A solidified body for molten fly ash from municipal solid waste incineration and its preparation method

Abstract

This invention belongs to the field of hazardous waste disposal, specifically relating to a method for preparing a solidified fly ash incineration furnace for molten disposal of municipal solid waste. The fly ash is obtained from three-stage countercurrent rinsing. Fluxing materials, pore-forming materials, and cementing materials are then compounded and homogenized using a forced mixer. The homogenized fly ash composite is then fed to a brick press and formed into cubes under mechanical pressure. A through-hole is then drilled in the center of each cube to obtain a solidified wet fly ash body. This wet solidified fly ash body is then placed in a sample library and allowed to stand for 3 days to obtain a dried and hardened solidified fly ash body. This invention provides a steam pressure relief channel during the high-temperature melting process, solving the problem of bursting, improving heat exchange, and increasing melting efficiency. While providing sufficient cold strength to the solidified body, it reduces solidification costs, achieving efficient and safe disposal of fly ash.

Description

Technical Field

[0001] This invention relates to the field of hazardous waste disposal, specifically to a solidified body for the molten fly ash disposal of municipal solid waste incineration and its preparation method. Background Technology

[0002] With the nation's increasing emphasis on environmental protection and the construction of ecologically livable environments, more and more cities are joining the ranks of "zero-waste cities." This is not only a powerful tool for deepening the comprehensive management reform of solid waste at the city level, but also an important measure to improve the level of ecological civilization and build a beautiful China.

[0003] Municipal solid waste incineration power generation produces a byproduct—fly ash (hereinafter referred to as fly ash). Due to its high content of heavy metals, chlorides, and dioxins, it is defined as hazardous waste. Furthermore, its proportion of total industrial hazardous waste is increasing year by year. High-temperature melting is a recognized safe disposal method for hazardous waste both domestically and internationally. The resulting vitrified product can be further processed to produce aggregates or mineral admixtures, achieving resource utilization of waste. For natural gas melting furnaces or resistance melting furnaces, municipal solid waste incineration fly ash cannot be directly fed into the furnace. It usually needs to be washed and dechlorinated first, reducing the chloride ion content to about 1%. Then, the washed fly ash is filtered, dried, chemically formulated, and solidified into a certain shape before being fed into the melting furnace to obtain the vitrified product. The formulation and structural morphology of the solidified body directly affect the melting effect and disposal volume. The solidified body should have a certain cold strength to ensure it does not break into powder during feeding. Currently, both domestically and internationally, artificial pelletizing or adding silicate cement is commonly used as the cementing material for the fly ash solidified body. Because the solidified body contains a certain amount of moisture, under high-temperature conditions, the water inside the solidified body transforms into water vapor. When the pressure exceeds the cold strength of the solidified body, it will burst. Under negative pressure inside the furnace, the broken pieces will scatter in all directions, and some pieces may even enter the flue gas. On the one hand, this affects the melting effect; on the other hand, it threatens the safe operation of subsequent flue gas treatment facilities. Meanwhile, silicate cement is a high-carbon-emission cementing material, with carbon emissions reaching 616 kg / t per ton of silicate cement produced. Therefore, in order to improve fly ash melting efficiency and enhance disposal safety, there is an urgent need for a process for preparing solidified bodies for municipal solid waste incineration fly ash melting and disposal that combines burst resistance, cold strength, and low-cost bonding. Summary of the Invention

[0004] The main objective of this invention is to provide a solidified body for the molten treatment of municipal solid waste incineration fly ash and its preparation method. The technical problem to be solved is to ensure that the solidified body contains both interconnected and closed pores. On one hand, this provides a steam pressure relief channel during the high-temperature melting process, solving the problem of bursting; on the other hand, the interconnected pores enhance heat exchange and improve melting efficiency. Simultaneously, a novel cementitious material is developed to replace silicate cement, providing sufficient cold strength to the solidified body while reducing solidification costs, thus achieving efficient and safe disposal of fly ash.

[0005] The specific technical solution of this invention is: a solidified body for the melting and treatment of fly ash from municipal solid waste incineration, characterized in that it comprises the following substances by mass percentage:

[0006] Washed fly ash: 75-80%;

[0007] Fluxing material: 12-17%;

[0008] Hole-forming material: 1-2%;

[0009] Cementing material: 4-7%;

[0010] Preferably, the fly ash is a three-stage countercurrent rinsing fly ash, which has a moisture content of 8% to 10% after being dried by a circulating fluidized bed, and has a chloride ion content of ≤1.0%.

[0011] Preferably, the fluxing material is silica sand powder, calcium fluoride sludge and boric acid, wherein the ratio of silica sand powder: calcium fluoride sludge: boric acid is 75-80:10-15:5-10;

[0012] Preferably, the hole-forming material is crop straw, wood shavings and waste polystyrene granules, wherein the ratio of crop straw: wood shavings: waste polystyrene granules is 40-50: 45-50: 5-10;

[0013] Preferably, the cementing material is ultrafine fly ash, fluorogypsum and aluminoferrite cement, wherein the ratio of ultrafine fly ash: fluorogypsum: aluminoferrite cement is 70-75: 5-10: 15-20.

[0014] Furthermore, the silica sand powder is river floodplain sedimentary silt with a silica content ≥85%, primarily used to adjust the alkalinity coefficient of fly ash and lower the melting temperature. The boric acid is industrial-grade boric acid with an H3BO3 content ≥99%. Its main function is to accelerate silicate reactions, reduce viscosity, and synergistically assist melting with calcium fluoride sludge, achieving a synergistic melting effect greater than the sum of its parts (1+1>2), thus improving melting efficiency.

[0015] Furthermore, calcium fluoride sludge is a type of sludge formed from fluoride-containing wastewater discharged during the production processes of fluorine-containing, specialty glass, and photovoltaic enterprises, after coagulation / calcium salt precipitation treatment. The calcium fluoride content is ≥60%, and the silica content is ≥5%. The main function of calcium fluoride is to disrupt the glass network structure, entering the structure of the molten glass phase in fly ash to form a solid solution, thereby lowering the melting temperature and improving melting efficiency.

[0016] Furthermore, the crop straw is pulverized, with a length of 30–50 mm and a diameter of 0.8–1.0 mm. The purpose of pulverizing the crop straw is twofold: firstly, it forms an interwoven network structure within the solidified body. After entering the melting furnace, the straw is ashed and burned at a high temperature of 1200–1300℃, creating interconnected pores within the solid structure that serve as channels for water vapor pressure relief. Secondly, it acts as a reinforcing agent, enhancing the cold strength and resistance to breakage of the solidified body.

[0017] Wood shavings are long strips, 30–50 mm in length and 1.0–2.0 mm in width. These long strips work synergistically with crop straw to form an interwoven network structure within the consolidated mass. During ashing and combustion in a melting furnace at 1200–1300°C, they create larger channels, providing pressure relief pathways for water vapor. Simultaneously, they also act as a toughening and reinforcing agent, similar to fibers, improving the consolidated mass's resistance to impact damage and preventing it from crumbling into powder during the feeding process.

[0018] Waste polystyrene granules are polystyrene granules obtained from the crushing of recycled polystyrene boards, and they are evenly distributed inside the solid structure. Their function is to be ashed and burned in a melting furnace at a high temperature of 1200-1300℃, forming small pores, which again serve the function of relieving water vapor pressure.

[0019] Furthermore, ultrafine fly ash is the coarse ash remaining after screening Grade I and Grade II fly ash, which is processed fly ash obtained by ultrafine grinding, and its specific surface area is 650-700 m². 2 / kg. Its main function is to act as an activating material, which, under the activating action of fluorogypsum and aluminoferrite cement, generates hydration products, binds cement fly ash, fluxing materials, and pore-forming materials together, and gives the solidified body a certain strength, ensuring that it does not break into small pieces during the melting and feeding process.

[0020] Furthermore, fluorogypsum is a byproduct of the production of hydrogen fluoride from sulfuric acid hydrolysis of fluorite, primarily composed of anhydrous calcium sulfate, with a calcium sulfate content ≥85%. The role of fluorogypsum is to synergistically activate ultrafine fly ash with aluminoferrite cement to generate hydration products, thus imparting a certain strength to the solidified body.

[0021] Furthermore, the aluminoferrite cement is an ultrafine aluminoferrite cement with an Fe2O3 content ≥ 6.0% and a specific surface area of ​​600–650 m². 2 / kg. The role of aluminoferrite cement is twofold: firstly, to activate ultrafine fly ash; and secondly, to rapidly develop strength as an early-strength and fast-hardening material, thereby further increasing the cold strength of the consolidated body.

[0022] A method for preparing a solidified body for the molten disposal of fly ash from municipal solid waste incineration includes the following steps:

[0023] (1) The water-washed fly ash, fluxing material, pore-forming material and cementing material are compounded and then mixed and homogenized using a forced mixer. The forced mixer speed is 48 rpm and the mixing time is 180-240s to obtain fly ash composite material.

[0024] (2) The mixed and homogenized fly ash composite material is transported to the brick press and held under mechanical pressure of 20-30t for 5-10s to form a cube with a side length of 50-100mm. Then the cube is moved to the drilling machine and 6-8 through holes with a diameter of 5-6mm are drilled in the middle of the cube to obtain the fly ash consolidated wet body.

[0025] (3) Place the fly ash solidified wet body in a sample library with a humidity of 40% to 60% and let it stand for 3 days to obtain the dry and hardened fly ash solidified body.

[0026] The function of the through holes is twofold: firstly, to provide a pressure relief channel for water vapor formed in the solidified body at high temperatures of 1200–1300℃; and secondly, to increase the heat exchange area and efficiency, accelerate the melting and reconstruction of the fly ash solidified body, shorten the melting time, and improve the melting efficiency.

[0027] Physical and mechanical properties of the dried and hardened fly ash solidified body are randomly tested: the solidified body is dropped vertically from a height of 3m onto the concrete ground, and the sample is observed to see if it is obviously broken (small fragments with sharp edges and cracks are not considered as brokenness). If there is no obvious damage, it is qualified.

[0028] The present invention, by adopting the above technical solution, has the following advantages:

[0029] 1) This invention utilizes interconnected and closed holes to, on the one hand, provide a channel for water vapor to release pressure during the high-temperature melting process of the solidified body, thus solving the problem of cracking. On the other hand, the interconnected holes enhance heat exchange and improve melting efficiency.

[0030] 2) This invention utilizes fluxing materials to lower the melting temperature and improve melting efficiency. The fluxing materials are silica sand powder and calcium fluoride sludge, which are bulk solid wastes, thus realizing the resource utilization of waste. At the same time, the calcium fluoride in the calcium fluoride sludge synergistically assists melting with boric acid, accelerating the formation of eutectic materials and saving energy and reducing consumption.

[0031] 3) This invention develops a novel cementitious material to replace high-carbon silicate cement, which has the characteristics of low-carbon and fast-hardening solid waste. While giving the solidified body sufficient cold strength, it reduces the solidification cost, shortens the cycle, accelerates the preparation efficiency, increases production capacity, and achieves efficient and safe disposal of fly ash.

[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0033] To further illustrate the technical means and effects adopted by the present invention to achieve the intended purpose, the following, in conjunction with preferred embodiments, details the specific implementation, structure, features, and effects of a solidified body for the melting and treatment of municipal solid waste incineration fly ash and its preparation method according to the present invention. Furthermore, specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form.

[0034] Example 1

[0035] A solidified feedstock for the melting and treatment of fly ash from municipal solid waste incineration, characterized in that it comprises the following substances by mass percentage:

[0036] Washed fly ash: 75%;

[0037] Fluxing material: 16%;

[0038] Hole-forming material: 2%;

[0039] Cementing material: 7%;

[0040] Preferably, the fly ash is a three-stage countercurrent rinsing fly ash, which has a moisture content of 8% to 10% after being dried by a circulating fluidized bed, and has a chloride ion content of ≤1.0%.

[0041] Preferably, the fluxing material is silica sand powder, calcium fluoride sludge and boric acid, wherein the ratio of silica sand powder: calcium fluoride sludge: boric acid is 75:15:10;

[0042] Preferably, the pore-forming material is crop straw, wood shavings and waste polystyrene granules, wherein the ratio of crop straw: wood shavings: waste polystyrene granules is 40:50:10;

[0043] Preferably, the cementing material is ultrafine fly ash, fluorogypsum and aluminoferrite cement, wherein the ratio of ultrafine fly ash: fluorogypsum: aluminoferrite cement is 70:10:20.

[0044] The silica sand powder is silt deposited in floodplains, with a silica content ≥85%. The boric acid is industrial-grade boric acid, with an H3BO3 content ≥99%.

[0045] Calcium fluoride sludge is a type of sludge formed from fluoride-containing wastewater discharged during the production processes of fluorine, special glass, and photovoltaic enterprises, after coagulation / calcium salt precipitation treatment. The sludge contains ≥60% calcium fluoride and ≥5% silica.

[0046] The crop straw is shredded crop straw, with a length of 30mm and a diameter of 0.8-1.0mm.

[0047] Wood shavings are long strips of wood chips, 30mm in length and 1.0-2.0mm in width.

[0048] Waste polystyrene particles are polystyrene particles obtained by crushing recycled polystyrene boards, and they are evenly distributed inside the solid structure.

[0049] Ultrafine fly ash is the coarse ash remaining after screening Grade I and Grade II fly ash, which is processed into fly ash through ultrafine grinding. Its specific surface area is 650-700 m². 2 / kg.

[0050] Fluorogypsum is a byproduct mainly composed of anhydrous calcium sulfate obtained from the acid hydrolysis of fluorite to produce hydrogen fluoride, with a calcium sulfate content of ≥85%.

[0051] Ferroaluminate cement is an ultrafine ferroaluminate cement with an Fe2O3 content ≥ 6.0% and a specific surface area of ​​600–650 m². 2 / kg.

[0052] A method for preparing a solidified body for the molten disposal of fly ash from municipal solid waste incineration includes the following steps:

[0053] (1) The water-washed fly ash, fluxing material, pore-forming material and cementing material are compounded and then mixed and homogenized using a forced mixer. The forced mixer speed is 48 rpm and the mixing time is 180s to obtain fly ash composite material.

[0054] (2) The mixed and homogenized fly ash composite material is transported to the brick press and held under 20t mechanical pressure for 10s to form a cube with a side length of 50mm. Then the cube is moved to the drilling machine and 6 through holes with a diameter of 5mm are drilled in the middle of the cube to obtain the fly ash consolidated wet body.

[0055] (3) Place the fly ash solidified wet body in a sample library with a humidity of 40% to 60% and let it stand for 3 days to obtain the dry and hardened fly ash solidified body.

[0056] Physical and mechanical properties of the dried and hardened fly ash solidified body were randomly tested: the solidified body was dropped vertically from a height of 3m onto the concrete ground and no obvious breakage was found.

[0057] Example 2

[0058] A solidified feedstock for the melting and treatment of fly ash from municipal solid waste incineration, characterized in that it comprises the following substances by mass percentage:

[0059] Washed fly ash: 80%;

[0060] Fluxing material: 13.5%;

[0061] Hole-forming material: 1.5%;

[0062] Cementing material: 5%;

[0063] Preferably, the fly ash is a three-stage countercurrent rinsing fly ash, which has a moisture content of 8% to 10% after being dried by a circulating fluidized bed, and has a chloride ion content of ≤1.0%.

[0064] Preferably, the fluxing material is silica sand powder, calcium fluoride sludge and boric acid, wherein the ratio of silica sand powder: calcium fluoride sludge: boric acid is 80:12:8;

[0065] Preferably, the pore-forming material is crop straw, wood shavings and waste polystyrene granules, wherein the ratio of crop straw: wood shavings: waste polystyrene granules is 50:45:5;

[0066] Preferably, the cementing material is ultrafine fly ash, fluorogypsum and aluminoferrite cement, wherein the ratio of ultrafine fly ash: fluorogypsum: aluminoferrite cement is 75:8:17.

[0067] The silica sand powder is silt deposited in floodplains, with a silica content ≥85%. The boric acid is industrial-grade boric acid, with an H3BO3 content ≥99%.

[0068] Calcium fluoride sludge is a type of sludge formed from fluoride-containing wastewater discharged during the production processes of fluorine, special glass, and photovoltaic enterprises, after coagulation / calcium salt precipitation treatment. The sludge contains ≥60% calcium fluoride and ≥5% silica.

[0069] The crop straw is shredded crop straw, with a length of 50mm and a diameter of 0.8-1.0mm.

[0070] The wood shavings are long strips, 50mm in length and 1.0-2.0mm in width.

[0071] Waste polystyrene particles are polystyrene particles obtained by crushing recycled polystyrene boards, and they are evenly distributed inside the solid structure.

[0072] Ultrafine fly ash is the coarse ash remaining after screening Grade I and Grade II fly ash, which is processed into fly ash through ultrafine grinding. Its specific surface area is 650-700 m². 2 / kg.

[0073] Fluorogypsum is a byproduct mainly composed of anhydrous calcium sulfate obtained from the acid hydrolysis of fluorite to produce hydrogen fluoride, with a calcium sulfate content of ≥85%.

[0074] Ferroaluminate cement is an ultrafine ferroaluminate cement with an Fe2O3 content ≥ 6.0% and a specific surface area of ​​600–650 m². 2 / kg.

[0075] A method for preparing a solidified body for the molten disposal of fly ash from municipal solid waste incineration includes the following steps:

[0076] (1) The water-washed fly ash, fluxing material, pore-forming material and cementing material are compounded and then mixed and homogenized using a forced mixer. The forced mixer speed is 48 rpm and the mixing time is 240s to obtain fly ash composite material.

[0077] (2) The mixed and homogenized fly ash composite material is transported to the brick press and held under 30t mechanical pressure for 5s to form a cube with a side length of 100mm. Then the cube is moved to the drilling machine and 8 through holes with a diameter of 6mm are drilled in the middle of the cube to obtain the fly ash consolidated wet body.

[0078] (3) Place the fly ash solidified wet body in a sample library with a humidity of 40% to 60% and let it stand for 3 days to obtain the dry and hardened fly ash solidified body.

[0079] Physical and mechanical properties of the dried and hardened fly ash solidified body were randomly tested: the solidified body was dropped vertically from a height of 3m onto the concrete ground and no obvious breakage was found.

[0080] Example 3

[0081] A solidified feedstock for the melting and treatment of fly ash from municipal solid waste incineration, characterized in that it comprises the following substances by mass percentage:

[0082] Washed fly ash: 77%;

[0083] Fluxing material: 15%;

[0084] Hole-forming material: 2%;

[0085] Cementing material: 6%;

[0086] Preferably, the fly ash is a three-stage countercurrent rinsing fly ash, which has a moisture content of 8% to 10% after being dried by a circulating fluidized bed, and has a chloride ion content of ≤1.0%.

[0087] Preferably, the fluxing material is silica sand powder, calcium fluoride sludge and boric acid, wherein the ratio of silica sand powder: calcium fluoride sludge: boric acid is 77:13:10;

[0088] Preferably, the pore-forming material is crop straw, wood shavings and waste polystyrene granules, wherein the ratio of crop straw: wood shavings: waste polystyrene granules is 45:48:7;

[0089] Preferably, the cementing material is ultrafine fly ash, fluorogypsum and aluminoferrite cement, wherein the ratio of ultrafine fly ash: fluorogypsum: aluminoferrite cement is 72:10:18.

[0090] The silica sand powder is silt deposited in floodplains, with a silica content ≥85%. The boric acid is industrial-grade boric acid, with an H3BO3 content ≥99%.

[0091] Calcium fluoride sludge is a type of sludge formed from fluoride-containing wastewater discharged during the production processes of fluorine, special glass, and photovoltaic enterprises, after coagulation / calcium salt precipitation treatment. The sludge contains ≥60% calcium fluoride and ≥5% silica.

[0092] The crop straw is shredded crop straw, with a length of 40mm and a diameter of 0.8-1.0mm.

[0093] The wood shavings are long strips, 40mm in length and 1.0-2.0mm in width.

[0094] Waste polystyrene particles are polystyrene particles obtained by crushing recycled polystyrene boards, and they are evenly distributed inside the solid structure.

[0095] Ultrafine fly ash is the coarse ash remaining after screening Grade I and Grade II fly ash, which is processed into fly ash through ultrafine grinding. Its specific surface area is 650-700 m². 2 / kg.

[0096] Fluorogypsum is a byproduct mainly composed of anhydrous calcium sulfate obtained from the acid hydrolysis of fluorite to produce hydrogen fluoride, with a calcium sulfate content of ≥85%.

[0097] Ferroaluminate cement is an ultrafine ferroaluminate cement with an Fe2O3 content ≥ 6.0% and a specific surface area of ​​600–650 m². 2 / kg.

[0098] A method for preparing a solidified body for the molten disposal of fly ash from municipal solid waste incineration includes the following steps:

[0099] (1) The water-washed fly ash, fluxing material, pore-forming material and cementing material are compounded and then mixed and homogenized using a forced mixer. The forced mixer speed is 48 rpm and the mixing time is 210s to obtain fly ash composite material.

[0100] (2) The mixed and homogenized fly ash composite material is transported to the brick press and held under 25t mechanical pressure for 8s to form a cube with a side length of 75mm. Then the cube is moved to the drilling machine and 7 through holes with a diameter of 5mm are drilled in the middle of the cube to obtain the fly ash consolidated wet body.

[0101] (3) Place the fly ash solidified wet body in a sample library with a humidity of 40% to 60% and let it stand for 3 days to obtain the dry and hardened fly ash solidified body.

[0102] Physical and mechanical properties of the dried and hardened fly ash solidified body were randomly tested: the solidified body was dropped vertically from a height of 3m onto the concrete ground and no obvious breakage was found.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solidified body fed into the furnace after melting and treatment of fly ash from municipal solid waste incineration, characterized in that: The following substances are included by mass percentage: Washed fly ash: 75-80%; Fluxing material: 12-17%; Hole-forming material: 1-2%; Cementing material: 4-7%; The fly ash is a three-stage countercurrent rinsing fly ash, which, after being dried in a circulating fluidized bed, has a moisture content of 8%~10%, and a chloride ion content of ≤1.0%. The fluxing material is silica sand powder, calcium fluoride sludge and boric acid, wherein the ratio of silica sand powder: calcium fluoride sludge: boric acid is 75-80:10-15:5-10; The pore-forming material is crop straw, wood shavings and waste polystyrene particles, wherein the ratio of crop straw: wood shavings: waste polystyrene particles is 40-50: 45-50: 5-10. The cementing material is ultrafine fly ash, fluorogypsum and aluminoferrite cement, wherein the ratio of ultrafine fly ash: fluorogypsum: aluminoferrite cement is 70-75: 5-10: 15-20. The silica sand powder is river floodplain sedimentary silt, wherein the silica content is ≥85%, and the boric acid is industrial grade boric acid, wherein the H3BO3 content is ≥99%. The calcium fluoride sludge is a type of sludge formed by coagulation / calcium salt precipitation treatment of fluoride-containing wastewater discharged during the production process of fluorine, special glass manufacturing enterprises and photovoltaic enterprises. The calcium fluoride content is ≥60% and the silicon dioxide content is ≥5%.

2. The solidified body for the molten treatment of fly ash from municipal solid waste incineration according to claim 1, characterized in that: The crop straw is crushed crop straw with a length of 30-50 mm and a diameter of 0.8-1.0 mm. The wood shavings are long strips of wood chips with a length of 30-50 mm and a width of 1.0-2.0 mm. The waste polystyrene particles are polystyrene particles obtained by crushing recycled polystyrene boards, which are evenly distributed inside the solid structure.

3. The solidified body for the molten treatment of fly ash from municipal solid waste incineration according to claim 1, characterized in that: The ultrafine fly ash mentioned is the coarse ash remaining after screening Grade I and Grade II fly ash, which is processed fly ash obtained by ultrafine grinding and has a specific surface area of ​​650-700 m². 2 / kg.

4. The solidified body for the molten treatment of fly ash from municipal solid waste incineration according to claim 1, characterized in that: The fluorogypsum is a byproduct mainly composed of anhydrous calcium sulfate obtained from the acid hydrolysis of fluorite to produce hydrogen fluoride, wherein the calcium sulfate content is ≥85%.

5. The solidified body for the molten treatment of fly ash from municipal solid waste incineration according to claim 1, characterized in that: The aforementioned aluminoferrite cement is an ultrafine aluminoferrite cement with an Fe2O3 content ≥ 6.0% and a specific surface area of ​​600–650 m². 2 / kg.

6. A method for preparing a solidified body for the molten treatment of fly ash from municipal solid waste incineration, as described in any one of claims 1 to 5, characterized in that... Includes the following steps: (1) The water-washed fly ash, fluxing material, pore-forming material and cementing material are compounded and then mixed and homogenized by a forced mixer. The forced mixer speed is 48 rpm and the mixing time is 180-240s to obtain fly ash composite material. (2) The mixed and homogenized fly ash composite material is transported to the brick press and held under mechanical pressure of 20-30t for 5-10s to form a cube with a side length of 50-100mm. Then the cube is moved to the drilling machine and 6-8 through holes with a diameter of 5-6mm are drilled in the middle of the cube to obtain the fly ash consolidated wet body. (3) Place the fly ash solidified wet body in a sample library with a humidity of 40% to 60% and let it stand for 3 days to obtain the dry and hardened fly ash solidified body.