Composite filling cementing material and preparation method thereof

Abstract

The invention relates to the technical field of mine filling materials, in particular to a composite filling cementing material and a preparation method thereof, and the composite filling cementing material comprises the following components: oil shale slag, ironmaking slag, clay mineral slag, Portland cement, a composite activator and a polycarboxylate superplasticizer. The composite activator comprises the following components: water glass, sodium carbonate, metakaolin, anhydrous sodium sulfate, calcium sulphoaluminate, dolomite, silica fume, potassium feldspar and an excitation accelerator. The gelling part is completely composed of various industrial wastes, the materials are convenient to obtain, the manufacturing cost is low, the composite exciting agent can effectively excite the potential activity of the oil shale residues, the ironmaking slag and the clay mineral residues and promote the hydration reaction of the oil shale residues, the ironmaking slag and the clay mineral residues, and the prepared composite filling gelling material has good moisture resistance and good durability.

Description

Technical Field

[0001] The present invention relates to the technical field of mine filling materials, and specifically to a composite filling cementitious material and a preparation method thereof. Background Art

[0002] With the development of the mining industry and the continuous expansion of mine scale, the formation of mine caves and the mining of ores generate a large amount of waste. These wastes not only occupy a large amount of land resources, but also have a certain impact on the environment. To solve these problems, composite filling cementitious materials are widely used in the treatment of mine wastes.

[0003] Chinese invention with publication number CN115745444B discloses an oil shale ash-based all-solid waste-based cementitious material. In the formula of this invention, adding gypsum provides more reaction sites and active centers for the hydration reaction, enabling the active components in the oil shale slag to react with water faster and generate more hydration products, such as ettringite and hydrated calcium silicate gel, etc. However, gypsum will introduce a large amount of sulfate ions. If the material is in a humid environment for a long time, the sulfate ions will react with the hydration products in the steel slag and oil shale slag to form insoluble sulfates (such as calcium sulfate). This reaction will cause the expansion and cracking of the material under long-term action, affecting the durability of the material. Summary of the Invention

[0004] The purpose of the present invention is to provide a composite filling cementitious material and a preparation method thereof to solve the problems raised in the above background art.

[0005] To achieve the above purpose, on the one hand, the present invention provides the following technical solution: A composite filling cementitious material, the composite filling cementitious material includes the following components by mass fraction: 100 parts of oil shale slag, 20 - 30 parts of iron-smelting slag, 10 - 15 parts of clay slag, 8 - 10 parts of portland cement, 6 - 9 parts of composite activator, 0.1 - 0.5 part of polycarboxylate water reducer;

[0006] The composite activator includes the following components by mass fraction: 50 parts of water glass, 20 - 30 parts of sodium carbonate, 5 - 10 parts of metakaolin, 4 - 8 parts of anhydrous sodium sulfate, 2 - 4 parts of calcium sulfoaluminate, 1 - 3 parts of dolomite, 1 - 3 parts of silica fume, 1 - 3 parts of potassium feldspar, 1 - 2 parts of activation promoter;

[0007] The activation promoter is a mixture of calcium aluminate and aluminum sulfate, and the mass ratio of calcium aluminate to aluminum sulfate is (1 - 5):1.

[0008] Optionally, the particle size of the oil shale residue is 4 - 8 mm. By mass fraction, the chemical composition of the oil shale residue includes 59.14% SiO₂, 7.74% Fe₂O₃, 16.26% Al₂O₃, 9.08% CaO, 1.20% MgO, 2.69% SO₃, 1.73% K₂O, and 2.16% Na₂O.

[0009] Optionally, the particle size of the iron ore slag is 4 - 6 mm. By mass fraction, the chemical composition of the iron ore slag includes 36.23% SiO₂, 1.89% Fe₂O₃, 9.76% Al₂O₃, 39.40% CaO, 12.11% MgO, 0.33% K₂O, and 0.28% Na₂O.

[0010] Optionally, the particle size of the clay slag is 3 - 5 mm. By mass fraction, the chemical composition of the clay slag includes 45.07% SiO₂, 7.64% Fe₂O₃, 30.83% Al₂O₃, 13.23% CaO, 2.16% MgO, 0.82% K₂O, and 0.25% Na₂O.

[0011] Optionally, the molar ratio of silicon dioxide to alkali metal oxides in the water glass is 1.5.

[0012] On the other hand, the present invention also discloses a preparation method of a composite filling cementitious material, including the following preparation steps:

[0013] S1. Drying: Place the oil shale residue, iron ore slag, and clay slag in a rotary dryer respectively, and continuously dry at 100 - 110 °C for 20 - 30 min;

[0014] S2. Grinding: Place the oil shale residue, iron ore slag, and clay slag in a ball mill and grind for 20 - 30 min to obtain a mixture with a particle size of 10 - 16 mesh;

[0015] S3. Mixing: Stir and mix the mixture, Portland cement, composite activator, and polycarboxylate water reducer to obtain the composite filling cementitious material.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The cementitious part of the present invention is completely composed of various industrial wastes, which is convenient for material collection and has a low cost. The composite activator can effectively activate the latent activity of the oil shale residue, iron ore slag, and clay slag, promote their hydration reaction, and the prepared composite filling cementitious material has good moisture resistance and durability;

[0018] 2. In the present invention, dolomite can provide magnesium ions and calcium ions to assist alkaline activation and regulate expansion. Silica fume can fill the pores of the material, enhance the density, and promote the later pozzolanic reaction to increase the later strength. Potassium feldspar contains a stable silicon-aluminum structure, and through ball milling and refinement, it can fill the pores of the material and optimize the pore structure of the material. Detailed implementation mode

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Example 1: The present invention provides a composite filling cementitious material, which includes the following components in parts by mass: 100 parts of oil shale residue, 20 parts of iron ore slag, 10 parts of clay slag, 8 parts of portland cement, 6 parts of composite activator, and 0.1 part of polycarboxylate water reducer;

[0021] The composite activator includes the following components in parts by mass: 50 parts of water glass, 20 parts of sodium carbonate, 5 parts of metakaolin, 4 parts of anhydrous sodium sulfate, 2 parts of calcium sulfoaluminate, 1 part of dolomite, 1 part of silica fume, 1 part of potassium feldspar, and 1 part of activation promoter;

[0022] The activation promoter is a mixture of calcium aluminate and aluminum sulfate, and the mass ratio of calcium aluminate to aluminum sulfate is 1:1.

[0023] The preparation method of the composite filling cementitious material includes the following preparation steps:

[0024] S1. Drying: Place the oil shale residue, iron ore slag, and clay slag in a rotary dryer respectively, and continuously dry at 100 °C for 20 min;

[0025] S2. Grinding: Place the oil shale residue, iron ore slag, and clay slag in a ball mill and grind for 20 min to obtain a mixture with a particle size of 10 mesh;

[0026] S3. Mixing: Stir and mix the mixture, portland cement, composite activator, and polycarboxylate water reducer to obtain the composite filling cementitious material.

[0027] Example 2: The present invention provides a composite filling cementitious material, which includes the following components in parts by mass: 100 parts of oil shale residue, 25 parts of iron ore slag, 12 parts of clay slag, 8 parts of portland cement, 7 parts of composite activator, and 0.3 part of polycarboxylate water reducer;

[0028] The composite activator comprises the following components by mass parts: 50 parts of water glass, 25 parts of sodium carbonate, 7 parts of metakaolin, 6 parts of anhydrous sodium sulfate, 3 parts of calcium sulfoaluminate, 2 parts of dolomite, 2 parts of silica fume, 2 parts of potassium feldspar, and 1 part of activation promoter;

[0029] The activation promoter is a mixture of calcium aluminate and aluminum sulfate, and the mass ratio of calcium aluminate to aluminum sulfate is 2.5:1.

[0030] The preparation method of the composite filling cementitious material comprises the following preparation steps:

[0031] S1. Drying: Respectively place the oil shale residue, iron ore slag and clay ore slag in a rotary dryer and continuously dry them at 105 °C for 25 min;

[0032] S2. Grinding: Place the oil shale residue, iron ore slag and clay ore slag in a ball mill and grind them for 24 min to obtain a mixture with a particle size of 12 mesh;

[0033] S3. Mixing: Stir and mix the mixture, Portland cement, composite activator and polycarboxylate water reducer to obtain the composite filling cementitious material.

[0034] Example 3: The present invention provides a composite filling cementitious material, which comprises the following components by mass parts: 100 parts of oil shale residue, 28 parts of iron ore slag, 14 parts of clay ore slag, 9 parts of Portland cement, 8 parts of composite activator, and 0.4 part of polycarboxylate water reducer;

[0035] The composite activator comprises the following components by mass parts: 50 parts of water glass, 28 parts of sodium carbonate, 9 parts of metakaolin, 7.5 parts of anhydrous sodium sulfate, 3.5 parts of calcium sulfoaluminate, 2.5 parts of dolomite, 2.5 parts of silica fume, 2.5 parts of potassium feldspar, and 1.5 parts of activation promoter;

[0036] The activation promoter is a mixture of calcium aluminate and aluminum sulfate, and the mass ratio of calcium aluminate to aluminum sulfate is 4:1.

[0037] The preparation method of the composite filling cementitious material comprises the following preparation steps:

[0038] S1. Drying: Respectively place the oil shale residue, iron ore slag and clay ore slag in a rotary dryer and continuously dry them at 108 °C for 28 min;

[0039] S2. Grinding: Place the oil shale residue, iron ore slag and clay ore slag in a ball mill and grind them for 28 min to obtain a mixture with a particle size of 14 mesh;

[0040] S3. Mixing: Stir and mix the mixture, Portland cement, composite activator and polycarboxylate water reducer to obtain the composite filling cementitious material.

[0041] Example 4: The present invention provides a composite filled cementitious material, which comprises the following components in parts by mass: 100 parts of oil shale residue, 30 parts of iron ore slag, 15 parts of clay slag, 10 parts of portland cement, 9 parts of composite activator, and 0.5 part of polycarboxylate water reducer;

[0042] The composite activator comprises the following components in parts by mass: 50 parts of water glass, 30 parts of sodium carbonate, 10 parts of metakaolin, 8 parts of anhydrous sodium sulfate, 4 parts of calcium sulfoaluminate, 3 parts of dolomite, 3 parts of silica fume, 3 parts of potassium feldspar, and 2 parts of activation promoter;

[0043] The activation promoter is a mixture of calcium aluminate and aluminum sulfate, and the mass ratio of calcium aluminate to aluminum sulfate is 5:1.

[0044] A preparation method of the composite filled cementitious material comprises the following preparation steps:

[0045] S1. Drying: The oil shale residue, iron ore slag and clay slag are respectively placed in a rotary dryer and continuously dried at 110°C for 30 min;

[0046] S2. Grinding: The oil shale residue, iron ore slag and clay slag are placed in a ball mill and ground for 30 min to obtain a mixture with a particle size of 16 mesh;

[0047] S3. Mixing: The mixture, portland cement, composite activator and polycarboxylate water reducer are stirred and mixed to obtain the composite filled cementitious material.

[0048] In Examples 1 to 4, the oil shale residue comes from Datang Taizhou Thermal Power Co., Ltd. and is the waste residue generated by its extraction of shale oil by low-temperature dry distillation method. The particle size of the oil shale residue is 4 - 8 mm. By mass fraction, the chemical composition of the oil shale residue includes 59.14% of SiO2, 7.74% of Fe2O3, 16.26% of Al2O3, 9.08% of CaO, 1.20% of MgO, 2.69% of SO3, 1.73% of K2O, and 2.16% of Na2O; the iron ore slag comes from Jiangsu Changqiang Steel Co., Ltd. The particle size of the iron ore slag is 4 - 6 mm. By mass fraction, the chemical composition of the iron ore slag includes 36.23% of SiO2, 1.89% of Fe2O3, 9.76% of Al2O3, 39.40% of CaO, 12.11% of MgO, 0.33% of K2O, and 0.28% of Na2O; the clay slag comes from Taizhou Changrong New Wall Material Co., Ltd. The particle size of the clay slag is 3 - 5 mm. By mass fraction, the chemical composition of the clay slag includes 45.07% of SiO2, 7.64% of Fe2O3, 30.83% of Al2O3, 13.23% of CaO, 2.16% of MgO, 0.82% of K2O, and 0.25% of Na2O; the molar ratio of silicon dioxide to alkali metal oxides in the water glass is 1.5.

[0049] Comparative Example 1

[0050] A composite filling cementitious material, comprising the following components by mass parts: 100 parts of oil shale slag, 20 parts of iron ore slag, 10 parts of clay slag, 8 parts of portland cement, and 6 parts of gypsum.

[0051] The preparation method of the composite filling cementitious material includes the following preparation steps:

[0052] S1, Drying: Place the oil shale slag, iron ore slag, and clay slag in a rotary dryer respectively, and continuously dry at 100 °C for 20 min;

[0053] S2, Grinding: Place the oil shale slag, iron ore slag, and clay slag in a ball mill and grind for 20 min to obtain a mixture with a particle size of 10 mesh;

[0054] S3, Mixing: Stir and mix the mixture, portland cement, and gypsum to obtain the composite filling cementitious material.

[0055] Comparative Example 2

[0056] A composite filling cementitious material, comprising the following components by mass parts: 100 parts of oil shale slag, 30 parts of iron ore slag, 15 parts of clay slag, 10 parts of portland cement, and 9 parts of gypsum.

[0057] The preparation method of the composite filling cementitious material includes the following preparation steps:

[0058] S1, Drying: Place the oil shale slag, iron ore slag, and clay slag in a rotary dryer respectively, and continuously dry at 100 °C for 20 min;

[0059] S2, Grinding: Place the oil shale slag, iron ore slag, and clay slag in a ball mill and grind for 30 min to obtain a mixture with a particle size of 16 mesh;

[0060] S3, Mixing: Stir and mix the mixture, portland cement, and gypsum to obtain the composite filling cementitious material.

[0061] Test Example 1

[0062] Test content: Weigh 500 g of the composite filled cementitious materials prepared in Examples 1 to 4 and Comparative Examples 1 to 2. Correspondingly, weigh six portions of 1500 g of standard sand and 200 g of water respectively. Place the six groups of composite filled cementitious materials, standard sand and water into a cement mortar mixer and stir for 30 min to obtain mortar. Pour the mortar into a mold with dimensions of 40 mm × 40 mm × 160 mm. After vibrating evenly, wrap it with a plastic film and cure it in a standard constant temperature curing room at a temperature of 25°C and a relative humidity of 95% for 28 days, and then demold it to obtain mortar specimens. Use a tensile testing machine to measure the tensile strength of the mortar specimens, and record the results in Table 1.

[0063] Table 1

[0064] Tensile strength / MPa Example 1 49.94 Example 2 50.12 Example 3 50.67 Example 4 50.89 Comparative Example 1 46.32 Comparative Example 2 48.91

[0065] As can be seen from Table 1, the tensile strength of the mortar specimens based on the composite filled cementitious materials prepared in Examples 1 to 4 is better than that of the mortar specimens based on the composite filled cementitious materials prepared in Comparative Examples 1 to 2.

[0066] Test Example 2

[0067] Test content: Place the six groups of mortar specimens obtained in Test Example 1 into a constant temperature and airtight environment at 25°C with relative humidities of 40%, 60%, and 80% for 20 days to simulate the mortar specimens in a humid environment. The tensile strength test of the cementitious material is the basis for evaluating its crack resistance. The crack resistance of the cementitious material can be evaluated by measuring its tensile strength. Use a tensile testing machine to measure the tensile strength of the simulated cementitious material, and record the results in Table 2.

[0068] Table 2

[0069]

[0070] As can be seen from Table 2, in a humid environment, the tensile strength of the mortar specimens based on Examples 1 to 4 is better than that of the mortar specimens based on Comparative Examples 1 to 2. The composite filled cementitious material disclosed in the present invention has good moisture resistance and good durability. The tensile strength of the mortar specimens based on the composite filled cementitious material prepared in Example 4 is the largest and is worthy of popularization and use.

[0071] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A composite filling cementitious material, characterized in that: The composite filling cementitious material comprises the following components by weight: 100 parts of oil shale slag, 20-30 parts of ironmaking slag, 10-15 parts of clay slag, 8-10 parts of Portland cement, 6-9 parts of composite activator, and 0.1-0.5 parts of polycarboxylate water reducer; The composite activator comprises the following components by weight: 50 parts of water glass, 20-30 parts of sodium carbonate, 5-10 parts of metakaolin, 4-8 parts of anhydrous sodium sulfate, 2-4 parts of calcium sulfoaluminate, 1-3 parts of dolomite, 1-3 parts of silica fume, 1-3 parts of potassium feldspar, and 1-2 parts of activation promoter; The excitation promoter is a mixture of calcium aluminate and aluminum sulfate, wherein the mass ratio of calcium aluminate to aluminum sulfate is (1-5):

1.

2. A composite filling cementitious material according to claim 1, characterized in that: The particle size of the oil shale slag is 4 to 8 mm. Calculated by mass fraction, the chemical composition of the oil shale slag includes 59.14% SiO2, 7.74% Fe2O3, 16.26% Al2O3, 9.08% CaO, 1.20% MgO, 2.69% SO3, 1.73% K2O, and 2.16% Na2O.

3. A composite filling cementitious material according to claim 1, characterized in that: The particle size of the ironmaking slag is 4 to 6 mm. Calculated by mass fraction, the chemical composition of the ironmaking slag includes 36.23% SiO2, 1.89% Fe2O3, 9.76% Al2O3, 39.40% CaO, 12.11% MgO, 0.33% K2O, and 0.28% Na2O.

4. A composite filling cementitious material according to claim 1, characterized in that: The particle size of the clay slag is 3-5 mm. In terms of mass fraction, the chemical composition of the clay slag includes 45.07% SiO2, 7.64% Fe2O3, 30.83% Al2O3, 13.23% CaO, 2.16% MgO, 0.82% K2O, and 0.25% Na2O.

5. The composite filling cementitious material according to claim 1, characterized in that: The molar ratio of silicon dioxide to alkali metal oxide in the water glass is 1.

5.

6. A method for preparing the composite filling gelling material according to any one of claims 1 to 5, characterized in that: The method comprises the following preparation steps: S1. Drying: Place the oil shale slag, iron smelting slag and clay slag in a drum dryer respectively, and dry them continuously at 100-110°C for 20-30 minutes; S2, grinding: grinding the oil shale slag, iron smelting slag and clay slag in a ball mill for 20 to 30 minutes to obtain a mixture with a particle size of 10 to 16 mesh; S3, mixing: stirring and mixing the mixture, silicate cement, composite activator and polycarboxylate water reducer to obtain the composite filling cementitious material.

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