High-strength low-carbon cementing material regulated and controlled through pH value as well as preparation method and application of high-strength low-carbon cementing material

Abstract

The invention relates to the field of building materials, and discloses a high-strength low-carbon cementing material regulated and controlled by a pH value and a preparation method and application thereof, the cementing material contains a main agent and an auxiliary agent, and the mass ratio of the main agent to the auxiliary agent is 100: 0.03-0.3; on the basis of the total mass of the main agent, the main agent comprises 60-80 wt% of an active component, 5-25 wt% of gypsum and 1-15 wt% of an exciting agent; the active component contains S95-grade mineral powder and a component A; the component A is selected from at least one of secondary steel slag powder, phosphorus slag powder, slag, secondary fly ash, metakaolin and silica fume; the exciting agent is selected from at least two of sintering process red mud, sulphoaluminate cement, salty mud, carbide slag, papermaking white mud and boric sludge, the exciting agent comprises the sintering process red mud, and the sintering process red mud accounts for 30-60 wt% of the total mass of the exciting agent; the pH value of the cementing material is 12.6-13.2 under the condition that the mass ratio of the cementing material to the water is 1: 10. The cementing material provided by the invention has the advantages of low production cost, no harm, moderate alkalinity and excellent mechanical strength.

Description

Technical Field

[0001] The present invention relates to the field of building materials, and specifically relates to a high-strength and low-carbon cementitious material regulated by pH value, a preparation method thereof, and an application thereof. Background Art

[0002] Silico-aluminous cementitious material products have excellent properties such as high strength, radiation protection, corrosion resistance, and low carbon, and the raw materials are widely sourced, mainly industrial waste (such as slag, fly ash) or other materials mainly composed of silicon, aluminum, and oxygen. Compared with traditional portland cement, its carbon emissions during production are only 24% of those of ordinary portland cement, and the energy consumption is lower, only accounting for about 30% of the energy consumption in cement production. If the activity of solid waste is further improved, its energy consumption can even be reduced to 10% of cement production. This low-energy consumption characteristic enables silico-aluminous cementitious materials to more effectively utilize solid waste resources during production, reduce energy consumption, and thus reduce carbon emissions.

[0003] CN117486574A discloses a silico-manganese slag-based low-carbon cementitious material for resource utilization of industrial solid waste and a preparation method thereof. This prior art uses carbide slag to activate the activity of silico-manganese slag, slag, and fly ash to generate strength. However, the content of carbide slag (Ca(OH)2 content ≥ 85%) is 5% - 10%, and the alkalinity is too high, which is prone to alkali-aggregate reaction during use. Secondly, after ultra-finely grinding various raw materials separately and then mixing them evenly to obtain the finished product, the production cost will be greatly increased, lacking practicality.

[0004] CN117735933A discloses a non-fired phosphogypsum low-carbon cementitious material, a preparation method thereof, and an application thereof. This prior art also has the problem of excessive alkalinity. At the same time, phosphogypsum is not harmlessly treated and the dosage is too large, which is prone to releasing heavy metals and radioactive substances, causing environmental pollution and affecting human health.

[0005] CN119898984A discloses a silico-aluminous material, a preparation method thereof, and an application thereof. This prior art uses high-carbon emission materials such as portland cement clinker, sodium hydroxide, and aluminate as raw materials, and its 28-day strength reaches a maximum of 55 MPa. However, overall, this silico-aluminous material has a high carbon dioxide emission and a high production cost. Summary of the Invention

[0006] The purpose of the present invention is to provide a cementitious material with high compressive strength, low cost, and low harm.

[0007] To achieve the above object, a first aspect of the present invention provides a cementitious material, which contains a main agent and an auxiliary agent, and the mass ratio of the main agent to the auxiliary agent is 100:0.03 - 0.3; based on the total mass of the main agent, the main agent includes: 60 - 80 wt% of active components, 5 - 25 wt% of gypsum, and 1 - 15 wt% of an activator;

[0008] The active components contain S95 - grade mineral powder and component A; component A is selected from at least one of secondary steel slag powder, phosphorus slag powder, slag, secondary fly ash, metakaolin, and silica fume;

[0009] The activator is selected from at least two of sintering - process red mud, sulfoaluminate cement, salt mud, carbide slag, papermaking white mud, and boron mud, and the activator includes sintering - process red mud, and the sintering - process red mud accounts for 30 - 60 wt% of the total mass of the activator;

[0010] The pH value of the cementitious material under the condition that the mass ratio of the cementitious material to water is 1:10 is 12.6 - 13.2.

[0011] A second aspect of the present invention provides a method for preparing the cementitious material described in the first aspect above, and the method includes:

[0012] (1) First - mix the components in composition a to obtain mixture I; composition a includes: active components, gypsum, and an activator;

[0013] (2) Second - mix the mixture I with an auxiliary agent to obtain mixture II;

[0014] (3) Grind the mixture II to obtain the cementitious material.

[0015] A third aspect of the present invention provides an application of the cementitious material described in the first aspect above in building materials.

[0016] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0017] The cementitious material provided by the present invention is harmless and has a moderate alkalinity. By selecting the types and dosages of specific components, especially the types and dosages of the activator, the pH value is regulated within a specific range, the mechanical strength of the cementitious material is controlled, the active components in the cementitious material are fully activated, and higher mechanical properties are obtained.

[0018] The preparation method of the cementitious material provided by the present invention can obtain a high - strength low - carbon cementitious material, which is low - carbon and environmentally friendly, effectively utilizes solid waste resources, reduces energy consumption, has a low production cost, and has a wide range of application scenarios. Detailed Embodiments

[0019] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0020] As described above, the first aspect of the present invention provides a cementitious material, which contains a main agent and an auxiliary agent, and the mass ratio of the main agent to the auxiliary agent is 100:0.03 - 0.3; based on the total mass of the main agent, the main agent includes: 60 - 80 wt% of active components, 5 - 25 wt% of gypsum, and 1 - 15 wt% of an activator;

[0021] The active components contain S95 - grade mineral powder and component A; component A is selected from at least one of secondary steel slag powder, phosphorus slag powder, slag, secondary fly ash, metakaolin, and silica fume;

[0022] The activator is selected from at least two of red mud from the sintering process, sulphoaluminate cement, salt mud, carbide slag, paper - making white mud, and boron mud, and the activator includes red mud from the sintering process, and the red mud from the sintering process accounts for 30 - 60 wt% of the total mass of the activator;

[0023] The pH value of the cementitious material under the condition that the mass ratio of the cementitious material to water is 1:10 is 12.6 - 13.2.

[0024] The pH value of the cementitious material described in the present invention refers to testing the pH value of the mixed system obtained by mixing the cementitious material and water in a mass ratio of 1:10, which is the pH value of the cementitious material. Among them, the water is deionized water, and the pH value of the deionized water is controlled within the range of 6 - 7.

[0025] The inventors found in the research that by regulating the pH value of the cementitious material system within the range required by the present invention and combining with the remaining technical features of this solution, the active components in the cementitious material can be fully activated, thereby obtaining higher mechanical properties.

[0026] The inventors found in the research that by selecting an activator that meets the specific conditions of the present invention and applying it to the cementitious material, the active components in the cementitious material can be fully activated, thereby obtaining a product with more excellent compressive strength.

[0027] The S95-grade mineral powder described in the present invention refers to the mineral powder that meets the requirements of the S95 grade in the national standard GB / T 18046-2017; the secondary steel slag powder described in the present invention refers to the steel slag powder that meets the secondary requirements in the national standard GB / T 20491-2017; the secondary fly ash described in the present invention refers to the fly ash that meets the secondary requirements in the national standard GB / T 1596-2017.

[0028] The present invention does not particularly limit the specific parameters of the phosphorus slag powder, the slag, the metakaolin, and the silica fume. Those skilled in the art can select according to the types of the foregoing substances already existing in the art, and the present invention will not elaborate herein. Those skilled in the art should not understand this as a limitation of the present invention.

[0029] Preferably, the content of CaO in the active component is ≥32 wt%, and the content of Al2O3 is ≥12.0 wt%. The inventors found in the research that under this preferred condition, the cementitious material obtained in the present invention has better mechanical properties and durability.

[0030] Preferably, the content of Ca(OH)2 in the carbide slag is 50-92 wt%.

[0031] The present invention does not particularly limit the specific parameters of the sintering method red mud, the sulfoaluminate cement, the salt mud, the papermaking white mud, and the boron mud. Those skilled in the art can select according to the types of the foregoing substances already existing in the art, and the present invention will not elaborate herein. Those skilled in the art should not understand this as a limitation of the present invention.

[0032] Preferably, the gypsum is industrial by-product gypsum, and the industrial by-product gypsum is selected from at least one of desulfurized gypsum, fluorogypsum, and phosphogypsum.

[0033] More preferably, the content of SO3 in the gypsum is ≥41 wt%. The inventors found in the research that selecting the gypsum under this preferred condition as an essential component of the cementitious material can provide a sufficient amount of SO4 2- for the hydration reaction process, while reducing other useless components introduced by the gypsum, and further improving the mechanical properties of the cementitious material.

[0034] Preferably, the main agent further contains an early strength agent. Based on the total mass of the main agent, the content of the early strength agent is 1-5 wt%.

[0035] Preferably, the early strength agent is selected from at least one of sodium carbonate, aluminum sulfate, anhydrous sodium sulfate, calcium nitrate, calcium formate, and sodium acetate.

[0036] Preferably, the auxiliary agent is a grinding aid, and the grinding aid is selected from at least one of triethanolamine, diethanolmonoisopropanolamine, polyglycerol, molasses, ethylene glycol, sodium thiosulfate, and sodium thiocyanate.

[0037] As described above, the second aspect of the present invention provides a method for preparing the cementitious material described in the first aspect above, and the method includes:

[0038] (1) Perform a first mixing on the components in composition a to obtain mixture I; the composition a includes: active components, gypsum, and an activator;

[0039] (2) Perform a second mixing on the mixture I and the auxiliary agent to obtain mixture II;

[0040] (3) Perform a grinding treatment on the mixture II to obtain the cementitious material.

[0041] Preferably, in step (1), the composition a further contains an early strength agent.

[0042] Preferably, in step (1), the water content in the activator < 0.5 wt%, and the average particle diameter of the activator < 0.5 mm. The inventors found in the research that under this preferred condition, the prepared cementitious material has better uniformity, and the mill runs stably without the phenomena of grinding paste and paste balls.

[0043] The present invention can directly use an activator that meets the foregoing preferred conditions, or can perform a pretreatment operation of drying and / or crushing the activator before step (1) so that the activator meets the foregoing preferred conditions. The present invention will not elaborate on the specific operations of the pretreatment herein, and those skilled in the art can select according to the known technical means in the art.

[0044] According to a preferred specific embodiment, in step (2), the second mixing is performed by spraying the grinding aid on the mixture I.

[0045] Preferably, in step (3), control the conditions of the grinding treatment so that the specific surface area of the cementitious material ≥ 550 m 2 / kg, more preferably ≥ 600 m 2 / kg.

[0046] According to a preferred specific embodiment, the grinding treatment is performed by ball milling.

[0047] The present invention does not particularly limit the specific conditions of the grinding treatment, as long as the cementitious material with the expected specific surface area of the present invention can be obtained. The present invention will not elaborate herein, and those skilled in the art should not understand it as a limitation of the present invention.

[0048] As described above, the third aspect of the present invention provides the application of the gelling material described in the first aspect above in building materials.

[0049] The present invention will be described in detail below by way of examples. In the following examples, unless otherwise specified, the raw materials used are commercially available products.

[0050] In the following examples, unless otherwise specified, the activators used are all activators after drying and crushing treatments, with a water content < 0.5 wt%, and an average particle diameter < 0.5 mm.

[0051] In the following examples, the composition of the grinding aid is: alkanolamine substances (diethanol monoisopropanolamine, triethanolamine) 20 - 40 wt%, molasses 5 - 15 wt%, inorganic strengthening components (sodium thiosulfate, sodium thiocyanate) 50 - 70 wt%, and the balance is water.

[0052] In the following examples, the test method for the pH value of the gelling material is: stir and mix the gelling material and deionized water (pH value 6.5) in a mass ratio of 1:10 for 5 min, and test the pH value of the mixed system.

[0053] Example 1

[0054] Mix the active component, industrial by - product gypsum, activator and early strength agent evenly to obtain mixture I; spray the grinding aid on mixture I, and then carry out ball - milling treatment in a ball mill to obtain the gelling material.

[0055] The types, dosages of each component and the physicochemical property parameters of the gelling material are specifically listed in Table 1.

[0056] Examples 2 and 3

[0057] The same process as in Example 1 is adopted, except that the types, dosages of each component and the physicochemical property parameters of the gelling material are different, and are specifically listed in Table 1;

[0058] The gelling material is prepared.

[0059] Comparative Examples 1 to 5

[0060] The same process as in Example 1 is adopted, except that the types, dosages of each component and the physicochemical property parameters of the gelling material are different, and are specifically listed in Table 1;

[0061] The gelling material is prepared.

[0062] Comparative Example 6

[0063] The process is similar to that of Example 1, except that the activator used is not pretreated by drying and crushing. The water content of the activator is 0.9 wt%, and the average particle diameter is 0.8 mm. The rest remains unchanged, and a cementitious material (specific surface area is 527 m 2 / kg, pH value is 12.31) is prepared.

[0064] Table 1

[0065]

[0066] Continued Table 1

[0067]

[0068]

[0069] Note: The types and dosages of each component in Table 1 correspond in sequence. For example, the type of the active component is "S95 slag powder + secondary fly ash", and the dosage of the active component is "60 + 17", which means the dosage of S95 slag powder is 60 parts and the dosage of secondary fly ash is 17 parts.

[0070] Test Example 1

[0071] The cementitious materials prepared in the above-mentioned examples and comparative examples were tested for powdering and compressive strength. The cementitious material and water were mixed evenly at a mass ratio of 2:1, and then formed into mortar specimens.

[0072] Wipe the surface of the specimen with hand, and observe the powdering situation of the mortar specimen. If there is no powder on the hand, it is "no powdering"; if there is a small amount of powder on the hand and there are scratches on the surface of the specimen, it is "powdering"; if there is a large amount of powder and standard sand on the hand and the surface of the specimen falls off, it is "serious powdering".

[0073] The test method for the 3-day, 7-day, and 28-day compressive strength of the mortar specimen: Test according to the standard GB / T 17671-2021.

[0074] The results are shown in Table 2.

[0075] Table 2

[0076]

[0077] It can be seen from the above results that the mechanical strength of the mortar specimens prepared with the cementitious material provided by the present invention is significantly higher than that of commercially available ordinary Portland cement of grades PO 42.5 and PO 52.5 and sulfate-activated aluminosilicate cementitious materials, and it does not require calcination, can reduce CO2 emissions, and has a lower cost, having higher application value.

[0078] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A gelling material, characterized in that, The gelling material contains a main agent and an auxiliary agent, and the mass ratio of the main agent to the auxiliary agent is 100:0.03 - 0.3; Based on the total mass of the main agent, the main agent includes: 60 - 80 wt% of active components, 5 - 25 wt% of gypsum, and 1 - 15 wt% of activator; The active components contain S95 grade mineral powder and component A; Component A is selected from at least one of secondary steel slag powder, phosphorus slag powder, slag, secondary fly ash, metakaolin, and silica fume; The activator is selected from at least two of red mud from sintering process, sulphoaluminate cement, salt mud, carbide slag, paper-making white mud, and boron mud, and the activator includes red mud from sintering process, and the red mud from sintering process accounts for 30 - 60 wt% of the total mass of the activator; The pH value of the gelling material under the condition that the mass ratio of the gelling material to water is 1:10 is 12.6 - 13.

2.

2. The gelling material according to claim 1, wherein, The content of Ca(OH)₂ in the carbide slag is 50 - 92 wt%.

3. The gelling material according to claim 1, wherein, The content of CaO in the active components is ≥32 wt%, and the content of Al₂O₃ is ≥12.0 wt%; And / or, the content of SO₃ in the gypsum is ≥41 wt%.

4. The gelling material according to claim 3, characterized in that, The gypsum is industrial by-product gypsum, and the industrial by-product gypsum is selected from at least one of desulfurized gypsum, fluorogypsum, and phosphogypsum.

5. The gelling material according to claim 1, characterized in that, The main agent also contains an early strength agent, and based on the total mass of the main agent, the content of the early strength agent is 1 - 5 wt%; And / or, the early strength agent is selected from at least one of sodium carbonate, aluminum sulfate, anhydrous sodium sulfate, calcium nitrate, calcium formate, and sodium acetate.

6. The gelling material according to claim 1, characterized in that, The auxiliary agent is a grinding aid, and the grinding aid is selected from at least one of triethanolamine, diethanol monoisopropanolamine, polymeric glycerol, molasses, ethylene glycol, sodium thiosulfate, and sodium thiocyanate.

7. A method for preparing the gelling material according to any one of claims 1-6, characterized in that, The method includes: (1) First mix the components in composition a to obtain mixture I; Composition a includes: active components, gypsum, and activator; (2) Second mix the mixture I with the auxiliary agent to obtain mixture II; (3) Grind the mixture II to obtain the gelling material.

8. The method according to claim 7, characterized in that, In step (1), the water content in the activator is <0.5 wt%, and the average particle diameter of the activator is <0.5 mm; And / or, in step (1), composition a also contains an early strength agent.

9. The method according to claim 7, characterized in that, In step (3), control the conditions of the grinding treatment so that the specific surface area of the cementitious material ≥ 550 m 2 / kg.

10. Application of the gelling material according to any one of claims 1 - 6 in building materials.

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