Coal gangue foaming thermal insulation building material and preparation method thereof

Abstract

The invention provides a coal gangue foaming thermal insulation building material and a preparation method thereof, and relates to the technical field of waste resource utilization. The coal gangue foaming thermal insulation building material provided by the invention is prepared from the following raw materials: cement, coal gangue, water, a water reducing agent and a nano foaming agent. The coal gangue is recycled, the efficient and green cement-based light thermal insulation material is provided, and compared with a traditional building thermal insulation material, the efficient and green cement-based light thermal insulation material has the following advantages that environmental friendliness and sustainability are achieved, waste materials are utilized, consumption of natural resources is reduced, and reduction of pollution of waste to the environment is facilitated; the building material obtained by utilizing the foam concrete has excellent thermal insulation performance, can effectively insulate heat and can improve the energy utilization efficiency of buildings; the building material provided by the invention is relatively low in density, but has enough strength, so that the requirements of a building structure can be met, and the load of a building is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of waste resource utilization, and in particular to a gangue foaming thermal insulation building material and a preparation method thereof. Background Art

[0002] With the development of the construction industry, the demand for lightweight insulation materials is growing. At present, the mainstream of lightweight insulation materials is to use cement and fly ash as raw materials, introduce sand and other reinforcing materials, and prepare lightweight blocks / insulating wall panels by chemical foaming by adding foaming agents. This method of preparing foamed insulation materials is greatly affected by the external environment, the material yield is not high, the price is expensive, and the preparation of materials consumes a lot of energy, which is not conducive to achieving energy conservation and emission reduction.

[0003] Coal gangue is a carbon-containing rock discharged during coal mining and coal washing, and is an industrial solid waste in the coal mining industry. How to absorb and dispose of coal gangue has always been an issue that cannot be avoided in the high-quality development of the coal mining industry. Realizing the resource disposal of coal gangue will be of great significance. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a coal gangue foamed thermal insulation building material and a preparation method thereof. The present invention uses coal gangue, an industrial solid waste, as raw material and adopts physical foaming to obtain a high-performance foamed thermal insulation building material.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a coal gangue foaming heat-insulating building material, the preparation raw materials of which include: cement, coal gangue, water, water reducing agent and nano foaming agent;

[0007] The mass ratio of the coal gangue to cement is 7:3-3:7, the mass ratio of the water to the total mass of cement and coal gangue is 0.2:1, and the mass of the water reducing agent is 0.1-0.3% of the total mass of coal gangue and cement;

[0008] The nano foaming agent comprises the following components in percentage by weight: 0.1-1% of α-olefin sulfonate, 0.1-1% of nano kaolin, 0.05-1% of cellulose reinforcing agent, and the balance of water; the weight of the nano foaming agent is 6-16% of the total weight of coal gangue and cement.

[0009] Preferably, the cement is PO 42.5 cement.

[0010] Preferably, the particle size of the coal gangue is 160-200 mesh.

[0011] Preferably, the nano foaming agent comprises the following components in percentage by weight: 0.1-0.2% of α-olefin sulfonate, 0.1-0.2% of nano kaolin, 0.1-0.2% of cellulose reinforcing agent, and the balance of water.

[0012] Preferably, the particle size of the nano kaolin is 40-100 nm.

[0013] Preferably, the cellulose-based strengthening agent comprises cellulose and / or cellulose derivatives.

[0014] Preferably, the water reducer is a polycarboxylate water reducer.

[0015] The present invention provides a method for preparing the coal gangue foamed thermal insulation building material described in the above technical solution, comprising the following steps:

[0016] Mechanically foaming the nano foaming agent to obtain prefabricated foam;

[0017] After the coal gangue is crushed, it is mixed with cement, water and a water reducing agent to obtain a mixture;

[0018] mixing the mixed material with prefabricated foam to obtain concrete foam;

[0019] The concrete foam is molded and cured in sequence to obtain the lightweight heat-insulating building material with a large amount of coal gangue.

[0020] Preferably, the air pressure of the mechanical foaming is 0.3-3 MPa, and the density of the prefabricated foam is 35-70 g / L.

[0021] Preferably, the mixing of the mixed material and the prefabricated foam is carried out under stirring, and the stirring rate is 10 r / min.

[0022] The invention provides a coal gangue foaming heat-insulating building material. The raw materials for preparing the material include cement, coal gangue, water, a water reducing agent and a nano foaming agent. The mass ratio of the coal gangue to the cement is 7:3-3:7, the mass ratio of the water to the total mass of the cement and the coal gangue is 0.2:1, the mass of the water reducing agent is 0.1-0.3% of the total mass of the coal gangue and the cement; the nano foaming agent includes the following components in mass percentage: 0.1-1% of alpha-olefin sulfonate, 0.1-1% of nano kaolin, 0.05-1% of cellulose reinforcing agent and the balance of water; the mass of the nano foaming agent is 6-16% of the total mass of the coal gangue and the cement. The chemical composition of coal gangue is relatively complex, which poses a great challenge to chemical foaming. Ordinary foaming agents have poor stability, and the foam is easily broken, resulting in material collapse. The present invention uses a specific nano foaming agent, which is a physical foaming method with good stability and can achieve early setting of the slurry, which can well avoid bubble collapse and improve the strength of the material. The present invention realizes the reuse of coal gangue and provides an efficient and green cement-based lightweight thermal insulation material. Compared with traditional building thermal insulation materials, the present invention has the following advantages:

[0023] Environmentally friendly and sustainable: The present invention utilizes waste materials, reduces the consumption of natural resources, and helps to reduce the pollution caused by waste to the environment;

[0024] Excellent thermal insulation performance: The building materials obtained by using foam concrete have excellent thermal insulation performance, which can effectively insulate and improve the energy efficiency of buildings;

[0025] Low density and high strength: The building material provided by the present invention has a low density but sufficient strength to meet the requirements of the building structure and reduce the load on the building itself.

[0026] The present invention provides a method for preparing the coal gangue foamed thermal insulation building material described in the above technical solution, which has a simple and efficient process flow and can quickly realize large-scale production.

[0027] The results of the examples show that the coal gangue foamed thermal insulation building material provided by the present invention has a 28d strength of 4.4-11.1 MPa and a density of 770-1220 kg / m 3 , the thermal conductivity is 0.18~0.32W / (m·K). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The present invention is a schematic diagram of the process of preparing coal gangue foamed thermal insulation building materials according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] The present invention provides a coal gangue foaming heat-insulating building material, the preparation raw materials of which include: cement, coal gangue, water, water reducing agent and nano foaming agent;

[0030] The mass ratio of the coal gangue to cement is 7:3-3:7, the mass ratio of the water to the total mass of cement and coal gangue is 0.2:1, and the mass of the water reducing agent is 0.1-0.3% of the total mass of the coal gangue and cement;

[0031] The nano foaming agent comprises the following components in percentage by weight: 0.1-1% of α-olefin sulfonate, 0.1-1% of nano kaolin, 0.05-1% of cellulose reinforcing agent, and the balance of water; the weight of the nano foaming agent is 6-16% of the total weight of coal gangue and cement.

[0032] In the present invention, unless otherwise specified, all preparation raw materials / components are commercially available products well known to those skilled in the art.

[0033] The coal gangue foamed heat-insulating building material provided by the present invention comprises cement. In the present invention, the cement is preferably PO 42.5 cement.

[0034] The coal gangue foamed thermal insulation building material provided by the present invention includes coal gangue. The present invention has no special requirements for the source of the coal gangue, and coal gangue from sources familiar to those skilled in the art can be used. The mass content of silicon dioxide (SiO2) in coal gangue is usually 30-60%, and it also contains 10-30wt% of aluminum oxide (Al2O3), 5-20wt% of iron oxide (Fe2O3), 1-10wt% of calcium oxide (CaO), and 1-5wt% of magnesium oxide (MgO), wherein silicon dioxide is the main component in coal gangue, aluminum oxide is mainly derived from clay minerals, iron oxide is mainly derived from iron minerals, and calcium oxide is mainly derived from carbonate minerals. In the present invention, the particle size of the coal gangue is preferably 160-200 meshes. In the present invention, the mass ratio of the coal gangue to cement is 7:3-3:7, preferably 7:3, 3:2 or 3:7.

[0035] The coal gangue foaming thermal insulation building material provided by the invention comprises water, and the ratio of the mass of the water to the total mass of cement and coal gangue is 0.2:1.

[0036] The coal gangue foamed thermal insulation building material provided by the present invention comprises a water reducing agent, the mass of the water reducing agent is 0.1-0.3% of the total mass of the coal gangue and cement, preferably 0.1-0.15%. In the present invention, the water reducing agent is preferably a polycarboxylate water reducing agent.

[0037] The coal gangue foaming heat-insulating building material provided by the invention comprises a nano foaming agent, which comprises the following components in percentage by mass: 0.1-1% of alpha-olefin sulfonate, 0.1-1% of nano kaolin, 0.05-1% of cellulose reinforcing agent and the balance of water.

[0038] Taking the total mass of the nano foaming agent as 100%, the nano foaming agent in the present invention comprises 0.1-1% of α-olefin sulfonate, preferably 0.1-0.2%. In the present invention, the α-olefin sulfonate is preferably sodium α-olefin sulfonate. In the present invention, the α-olefin sulfonate as a surfactant can reduce the surface tension, form a monomolecular film on the water surface, stabilize the air bubbles, and make them not easy to break; when the aqueous solution is mechanically agitated or injected with air, the air will be wrapped in the surfactant molecule layer to form bubbles, and since the α-olefin sulfonate reduces the surface tension of water, these bubbles can exist relatively stably.

[0039] Taking the total mass of the nano foaming agent as 100%, the nano foaming agent in the present invention includes 0.1-1% of nano kaolin, preferably 0.1-0.2%. In the present invention, the particle size of the nano kaolin is preferably 40-100nm, more preferably 50-80nm. In the present invention, the nano kaolin is used as a nano foam stabilizer; the nano kaolin has an extremely small particle size and a large specific surface area, which allows them to be evenly distributed in the liquid, increase the viscosity of the liquid, and reduce the bursting rate of the bubbles; the nano kaolin particles form a network structure on the bubble surface or in the foam, and the presence of these particles can increase the mechanical strength of the foam and prevent the merging and bursting of the bubbles; the addition of nano kaolin can improve the rheological properties of the liquid, making the liquid more viscous, thereby making the foam more stable and reducing the foam bursting caused by the fluidity of the liquid; the nano kaolin particles can be adsorbed on the gas-liquid interface of the foam, enhance the interfacial tension of the foam, and further stabilize the foam structure.

[0040] Taking the total mass of the nano foaming agent as 100%, the nano foaming agent in the present invention includes 0.05-1%, preferably 0.1-0.2% of a cellulose reinforcing agent. In the present invention, the cellulose reinforcing agent preferably includes cellulose and / or a cellulose derivative, and the cellulose derivative preferably includes methyl cellulose. In the present invention, the relative molecular weight of the cellulose is preferably 50,000-300,000, more preferably 100,000-200,000; the relative molecular weight of the methyl cellulose is preferably 50,000-300,000, more preferably 100,000-200,000. In the present invention, the cellulose-based reinforcing agent can increase the viscosity of the solution, slow down the flow rate of the liquid in the bubble film, thereby reducing the rupture and merging of the foam and improving the stability of the foam; the cellulose molecular chain can form a three-dimensional network structure in the aqueous solution, which can effectively surround and support the bubbles, prevent the merging of the bubbles and the discharge of the liquid, thereby extending the life of the foam; the cellulose molecules can be adsorbed on the gas-liquid interface of the bubbles to form a dense protective film, which can increase the elasticity and toughness of the bubble film and reduce the damage to the bubbles caused by external stress; cellulose can effectively prevent the merging of bubbles by increasing the strength of the foam liquid film, that is, the film between the bubbles ruptures and forms larger bubbles, so that the fineness and uniformity of the foam can be maintained; the presence of cellulose in the solution will increase the yield stress and elastic modulus of the solution, which makes the foam show better elastic recovery under the action of external force, thereby resisting the collapse and deformation of the foam.

[0041] The present invention has no special requirements for the preparation method of the nano foaming agent, and the components can be directly mixed evenly. In the embodiment of the present invention, the α-olefin sulfonate, nano kaolin and cellulose reinforcing agent are also called foaming powder, and the nano foaming agent is also called foaming liquid.

[0042] In the present invention, the mass of the nano foaming agent is 6-16% of the total mass of the gangue and cement, preferably 8-10%. The chemical composition of gangue is relatively complex, which poses a great challenge to chemical foaming. Ordinary foaming agents have poor stability, and the foam is easily broken, resulting in the collapse of the material. The present invention adopts a specific nano foaming agent, which has a physical foaming method, has good stability, and can achieve early setting of the slurry, which can well avoid bubble collapse and improve the strength of the material.

[0043] In the present invention, the gangue foamed thermal insulation building material preferably includes blocks or thermal insulation wallboards. The gangue foamed thermal insulation material provided by the present invention realizes the "green", "low-carbon" and "high-quality" development of lightweight thermal insulation materials.

[0044] The present invention provides a method for preparing the coal gangue foamed thermal insulation building material described in the above technical solution, comprising the following steps:

[0045] Mechanically foaming the nano foaming agent to obtain prefabricated foam;

[0046] The coal gangue is crushed and then mixed with cement, water and a water reducing agent to obtain a mixture;

[0047] mixing the mixed material with prefabricated foam to obtain concrete foam;

[0048] The concrete foam is molded and cured in sequence to obtain the lightweight heat-insulating building material with a large amount of coal gangue.

[0049] Figure 1 The schematic diagram of the process of preparing coal gangue foam insulation building materials according to the embodiment of the present invention is as follows. Figure 1 Provide detailed explanation.

[0050] The present invention performs mechanical foaming (i.e., physical foaming) on ​​the nano foaming agent to obtain prefabricated foam. In the present invention, the mechanical foaming is preferably performed by a foaming machine; the air pressure of the mechanical foaming is preferably 0.3-3MPa (the injection air pressure in the foaming gun of the foaming machine), more preferably 0.5-0.8MPa, and the density of the prefabricated foam is preferably 35-70g / L, more preferably 50-60g / L.

[0051] In the present invention, the coal gangue is crushed and then mixed with cement, water and a water reducing agent to obtain a mixture. In the present invention, the crushing (also referred to as breaking in the embodiment) is preferably performed by a hammer crusher, and after crushing, the coal gangue is sieved to obtain coal gangue powder with a particle size of 160 to 200 meshes.

[0052] In the present invention, the specific operation of mixing the crushed gangue with cement, water and water reducing agent is preferably: adding water to the mixer, then adding the water reducing agent for the first stirring and mixing, and then adding cement and the crushed gangue powder for the second stirring and mixing. In the present invention, the speed of the first stirring and mixing is preferably 20r / min, and the stirring time is preferably 2min; the speed of the second stirring and mixing is preferably 50r / min, and the clockwise and counterclockwise stirring are respectively 2 to 5min. After the cement, gangue, water and water reducing agent are mixed, a uniform slurry is obtained, that is, the mixture.

[0053] In the present invention, the fluidity of the mixture is preferably 240 to 250 mm.

[0054] After obtaining the mixture and the prefabricated foam, the present invention mixes the mixture and the prefabricated foam to obtain concrete foam. In the present invention, the mixing of the mixture and the prefabricated foam is preferably carried out under stirring, and the stirring rate is preferably 10r / min; the specific operation of mixing the mixture and the prefabricated foam is preferably: reducing the speed of the mixer containing the mixture to 10r / min, injecting the prefabricated foam into the mixture, stirring clockwise and counterclockwise for 1 to 2 minutes respectively, so that a uniform foam structure is formed in the concrete, that is, the concrete foam is obtained.

[0055] After obtaining the concrete foam, the present invention sequentially performs mold forming and curing on the concrete foam to obtain the coal gangue foamed thermal insulation building material. In the present invention, the mold forming preferably includes mold loading (i.e., pouring the concrete foam into a pre-prepared mold) and pre-curing, and the mold loading can also be vibrated, and the mold is removed after the pre-curing; the pre-curing is preferably natural curing, and the time of the natural curing is preferably 0.5 to 2 days. The present invention forms the concrete into a material with a certain size and shape through the mold forming. In the present invention, the curing curing is preferably standard curing (i.e., standard curing), and the time of the standard curing is preferably 25 to 28 days. The present invention ensures that the material obtains sufficient strength and stability during the hardening process through the curing curing. In the present invention, when preparing blocks, the time of the natural curing is more preferably 12 hours, and after the natural curing, the wire cutting is performed to the required size, and then the standard curing is performed, and the time of the standard curing is more preferably 27.5 days; when preparing thermal insulation wallboards, the time of the natural curing is more preferably 1 day, and the time of the standard curing is more preferably 27 days.

[0056] The process flow of preparing thermal insulation building materials using coal gangue is simple and efficient, and can quickly realize large-scale production. The thermal insulation building materials prepared by foamed concrete have low density, excellent thermal insulation performance and good compressive strength. Compared with traditional thermal insulation materials, they are lighter, more environmentally friendly and more energy-saving. In addition, the foam structure of foamed concrete makes the wall panels have better thermal insulation performance, which can effectively reduce the energy consumption of the building and improve the energy utilization rate of the building.

[0057] In order to further illustrate the present invention, the gangue foamed thermal insulation building material and the preparation method thereof provided by the present invention are described in detail below in conjunction with examples, but they should not be construed as limiting the protection scope of the present invention.

[0058] The preparation process of the nano foaming agent used in the following examples is as follows:

[0059] The surfactant sodium α-olefin sulfonate is dissolved in water and stirred with a glass rod until it is dissolved to prepare a sodium α-olefin sulfonate solution with a concentration of 0.2wt% (solution 1); nano kaolin (particle size 50-80nm) is dispersed in solution 1 and stirred with a glass rod until it is evenly dispersed, and the mass ratio of the nano kaolin to the sodium α-olefin sulfonate is 1:1 (solution 2); methyl cellulose (relative molecular weight 200000) is added to solution 2, wherein the amount of methyl cellulose is 90wt% of the nano kaolin, and stirred with a glass rod until it is evenly dispersed, and the stirring speed is 20r / min to obtain a nano foaming agent.

[0060] Example 1

[0061] A coal gangue foamed thermal insulation building material (building block / thermal insulation wallboard) is prepared from the following materials: 560kg of PO 42.5 cement, 240kg of coal gangue powder, 160kg of water, 1.2kg of polycarboxylic acid water reducer, and 64kg of nano foaming agent, wherein the coal gangue powder is obtained by crushing the coal gangue with a hammer crusher and sieving the coal gangue powder with a particle size of 160-200 meshes.

[0062] The preparation steps are as follows (process as Figure 1 shown):

[0063] (1) Weigh the required amount of water and add it into a blender.

[0064] (2) Weigh the required amount of polycarboxylate water reducer and pour it into a blender at a speed of 20 r / min for 2 min.

[0065] (3) Weigh the required cement and coal gangue powder, pour them into the mixer, and stir at 50 r / min in clockwise and counterclockwise directions for 2 to 5 minutes respectively until the slurry is uniform.

[0066] (4) The speed of the mixer was reduced to 10 r / min, and the nano foaming agent was foamed using a foaming machine (the foaming pressure was 0.6 MPa, and the density was 60 g / L), and then injected into the mixer, and stirred clockwise and counterclockwise for 1 to 2 min respectively.

[0067] (5) For foam insulation wall panels, simply inject the mixed slurry into the required mold, naturally cure for 1 day, remove the mold, and continue standard curing for 27 days; for lightweight blocks, simply inject the mixed slurry into the required mold, naturally cure for 12 hours, remove the mold, and then perform wire cutting to the required size. After cutting, continue standard curing for 27.5 days.

[0068] The strength of coal gangue foamed block / insulation wallboard after 28 days (natural curing + standard curing) is 5.2-6.3MPa, and the density is 770-805kg / m 3, the thermal conductivity is 0.18~0.20W / (m·K).

[0069] Example 2

[0070] A coal gangue foamed thermal insulation building material (building block / thermal insulation wallboard) is prepared from the following materials: 320kg of PO 42.5 cement, 480kg of coal gangue powder (160-200 meshes), 160kg of water, 1.2kg of polycarboxylic acid water reducer, and 64kg of nano foaming agent.

[0071] The preparation steps are the same as those in Example 1.

[0072] The 28d strength of coal gangue foamed blocks / insulation wall panels is 4.4-5.2MPa, and the density is 890-970kg / m 3 , the thermal conductivity is 0.24~0.27W / (m·K).

[0073] Example 3

[0074] A coal gangue powder foamed thermal insulation building material (building block / thermal insulation wallboard) is prepared from the following materials: 240 kg of PO 42.5 cement, 560 kg of coal gangue powder (160-200 meshes), 160 kg of water, 1.2 kg of polycarboxylic acid water reducer, and 64 kg of nano foaming agent.

[0075] The preparation steps are the same as those in Example 1.

[0076] The 28d strength of coal gangue foamed blocks / insulation wall panels is 8.9-11.1MPa, and the density is 1120-1220kg / m 3 , the thermal conductivity is 0.29~0.32W / (m·K).

[0077] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A coal gangue foamed thermal insulation building material, characterized in that: The preparation raw materials include: cement, coal gangue, water, water reducing agent and nano foaming agent; The mass ratio of the coal gangue to cement is 7:3-3:7, the mass ratio of the water to the total mass of cement and coal gangue is 0.2:1, and the mass of the water reducing agent is 0.1-0.3% of the total mass of coal gangue and cement; The nano foaming agent comprises the following components in percentage by mass: 0.1-1% of α-olefin sulfonate, 0.1-1% of nano kaolin, 0.05-1% of cellulose reinforcing agent and the balance of water; the mass of the nano foaming agent is 6-16% of the total mass of coal gangue and cement.

2. The coal gangue foamed thermal insulation building material according to claim 1, characterized in that: The cement is PO 42.5 cement.

3. The coal gangue foamed thermal insulation building material according to claim 1, characterized in that: The particle size of the coal gangue is 160-200 meshes.

4. The coal gangue foamed thermal insulation building material according to claim 1, characterized in that: The nano foaming agent comprises the following components in percentage by weight: 0.1-0.2% of α-olefin sulfonate, 0.1-0.2% of nano kaolin, 0.1-0.2% of cellulose reinforcing agent, and the balance of water.

5. The coal gangue foamed thermal insulation building material according to claim 1 or 4, characterized in that: The particle size of the nano kaolin is 40-100 nm.

6. The coal gangue foamed thermal insulation building material according to claim 1 or 4, characterized in that: The cellulose-based strengthening agent includes cellulose and / or cellulose derivatives.

7. The coal gangue foamed thermal insulation building material according to claim 1, characterized in that: The water reducer is a polycarboxylate water reducer.

8. The method for preparing the coal gangue foamed thermal insulation building material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Mechanically foaming the nano foaming agent to obtain prefabricated foam; After the coal gangue is crushed, it is mixed with cement, water and a water reducing agent to obtain a mixture; mixing the mixed material with prefabricated foam to obtain concrete foam; The concrete foam is sequentially molded and cured to obtain the coal gangue foamed thermal insulation building material.

9. The preparation method according to claim 8, characterized in that: The air pressure of the mechanical foaming is 0.3-3 MPa, and the density of the prefabricated foam is 35-70 g / L.

10. The preparation method according to claim 8, characterized in that: The mixing of the mixed material and the prefabricated foam is carried out under stirring, and the stirring rate is 10 r / min.

Images