Magnesite tailing-based composite thermal-insulation energy-saving wall material and preparation method thereof

Abstract

The invention discloses a magnesite tailing-based composite heat-insulating and energy-saving wall material and a preparation method thereof, and belongs to the technical field of heat-insulating materials. The magnesite tailing-based composite heat-insulating and energy-saving wall material comprises the following components in parts by mass: 573-588 parts of magnesite tailings; 187 to 202 parts of metakaolin; 4.8 to 6.2 parts of brucite fiber; 2.2 to 2.7 parts of calcium diethylene triamine penta (methylene phosphonic acid); 1.6 to 2.1 parts of magnesium formate; 62 to 68 parts of deionized water; 116 to 132 parts of an alkali activator; 58 parts to 62 parts of calcium oxide; 12.6 to 14.1 parts of micro foam; and 21.4 to 27.1 parts of an additive. The invention solves the problems of low strength, easy cracking, poor durability, poor thermal insulation, consumption of a large amount of resources and energy in the production process, and emission of a large amount of dust and harmful waste gases such as CO2, CO, NOX, SO2 and the like in the existing foam concrete inorganic thermal insulation material prepared from cement.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal insulation wall materials, and particularly relates to a siderite tailing-based composite thermal insulation and energy-saving wall material and a preparation method thereof. Background Art

[0002] In China, the resources of siderite (FeCO 3 ) are relatively rich, and the reserves rank among the top in the world. However, with the rapid development of China's iron and steel industry, the demand for iron ore has increased rapidly, the import volume of iron ore is huge, and the external dependence is more than 85%. In the case of a sharp reduction in the reserves of easily beneficiated iron ores such as magnetite ores, in order to alleviate the shortage of iron ore in China, improve the self-sufficiency rate of iron ore, and strengthen the efficient development and utilization of complex and difficult-to-beneficiate siderite ores in China is extremely urgent and of great strategic significance. At present, the beneficiation process commonly used for siderite in China is the "roasting magnetization - magnetic separation - flotation" process to obtain iron concentrate. The largest siderite deposit in China is the Daxigou siderite deposit in Zhashui County, Shaanxi Province. A production line with an annual processing capacity of 8 million tons of siderite will be put into operation soon, and at the same time, more than 5 million tons of siderite tailings will be produced every year. The particle size of the siderite tailings produced by beneficiation is extremely fine, about 80% of which is below 325 mesh, and the comprehensive utilization is extremely difficult. At present, there is no effective utilization way and it can only be stored in the tailings pond. However, the state has extremely strict approval and control over tailings ponds. According to the requirements in the "Work Plan for Preventing and Resolving Safety Risks of Tailings Ponds", "Each province (autonomous region, municipality directly under the Central Government) should implement total control over the tailings ponds in its region. Since 2020, on the premise of ensuring the normal construction and development of scarce and strategic mineral mines, the number of tailings ponds should generally only decrease and not increase." Therefore, across the country, it is extremely urgent to seek effective methods and ways for the large-scale consumption of siderite tailings, which is a key link to ensure the normal production and operation of siderite mining enterprises and has received great attention from the government and major siderite enterprises.

[0003] With the development of science and technology and the increasing demand for energy in human society, the energy problem has become a serious obstacle restricting the progress of human society. According to relevant reports, building energy consumption accounts for 30% - 40% of the total energy consumption. Therefore, how to reduce building energy consumption has become a very important topic in the field of national science and technology research. At present, most solutions mainly focus on reducing the heating and air-conditioning energy consumption of buildings, which also places more stringent requirements on the building insulation system, making the building have good thermal insulation performance throughout the year. The most direct solution is to add building insulation materials inside and outside the building to improve the overall thermal insulation performance of the building. At present, such building insulation materials are mainly divided into two categories, one is organic insulation materials, and the other is inorganic insulation materials. At present, the most widely used inorganic insulation material is foam concrete insulation material. However, foam concrete must use cement, and a large amount of resources and energy are consumed in the production process of cement, and a large amount of dust and CO 2, CO, NO X , SO 2 and other harmful waste gases. Their limitations such as high energy consumption, high pollution, and high emissions are bound to pose a serious threat to the ecological environment.

[0004] In summary, it is urgent to solve the problems that the foam concrete inorganic thermal insulation materials made of cement currently have low strength, are prone to cracking, have poor durability, poor heat insulation, consume a large amount of resources and energy during the production process, emit a large amount of dust, and CO 2 , CO, NO X , SO 2 and other harmful waste gases. Summary of the Invention

[0005] The purpose of the embodiments of the present invention is to provide a siderite tailing-based composite thermal insulation and energy-saving wall material and its preparation method to solve the problems that the foam concrete inorganic thermal insulation materials made of cement currently have low strength, are prone to cracking, have poor durability, poor heat insulation, consume a large amount of resources and energy during the production process, emit a large amount of dust, and CO 2 , CO, NO X , SO 2 and other harmful waste gases.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is a siderite tailing-based composite thermal insulation and energy-saving wall material, and the components and mass parts thereof are:

[0007]

[0008] Further, the alkali activator is prepared from water glass, sodium hydroxide and deionized water.

[0009] Further, the microfoam is prepared from a composite foaming agent and deionized water according to a mass ratio of 1.2:100.

[0010] Further, the components and mass parts of the admixture are:

[0011]

[0012] Further, the particle size of the siderite tailings is below 325 mesh, the particle size of the metakaolin is 800 mesh, the length of the brucite fiber is 4-12 mm, the diameter is 15-22 μm, and the particle size of the calcium oxide is 800 mesh.

[0013] Further, the alkali activator is prepared by mixing water glass with a modulus of 3.0 and an aqueous sodium hydroxide solution with a mass concentration of 35% to a modulus of 1.1-1.3.

[0014] Further, the composite foaming agent is prepared from cocamidopropyl betaine and alpha-olefin sulfonate in a mass ratio of 3:1.

[0015] Another technical solution adopted by the present invention is a preparation method of a ferrous carbonate tailing-based composite heat-insulating and energy-saving wall material, comprising the following steps:

[0016] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate to a disperser, stir and mix, and then add antigorite fiber and continue stirring to obtain a mixed liquid A;

[0017] S2. Add the mixed liquid A to a planetary cement mortar mixer, then add ferrous carbonate tailings, stir and mix, and then add metakaolin, and continue stirring and mixing to obtain a mixture B;

[0018] S3. Prepare an aqueous sodium hydroxide solution, age it, and then compound it with water glass to prepare an alkali activator;

[0019] S4. Add the composite foaming agent and deionized water to an ultrasonic micro-foam machine, stir and mix to obtain micro-foams;

[0020] S5. Add the mixture B and the alkali activator to a cement paste mixer in proportion, stir and mix, and then add calcium oxide and stir and mix to obtain a slurry C;

[0021] S6. Add an admixture to the slurry C, stir and mix, then add micro-foams, continue stirring and mixing, and then transfer all to an ultrasonic micro-foam machine for dispersion to obtain a micro-foam slurry D;

[0022] S7. Pour the micro-foam slurry D into a mold for molding, let it stand to obtain a micro-foam composite block, and seal it with a plastic film;

[0023] S8. Place the wrapped micro-foam composite block in a curing box for curing to obtain a ferrous carbonate tailing-based composite heat-insulating and energy-saving wall material.

[0024] Another technical solution adopted by the present invention is a preparation method of a ferrous carbonate tailing-based composite heat-insulating and energy-saving wall material, comprising the following steps:

[0025] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate to a disperser, stir and mix at 800-1000 r / min for 10-15 min, and then add antigorite fiber and continue stirring for 30-40 min to obtain a mixed liquid A;

[0026] S2. Add the mixed liquid A to a planetary cement mortar mixer, then add ferrous carbonate tailings, stir and mix at 140±2 r / min for 15-20 min, and then add metakaolin, and continue stirring and mixing at 285±3 r / min for 40-50 min to obtain a mixture B;

[0027] S3. Prepare an aqueous sodium hydroxide solution with a mass concentration of 35%, age it for 12 - 16 h, and then compound it with water glass to adjust the modulus of water glass to 1.1 - 1.3 to obtain an alkali activator;

[0028] S4. Add the compound foaming agent and deionized water to an ultrasonic micro - foam machine, stir and mix them at 25 KHz for 3 - 5 min to obtain micro - foam;

[0029] S5. Add mixture B and the alkali activator to a cement paste mixer in proportion, stir and mix them for 3 - 5 min, then add calcium oxide and continue to stir and mix for 5 - 8 min to obtain slurry C;

[0030] S6. Add an admixture to slurry C, stir and mix for 6 - 8 min, then add micro - foam and continue to stir and mix for 4 - 6 min, and then transfer all of them to an ultrasonic micro - foam machine and disperse them at 40 KHz for 20 - 40 s to obtain micro - foam slurry D;

[0031] S7. Pour the micro - foam slurry D into a mold for molding, place it at 25 °C for 24 h to obtain a micro - foam composite block, and seal it with a plastic film;

[0032] S8. Place the wrapped micro - foam composite block in a curing box at 60 - 80 °C for 28 d to obtain a ferrous iron tailing - based composite heat - insulating and energy - saving wall material.

[0033] The beneficial effects of the present invention are as follows:

[0034] (1) In the embodiments of the present invention, taking ferrous iron tailings as the main raw material, while making high - value utilization of ferrous iron tailings, it solves to a certain extent the ecological environment problems and safety hazards brought by the large - scale long - term stacking of ferrous iron tailings, and also solves to a certain extent the problem that the stacking of ferrous iron tailings in ferrous iron ore mining enterprises restricts the production capacity of enterprises; at the same time, because ferrous iron tailings belong to industrial solid waste, the materials prepared do not need to add cement, which can solve the problems of high cost of foam concrete heat - insulating and energy - saving wall materials, high energy consumption, huge carbon emissions and serious environmental pollution in the preparation process of raw materials.

[0035] (2) In the embodiment of the present invention, siderite tailings are used as the main raw material. The "magnetic roasting - magnetic separation - flotation" process is generally adopted for siderite. The produced siderite tailings have high activity due to high-temperature roasting and do not need to be activated. After adjusting the silicon-aluminum ratio with metakaolin and combining with the formula design of the present invention, a mutually penetrating network micro-foam composite structure of brucite fiber-reinforced silicon-aluminum inorganic polymer and hydrated gel (including: hydrated calcium silicate gel, hydrated calcium aluminate gel, hydrated calcium sulfoaluminate (ferrite) (mono-component, tri-component) gel) is finally formed, which greatly improves the strength and corrosion resistance of the obtained thermal insulation and energy-saving material, ensures the durability and service performance of the material, and solves the problems of low strength, easy shrinkage and cracking, and poor durability of traditional foam concrete.

[0036] (3) During the preparation and use of the mutually penetrating network micro-foam thermal insulation and energy-saving material of brucite fiber-reinforced silicon-aluminum inorganic polymer and hydrated cementitious material based on siderite tailings in the embodiment of the present invention, it can greatly save energy and reduce consumption, reduce carbon emissions, contribute to the realization of the goals of "carbon peak and carbon neutrality" in China, reduce the consumption of a large amount of resources and energy in the production process of cement, and avoid the emission of a large amount of dust and harmful waste gases such as CO 2 , CO, NO X , SO 2 .

[0037] (4) In the embodiment of the present invention, brucite fiber is used as the reinforcing material, which greatly improves the compressive strength and flexural strength of the composite thermal insulation and energy-saving wall material. At the same time, since the main component of brucite fiber is magnesium hydroxide, its crystal chemical properties are stable, which can greatly improve the carbonation resistance and chloride ion permeability of the material. After the paste is completely hardened, it fills the capillary pores and cracks in the micro-foam walls inside the material, improves the internal pore structure of the matrix, blocks the water seepage path of the matrix, thereby improving the anti-seepage performance of the foam structure, and greatly improving the environmental erosion resistance of the foam material.

[0038] (5) In the embodiment of the present invention, cocamidopropyl betaine and α-olefin sulfonate are combined with the second flotation oil and the fourth flotation oil foaming agents remaining in the siderite tailings in the siderite flotation process. Through ultrasonic foaming by an ultrasonic micro-foam machine, the micro-foam has a small sedimentation distance and bleeding water volume, and a large foaming multiple and foaming height; calcium stearate and hydroxypropyl methyl cellulose are used as foam stabilizers, which can reduce the surface tension of the slurry, synergistically act with anionic surfactants, improve the stability of the foam, reduce the bubble diameter of the foam, improve the uniformity of the foam, reduce the connected proportion of the foam in the slurry, and at the same time improve the mechanical properties and stability of the foam; the foam is an independent closed bubble, and the foam is fine. When heat is transferred in these closed micro-holes in this silicon-aluminum inorganic polymer and hydrated gel interpenetrating network micro-foam material, due to being weakened layer by layer by the barriers formed by countless micro-foams, the thermal conductivity of the material is greatly reduced, thus achieving the effect of high-efficiency heat preservation and insulation. At the same time, the dense closed cavity three-dimensional network structure of the material endows it with excellent mechanical properties and durability, overcoming the problems of low strength, easy cracking, poor durability, and poor heat preservation of traditional foam concrete thermal insulation materials.

[0039] (6) In the embodiment of the present invention, calcium diethylenetriamine pentamethylene phosphonate and magnesium formate are added. Their synergistic effect can promote the dissolution and activation of calcium, aluminum, iron and other hydrated gel reactants in the raw materials, greatly enhance the formation of hydrated gel, and promote the formation of a silicon-aluminum inorganic polymer and hydrated gel interpenetrating network structure; the addition of trisodium nitrilotriacetate can form a stable complex with the cations in the finally formed silicon-aluminum inorganic polymer and hydrated gel interpenetrating network structure, making the interpenetrating network structure more firm and further improving the stability of the material; at the same time, the addition of the water reducer 2-methyl-2,4-pentanediol effectively reduces the water absorption rate of the material and improves the stability and durability of the material during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0041] Figure 1 It is a process flow chart of the preparation of the siderite tailings-based composite thermal insulation and energy-saving wall material in the embodiment of the present invention.

[0042] Figure 2 It is an XRD diffraction pattern of the siderite tailings in the embodiment of the present invention.

[0043] Figure 3 It is a particle size distribution diagram of the siderite tailings in the embodiment of the present invention. Specific Embodiments

[0044] 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.

[0045] The present invention provides a siderite tailing-based composite heat-insulating and energy-saving material, and the components and parts by mass thereof are as follows:

[0046]

[0047] The siderite tailings used in the present invention are produced after the magnetization roasting - magnetic separation - flotation process of siderite. After the specific activity of radionuclides is detected, they belong to Class A decorative materials and can be used without restrictions; as Figure 2 shown in the XRD diffraction pattern of the siderite tailings, its main mineral components include quartz, muscovite, diopside, barite, magnetite, and the main chemical components are SiO 2 、Al 2 O 3 、Fe 2 O 3 、BaO, etc.; among them, the silicon and aluminum contained in muscovite can be partially activated to form silicon-aluminum inorganic polymers in an alkaline environment. The silicon-aluminum inorganic polymer is a three-dimensional network structure formed by connecting silicon-oxygen tetrahedrons and aluminum-oxygen tetrahedrons through shared oxygen. At the same time, muscovite has a lamellar structure and is an excellent reinforcing and toughening filler, which can improve the strength of the material. Muscovite also has good thermal insulation properties and can improve the heat insulation performance of the material. Diopside is a new type of industrial mineral resource with unique functions. It can reduce the shrinkage rate of the material and improve the stability of wall materials. Barite has high density and chemical stability and, as an excellent mineralizer, promotes the hydration reaction and enhances the material strength. A small amount of magnetite remaining in the siderite tailings after the "magnetic separation - flotation" process can participate in the hydration reaction in an alkaline environment and promote the formation of hydration products. The present invention makes full use of the components in the siderite tailings and participates in the reaction to varying degrees during the formation of silicon-aluminum inorganic polymers and hydrated cementitious materials, so that the prepared siderite tailing-based composite heat-insulating and energy-saving wall material has excellent compressive and flexural strengths.

[0048] As Figure 3 shown in the particle size analysis of the siderite tailings, its particle size is mainly distributed between 10 -2 ~10 -3 μm, the particle diameter is below 325 mesh, and the specific surface area S is 0.316 m 2 / g, it can be seen that the particle size of the ferruginous tailings is relatively fine and the specific surface area is relatively large, which is conducive to the formation of silicon-aluminum inorganic polymers and hydrated gels, and there is no need for additional energy consumption for grinding treatment. In addition, the ferruginous tailings are subjected to high-temperature roasting during ore dressing, and their constituent components have extremely high activity, and no additional activation treatment is required, which greatly saves the cost of the prepared ferruginous tailings-based composite thermal insulation and energy-saving wall materials.

[0049] The particle size of metakaolin is 800 mesh; the length of the brucite fiber is 4 - 12 mm, and the diameter is 15 - 22 μm; the particle size of calcium oxide is 800 mesh and the purity is 98%. Under the limited size and particle diameter of metakaolin, brucite fiber, and calcium oxide in the present invention, it can be ensured that each component can fully react with the ferruginous tailings, and the prepared ferruginous tailings-based composite thermal insulation and energy-saving wall materials can reach the optimal performance. The reason is that under the limited particle diameter and size, each component can reach the required grading with the ferruginous tailings, and sufficient contact can be achieved between the reaction components, reaching a large contact area, so as to ensure efficient and sufficient reaction under the set process conditions, thereby generating an interpenetrating network structure of silicon-aluminum inorganic polymers and hydrated gels, and ensuring the strength and workability of the material.

[0050] The compound of calcium diethylenetriamine pentamethylene phosphonate and magnesium formate can play a role in the dissolution and dispersion of each reaction ion during the mixing process of ferruginous tailings, metakaolin, brucite fiber, and deionized water, making various components highly dispersed, increasing the effective contact area between the reaction components, and promoting the full progress of subsequent reactions; on the one hand, calcium oxide can provide a calcium source for the formation of hydrated calcium silicate gel, hydrated calcium aluminate gel, and hydrated calcium sulfoaluminate (ferrite) gel (mono-component, ternary), and on the other hand, it can react with deionized water to release a large amount of heat, accelerating and promoting the formation of silicon-aluminum inorganic polymers and various hydrated products.

[0051] The alkali activator is prepared from water glass, sodium hydroxide and deionized water. Specifically, water glass with a modulus of 3.0 is mixed with an aqueous sodium hydroxide solution with a mass concentration of 35% to adjust the modulus to 1.1 - 1.3. In the strongly alkaline environment prepared by the alkali activator, magnetite contained in the ferrosiderite tailings can react with sodium ions to form trisodium hexahydroxyferrate complexes. The modulus of water glass directly affects the properties of silica-aluminum inorganic polymers and hydrated gels. Specifically, the larger the modulus, the more silica content, the greater the viscosity of water glass, and when mixed with other components, the dispersibility will become worse, unable to ensure uniform dispersion, thus affecting the degree of full reaction. Secondly, the larger the modulus, the weaker the alkalinity, which greatly affects the alkalinity of the reaction system and fails to play a catalytic and initiating role in the reaction, and the reaction effect of each component will be greatly reduced. Thirdly, water glasses with different moduli have different degrees of polymerization, resulting in significant differences in the silicate components in their hydrolysis products, thus directly affecting the structure and reaction degree of the reaction products. To sum up, within the range of water glass modulus set in the present invention, the viscosity and alkalinity of water glass can be ensured to be appropriate, ensuring the final effect of the reaction.

[0052] The microfoam is prepared from a composite foaming agent and deionized water according to a mass ratio of 1.2:100, and is obtained by an ultrasonic microfoam machine. The composite foaming agent is prepared by compounding cocamidopropyl betaine and alpha-olefin sulfonate in a ratio of 3:1, and can synergistically foam with the residual No. 2 flotation oil and No. 4 flotation oil in the ferrosiderite tailings. The prepared microfoam is fine, stable, has a small sedimentation distance and water bleeding property, and a high closed cell rate, enabling the ferrosiderite tailings-based composite heat-insulating and energy-saving wall material to effectively block the transfer of heat.

[0053] The components and parts by mass included in the admixture are:

[0054]

[0055] Among them, calcium stearate and hydroxypropyl methylcellulose are foam stabilizers, trisodium nitrilotriacetate is a complexing agent, and 2-methyl-2,4-pentanediol is a water reducing agent.

[0056] As Figure 1 shown, the present invention provides a preparation method of a ferrosiderite tailings-based composite heat-insulating and energy-saving wall material, including the following steps:

[0057] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate into a disperser, stir and mix at 800 - 1000 r / min for 10 - 15 min, and then add antigorite fiber and continue to stir for 30 - 40 min to obtain a mixed liquid A;

[0058] S2. Add the mixed solution A to a planetary cement mortar mixer, then add ferrous iron tailings, and mix at 140 ± 2 r / min for 15 - 20 min. Then add metakaolin and continue to mix at 285 ± 3 r / min for 40 - 50 min to obtain a mixture B;

[0059] S3. Prepare an aqueous sodium hydroxide solution with a mass concentration of 35%, age it for 12 - 16 h, and then compound it with water glass to adjust the water glass modulus to 1.1 - 1.3 to obtain an alkali activator;

[0060] S4. Add a composite foaming agent and deionized water to an ultrasonic micro-foam machine, and mix at 25 KHz for 3 - 5 min to obtain micro-foams;

[0061] S5. Add the mixture B and the alkali activator to a cement paste mixer in proportion and mix for 3 - 5 min, then add calcium oxide and continue to mix for 5 - 8 min to obtain a slurry C;

[0062] S6. Add an admixture to the slurry C and mix for 6 - 8 min, then add micro-foams and continue to mix for 4 - 6 min. Then transfer all to an ultrasonic micro-foam machine and disperse at 40 KHz for 20 - 40 s to obtain a micro-foam slurry D;

[0063] S7. Pour the micro-foam slurry D into a mold and cure at 25 °C for 24 h to obtain a micro-foam composite block, which is sealed with a plastic film;

[0064] S8. Place the wrapped micro-foam composite block in a curing box at 60 - 80 °C for 28 d to obtain a ferrous iron tailings-based composite heat-insulating and energy-saving wall material.

[0065] The embodiment of the present invention provides a ferrous iron tailings-based composite heat-insulating and energy-saving wall material, and its formula is shown in Table 1:

[0066] Table 1 Formula table of a ferrous iron tailings-based composite heat-insulating and energy-saving wall material (parts by mass)

[0067]

[0068] Example 1

[0069] To prepare a ferrous iron tailings-based composite heat-insulating and energy-saving wall material using the formula of Example 1, the following steps are included:

[0070] S1. Add deionized water, calcium diethylenetriamine pentamethylenephosphonate, and magnesium formate to a disperser, mix at 800 r / min for 10 min, and then add brucite fiber and continue to stir for 30 min to obtain a mixed solution A;

[0071] S2. Add the mixture A into a planetary cement mortar mixer, then add ferrous iron tailings, stir and mix at 140±2 r / min for 15 min, then add metakaolin, and continue to stir and mix at 285±3 r / min for 40 min to obtain mixture B;

[0072] S3. Prepare a sodium hydroxide aqueous solution with a mass concentration of 35%, age it for 12 h, then compound it with water glass and adjust the water glass modulus to 1.1 to obtain an alkali activator;

[0073] S4. Add the composite foaming agent and deionized water into an ultrasonic micro-foam machine, stir and mix at 25 KHz for 3 min to obtain micro-foams;

[0074] S5. Add mixture B and the alkali activator into a cement paste mixer according to the proportion, stir and mix for 3 min, then add calcium oxide and continue to stir and mix for 5 min to obtain slurry C;

[0075] S6. Add an admixture into slurry C, stir and mix for 6 min, then add micro-foams, continue to stir and mix for 4 min, and then transfer all to an ultrasonic micro-foam machine and disperse at 40 KHz for 20 s to obtain micro-foam slurry D;

[0076] S7. Pour the micro-foam slurry D into a mold for molding, place it at 25 °C for 24 h to obtain a micro-foam composite block, and seal it with a plastic film;

[0077] S8. Place the wrapped micro-foam composite block in a curing box at 60 °C for 28 d to obtain a ferrous iron tailings-based composite heat-insulating and energy-saving wall material.

[0078] Example 2

[0079] Prepare a ferrous iron tailings-based composite heat-insulating and energy-saving wall material using the formulation of Example 2, including the following steps:

[0080] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate into a disperser, stir and mix at 850 r / min for 12 min, then add antigorite fiber and continue to stir for 32 min to obtain mixture A;

[0081] S2. Add the mixture A into a planetary cement mortar mixer, then add ferrous iron tailings, stir and mix at 140±2 r / min for 17 min, then add metakaolin, and continue to stir and mix at 285±3 r / min for 43 min to obtain mixture B;

[0082] S3. Prepare a sodium hydroxide aqueous solution with a mass concentration of 35%, age it for 12 h, then compound it with water glass and adjust the water glass modulus to 1.2 to obtain an alkali activator;

[0083] S4. Add the composite foaming agent and deionized water to an ultrasonic micro-foam machine, stir and mix them at 25 KHz for 4 min to obtain micro-foams.

[0084] S5. Add mixture B and the alkali activator to a cement paste mixer in proportion, stir and mix them for 3 min, then add calcium oxide and continue to stir and mix for 6 min to obtain slurry C.

[0085] S6. Add the admixture to slurry C, stir and mix for 6 min, then add the micro-foams and continue to stir and mix for 5 min. Then transfer all of them to the ultrasonic micro-foam machine and disperse them at 40 KHz for 25 s to obtain micro-foam slurry D.

[0086] S7. Pour the micro-foam slurry D into a mold and let it stand at 25 °C for 24 h to obtain a micro-foam composite block, which is then sealed and wrapped with a plastic film.

[0087] S8. Place the wrapped micro-foam composite block in a curing box at 65 °C for 28 d to obtain the siderite tailings-based composite heat-insulating and energy-saving wall material.

[0088] Example 3

[0089] Prepare a siderite tailings-based composite heat-insulating and energy-saving wall material using the formulation of Example 3, which includes the following steps:

[0090] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate to a disperser, stir and mix them at 900 r / min for 13 min, then add antigorite fiber and continue to stir for 35 min to obtain mixture A.

[0091] S2. Add mixture A to a planetary cement mortar mixer, then add siderite tailings, stir and mix them at 140 ± 2 r / min for 17 min, then add metakaolin and continue to stir and mix at 285 ± 3 r / min for 45 min to obtain mixture B.

[0092] S3. Prepare a 35% mass concentration sodium hydroxide aqueous solution and age it for 12 h; then compound it with water glass to adjust the water glass modulus to 1.2 to obtain the alkali activator.

[0093] S4. Add the composite foaming agent and deionized water to an ultrasonic micro-foam machine, stir and mix them at 25 KHz for 4 min to obtain micro-foams.

[0094] S5. Add mixture B and the alkali activator to a cement paste mixer in proportion, stir and mix them for 4 min, then add calcium oxide and continue to stir and mix for 7 min to obtain slurry C.

[0095] S6. Add admixtures to Slurry C, stir and mix for 7 min, then add microfoam, continue to stir and mix for 5 min, and then transfer all to an ultrasonic microfoam machine and disperse for 30 s at 40 KHz to obtain microfoam slurry D;

[0096] S7. Pour the microfoam slurry D into a mold and let it stand at 25 °C for 24 h to obtain a microfoam composite block, which is sealed and wrapped with a plastic film;

[0097] S8. Place the wrapped microfoam composite block in a curing box at 70 °C for 28 d to obtain the siderite tailings-based composite thermal insulation and energy-saving wall material.

[0098] Example 4

[0099] Prepare a siderite tailings-based composite thermal insulation and energy-saving wall material using the formulation of Example 4, including the following steps:

[0100] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate to a disperser, stir and mix at 950 r / min for 14 min, and then add antigorite fiber and continue to stir for 37 min to obtain mixture A;

[0101] S2. Add mixture A to a planetary cement mortar mixer, then add siderite tailings, stir and mix at 140 ± 2 r / min for 19 min, and then add metakaolin, stir at 285 ± 3 r / min for 48 min to obtain mixture B;

[0102] S3. Prepare a 35% mass concentration sodium hydroxide aqueous solution and age it for 12 h; then compound it with water glass to adjust the water glass modulus to 1.3 to obtain an alkali activator;

[0103] S4. Add the composite foaming agent and deionized water to an ultrasonic microfoam machine, stir and mix at 25 KHz for 5 min to obtain microfoam;

[0104] S5. Add mixture B and the alkali activator to a cement paste mixer in proportion, stir and mix for 5 min, and then add calcium oxide and continue to stir and mix for 8 min to obtain Slurry C;

[0105] S6. Add admixtures to Slurry C, stir and mix for 8 min, then add microfoam, continue to stir and mix for 6 min, and then transfer all to an ultrasonic microfoam machine and disperse for 35 s at 40 KHz to obtain microfoam slurry D;

[0106] S7. Pour the microfoam slurry D into a mold and let it stand at 25 °C for 24 h to obtain a microfoam composite block, which is sealed and wrapped with a plastic film;

[0107] S8. Place the wrapped micro-foam composite material block in a curing box at 75 °C for 28 days to obtain the siderite tailing-based composite thermal insulation and energy-saving wall material.

[0108] Example 5

[0109] Prepare a siderite tailing-based composite thermal insulation and energy-saving wall material using the formulation of Example 5, including the following steps:

[0110] S1. Add deionized water, calcium diethylenetriamine pentamethylene phosphonate, and magnesium formate to a disperser, stir and mix at 1000 r / min for 15 min, then add antigorite fiber and continue to stir for 40 min to obtain a mixed liquid A;

[0111] S2. Add the mixed liquid A to a planetary cement mortar mixer, then add siderite tailings, stir and mix at 140 ± 2 r / min for 20 min, then add metakaolin, and continue to stir and mix at 285 ± 3 r / min for 50 min to obtain a mixed material B;

[0112] S3. Prepare a 35% mass concentration sodium hydroxide aqueous solution, age it for 16 h, and then compound it with water glass to adjust the water glass modulus to 1.3 to obtain an alkali activator;

[0113] S4. Add the composite foaming agent and deionized water to an ultrasonic micro-foam machine, stir and mix at 25 kHz for 5 min to obtain micro-foams;

[0114] S5. Add the mixed material B and the alkali activator to a cement paste mixer in proportion and stir and mix for 5 min, then add calcium oxide and continue to stir and mix for 8 min to obtain a slurry C;

[0115] S6. Add an admixture to the slurry C, stir and mix for 8 min, then add micro-foams, continue to stir and mix for 6 min, and then transfer all to an ultrasonic micro-foam machine and disperse at 40 kHz for 40 s to obtain a micro-foam slurry D;

[0116] S7. Pour the micro-foam slurry D into a mold, place it at 25 °C for 24 h to obtain a micro-foam composite material block, and seal and wrap it with a plastic film;

[0117] S8. Place the wrapped micro-foam composite material block in a curing box at 80 °C for 28 days to obtain the siderite tailing-based composite thermal insulation and energy-saving wall material.

[0118] Since the material prepared in Example 3 has better material properties and dimensional stability, Example 3 is used as the basis to design a comparative example for further research.

[0119] Comparative Example 1

[0120] The differences from Example 3 are as follows: the dosages of each component are lower than those in Example 3, and specifically refer to the formulation of Comparative Example 1. In S1, deionized water, calcium diethylenetriamine pentamethylenephosphonate, and magnesium formate are added to a disperser, stirred and mixed at 1050 r / min for 18 min, then antigorite fiber is added and stirring continues for 45 min to obtain a mixed liquid A; in S8, the wrapped micro-foam composite material block is placed in a curing box at 85 °C for 28 d to obtain a siderite tailing-based composite heat-insulating and energy-saving wall material. The remaining steps are the same as those in Example 3.

[0121] Comparative Example 2

[0122] The differences from Example 3 are as follows: in S1, antigorite fiber is not added and stirring does not continue; in S5, the mixture B and the alkali activator are stirred and mixed for 6 min, and then calcium oxide is added and stirring continues for 9 min. The remaining steps are the same as those in Example 3.

[0123] Comparative Example 3

[0124] The differences from Example 3 are as follows: in S1, deionized water and antigorite fiber are added to a disperser, stirred and mixed at 750 r / min for 17 min to obtain a mixed liquid A; in S6, stirring and mixing are carried out for 4 min, then micro-foam is added, stirring continues for 8 min, and dispersion is carried out for 18 s at 40 KHz. The remaining steps are the same as those in Example 3.

[0125] Comparative Example 4

[0126] The differences from Example 3 are as follows: in S5, the mixture B and the alkali activator are added to a cement paste mixer and stirred and mixed for 7 min to obtain a slurry C; in S8, the wrapped micro-foam composite material block is placed in a curing box at 55 °C for curing. The remaining steps are the same as those in Example 3.

[0127] Comparative Example 5

[0128] The differences from Example 3 are as follows: in S6, nitrilotriacetic acid trisodium salt and 2-methyl-2,4-pentanediol are added to the slurry C in proportion, stirred for 8 min, then micro-foam is added, stirred for 4 min, and then transferred to an ultrasonic micro-foam machine, and dispersion is carried out for 45 s at 40 KHz to obtain a micro-foam slurry D. The remaining steps are the same as those in Example 3.

[0129] Comparative Example 6

[0130] The differences from Example 3 are as follows: in S5, the mixture B and the alkali activator are added and stirred and mixed for 8 min, and then calcium oxide is added and stirring continues for 9 min; in S6, calcium stearate, hydroxypropyl methylcellulose, and 2-methyl-2,4-pentanediol are added to the slurry C in proportion, stirred for 10 min, then micro-foam is added, stirred for 3 min, and then transferred to an ultrasonic micro-foam machine, and dispersion is carried out for 45 s at 40 KHz to obtain a micro-foam slurry D. The remaining steps are the same as those in Example 3.

[0131] Comparative Example 7

[0132] The differences from Example 3 are as follows: in S1, stir and mix at 1100 r / min for 7 min, then add antigorite fiber and continue to stir for 45 min; in S4, stir and mix at 25 KHz for 6 min to obtain microfoam. In S6, 2-methyl-2,4-pentanediol is not added to the admixture. The remaining steps are the same as those in Example 3.

[0133] Comparative Example 8

[0134] The differences from Example 3 are as follows: in S4, add the composite foaming agent and deionized water to the disperser, stir at 1200 r / min for 8 min to obtain foam; in S6, add the admixture to the slurry C in proportion, stir for 8 min, then add the foam and stir for 6 min to obtain the foam slurry D. The remaining steps are the same as those in Example 3.

[0135] Comparative Example 9

[0136] The differences from Example 3 are as follows: the dosage of each component is higher than that in Example 3, specifically referring to the formulation of Comparative Example 9; in S1, stir and mix at 1200 r / min for 17 min, then add antigorite fiber and continue to stir for 42 min; in S2, stir and mix at 140±2 r / min for 22 min and continue to stir and mix at 285±3 r / min for 53 min; in S8, place the wrapped microfoam composite block in a curing box at 90 °C for 28 d. The remaining steps are the same as those in Example 3.

[0137] Perform performance tests on a kind of ferrous tailings-based composite heat-insulating and energy-saving wall material prepared in Examples 1-5 and Comparative Examples 1-9 of the present invention. With reference to the engineering construction standard JG / T 266-2011 (foamed concrete), the specific standards are shown in Tables 2-5, and the test results are shown in Table 6.

[0138] Table 2 Dry density and thermal conductivity of foamed concrete

[0139]

[0140] Table 3 Strength grade (compressive) of foamed concrete

[0141]

[0142] Table 4 Water absorption rate of foamed concrete

[0143]

[0144] Table 5 Allowable deviation of dimensions of foamed concrete products

[0145] Project Name Index Length ±4mm Width ±2mm Height ±2mm

[0146] Table 6 Performance test results of the siderite tailings-based composite thermal insulation and energy-saving wall materials in the examples and comparative examples of the present invention

[0147]

[0148] Continued Table 6

[0149]

[0150]

[0151] Continued Table 6

[0152]

[0153] As can be seen from Table 6, among the performance test results of the siderite tailings-based composite thermal insulation and energy-saving wall materials prepared in Examples 1-5 of the present invention, all indicators have met the requirements of the building industry standard JG / T 266-2011, and the performance is relatively excellent. In particular, the thermal conductivity coefficients are all smaller than the minimum value of foam concrete, with excellent heat insulation effect. Moreover, the dry density in the examples is between A03 and A06, and the dry density is relatively small.

[0154] The thermal conductivity coefficients of Examples 1, 2, 3, 4, and 5 of the present invention are all much lower than the minimum thermal conductivity coefficient in the standard. The thermal conductivity coefficient of Example 3 is the smallest, and the two indicators of dry density and thermal conductivity coefficient of the 5 examples are excellent. The strengths of Examples 1, 2, 3, 4, and 5 are all higher than the C15 grade. Among them, the strengths of Examples 3, 4, and 5 are higher than the C20 grade in the standard, and the strength of Example 3 is the highest. The water absorption rates of Examples 1, 2, 3, 4, and 5 are all lower than the minimum value in the standard, and the water absorption rate of Example 4 is the lowest; the flexural strength of the examples is between 2.35 and 2.81 MPa, with excellent flexural performance, indicating that the prepared materials have small deformability and high strength.

[0155] Among the performance test results of the siderite tailings-based composite thermal insulation and energy-saving wall materials prepared in Comparative Examples 1-9 of the present invention, most of the indicators of the prepared materials have not met the requirements of the building industry standard JG / T 266-2011, and the relative performance is poor.

[0156] The main reasons for Comparative Examples 1 and 9 are that the dosages of each component in the formula exceed the range of the optimal formula, resulting in unbalanced ratio, incomplete reaction, and loose interpenetrating network structure of the formed silicon-aluminum inorganic polymer and hydrated gel. The roles of each component in the formula are not fully exerted. Therefore, the performance of the finally prepared siderite tailings-based composite thermal insulation and energy-saving wall materials is poor. Although the stirring speed in S1 is increased, the stirring time is prolonged, and the curing temperature in S8 is increased at the same time, its strength and dimensional stability still decrease.

[0157] The properties of the ferroan tailings-based composite heat-insulating and energy-saving wall materials prepared in Comparative Example 2 do not meet the standards. In particular, the strength decreases significantly. The main reason is that no antigorite fiber is added, which causes the prepared materials to lose the reinforcing effect of antigorite fiber and the filling and strengthening of fine cracks in the foam wall. Therefore, the strength is extremely low, further leading to deterioration of other properties. Even if the stirring speed in S5 is increased and the stirring time is prolonged, the strength, water absorption rate, and dimensional stability do not reach optimal values.

[0158] The properties of the ferroan tailings-based composite heat-insulating and energy-saving wall materials prepared in Comparative Example 3 do not meet the standards. The main reason is that no calcium diethylenetriamine pentamethylene phosphonate and magnesium formate are added. The addition of these two components can promote the dissolution and full dispersion and contact of various reaction ions in the raw materials. The absence of these two components greatly weakens the degree of full reaction of each component in the raw materials, resulting in a significant reduction in the amounts of both the silicon-aluminum inorganic polymer and the hydrated gel finally formed. A large amount of unreacted substances are loosely piled up, making the properties of the final materials extremely poor. Although the stirring speed, stirring time, and ultrasonic time in S1 and S6 are adjusted simultaneously, the ideal effect is not achieved.

[0159] The properties of the ferroan tailings-based composite heat-insulating and energy-saving wall materials prepared in Comparative Example 4 do not meet the standards. The main reason is that no calcium oxide is added, resulting in a lack of calcium proportion in the reactants and a significant reduction in the amount of hydrated gel formed. Secondly, due to the absence of calcium oxide, the high-temperature aging of the reaction is lost, leading to insufficient reaction and thus deterioration of the properties of the final product in all aspects. At the same time, the stirring time in S5 and the curing temperature in S8 are changed, and none of the properties reach optimal values.

[0160] The properties of the ferroan tailings-based composite heat-insulating and energy-saving wall materials prepared in Comparative Example 5 do not meet the standards. The main reason is that no composite foam stabilizer of calcium stearate and hydroxypropyl methylcellulose is added, resulting in uneven foam size, reduced closed-cell rate, and poor foam stability, leading to deterioration of the strength, heat insulation performance, and dimensional stability of the final product. The stirring and ultrasonic times in S6 are adjusted, but the optimal effect is not achieved.

[0161] The properties of the ferroan tailings-based composite heat-insulating and energy-saving wall materials prepared in Comparative Example 6 do not meet the standards. The main reason is that no complexing agent nitrilotriacetic acid trisodium is added, resulting in ineffective bonding of cations in the silicon-aluminum inorganic polymer and the hydrated gel, thus reducing the stability of the final interpenetrating network structure. The stirring and ultrasonic times in S5 and S6 are adjusted, but the effect is not good.

[0162] The properties of the ferroan tailings-based composite heat-insulating and energy-saving wall materials prepared in Comparative Example 7 do not meet the standards. In particular, the water absorption rate increases. The reason is that no water reducing agent 2-methyl-2,4-pentanediol is added, resulting in poor hydrophobicity of the prepared materials. The stirring speed and time in S1 and the ultrasonic time in S4 are adjusted, and all indicators are still poor.

[0163] The performance of the ferruginous tailings-based composite thermal insulation and energy-saving wall material prepared in Comparative Example 8 does not meet the standards. In particular, its thermal conductivity is relatively large, and the heat insulation effect of the material is extremely poor. The main reason is that the ultrasonic micro-foam preparation technology is not adopted, but conventional stirring and dispersion are used, resulting in relatively large foams and a reduced closed-cell rate. When heat is transferred through the prepared material, there is a lack of multiple layers of obstacles from a large number of closed-cell micro-foam walls, thus leading to a deteriorated heat insulation effect. At the same time, the impedance and dispersion effects of a large number of micro-foam walls on pressure and torque are missing, resulting in a sharp drop in the compressive and flexural strengths, and the geometric dimension stability also deteriorates. By changing the stirring speed and time in S4 and S6, the performance indexes of the prepared material are still poor.

[0164] In summary, it can be seen that the performance of the composite micro-foam thermal insulation and energy-saving wall material based on ferruginous tailings as the basic raw material designed in the present invention far exceeds the index requirements of foam concrete, and it can replace foam concrete as a thermal insulation and energy-saving wall material. At the same time, it improves the problems of low strength, easy shrinkage and cracking, poor durability, and poor heat insulation performance of foam concrete. At the same time, it greatly reduces the production cost of thermal insulation and energy-saving wall materials, and avoids the disadvantages of high energy consumption, high pollution, and high carbon emissions of the main cementitious material - cement in the production process of foam concrete. It can consume a large amount of the stockpiling of ferruginous tailings and the resulting environmental damage and ecological safety problems, and alleviate the problem of difficult stockpiling and treatment of ferruginous tailings in ferruginous ore enterprises, thereby ensuring the normal operation of ferruginous ore mining enterprises.

[0165] Each embodiment in this specification is described in a related manner. For the same and similar parts between each embodiment, reference can be made to each other. The key point described in each embodiment is the difference from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and reference can be made to the partial description of the method embodiment for the related parts.

[0166] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A composite thermal insulation and energy-saving wall material based on siderite tailings, characterized in that: The components and mass parts included are:

2. The siderite tailings-based composite thermal insulation and energy-saving wall material according to claim 1, characterized in that: The alkaline activator is prepared from water glass, sodium hydroxide and deionized water.

3. The siderite tailings-based composite thermal insulation and energy-saving wall material according to claim 1, characterized in that: The micro foam is prepared from a composite foaming agent and deionized water in a mass ratio of 1.2:

100.

4. The siderite tailings-based composite thermal insulation and energy-saving wall material according to claim 1, characterized in that: The components and weight percentages of the admixture are as follows:

5. The siderite tailings-based composite thermal insulation and energy-saving wall material according to claim 1, characterized in that: The particle size of the siderite tailings is less than 325 meshes, the particle size of the metakaolin is 800 meshes, the length of the brucite fiber is 4-12 mm, the diameter is 15-22 μm, and the particle size of the calcium oxide is 800 meshes.

6. The siderite tailings-based composite thermal insulation and energy-saving wall material according to claim 2, characterized in that: The alkaline activator is prepared by mixing water glass with a modulus of 3.0 and a sodium hydroxide aqueous solution with a mass concentration of 35% to a modulus of 1.1 to 1.

3.

7. The siderite tailings-based composite thermal insulation and energy-saving wall material according to claim 3, characterized in that: The composite foaming agent is prepared from cocamidopropyl betaine and sodium α-olefin sulfonate in a mass ratio of 3:

1.

8. The method for preparing a siderite tailings-based composite thermal insulation and energy-saving wall material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, add deionized water, calcium diethylenetriamine penta (methylenephosphonate) and magnesium formate into a disperser, stir and mix, then add brucite fiber and continue stirring to obtain a mixed solution A; S2, adding the mixed solution A into a planetary cement mortar mixer, adding the siderite tailings, stirring and mixing, and then adding the metakaolin, continuing to stir and mix, to obtain a mixed material B; S3, prepare a sodium hydroxide aqueous solution, age it, and then compound it with water glass to obtain an alkali activator; S4, adding the composite foaming agent and deionized water into an ultrasonic micro-foam machine, stirring and mixing to obtain micro-foam; S5. Add mixture B and alkali activator in a cement slurry mixer according to proportion, stir and mix, and then add calcium oxide, stir and mix to obtain slurry C; S6, adding an admixture to slurry C, stirring and mixing, then adding microfoam, continuing to stir and mix, and then transferring all to an ultrasonic microfoam machine for dispersion to obtain microfoam slurry D; S7, injection molding the micro-foam slurry D, leaving it to stand to obtain a micro-foam composite material block, and sealing and wrapping it with a plastic film; S8. Place the wrapped micro-foam composite material block in a curing box for curing to obtain a siderite tailings-based composite thermal insulation and energy-saving wall material.

9. The method for preparing a siderite tailings-based composite thermal insulation and energy-saving wall material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Add deionized water, calcium diethylenetriamine penta (methylenephosphonate) and magnesium formate into a disperser, stir and mix at 800-1000 r / min for 10-15 min, then add brucite fiber and continue stirring for 30-40 min to obtain a mixed solution A; S2. Add the mixed solution A into a planetary cement mortar mixer, add the siderite tailings, stir and mix at 140±2r / min for 15-20min, then add the metakaolin, continue stirring and mixing at 285±3r / min for 40-50min to obtain a mixed material B; S3, prepare a 35% mass solubility sodium hydroxide aqueous solution, age it for 12 to 16 hours, and then compound it with water glass, adjust the water glass modulus to 1.1 to 1.3, and prepare an alkali activator; S4, adding the composite foaming agent and deionized water into an ultrasonic micro-foam machine, stirring and mixing at 25KHz for 3 to 5 minutes to obtain micro-foam; S5. Add mixture B and alkali activator in proportion to a cement slurry mixer and stir for 3 to 5 minutes, then add calcium oxide and continue stirring for 5 to 8 minutes to obtain slurry C. S6. Add an admixture to slurry C, stir and mix for 6 to 8 minutes, then add microfoam, continue to stir and mix for 4 to 6 minutes, and then transfer all to an ultrasonic microfoam machine, disperse at 40KHz for 20 to 40 seconds to obtain microfoam slurry D; S7, injection molding the micro-foam slurry D, placing it at 25° C. for 24 hours to obtain a micro-foam composite material block, and sealing and wrapping it with a plastic film; S8. Place the wrapped micro-foam composite material block in a curing box at 60-80° C. for curing for 28 days to obtain a siderite tailings-based composite thermal insulation and energy-saving wall material.

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