A method for preparing environmentally friendly building panels using solid waste

Abstract

The present invention discloses a system and method for producing environmentally friendly building panels using solid waste. This system utilizes bulk industrial solid waste, such as coal gangue of varying composition from the coal mining industry, calcium carbide slag from the chemical industry, aluminum ash from the metallurgical industry, and desulfurized gypsum and fly ash from the power and steel industries. Through raw material grinding, homogenization, sintering, and clinker grinding, a matrix material is produced. This matrix material serves as the core material, supplemented with activated carbon, short fibers, sawdust, and other materials to form a slurry. High-performance, environmentally friendly building panels are produced using specific molding and curing processes. This process uses near-zero-cost solid waste as raw material, replacing high-quality mineral resources, significantly promoting environmental protection and energy conservation and consumption reduction.

Description

Technical Field

[0001] The present invention belongs to the field of solid waste resource utilization and environmental protection, and specifically relates to a system and method for preparing environmentally friendly building panels using solid waste. Background Art

[0002] With the rapid advancement of my country's industrialization process, a large amount of solid waste from mining, metallurgy, electricity, chemical industry and other industries has occupied more and more precious land resources and caused huge pollution to the environment. The "13th Five-Year Plan" lists coal gangue, tailings, smelting slag, red mud, by-product gypsum and fly ash as the main targets of solid waste treatment.

[0003] Foam concrete, also known as foamed cement, is a lightweight porous concrete product made by preparing a foaming agent aqueous solution into foam, then adding the foam to a slurry made of cement-based binder, aggregate, admixture, additive and water, and mixing, pouring and naturally curing. It has the following advantages: compressive strength and aging resistance; good lightness; good sound insulation; good high temperature resistance; can improve the stability and life of the insulation layer; good environmental performance; good thermal insulation, which is 20-30 times that of ordinary cement; simple construction; good moisture resistance; good bonding; fast construction speed; good integrity; anti-seepage effect; and certain fire resistance.

[0004] Due to its excellent thermal insulation and sound absorption properties, foamed concrete is widely used in roofing and floor insulation, as well as as an excellent sound-absorbing material. However, foamed concrete still suffers from high thermal conductivity and poor insulation, making it incomparable to organic panels. Furthermore, foamed concrete is not as strong as ordinary concrete, making it difficult to use in certain applications requiring high strength. For example, prefabricated buildings using steel and concrete structures place high demands on the performance of building panels, requiring not only excellent thermal insulation and sound insulation properties but also high strength to extend the service life of the prefabricated building.

[0005] As people's quality of life gradually improves, they have higher requirements for the environmental friendliness and quality of decoration products. However, there is a lot of formaldehyde released in decoration materials, which is harmful to the human body. Summary of the Invention

[0006] In response to the technical problems existing in the above-mentioned prior art, the present invention aims to provide a system and method for producing environmentally friendly building panels using solid waste. In this method, the raw materials for producing the building panels are primarily derived from desulfurization products from power plants and the metallurgical industry, coal gangue from the coal mining industry, and calcium carbide slag from chemical plants, resulting in low raw material costs. This method not only recycles industrial solid waste, thus avoiding environmental pollution, but also produces high-performance building panels that can be used as interior and exterior building walls, decorative materials, and more.

[0007] In order to solve the above technical problems, the technical solution of the present invention is:

[0008] A system for preparing environmentally friendly building boards using solid waste includes a crusher, a dryer, a pulverizer, a homogenizer, a rotary kiln, and a batching device. After the coal gangue is crushed by the crusher, it is conveyed into the dryer for drying. Desulfurized gypsum, aluminum ash, and carbide slag are conveyed to the dryer for drying. The dried materials are mixed according to a set proportion and ground in a pulverizer. After being conveyed to the homogenizer for homogenization, they are conveyed to a rotary kiln for calcination. The ground coal powder is added to the rotary kiln and burned to provide heat to obtain a base material. The base material, activated carbon, additives, and water are mixed in a certain proportion in the batching device, and the obtained mixture is formed in a mold to obtain a surface layer. The base material, wood chips, additives, and water are mixed in a certain proportion in the batching device, and the obtained mixture is formed and cured on the surface layer to obtain a finished board product.

[0009] The system utilizes industrial solid wastes such as desulfurization gypsum, aluminum ash, carbide slag and coal gangue to produce high-water filling materials, replacing the use of a large amount of high-quality mineral resources. At the same time, it avoids the occupation and pollution of land resources by solid waste and realizes the comprehensive resource utilization of bulk industrial solid waste.

[0010] The base material prepared from industrial solid waste is combined with activated carbon and other additives to produce boards that can not only absorb harmful gases such as formaldehyde generated during decoration, but also the activated carbon is loose and porous, which reduces the density of the boards. The prepared boards have the advantages of being light, having good thermal insulation properties and high strength.

[0011] The system is set up so that the matrix material can be obtained after each component is ground, homogenized and calcined.

[0012] Preferably, the flue gas outlet of the rotary kiln is connected to a waste heat recovery device, and the flue gas discharged from the rotary kiln heats the water in the waste heat recovery device, and the obtained high-temperature steam is introduced into the dryer as a heating medium.

[0013] The use of waste heat recovery equipment can recover a large amount of heat contained in the flue gas, avoiding heat waste. At the same time, it heats and dries the materials, realizes waste heat utilization, and reduces energy consumption.

[0014] A method for preparing environmentally friendly building panels using solid waste comprises the following steps:

[0015] 1) Grinding the coal gangue and drying it, and drying the desulfurized gypsum, aluminum ash and carbide slag;

[0016] 2) Mix the dried materials according to the set ratio, grind and homogenize;

[0017] 3) The ground and homogenized material is conveyed into a rotary kiln for calcination at a temperature of 1250-1300° C. for 60-80 min to obtain a matrix material;

[0018] 4) mixing the base material with activated carbon, sawdust, short fibers, additives, and water in a certain proportion, paving the surface layer and the main body layer, and curing the mixture to obtain an environmentally friendly building board; the additives include a retarder and a foaming agent, and the mass ratio of the retarder to the foaming agent is 0.5-2;

[0019] The mass ratio of desulfurized gypsum, aluminum ash, carbide slag and coal gangue is: 12-15:15-20:20-30:25-30;

[0020] In the surface layer, the mass ratio of base material, activated carbon, additive and water is: 35-43:11-16:1.0-1.8:30-35;

[0021] In the main layer, the mass ratio of the base material, wood chips, short fibers, additives and water is: 35-43:20-30:3-8:1.0-1.8:30-35.

[0022] This method utilizes industrial solid wastes such as coal gangue, desulfurization gypsum, aluminum ash and carbide slag instead of high-quality mineral resources to prepare high-performance environmentally friendly building panels, avoiding the occupation and pollution of land resources by solid waste, realizing the comprehensive resource utilization of bulk industrial solid waste, and greatly reducing the preparation cost of high-performance building panels.

[0023] When the mass ratio of desulfurized gypsum, aluminum ash, carbide slag and coal gangue is 12-15:15-20:20-30:25-30, the calcination temperature is 1250-1300℃, and the calcination time is 60-80min, the chemical composition of the prepared matrix material is shown in Table 1:

[0024] Table 1 Chemical composition of matrix materials

[0025] chemical composition <![CDATA[SiO2]]> <![CDATA[Al2O3]]> CaO <![CDATA[SO3]]> <![CDATA[Fe2O3]]> content 5～14 34～41 35～43 8～16 1～2.5

[0026] When this matrix material is used as the core material and supplemented with a certain mass ratio of activated carbon, water, sawdust, short fibers, retarder and foaming agent, there is no need to add fly ash, silica fume and other substances. The prepared building panels still have high strength and can meet the load-bearing requirements of prefabricated buildings.

[0027] Moreover, a certain amount of activated carbon is added to the base material. The activated carbon can adsorb harmful gases such as formaldehyde in the air. It is a new type of environmentally friendly board.

[0028] At the same time, because the activated carbon is loose and porous, and a large amount of light materials such as sawdust are added to the board, the prepared foamed building board not only has good thermal insulation performance, but also has the advantages of low density and light weight, which is especially suitable for use in prefabricated buildings.

[0029] The method for preparing the environmentally friendly building board comprises the following steps:

[0030] First, the matrix material, activated carbon, water and additives are mixed into slurry according to the ratio of 35-43:11-16:1.0-1.8:30-35, and the slurry density is controlled at 1.2-1.5g / cm 3 , and spread a material layer with a thickness of 1-2 mm on the mold to obtain a surface layer;

[0031] Then, the base material, wood chips, fiber, additives and water are mixed in the ratio of 35-43:20-30:3-8:1.0-1.8:30-35 to prepare a slurry. The density of the slurry is controlled at 0.9-1.2 g / cm 3 , spread the slurry on the surface layer and pave it to a set thickness to obtain the main layer;

[0032] Finally, the prepared wet board is cured for 24-48 hours to obtain the required board.

[0033] Preferably, in step 3), the main chemical composition of the matrix material is: SiO2 5-14%, Al2O3 34-41%, CaO 35-43%, SO3 8-16%, and Fe2O3 1-2.5%.

[0034] Preferably, in step 3), the matrix material has calcium sulfoaluminate (3CaO·3Al2O3·CaSO4) and dicalcium silicate (2CaO·SiO2) as main mineral phases, accounting for 30-50% and 35-55% respectively.

[0035] Preferably, the mass percentage of the retarder in the base material is 0.5%-1.0%.The retarder is an additive that reduces the cement hydration rate and hydration heat and prolongs the setting time.

[0036] Preferably, the foaming agent comprises 0.5% to 1.0% by mass of the base material. The foaming agent is a substance that creates pores in the building board. This foaming agent is particularly suitable for the prepared base material, resulting in small, rounded pores with uniform pore distribution. This results in improved thermal insulation, sound insulation, and strength for the prepared building board.

[0037] Preferably, the length of the short fibers is 20-50 mm. Experimental verification shows that short fibers within this length range are particularly effective in improving the strength of building boards.

[0038] There is no particular requirement for the type of staple fibers, which may be commonly used synthetic staple fibers such as nylon, polyester, aramid, and glass fiber, or natural fibers such as cellulose fiber.

[0039] Preferably, step 3) further includes utilizing the high-temperature flue gas discharged from the rotary kiln to heat water to obtain high-temperature steam, and using the high-temperature steam to heat and dry the material.

[0040] It can effectively recover the waste heat in high-temperature flue gas, avoid heat waste, save energy consumption and reduce production costs.

[0041] The strong sulphoaluminate-based environmentally friendly building board prepared by the preparation method.

[0042] The beneficial technical effects of the present invention are:

[0043] (1) The raw materials are taken from bulk industrial solid waste, and the cost is almost zero. This not only avoids the occupation of land resources, but also replaces a large amount of high-quality mineral resources, thus realizing the comprehensive resource utilization of bulk industrial solid waste.

[0044] (2) Since the temperature required for calcining the matrix material is between 1250 and 1300 °C, which is 100-200 °C lower than the temperature for calcining silicate cement, waste heat recovery equipment is installed at the tail of the rotary kiln to dry the raw materials entering the kiln, which greatly reduces the use of energy and can fundamentally achieve energy saving and consumption reduction.

[0045] (3) Environmentally friendly building panels have excellent performance and can absorb harmful gases such as formaldehyde in the environment. At the same time, they have good thermal insulation performance, sound insulation performance and load-bearing strength. They can be used alone for interior and exterior wall construction and decoration, and can also be used as the basic wall material for integrated buildings, which is in line with the country's policy of vigorously developing residential industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the process flow of the method of the present invention. DETAILED DESCRIPTION

[0047] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0048] Example 1

[0049] Aluminum ash, carbide slag, and desulfurized gypsum are dried to a moisture content of 5% or less. Coal gangue is crushed and mixed with aluminum ash, carbide slag, and desulfurized gypsum. Based on solid matter, the coal gangue accounts for 25 parts by weight, the desulfurized gypsum accounts for 13 parts by weight, the carbide slag accounts for 20 parts by weight, and the aluminum ash accounts for 17 parts by weight. After grinding and homogenizing, the components are then transferred to a rotary kiln for calcination at a temperature of 1250°C for 70 minutes to produce the matrix material.

[0050] Take 35 parts by weight of base material, add 11 parts by weight of activated carbon, 1 part by weight of a mixture of retarder and foaming agent, and then add 30 parts by weight of industrial water to prepare a slurry for surface paving. The thickness of the surface layer is 1.5 mm.

[0051] Take 20 parts by weight of base material, 21 parts by weight of sawdust, 4 parts by weight of short fibers, 1.2 parts by weight of a mixture of a retarder and a foaming agent, and then add 32 parts by weight of industrial water to prepare a slurry, and then lay the main layer. After forming, send it into a primary curing kiln with a temperature of 20°C and a humidity of 98% for curing for 24 hours, and then demold it. The demolded board is sent to a secondary curing kiln with a temperature of 25°C and a humidity of 98% for curing for 48 hours to make a finished board.

[0052] Example 2

[0053] Aluminum ash, carbide slag, and desulfurized gypsum are dried to a moisture content of 5% or less. Coal gangue is crushed and mixed with aluminum ash, carbide slag, and desulfurized gypsum. Based on solids, the coal gangue accounts for 30 parts by weight, desulfurized gypsum accounts for 15 parts by weight, carbide slag accounts for 30 parts by weight, and aluminum ash accounts for 20 parts by weight. After grinding and homogenizing, the components are then transferred to a hollow kiln for calcination at a temperature of 1300°C for 70 minutes.

[0054] Take 39 parts by weight of base material, add 13 parts by weight of activated carbon, 1.1 parts by weight of a mixture of retarder and foaming agent, and then add 34 parts by weight of industrial water to prepare a slurry for surface paving. The thickness of the surface layer is 1.7 mm.

[0055] Take 35 parts by weight of base material, 25 parts by weight of sawdust, 6 parts by weight of short fibers, 1.4 parts by weight of a mixture of retarder and foaming agent, and then add 34 parts by weight of industrial water to prepare a slurry for paving the main layer.

[0056] After forming, it is sent to a primary curing kiln with a temperature of 20°C and a humidity of 98% for curing for 24 hours, and then demoulded. The demoulded board is sent to a secondary curing kiln with a temperature of 25°C and a humidity of 98% for curing for 48 hours to form a finished product.

[0057] Example 3

[0058] Aluminum ash, carbide slag, and desulfurized gypsum are dried to a moisture content of 5% or less. Coal gangue is crushed and mixed with aluminum ash, carbide slag, and desulfurized gypsum. Based on solids, the coal gangue accounts for 27 parts by weight, desulfurized gypsum accounts for 12 parts by weight, carbide slag accounts for 20 parts by weight, and aluminum ash accounts for 17 parts by weight. After grinding and homogenizing, the components are then calcined in a hollow kiln at a temperature of 1300°C for 80 minutes.

[0059] Take 41 parts by weight of base material, add 14 parts by weight of activated carbon, 1.6 parts by weight of a mixture of retarder and foaming agent, and then add 30 parts by weight of industrial water to prepare a slurry, and pave the surface layer with a thickness of 1 mm.

[0060] Take 40 parts by weight of base material, 30 parts by weight of sawdust, 8 parts by weight of short fibers, 1.8 parts by weight of a mixture of retarder and foaming agent, and then add 30 parts by weight of industrial water to prepare a slurry for paving the main layer.

[0061] After forming, it is sent to a primary curing kiln with a temperature of 20°C and a humidity of 98% for curing for 24 hours, and then demoulded. The demoulded board is sent to a secondary curing kiln with a temperature of 25°C and a humidity of 98% for curing for 48 hours to form a finished product.

[0062] The properties of the finished panels prepared in Examples 1-3 are shown in Table 2.

[0063] Table 2 Measured values of physical indicators of high performance building panels

[0064]

[0065]

[0066] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A method for preparing environmentally friendly building panels using solid waste, characterized by: include: 1) Crush the coal gangue and dry it, and also dry the desulfurized gypsum, aluminum ash and carbide slag; 2) Mix various dried materials according to the set ratio, grind and homogenize; 3) The ground and homogenized material is transported into a rotary kiln for calcination at a temperature of 1250-1300°C for 60-80 minutes to obtain the matrix material; 4) Mixing the base material with activated carbon, sawdust, short fibers, additives, and water in a certain proportion, paving the surface layer and the main body layer, and curing the mixture to produce an environmentally friendly building board; the additives include a retarder and a foaming agent, and the mass ratio of the retarder to the foaming agent is 0.5-2; The mass ratio of desulfurized gypsum, aluminum ash, carbide slag and coal gangue is: 12-15:15-20:20-30:25-30; In the surface layer, the mass ratio of base material, activated carbon, additive and water is: 35-43:11-16:1.0-1.8:30-35; In the main layer, the mass ratio of base material, wood chips, short fibers, additives and water is: 35-43:20-30:3-8:1.0-1.8:30-35; The method is implemented by the following devices, including a crusher, a dryer, a pulverizer, a homogenizing device, a rotary kiln and a batching device. After the coal gangue is crushed by the crusher, it is transported to the dryer for drying, and the desulfurized gypsum, aluminum ash and carbide slag are transported to the dryer for drying; the dried materials are mixed according to a set proportion and ground in a pulverizer, and then transported to a homogenizing device for homogenization, and then transported to a rotary kiln for calcination. The ground coal powder is added to the rotary kiln, and combustion provides heat to obtain a base material; the base material, activated carbon, additives and water are mixed in a certain proportion in the batching device, and the obtained mixture is formed in a mold to obtain a surface layer; the base material, sawdust, additives and water are mixed in a certain proportion in the batching device, and the obtained mixture is formed and cured on the surface layer to obtain a finished board product.

2. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: The flue gas outlet of the rotary kiln is connected to a waste heat recovery device. The flue gas discharged from the rotary kiln heats the water in the waste heat recovery device, and the obtained high-temperature steam is introduced into the dryer as a heating medium.

3. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: In step 3), the main chemical composition of the matrix material is: SiO2 5-14%, Al2O3 34-41%, CaO 35-43%, SO3 8-16%, and Fe2O3 1-2.5%.

4. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: In step 3), the matrix material has calcium sulfoaluminate and dicalcium silicate as main mineral phases, accounting for 30-50% and 35-55% respectively.

5. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: The mass percentage of the retarder to the base material is 0.5%-1.0%.

6. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: The mass percentage of the foaming agent in the base material is 0.5%-1.0%.

7. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: The length of the short fibers is 20-50 mm.

8. The method for preparing environmentally friendly building boards using solid waste according to claim 1, characterized in that: Step 3) also includes the step of utilizing the high-temperature flue gas discharged from the rotary kiln to heat water to obtain high-temperature steam, and using the high-temperature steam to heat and dry the material.

9. An environmentally friendly building board prepared by the method according to any one of claims 1 to 8.

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