A fully solid waste cementitious material and its preparation method

Abstract

The present invention discloses an all-solid waste cementitious material and a preparation method thereof, belonging to the technical field of building materials. The all-solid waste cementitious material comprises the following components by weight: 30-45 parts of steel slag, 20-30 parts of slag, 10-20 parts of red mud, 20-25 parts of carbide slag, 10-20 parts of fly ash, 5-10 parts of an interface modifier, and 5-20 parts of gypsum. The present invention fully utilizes various industrial solid wastes such as steel slag, red mud, carbide slag, fly ash, slag, and gypsum as raw materials, achieving resource recycling. These solid wastes can generate hydration products to form a strong network structure, providing strength, achieving harmless treatment of solid waste and resource utilization. As a cement substitute, the all-solid waste cementitious material has excellent economic and environmental benefits, achieving the goal of carbon reduction in the cementitious material field, and meeting the current industrial development requirements of energy conservation, environmental protection, and a circular economy.

Description

Technical Field

[0001] The present invention relates to the technical field of building materials, and in particular to an all-solid waste gelling material and a preparation method thereof. Background Art

[0002] With the accelerated development of industrialization, the generation of industrial solid wastes such as red mud, steel slag, and fly ash continues to increase. While occupying a large amount of arable land, the heavy metal ions they contain cause serious environmental pollution. Currently, industrial solid waste is mainly used as filling cementitious materials. However, due to the high cost of ordinary silicate cement, relevant researchers have been continuously trying to use solid waste to replace cement to reduce material costs. However, due to the various characteristics of solid waste, such as low hydration activity and volume stability, filling materials prepared using large amounts of solid waste instead of cement have difficulty meeting the designed mechanical strength, stability and durability requirements.

[0003] Solid waste-based cementitious materials are mostly composed of non-clinker base materials and active stimulants. Currently, cementitious materials prepared from all solid waste have low activity and raw material pretreatment is difficult. Mechanical activation measures such as grinding are usually used to improve the activity of cementitious materials, but the effect is very limited.

[0004] Chinese patent document CN111499228A discloses a cementitious material for mortar and its use, comprising: pre-treating steel slag particles with a 0.35mm sieve residue of less than 3%; subjecting the pre-treated steel slag particles to mechanical pulses to produce steel slag powder with a particle size distribution of 5-35% of particles ≤15μm, 40-75% of particles ≤45μm, and 92-97% of particles ≤60μm; and grinding the steel slag powder with blast furnace slag powder and gypsum to produce the cementitious material. The cementitious material prepared by this invention exhibits rapid early hydration reaction, high strength, low autogenous shrinkage, strong volume stability, and excellent crack resistance and freeze-thaw resistance. It combines high dosage with low slump, good pumpability, and purification capabilities. It can be used to replace Portland cement in mortar to reduce cement usage and production costs. This patent pre-dopes steel slag and then grinds it to prepare cementitious material. After the pre-dope treatment, it needs to undergo mechanical pulse, which places high demands on equipment, increases production costs, and is not suitable for large-scale industrial production. Summary of the Invention

[0005] The main purpose of the present invention is to propose a solid waste gelling material suitable for large-scale industrial production and a preparation method thereof. By adding an interface regulator during the grinding process, the particles can be prevented from agglomerating, the fluidity of the powder can be improved, the particles can be made easier to crush, the reaction activity inside the solid waste gelling material can be better stimulated, the fluidity of the ground powder can be improved, thereby reducing the power consumption of the mill, improving the grinding efficiency, and better stimulating the reaction activity inside the solid waste gelling material.

[0006] To achieve the above objectives, the present invention proposes an all-solid waste cementitious material, characterized in that it comprises the following components in parts by mass: 30-45 parts of steel slag, 20-30 parts of slag, 10-20 parts of red mud, 20-25 parts of carbide slag, 10-20 parts of fly ash, 5-10 parts of interface regulator, and 5-20 parts of gypsum.

[0007] Preferably, the slag is a by-product of the blast furnace ironmaking process.

[0008] Preferably, the fly ash is Class II fly ash.

[0009] Preferably, the preparation method of the interface regulator is as follows:

[0010] Molybdenum disulfide is added to an ethanol aqueous solution, KH550 is added, the mixture is heated to react, filtered, the solid is collected, washed, dried, and then dispersed in chloroform, tiglic acid and an EDC / NHS aqueous solution are added, the pH value is adjusted to weak acidity, the mixture is heated to react, filtered, the solid is collected, washed, dried, and then added to N,N-dimethylformamide, azobisisobutyronitrile is added, and acryloyloxyethyltrimethylammonium chloride is added dropwise under heating conditions. After the addition is complete, the mixture is kept warm for reaction, cooled and filtered after the reaction is complete, the solid is collected, washed, and dried to obtain the interface regulator.

[0011] Preferably, the mass ratio of molybdenum disulfide, KH550, tiglic acid, and acryloyloxyethyltrimethylammonium chloride is 15-25:2-3:10-13:6-8.

[0012] Preferably, the concentration of EDC in the EDC / NHS aqueous solution is 30-40 mM / L, and the concentration of NHS is 40-50 mM / L.

[0013] The interface regulator of the present invention can significantly reduce the surface energy of powder particles, prevent particle agglomeration, improve the fluidity of powder, make particles easier to crush, better stimulate the reaction activity inside solid waste gelling materials, improve the fluidity of ground powder, thereby reducing mill power consumption and improving grinding efficiency, and better stimulate the reaction activity inside solid waste gelling materials, promote material hydration reaction, generate more hydration products, and thus improve the strength and durability of the material.

[0014] Preferably, the gypsum is at least one of anhydrite, fluorgypsum, phosphogypsum and desulfurized gypsum.

[0015] More preferably, the gypsum is desulfurized gypsum.

[0016] The present invention also provides a method for preparing the all-solid waste gelling material, comprising the following steps:

[0017] The steel slag, carbide slag and gypsum are mixed, crushed and sieved, and then an interface regulator is added and ground for the first time to obtain a first mixture; the slag, red mud and interface regulator are mixed and ground for the second time to obtain a second mixture; the fly ash, the first mixture and the second mixture are mixed and stirred evenly to obtain the all-solid waste cementitious material.

[0018] Preferably, the particle size of the crushed steel slag, carbide slag and gypsum is 2-10 mm.

[0019] Preferably, the specific surface area of the first mixture is 700-800m 2 / kg; the specific surface area of the second mixture is 650-750m 2 / kg.

[0020] The present invention makes full use of various industrial solid wastes such as steel slag, red mud, carbide slag, fly ash, slag, gypsum, etc., and realizes the recycling of resources. These solid wastes can generate hydration products, form a dense network structure, provide strength, and realize the harmless treatment and resource utilization of solid waste. As a substitute for cement, it has good economic and environmental benefits, achieves the goal of carbon reduction in the field of cementitious materials, and meets the current energy conservation, environmental protection, and circular economy industrial development requirements; the first mixture obtained by grinding steel slag, carbide slag, and gypsum is mixed with the second mixture obtained by grinding slag and red mud, which can better play its role in filling and improving the aggregate interface, thereby significantly improving the activity index, compressive strength, and flexural strength of the solid waste-based cementitious material.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) In the all-solid waste gelling material of the present invention, the high content of alkaline components in steel slag and red mud can provide an alkaline hydration environment for the system, stimulate the condensation of slag to form CSH gel, which can effectively fill and connect pores and improve the strength and density of the material. The fly ash has high reactivity inside. Under alkaline conditions, its inert coating is destroyed, thus having volcanic ash activity, which can participate in the hydration reaction to generate hydration products such as CASH / CSH, thereby improving the strength and durability of the material. Gypsum contains a large amount of sulfate ions, which can promote the reaction of slag with Al in red mud under alkaline conditions. 3+ and Si 4+ Ions dissolve, promoting the formation of more hydration products, and sulfate can further react with hydration products to form ettringite, forming a dense network structure, providing strength, and achieving harmless treatment and resource utilization of solid waste;

[0023] (2) The present invention adds an interface regulator during the grinding process. The preparation of the interface regulator is to first introduce an amino group on the lubricant molybdenum disulfide, and then react with tiglic acid to generate amidated molybdenum disulfide. The carbon-carbon double bond on the tiglic acid molecule can react with the positively charged acryloyloxyethyl trimethyl ammonium chloride to graft acryloyloxyethyl trimethyl ammonium chloride onto the molybdenum disulfide. The molybdenum disulfide can effectively reduce the friction resistance between the powder particles, reduce wear, and improve the grinding efficiency. By amidating it, the amide group can adsorb heavy metal ions in the solid waste powder, which is beneficial to improving the mechanical properties of the material. By introducing the positively charged acryloyloxyethyl trimethyl ammonium chloride on its surface, the interface regulator is adsorbed on the surface of the powder particles and in new and old cracks through the charge during the grinding process, so that the powder particles are hindered from approaching each other during the grinding process, preventing the particles from agglomerating. The particles are easier to crush, and the reaction activity inside the solid waste gel material can be better stimulated, the material hydration reaction is promoted, and more hydration products are generated, thereby improving the strength and durability of the material. DETAILED DESCRIPTION

[0024] To avoid redundancy, the items used in the following examples are all commercially available products unless otherwise specified, and the methods used are all conventional methods unless otherwise specified.

[0025] The sources of some raw materials used in the present invention are as follows:

[0026] Steel slag was purchased from Shijiazhuang Zenghua New Material Technology Co., Ltd., and its chemical composition is CaO content of 42.3%, Fe2O3 content of 22.9%, SiO2 content of 15.2%, MgO content of 7.1%, Al2O3 content of 5.3%, and other substances content of 7.2%.

[0027] The slag comes from Yongfeng Steel Co., Ltd., and its chemical composition is Al2O3 content of 15.26%, SiO2 content of 35.26%, Fe2O3 content of 0.81%, SO3 content of 1.27%, K2O content of 0.43%, CaO content of 36.03%, Na2O content of 0.10%, and other substances content of 10.84%.

[0028] Red mud, sintered red mud, comes from Wanfang Aluminum Co., Ltd. in Jiaozuo, Henan Province. Its chemical composition is SiO2 content of 18.43%, Al2O3 content of 7.36%, Fe2O3 content of 7.04%, TiO2 content of 2.77%, CaO content of 36.46%, SO3 content of 2.05%, Na2O content of 2.56%, other substances content of 1.68%, and loss on ignition of 20.43%.

[0029] The chemical composition of carbide slag comes from Xingtai Fuyuan Acetylene Plant. Its CaO content is 67.95%, SiO2 content is 4.99%, Al2O3 content is 2.344%, Fe2O3 content is 0.48%, MgO content is 0.24%, SO3 content is 0.2%, and the loss on ignition is 23.57%.

[0030] Fly ash, grade II, comes from the Fly Ash Development Company of Wuhan Huadian Industrial Co., Ltd. Its chemical composition is 37.45% Al2O3, 32.27% SiO2, 20.7% Fe2O3, 3.9% TiO2, 2.4% CaO, 0.6% SO3, 0.45% MgO, and 0.23% other substances.

[0031] Molybdenum disulfide, 500 mesh, was purchased from Hebei Teng Bimetallic Materials Co., Ltd.

[0032] Gypsum, desulfurized gypsum, 200 mesh, was purchased from Hebei Henghe Mineral Products Co., Ltd.

[0033] Example 1

[0034] A method for preparing a solid waste gelling material comprises the following steps:

[0035] 400g steel slag, 220g carbide slag and 100g desulfurized gypsum were mixed and crushed to a particle size of 2-10mm. After screening, 30g interface regulator was added and the first grinding was performed to obtain a specific surface area of 700-800m 2 / kg of the first mixture; 250g of slag, 150g of red mud, and 30g of the interface regulator were mixed and ground for the second time to obtain 650-750m 2 / kg second mixture; 168g fly ash, the first mixture, and the second mixture were mixed and stirred evenly to obtain the all-solid waste cementitious material.

[0036] The preparation method of the interface regulator comprises the following steps:

[0037] 21.5 g of molybdenum disulfide was added to 200 mL of 50 wt% ethanol aqueous solution, 2.56 g of KH550 was added, and the mixture was heated at 60° C. for 2 h. After the reaction was completed, the mixture was cooled and filtered. The solid was collected, washed, dried, and dispersed in 200 mL of chloroform. 11.6 g of tiglic acid and 160 mL of EDC / NHS aqueous solution were added. The concentration of EDC in the EDC / NHS aqueous solution was 35 mM / L, and the concentration of NHS was 45 mM / L. The pH value was adjusted to 6, the mixture was heated at 60° C. for 6 h, the reaction was completed, the mixture was cooled and filtered, the solid was collected, washed, dried, and added to 200 mL of N,N-dimethylformamide. 0.3 g of azobisisobutyronitrile was added, the mixture was heated to 70° C., 7.2 g of acryloyloxyethyltrimethylammonium chloride was added dropwise, and the mixture was kept warm for 3 h after the addition was completed. After the reaction was completed, the mixture was cooled and filtered, the solid was collected, washed, and dried to obtain the interface regulator.

[0038] Example 2

[0039] A method for preparing a solid waste gelling material comprises the following steps:

[0040] 300g steel slag, 200g carbide slag and 50g desulfurized gypsum were mixed and crushed to a particle size of 2-10mm. After screening, 25g interface regulator was added and the first grinding was performed to obtain a specific surface area of 700-800m 2 / kg of the first mixture; 200g of slag, 100g of red mud, and 25g of the interface regulator were mixed and ground for the second time to obtain a specific surface area of 650-750m 2 / kg second mixture; 100g fly ash, the first mixture and the second mixture were mixed and stirred evenly to obtain the all-solid waste gelling material.

[0041] The preparation method of the interface regulator comprises the following steps:

[0042] 15 g of molybdenum disulfide was added to 200 mL of 50 wt% ethanol aqueous solution, 2 g of KH550 was added, and the mixture was heated at 60 ° C for 2 h, filtered, and the solid was collected, washed, dried, and dispersed in 200 mL of chloroform. 10 g of tiglic acid and 150 mL of EDC / NHS aqueous solution were added, and the concentration of EDC in the EDC / NHS aqueous solution was 30 mM / L and the concentration of NHS was 40 mM / L; the pH value was adjusted to 6, and the mixture was heated at 60 ° C for 6 h. After the reaction was completed, the mixture was cooled and filtered, the solid was collected, washed, dried, and added to 200 mL of N, N-dimethylformamide, 0.25 g of azobisisobutyronitrile, and 6 g of acryloyloxyethyltrimethylammonium chloride under heating conditions were added. After the addition was complete, the mixture was kept warm for 3 h. After the reaction was completed, the mixture was cooled and filtered, and the solid was collected, washed, and dried to obtain the interface regulator.

[0043] Example 3

[0044] A method for preparing a solid waste gelling material comprises the following steps:

[0045] 450g steel slag, 250g carbide slag and 200g desulfurized gypsum were mixed and crushed to a particle size of 2-10mm. After screening, 50g interface regulator was added and the first grinding was performed to obtain a specific surface area of 700-800m 2 / kg of the first mixture; 300g of slag, 200g of red mud, and 50g of the interface regulator were mixed and ground for the second time to obtain a specific surface area of 650-750m 2 / kg second mixture; 200g fly ash, the first mixture and the second mixture were mixed and stirred evenly to obtain the all-solid waste gelling material.

[0046] The preparation method of the interface regulator comprises the following steps:

[0047] 25 g of molybdenum disulfide was added to 200 mL of 50 wt% ethanol aqueous solution, 3 g of KH550 was added, and the mixture was heated at 60° C. for 2 h. After the reaction was completed, the mixture was cooled and filtered, and the solid was collected, washed, dried, and dispersed in 200 mL of chloroform. 13 g of tiglic acid and 180 mL of EDC / NHS aqueous solution were added, wherein the concentration of EDC in the EDC / NHS aqueous solution was 40 mM / L and the concentration of NHS was 50 mM / L. The pH value was adjusted to 6, and the mixture was heated at 60° C. for 6 h. After the reaction was completed, the mixture was cooled and filtered, and the solid was collected, washed, dried, and added to 200 mL of N,N-dimethylformamide. 0.4 g of azobisisobutyronitrile and 8 g of acryloyloxyethyltrimethylammonium chloride were added under heating conditions. After the addition was complete, the mixture was kept warm for 3 h. After the reaction was completed, the mixture was cooled and filtered, and the solid was collected, washed, and dried to obtain the interface regulator.

[0048] Comparative Example 1

[0049] A method for preparing an all-solid waste cementitious material is similar to that of Example 1, except that acryloyloxyethyltrimethylammonium chloride is not added in the preparation of the interface regulator. The method specifically comprises the following steps:

[0050] 400g of steel slag, 220g of carbide slag, and 100g of desulfurization gypsum are mixed and crushed to a particle size of 2-10mm. After screening, 30g of interface regulator is added and ground for the first time to obtain a first mixture; 250g of slag, 150g of red mud, and 30g of interface regulator are mixed and ground for the second time to obtain a second mixture; 168g of fly ash, the first mixture, and the second mixture are mixed and stirred evenly to obtain the all-solid waste cementitious material.

[0051] The preparation method of the interface regulator comprises the following steps:

[0052] 21.5 g of molybdenum disulfide was added to 200 mL of a 50 wt% ethanol aqueous solution, 2.56 g of KH550 was added, and the mixture was heated at 60° C. for 2 h. After the reaction was completed, the mixture was cooled and filtered. The solid was collected, washed, dried, and dispersed in 200 mL of chloroform. 11.6 g of tiglic acid and 160 mL of an EDC / NHS aqueous solution were added. The concentration of EDC in the EDC / NHS aqueous solution was 35 mM / L, and the concentration of NHS was 45 mM / L. The pH value was adjusted to 6, and the mixture was heated at 60° C. for 6 h. After the reaction was completed, the mixture was cooled and filtered. The solid was collected, washed, and dried to obtain the interface regulator.

[0053] Comparative Example 2

[0054] A method for preparing an all-solid waste cementitious material is similar to that of Example 1, except that the interface regulator is a mixture of molybdenum disulfide and acryloyloxyethyltrimethylammonium chloride, and specifically comprises the following steps:

[0055] 400g of steel slag, 220g of carbide slag, and 100g of desulfurization gypsum are mixed and crushed to a particle size of 2-10mm. After screening, 22.5g of molybdenum disulfide and 7.5g of acryloyloxyethyltrimethylammonium chloride are added and mixed, and then ground for the first time to obtain a first mixture; 250g of slag, 150g of red mud, 30g 22.5g of molybdenum disulfide, and 7.5g of acryloyloxyethyltrimethylammonium chloride are mixed and ground for the second time to obtain a second mixture; 168g of fly ash, the first mixture, and the second mixture are mixed and stirred evenly to obtain the said all-solid waste cementitious material.

[0056] Comparative Example 3

[0057] A method for preparing an all-solid waste cementitious material is similar to that of Example 1, except that the interface modifier is molybdenum disulfide, and specifically comprises the following steps:

[0058] 400g of steel slag, 220g of carbide slag, and 100g of desulfurization gypsum are mixed and crushed to a particle size of 2-10mm. After screening, 30g of interface regulator is added and ground for the first time to obtain a first mixture; 250g of slag, 150g of red mud, and 30g of interface regulator are mixed and ground for the second time to obtain a second mixture; 168g of fly ash, the first mixture, and the second mixture are mixed and stirred evenly to obtain the all-solid waste cementitious material.

[0059] Performance Testing

[0060] Activity index: The 7d activity index of the all-solid waste cementitious materials prepared in Examples 1-3 and Comparative Examples 1-3 was determined by referring to the slag powder activity index method in Appendix A of GB / T18046-2017 "Granulated blast furnace slag powder for cement, mortar and concrete". The test results are shown in Table 1:

[0061] Table 1 Activity index test results of all-solid waste cementitious materials

[0062]

[0063]

[0064] Mechanical properties test: The all-solid waste cementitious materials obtained in Examples 1-3 and Comparative Examples 1-3 were prepared into mortar test blocks at a water-cement ratio of 0.32. The mortar mixing process was carried out in accordance with GB / T17671-2021 "Test Method for Cement Mortar Strength". Standard test pieces of 40 mm × 40 mm × 160 mm were made and cured under standard curing conditions to the corresponding age. The compressive and flexural strengths of the mortar were tested over time. The test results are shown in Table 2:

[0065] Table 2 Mechanical properties test of all-solid waste cementitious materials

[0066]

[0067] It can be seen from the experimental data in Table 1 and Table 2 that the all-solid waste cementitious material prepared by the present invention has good potential activity, and has good compressive strength and flexural strength.

[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of the present invention.

Claims

1. A solid waste cementitious material, characterized in that: The invention comprises the following components in parts by weight: 30-45 parts of steel slag, 20-30 parts of slag, 10-20 parts of red mud, 20-25 parts of carbide slag, 10-20 parts of fly ash, 5-10 parts of interface regulator, and 5-20 parts of gypsum; The preparation method of the interface regulator is as follows: Molybdenum disulfide was added to an aqueous ethanol solution, KH550 was added, the reaction was heated, filtered, the solid was collected, washed and dried, and then dispersed in chloroform, tiglic acid and EDC / NHS aqueous solution were added, the pH value was adjusted to weak acidity, the reaction was heated, filtered, the solid was collected, washed and dried, and then added to N, N-dimethylformamide, azobisisobutyronitrile was added, and acryloyloxyethyltrimethylammonium chloride was added dropwise under heating conditions. After the addition was complete, the reaction was kept warm. After the reaction was completed, the solid was cooled and filtered, and the solid was collected, washed and dried to obtain the interface regulator; The mass ratio of the molybdenum disulfide, KH550, tiglic acid, and acryloyloxyethyltrimethylammonium chloride is 15-25:2-3:10-13:6-8.

2. The all-solid waste gelling material according to claim 1, characterized in that: The fly ash is Class II fly ash.

3. The all-solid waste gelling material according to claim 1, characterized in that: The concentration of EDC in the EDC / NHS aqueous solution is 30-40 mM / L, and the concentration of NHS is 40-50 mM / L.

4. The all-solid waste gelling material according to claim 1, characterized in that: The gypsum is at least one of anhydrite, fluorgypsum, phosphogypsum and desulfurized gypsum.

5. The all-solid waste gelling material according to claim 4, characterized in that: The gypsum is desulfurized gypsum.

6. A method for preparing the all-solid waste gelling material according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: mixing steel slag, carbide slag and gypsum, crushing and screening the mixture, then adding an interface regulator and performing a first grinding to obtain a first mixture; mixing slag, red mud and the interface regulator and performing a second grinding to obtain a second mixture; and mixing fly ash, the first mixture and the second mixture and stirring them uniformly to obtain the all-solid waste cementitious material.

7. The preparation method according to claim 6, characterized in that: The particle size of the crushed steel slag, carbide slag and gypsum is 2-10 mm.

8. The preparation method according to claim 6, characterized in that: The specific surface area of the first mixture is 700-800m 2 / kg; the specific surface area of the second mixture is 650-750m 2 / kg.

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