratio of amorphous calcium carbonate to vaterite is (0.3 to 0.8): 1, a step of; still more preferably, in the calcium carbonate cement, when the calcium carbonate cement precursor is vaterite and amorphous calcium carbonate, the mass ratio of amorphous calcium carbonate to vaterite is (0.3 to 0.6): 1.
preferably, in the calcium carbonate cement, the average length-diameter ratio of the aragonite whisker in the crystal form regulator is 5-40; further preferably, in the calcium carbonate cement, the average length-diameter ratio of the aragonite whisker in the crystal form regulator is 7-20; still more preferably, in the calcium carbonate cement, the average aspect ratio of the aragonite whiskers in the crystal form modifier is 8 to 12.
Preferably, in the calcium carbonate cement, the content of aragonite in the crystal form regulator is 85-100 wt%; further preferably, in the calcium carbonate cement, the content of aragonite in the crystal form regulator is 90-100 wt%; still more preferably, in the calcium carbonate cement, the aragonite content of the aragonite whisker in the crystal form regulator is 98-100 wt%.
Preferably, in the calcium carbonate cement, the average particle size of coral sand in the crystal form regulator is 20-300 μm; further preferably, in the calcium carbonate cement, the average particle diameter of the coral sand in the crystal form regulator is 40-150 μm; still more preferably, in the calcium carbonate cement, the crystal form modifier has an average particle diameter of 60 to 100 μm.
Preferably, in the calcium carbonate cement, the aragonite content of the coral sand in the crystal form regulator is 75-100 wt%; further preferably, in the calcium carbonate cement, the aragonite content of the coral sand in the crystal form regulator is 90-98 wt%; still more preferably, in the calcium carbonate cement, the aragonite content of the coral sand in the crystal form modifier is 95 to 97wt%.
Preferably, in the calcium carbonate cement, in the crystal form regulator, the average particle size of the shell powder is 25-300 mu m; further preferably, in the calcium carbonate cement, the average particle size of the shell powder in the crystal form regulator is 30-200 μm; still more preferably, in the calcium carbonate cement, the average particle diameter of the shell powder in the crystal form modifier is 40 to 70. Mu.m.
Preferably, in the calcium carbonate cement, the aragonite content of the shell powder in the crystal form regulator is 70-100 wt%; further preferably, in the calcium carbonate cement, the aragonite content of the shell powder in the crystal form regulator is 85-95 wt%; still more preferably, in the calcium carbonate cement, the aragonite content of the shell powder in the crystal form regulator is 92-94 wt%.
Preferably, the raw materials of the calcium carbonate cement further comprise water; further preferably, the mass ratio of the water to the solid raw material is 0.1 to 0.5; still more preferably, the mass ratio of the water to the solid raw material is 0.2 to 0.4; more preferably, the mass ratio of the water to the solid raw material is 0.25 to 0.35.
Preferably, in the calcium carbonate cement, the mass part of the calcium carbonate cement precursor is 40-90 parts; further preferably, in the calcium carbonate cement, the mass part of the calcium carbonate cement precursor is 45-80 parts; still more preferably, in the calcium carbonate cement, the mass part of the calcium carbonate cement precursor is 50 to 70 parts.
Preferably, in the calcium carbonate cement, the mass part of the crystal form regulator is 20-70 parts; further preferably, in the calcium carbonate cement, the mass part of the crystal form regulator is 25-60 parts; still more preferably, in the calcium carbonate cement, the mass part of the crystal form regulator is 30-50 parts.
Preferably, the calcium carbonate cement comprises the following raw materials in parts by weight: 40-90 parts of calcium carbonate cement precursor and 20-70 parts of crystal form regulator.
Further preferably, the calcium carbonate cement comprises the following raw materials in parts by weight: 45-80 parts of calcium carbonate cement precursor and 25-60 parts of crystal form regulator.
Still more preferably, the calcium carbonate cement comprises the following raw materials in parts by weight: 50-70 parts of calcium carbonate cement precursor and 30-50 parts of crystal form regulator.
A second aspect of the present invention provides a hardened calcium carbonate cement body formed from a cement comprising the calcium carbonate cement of the first aspect of the present invention.
Preferably, the aragonite content of the calcium carbonate cement hardened body is 70-100 wt%; further preferably, the aragonite content of the calcium carbonate cement hardened body is 80-100 wt%; still more preferably, the aragonite content of the calcium carbonate cement hardened body is 94 to 99wt%.
Preferably, the porosity of the calcium carbonate cement hardened body is 20-60%; further preferably, the porosity of the calcium carbonate cement hardened body is 25 to 50%; still more preferably, the calcium carbonate cement hardened body has a porosity of 30 to 40%.
A third aspect of the present invention provides a method for producing a hardened calcium carbonate cement body according to the second aspect of the present invention, the method comprising the steps of: and mixing the raw materials of the calcium carbonate cement, and then forming and curing to obtain the calcium carbonate cement hardened body.
Preferably, in the preparation method, amorphous calcium carbonate and vaterite are mixed to obtain a calcium carbonate cement precursor, and then a crystal form regulator is added to perform mixing to obtain a solid raw material of the calcium carbonate cement.
Preferably, in the preparation method, the mixing time of amorphous calcium carbonate and vaterite is 1-8 min; further preferably, in the preparation method, the mixing time of amorphous calcium carbonate and vaterite is 2 to 6min; still more preferably, in the preparation method, the mixing time of amorphous calcium carbonate and vaterite is 2 to 4min.
Preferably, in the preparation method, the mixing time of adding the crystal form regulator for mixing is 2-10 min; further preferably, in the preparation method, the mixing time of adding the crystal form regulator for mixing is 3-8 min; still more preferably, in the preparation method, the mixing time of adding the crystal form regulator for mixing is 4-6 min.
Preferably, in the preparation method, the molding includes at least one of extrusion molding, casting molding, and compression molding.
Preferably, in the preparation method, the molding pressure is 0-200 MPa; further preferably, in the preparation method, the molding pressure is 50-150 MPa; still more preferably, in the production method, the molding pressure is 50 to 100MPa.
Preferably, in the preparation method, the curing includes at least one of air curing, water curing or steam curing.
Preferably, in the preparation method, the curing time is 1-5 days; further preferably, in the preparation method, the curing time is 1-3 days; still more preferably, in the production method, the curing time is 1 to 2 days.
Preferably, in the preparation method, the temperature of the maintenance is 20-120 ℃; further preferably, in the preparation method, the curing temperature is 30-110 ℃; still more preferably, in the preparation method, the curing temperature is 40 to 100 ℃.
A fourth aspect of the present invention provides the use of a calcium carbonate cement according to the first aspect of the present invention, or a hardened calcium carbonate cement according to the second aspect of the present invention, in the field of building materials.
Preferably, the building material field is a low carbon building material field.
The beneficial effects of the invention are as follows:
the calcium carbonate cement of the invention is converted into a cementing power source by a crystal form, the crystal form regulation and control are realized by doping aragonite whisker, coral sand or shell powder and other aragonite mineral materials as a crystal form regulator in a crystal nucleus induction mode, the conversion of a calcium carbonate cement precursor to target mineral aragonite is controlled, and aragonite can be lapped in a three-dimensional space to form a hardened body structure. In the calcium carbonate cement precursor, amorphous calcium carbonate and vaterite are both thermodynamically unstable calcium carbonate crystal forms, and can be converted into rod-shaped aragonite through the regulation and control of a crystal form regulator, wherein the amorphous calcium carbonate has higher activity, is easier to convert into aragonite than vaterite, is favorable for the reaction process, and has smaller influence on mechanical properties. The aragonite whisker is used as a modified material to realize industrial production, and aragonite mineral materials such as coral sand, shell powder and the like can be used in the field of sea islands and reefs according to local conditions.
Drawings
Figure 1 is an XRD pattern of amorphous calcium carbonate versus vaterite in examples and comparative examples.
Fig. 2 is an XRD pattern of the calcium carbonate cement hardened body of examples 1 to 4 and comparative example 1.
FIG. 3 is an SEM image of a hardened calcium carbonate cement of example 1 after curing for 1 day.
FIG. 4 is an SEM image of a hardened calcium carbonate cement of example 2 cured for 1 day.
FIG. 5 is an SEM image of a hardened calcium carbonate cement of example 3 after curing for 1 day.
FIG. 6 is an SEM image of a hardened calcium carbonate cement of example 4 after curing for 1 day.
FIG. 7 is an SEM image of a hardened calcium carbonate cement of comparative example 1 after curing for 1 day.
FIG. 8 is an SEM image of a hardened calcium carbonate cement of comparative example 2 cured for 1 day.
Detailed Description
The present invention will be described in further detail with reference to specific examples. It is also to be understood that the following examples are given solely for the purpose of illustration and are not to be construed as limitations on the scope of the invention, since various modifications and adaptations may be made by those skilled in the art in light of the teachings herein. The specific process parameters and the like described below are also merely examples of suitable ranges, i.e., one skilled in the art can make a selection within the suitable ranges by the description herein and are not intended to be limited to the specific data described below. The starting materials, reagents or apparatus used in the following examples and comparative examples were obtained from conventional commercial sources or by known methods unless otherwise specified.
The amorphous calcium acid and vaterite used in the examples and comparative examples of the present invention were prepared by precipitation.
The preparation method of the amorphous calcium carbonate comprises the following steps: the volume ratio of the use is 1:9, mixing 1mol/L anhydrous calcium chloride with 0.1mol/L sodium carbonate, immediately carrying out suction filtration on the precipitate, washing a filter cake by deionized water and absolute ethyl alcohol, and drying at 60 ℃ for 24 hours.
The preparation method of vaterite comprises the following steps: mixing 2.0mol/L of equal volume and equal concentration calcium chloride dihydrate with anhydrous potassium carbonate, carrying out suction filtration on the precipitate, washing a filter cake with deionized water and absolute ethyl alcohol, drying, and drying at 60 ℃ for 24 hours.
The amorphous calcium carbonate and vaterite products were characterized separately using XRD, shown in figure 1, with amorphous calcium carbonate purity of 100% and vaterite purity of 98%.
The average aspect ratio of the aragonite whiskers used in the examples and comparative examples of the present invention was 10, and the aragonite content was 99wt%; the average particle diameter of coral sand is 80 mu m, and the content of aragonite is 97wt%; the average particle size of the shell powder is 50 mu m, and the content of aragonite is 94wt%.
Example 1
The calcium carbonate cement comprises the following solid raw materials in parts by weight: 15 parts of amorphous calcium carbonate, 45 parts of vaterite and 10 parts of aragonite whisker.
The preparation method of the calcium carbonate cement hardened body comprises the following steps: amorphous calcium carbonate was combined with vaterite at 1:3, mixing the materials in a stirring pot in mass ratio, stirring for 3min, adding 40 parts of aragonite whisker, stirring for 5min, mixing water with solid raw materials according to a water-solid ratio of 0.35 to obtain calcium carbonate cement paste, pouring the paste into a stainless steel cylindrical die with the diameter of 20mm, pressurizing by using an automatic press machine, forming under the pressure of 100MPa, demoulding after pressurizing for 2min to obtain a test block with the height of 20mm and the diameter of 20mm, and placing the test block in a steam environment with the temperature of 60 ℃ for curing to obtain the calcium carbonate cement hardening body.
Example 2
The calcium carbonate cement comprises the following solid raw materials in parts by weight: 15 parts of amorphous calcium carbonate, 45 parts of vaterite and 30 parts of coral sand.
The preparation method of the calcium carbonate cement hardened body comprises the following steps: amorphous calcium carbonate was combined with vaterite at 1:3, mixing the materials in a stirring pot in mass ratio, stirring for 3min, adding 40 parts of coral sand, stirring for 5min, mixing water with solid raw materials according to a water-solid ratio of 0.35 to obtain calcium carbonate cement paste, pouring the paste into a stainless steel cylindrical die with the diameter of 20mm, pressurizing by using an automatic press machine, forming under the pressure of 100MPa, demolding after pressurizing for 2min to obtain a test block with the height of 20mm and the diameter of 20mm, and placing the test block in a steam environment with the temperature of 80 ℃ for curing to obtain the calcium carbonate cement hardening body.
Example 3
The calcium carbonate cement comprises the following solid raw materials in parts by weight: 20 parts of amorphous calcium carbonate, 40 parts of vaterite and 40 parts of shell powder.
The preparation method of the calcium carbonate cement hardened body comprises the following steps: amorphous calcium carbonate was combined with vaterite at 1:2, mixing in a stirring pot according to the mass ratio, stirring for 3min, adding 40 parts of shell powder, stirring for 5min, mixing water with solid raw materials according to the water-solid ratio of 0.30 to obtain calcium carbonate cement paste, pouring the paste into a stainless steel cylindrical die with the diameter of 20mm, pressurizing by using an automatic press machine, forming under the pressure of 100MPa, demolding after pressurizing for 2min to obtain a test block with the height of 20mm and the diameter of 20mm, and placing the test block in a steam environment with the temperature of 40 ℃ for curing to obtain a hardened body of the calcium carbonate cement.
Example 4
The calcium carbonate cement comprises the following solid raw materials in parts by weight: 60 parts of vaterite and 60 parts of coral sand.
The preparation method of the calcium carbonate cement hardened body comprises the following steps: mixing 60 parts of vaterite and 40 parts of coral sand in a stirring pot, stirring for 5min, mixing water with solid raw materials according to a water-solid ratio of 0.35 to obtain calcium carbonate cement slurry, pouring the slurry into a stainless steel cylindrical mold with the diameter of 20mm, pressurizing by using an automatic press machine, forming under the pressure of 50MPa, pressurizing for 2min, demoulding to obtain a test block with the height of 20mm and the diameter of 20mm, and placing the test block in a steam environment with the temperature of 100 ℃ for curing to obtain a hardened calcium carbonate cement.
Comparative example 1
The calcium carbonate cement comprises the following solid raw materials in parts by weight: 20 parts of amorphous calcium carbonate, 60 parts of vaterite and 20 parts of anhydrous magnesium chloride.
The preparation method of the calcium carbonate cement hardened body comprises the following steps: amorphous calcium carbonate was combined with vaterite at 1:3, mixing the materials in a stirring pot in mass ratio, stirring for 3min, adding 20 parts of anhydrous magnesium chloride, stirring for 5min, mixing water with solid raw materials according to a water-solid ratio of 0.35 to obtain calcium carbonate cement paste, pouring the paste into a stainless steel cylindrical die with the diameter of 20mm, pressurizing by using an automatic press machine, forming the pressure of 50MPa, demoulding after pressurizing for 2min to obtain a test block with the height of 20mm and the diameter of 20mm, and placing the test block in a steam environment with the temperature of 60 ℃ for curing to obtain a hardened body of the calcium carbonate cement.
Comparative example 2
The calcium carbonate cement comprises the following solid raw materials in parts by weight: 20 parts of amorphous calcium carbonate, 40 parts of vaterite.
The preparation method of the calcium carbonate cement hardened body comprises the following steps: amorphous calcium carbonate was combined with vaterite at 1:2, mixing the materials in a stirring pot according to the mass ratio of 0.35 after stirring for 3min, mixing water with solid raw materials to obtain calcium carbonate cement paste, pouring the paste into a stainless steel cylindrical die with the diameter of 20mm, pressurizing by using an automatic press machine, forming the pressure to be 50MPa, performing demoulding after pressurizing for 2min to obtain a test block with the height of 20mm and the diameter of 20mm, and placing the test block in a steam environment with the temperature of 60 ℃ for curing to obtain a hardened body of the calcium carbonate cement.
Performance testing
1) The hardened calcium carbonate cements obtained in examples 1 to 4 and comparative example 1 were subjected to compressive strength test using an electronic universal tester, and the loading speed was 1mm/min. Wherein, the compressive strength for 1 day is the compressive strength of the hardened calcium carbonate cement body cured for 1 day, and the compressive strength for 28 days is the compressive strength of the hardened calcium carbonate cement body cured for 28 days.
2) The calcium carbonate cements obtained in examples 1 to 4 and comparative example 1 were tested for setting time, aragonite content and porosity of the hardened calcium carbonate cement bodies. The curing time is curing time required by converting amorphous calcium carbonate and vaterite into aragonite, XRD and infrared are used for measuring calcium carbonate phase composition with different curing time, and after the conversion of the crystal form is completed, the curing is complete, and the curing time is curing time; quantitative analysis is carried out on the aragonite content according to an XRD pattern to obtain the aragonite; the porosity is obtained according to mercury porosimetry.
3) XRD patterns and SEM patterns of the calcium carbonate cement hardened bodies of examples 1 to 4 and comparative example 1 were tested.
The test results are shown in Table 1.
Table 1 test results of examples 1 to 4 and comparative example 1
Figure BDA0004102794040000111
Figure BDA0004102794040000121
The compressive strength of the hardened calcium carbonate cement bodies obtained in examples 1 to 4 is higher than that of comparative example 1, and it is seen that the compressive strength of the hardened calcium carbonate cement body formed by overlapping the aragonite in a three-dimensional space is remarkably improved by adding aragonite whisker, coral sand or shell powder and other aragonite mineral materials as a crystal form regulator and better promoting the conversion of the calcium carbonate cement precursor to the target mineral aragonite than inorganic ions such as magnesium ions. Specifically, fig. 2 shows XRD patterns of hardened calcium carbonate cement bodies of examples 1 to 4 and comparative examples 1 to 2 cured for 1 day, and it is seen that the hardened bodies of examples 1 to 4 and comparative example 1 are mainly aragonite phases, and the hardened bodies of comparative example 2 without adding a crystal form modifier are mainly calcite phases, indicating that anhydrous magnesium chloride has an effect of inducing aragonite formation with aragonite mineral materials such as aragonite whiskers, coral sand, or shell powder of the present invention. Fig. 3 is an SEM image of the calcium carbonate cement hardened body cured for 1 day in example 1, fig. 4 is an SEM image of the calcium carbonate cement hardened body cured for 1 day in example 2, fig. 5 is an SEM image of the calcium carbonate cement hardened body cured for 1 day in example 3, fig. 6 is an SEM image of the calcium carbonate cement hardened body cured for 1 day in example 4, fig. 7 is an SEM image of the calcium carbonate cement hardened body cured for 1 day in comparative example 1, and fig. 8 is an SEM image of the calcium carbonate cement hardened body cured for 1 day in comparative example 2. The rhombohedron is calcite structure, needle bar-shaped is aragonite structure, and from the figure, the aragonite structure formed in fig. 7 is shorter and thicker and is arranged irregularly, so that the formation of an interweaved and wound three-dimensional space structure is unfavorable, and the hardened body has poor cohesiveness, high porosity and low compressive strength. Compared with comparative example 1, examples 1 to 4 have a better effect of promoting the formation of a needle-like aragonite structure, and the aragonite is longer, which is more favorable for forming a three-dimensional structure of intertwined and entangled, and further, the compression strength of the hardened body is higher. As can be seen from fig. 8, comparative example 2 was transformed into calcite, which had a rhombohedron morphology, and could not form an aragonite-like lap joint structure, and the cohesive force was poor, and the resulting hardened body had a large pore size and many pores, resulting in low strength. In addition, the test block with larger molding pressure has relatively higher compressive strength; properly raising the curing temperature can accelerate the curing rate without affecting the strength.
According to the invention, by adding the aragonite whisker, coral sand or shell powder and other aragonite mineral materials as a crystal form regulator, the conversion of the calcium carbonate cement precursor to the target mineral aragonite is controlled, the aragonite can be lapped in a three-dimensional space to form a hardened body structure, so that the compressive strength is improved.

Claims (10)

1. The calcium carbonate cement is characterized by comprising the following solid raw materials in parts by weight: 30-100 parts of calcium carbonate cement precursor and 5-80 parts of crystal form regulator; the calcium carbonate cement precursor is vaterite, or vaterite and amorphous calcium carbonate; the crystal form regulator comprises at least one of aragonite whisker, coral sand or shell powder.
2. The calcium carbonate cement according to claim 1, wherein when the calcium carbonate cement precursor is vaterite and amorphous calcium carbonate, the mass ratio of amorphous calcium carbonate to vaterite is (0.25-1): 1.
3. the calcium carbonate cement according to claim 1, wherein the aragonite whiskers have an average aspect ratio of 5 to 40;
and/or the aragonite content of the aragonite whisker is 85-100 wt%;
and/or the coral sand has an average particle diameter of 20-300 μm;
and/or the aragonite content of the coral sand is 75-100 wt%;
and/or the average grain size of the shell powder is 25-300 mu m;
and/or the aragonite content of the shell powder is 70-100 wt%.
4. A calcium carbonate cement according to any one of claims 1 to 3, wherein the raw material of the calcium carbonate cement further comprises water; the mass ratio of the water to the solid raw material is 0.1-0.5.
5. A hardened calcium carbonate cement body, characterized in that the hardened calcium carbonate cement body is formed from the calcium carbonate cement according to any one of claims 1 to 4.
6. The hardened calcium carbonate cement body according to claim 5, wherein the aragonite content of the hardened calcium carbonate cement body is 70 to 100wt%.
7. The hardened calcium carbonate cement body according to claim 5, wherein the porosity of the hardened calcium carbonate cement body is 20 to 60%.
8. The method for producing a hardened calcium carbonate cement body according to any one of claims 5 to 7, comprising the steps of:
and mixing the raw materials of the calcium carbonate cement, and then forming and curing to obtain the calcium carbonate cement hardened body.
9. The method according to claim 8, wherein the molding pressure is 0 to 200MPa;
and/or, the maintenance time is 1-5 days;
and/or the temperature of the curing is 20-120 ℃.
10. Use of the calcium carbonate cement according to any one of claims 1 to 4, or the hardened calcium carbonate cement according to any one of claims 5 to 7 in the field of construction materials.
CN202310182489.8A 2023-02-27 2023-02-27 Calcium carbonate cement, calcium carbonate cement hardened body and application thereof Pending CN116282997A (en)

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