Fly ash sintering material with high fly ash mixing amount as well as preparation method and application of fly ash sintering material

Abstract

The invention relates to a fly ash sintered material with high fly ash mixing amount and a preparation method and application thereof. The method comprises the following steps: uniformly mixing silicon powder, alkali, water and a dispersing agent, and stirring and reacting at 75-95 DEG C for 4-12 hours to obtain a special silicon aggregate solution; uniformly mixing a sintering aid and the waste incineration fly ash to obtain solid powder, and then putting the solid powder and the special silicon aggregate solution into a forming and granulating device for forming and granulating to obtain formed particles; the waste incineration fly ash is calcined for 0.2-1.2 h in high-temperature treatment equipment at the temperature of 600-900 DEG C, the fly ash sintered material is obtained, the mass fraction of the waste incineration fly ash in the fly ash sintered material is 70-85%, and the mass fraction of the sintering aid is 2-5%; according to the method, the high doping amount of the waste incineration fly ash can be achieved in the fly ash sintering heat treatment process, the sintering temperature can be reduced, and the fly ash sintered material with the heavy metal leaching toxicity reaching the standard and the strength reaching the standard can be obtained by conducting low-temperature sintering treatment on the waste incineration fly ash with the high fly ash doping amount.

Description

Technical Field

[0001] The invention relates to the technical field of waste incineration fly ash disposal, and relates to a fly ash sintering material with a high fly ash content, and a preparation method and application thereof. Background Art

[0002] Waste incineration fly ash is a substance produced during the incineration of municipal domestic waste and enters the flue gas purification system along with the flue gas, and is eventually captured in the dust collector. The output of fly ash from the grate furnace type waste incinerator is about 2-5% of the total amount of waste entering the furnace. Since fly ash from waste incineration is enriched with heavy metals such as Pb, Cd, Cu, Ni and Zn, and also contains carcinogens such as dioxins, fly ash is listed as hazardous waste. At present, the disposal method of fly ash in domestic waste incineration power plants still remains at the stage of adding cement and stabilizer solidification landfill, and resource utilization has not yet reached a large scale. Fly ash also contains rich calcium and silicon resources, and the resource utilization of fly ash is of great significance. Fly ash water washing cement kiln synergy is a relatively mature means of fly ash resource utilization, but the whole process disposal process is complicated and costly. Fly ash sintering heat treatment can achieve dioxin detoxification of fly ash and is an effective means to realize fly ash resource utilization. However, the current fly ash sintering heat treatment process generally has problems such as low fly ash content and high sintering temperature. This is because the existing fly ash sintering heat treatment process can only obtain fly ash sintering materials with stable heavy metal content and strength that meet the standards under low fly ash doping and high sintering temperature, which results in the high-temperature disposal cost being much higher than the landfill disposal cost. Therefore, it is of great value and significance to develop efficient and cost-effective fly ash sintering heat treatment technology.

[0003] In summary, it is very necessary to provide a fly ash sintered material with a high fly ash content and a preparation method and application thereof. Summary of the invention

[0004] In order to solve one or more technical problems existing in the prior art, the present invention provides a fly ash sintering material with a high fly ash content and a preparation method and application thereof. The present invention realizes low sintering temperature treatment of high-content waste incineration fly ash, and the obtained fly ash sintering material has the characteristics of meeting the heavy metal leaching toxicity standard and high strength.

[0005] In a first aspect, the present invention provides a method for preparing a fly ash sintered material with a high fly ash content, the method comprising the following steps:

[0006] (1) mixing silicon powder, alkali, water and dispersant uniformly and stirring at 75 to 95° C. for 4 to 12 hours to obtain a special silicon aggregate solution;

[0007] (2) mixing the sintering aid and the waste incineration fly ash uniformly to obtain a solid powder, and then placing the solid powder and the special silicon aggregate solution in a molding and granulating device for molding and granulating to obtain molded particles;

[0008] (3) calcining the formed particles in a high temperature treatment device at 600-900° C. for 0.2-1.2 h to obtain a fly ash sintered material with a high fly ash content; the fly ash sintered material contains 70-85wt% of waste incineration fly ash and 2-5wt% of a sintering aid;

[0009] Preferably, in step (1), the base is one or more of sodium hydroxide, potassium hydroxide and lithium hydroxide.

[0010] Preferably, in step (1), the dispersant is one or more of methyltriethoxysilane, propyltriethoxysilane and sodium tripolyphosphate.

[0011] Preferably, in step (1), the mass ratio of the silicon powder, the alkali and the dispersant is 100:(5-15):(0.1-1.5).

[0012] Preferably, in step (1), the mass amount of the water is 3 to 6 times the mass amount of the silicon powder.

[0013] Preferably, the special silicon aggregates contained in the special silicon aggregate solution obtained in step (1) are silicon dioxide with a particle size of 1 to 10 nm.

[0014] Preferably, in step (2): the sintering aid is one or more of calcium fluoride, boron powder and borax with a particle size not greater than 100 nm.

[0015] Preferably, the compressive strength of the fly ash sintered material with a high fly ash content obtained in step (3) is not less than 4 MPa.

[0016] Preferably, the molding granulation device comprises a powder feeding plate, a liquid atomizer, a wet material feeding device and a granulation molding machine; a cavity is formed between the powder feeding plate, the liquid atomizer and the wet material feeding device, the powder feeding plate is located above the cavity, the liquid atomizer is located in the circumference of the cavity, the wet material feeding device is located below the cavity, and the granulation molding machine is located below the wet material feeding device; when the molding granulation device is used for molding and granulation, the solid powder enters the cavity through the powder feeding plate, and at the same time, the special silicon aggregate solution is atomized into liquid droplets under the action of the liquid atomizer and enters the cavity, and the liquid droplets are fully contacted and evenly mixed with the solid powder in the cavity to obtain wet material, and then the wet material enters the granulation molding machine through the wet material feeding device for molding to obtain molded particles.

[0017] Preferably, the high temperature treatment equipment comprises a heating section cylinder located at the top, a cooling section cylinder located in the middle and a solid material quenching pool located at the bottom, which are connected in sequence. The outside of the heating section cylinder is provided with a heat insulation layer, the inside of the heating section cylinder is provided with an internal heating plate, and the outside of the cooling section cylinder is provided with a cooling section cylinder jacket for the cooling medium to pass through; the top of the heating section cylinder is provided with an exhaust gas discharge port, a vacuum port, a gas inlet and a solid material inlet; a porous partition is provided between the heating section cylinder and the cooling section cylinder. The bottom of the cooling section cylinder is a solid material outlet, and the solid material outlet is connected to the solid material quenching pool. In step (3), after the molded particles are obtained by molding and granulation, the molded particles are allowed to enter the heating section cylinder of the high-temperature treatment equipment through the solid material inlet, are heated to 600-900°C by the internal heating plate, and are calcined at 600-900°C for 0.2-1.2h, and then enter the cooling section cylinder through the porous partition to be cooled, and then enter the solid material quenching pool through the solid material outlet to be quenched, so as to obtain fly ash sintered material with a high fly ash content.

[0018] In a second aspect, the present invention provides a fly ash sintered material with a high fly ash content, which is prepared by the preparation method described in the first aspect of the present invention.

[0019] The present invention provides, in a third aspect, the use of a fly ash sintered material with a high fly ash content prepared by the preparation method described in the first aspect of the present invention as a filler in building materials.

[0020] In a fourth aspect, the present invention provides a forming granulation device, which includes a powder feeding plate, a liquid atomizer, a wet material feeding device and a granulation forming machine; a cavity is formed between the powder feeding plate, the liquid atomizer and the wet material feeding device, the powder feeding plate is located above the cavity, the liquid atomizer is located in the circumference of the cavity, the wet material feeding device is located below the cavity, and the granulation forming machine is located below the wet material feeding device.

[0021] The fifth aspect of the present invention provides a high-temperature treatment equipment, which includes a heating section cylinder located at the top, a cooling section cylinder located in the middle and a solid material quenching pool located at the bottom, which are connected in sequence. The outside of the heating section cylinder is provided with an insulation layer, the inside of the heating section cylinder is provided with an internal heating plate, and the outside of the cooling section cylinder is provided with a cooling section cylinder jacket for the passage of cooling medium; the top of the heating section cylinder is provided with an exhaust gas discharge port, a vacuum port, a gas inlet and a solid material inlet; a porous partition is provided between the heating section cylinder and the cooling section cylinder, and the bottom of the cooling section cylinder is a solid material outlet, which is connected to the solid material quenching pool.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] The present invention innovatively adds a self-made special silicon aggregate solution when preparing fly ash sintering material. The special silicon aggregate contained in the special silicon aggregate solution is in-situ generated silicon dioxide with a very small particle size range (1nm~10nm); the present invention finds that the self-made special silicon aggregate has extremely high activity, significantly better than traditional silicon dioxide nanoparticles, and can effectively improve the sintering activity; at the same time, the sintering aid selected by the present invention is preferably calcium fluoride, boron powder, borax and other additives with a particle size not greater than 100nm, which also helps to improve the sintering activity of waste incineration fly ash; the combination of the special silicon aggregate and the sintering aid of the present invention not only ensures the realization of high doping amount during the fly ash sintering process, but also effectively reduces the sintering temperature. The present invention can prepare fly ash sintering material with both heavy metal leaching toxicity and strength that meet the standards by low-temperature sintering of high-doped waste incineration fly ash. Compared with traditional methods, the present invention has significant high efficiency and cost advantages, which can not only greatly reduce the process cost, but also has the potential for application on an industrial scale. The present invention also adopts a new type of molding equipment (molding and granulation device) to shape the material, effectively realizing the uniform mixing of powdered material (solid powder) and liquid material (special silicon aggregate solution), and improving the molding density and uniformity. The present invention realizes the uniform mixing of solid powder and special silicon aggregate solution and then molding, granulation and calcination, which is beneficial to improving the heavy metal stabilization and sintering uniformity of the prepared fly ash sintered material, while conventional molding and granulation devices usually need to use other mixing equipment to achieve mixing between solid and liquid, and there is usually a problem of uneven mixing. The present invention also adopts a new type of heat treatment equipment (high temperature treatment equipment) to heat treat (high temperature calcination) the formed particles after forming and granulation, so as to achieve heating of the solid material (formed particles) from the inside, and the heating efficiency is high. The common sintering equipment is generally a rotary kiln type equipment, which is very long and occupies a large area. At the same time, the material filling rate in the rotary kiln is less than 30%, while the equipment filling rate of the high temperature treatment equipment in the present invention can reach 100%, with a small footprint, high thermal efficiency, more complete sintering, and also conducive to improving the heavy metal stabilization effect of the fly ash sintering material. Overall, the present invention provides a fly ash sintering heat treatment technology with important practical value, which has both environmental benefits and economic benefits, and has broad application prospects in the field of solid waste treatment in the future. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings of the present invention are provided for illustrative purposes only, and the proportions, sizes and quantities of the various parts in the drawings may not necessarily be consistent with the actual products.

[0025] Figure 1 is a flow chart of the preparation of fly ash sintering material in some specific embodiments of the present invention;

[0026] Figure 2 The structural schematic diagram of the molding and granulating device provided by the present invention; in the figure, 81: powder feeding plate; 82: liquid atomizer; 83: wet material feeding device; 84: granulating molding machine;

[0027] Figure 3 A schematic structural diagram of the high-temperature treatment equipment provided by the present invention; in the figure, 1: insulation layer of the heating section cylinder; 2: cooling medium outlet of the cooling section cylinder jacket; 3: cooling medium inlet of the cooling section cylinder jacket; 4: solid material outlet; 5: solid material quenching pool; 6: porous partition; 7: internal heating plate; 8: exhaust gas discharge port; 9: vacuum port; 10: gas inlet; 11: solid material inlet. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] In a first aspect, the present invention provides a method for preparing a fly ash sintering material with a high fly ash content. The preparation process is as follows: Figure 1 As shown, the method comprises the following steps:

[0030] (1) mixing silicon powder, alkali, water and dispersant uniformly and stirring at 75-95° C. (e.g., 75° C., 80° C., 85° C., 90° C. or 95° C.) for 4-12 hours (e.g., 4, 5, 6, 7, 8, 9, 10, 11 or 12 hours) to obtain a special silicon aggregate solution; the present invention has no special requirements on the particle size of silicon powder, for example, silicon powder with a mesh size of 400 or more can be selected;

[0031] (2) mixing the sintering aid and the waste incineration fly ash uniformly to obtain a solid powder, and then placing the solid powder and the special silicon aggregate solution in a molding and granulating device for molding and granulating to obtain molded particles; in the present invention, for example, the molded particles having a size of less than 30 mm are obtained by molding and granulating;

[0032] (3) calcining the formed particles in a high temperature treatment device at 600 to 900° C. (e.g., 600° C., 650° C., 700° C., 750° C., 800° C., 850° C. or 900° C.) for 0.2 to 1.2 h (e.g., 0.2, 0.5, 0.8, 1 or 1.2 h) to obtain a fly ash sintered material with a high fly ash content (abbreviated as fly ash sintered material); the fly ash sintered material contains 70 to 85% by mass of waste incineration fly ash. wt% (e.g., 70wt%, 71wt%, 72wt%, 73wt%, 74wt%, 75wt%, 76wt%, 77wt%, 78wt%, 79wt%, 80wt%, 81wt%, 82wt%, 83wt%, 84wt% or 85wt%), and the mass fraction of the sintering aid is 2-5wt% (e.g., 2wt%, 3wt%, 4wt% or 5wt%); in this In the present invention, the sum of the mass percentages of waste incineration fly ash, sintering aid and special silicon aggregate in the fly ash sinter material is 100%; in the present invention, high fly ash content refers to the mass fraction of waste incineration fly ash in the prepared fly ash sinter material being 70-85wt%; in the present invention, the calcination temperature is low, only 600-900°C, while in conventional fly ash sintering heat treatment, the calcination temperature is generally higher than 1100°C, and the content of waste incineration fly ash is generally not higher than 50wt%; in the present invention, the special silicon aggregate solution contains water, and the fly ash sinter material with high fly ash content obtained by calcination does not contain water. According to the water content in the special silicon aggregate and the content of waste incineration fly ash, sintering aid and special silicon aggregate in the fly ash sinter material, the dosage ratio of the sintering aid, waste incineration fly ash and special silicon aggregate solution in step (2) can be determined.

[0033] The present invention innovatively adds a self-made special silicon aggregate solution when preparing fly ash sintering material. The special silicon aggregate contained in the special silicon aggregate solution is in-situ generated silicon dioxide with an extremely small particle size range (1nm to 10nm). The present invention finds that the self-made special silicon aggregate has extremely high activity, significantly better than traditional silicon dioxide nanoparticles, and can effectively improve the sintering activity. The combination of the special silicon aggregate of the present invention and the sintering aid not only ensures a high doping amount during the fly ash sintering process, but also effectively reduces the sintering temperature. The present invention processes high-doped waste incineration fly ash by low-temperature sintering, and can prepare fly ash sintering materials with both heavy metal leaching values ​​and strength that meet the standards, especially can significantly reduce the leaching values ​​of Pb and Cd that seriously exceed the standards in waste incineration fly ash. The present invention can reduce the Pb (lead) leaching value in the fly ash sintering material by more than 98.4% compared with the Pb leaching value in the waste incineration fly ash, and can reduce the Cd (cadmium) leaching value in the fly ash sintering material by more than 99% compared with the Cd leaching value in the waste incineration fly ash; in addition, the present invention can make the compressive strength of the fly ash sintering material not less than 4MPa; compared with the traditional method, the present invention has significant high efficiency and cost advantages, which can not only greatly reduce the process cost, but also has the potential for application on an industrial scale. Overall, the present invention provides a fly ash sintering heat treatment technology with important practical value, which has both environmental protection benefits and economic benefits, and has broad application prospects in the field of solid waste treatment in the future.

[0034] In the process of preparing the special silicon aggregate solution, the reaction temperature is controlled to be 75-95° C. and the reaction time is 4-12 hours, so as to ensure the generation of special silicon aggregates with extremely small particle size (1nm to 10nm), uniformity and high activity. The present invention finds that reacting at 75-95° C. for 4-12 hours can effectively promote the aggregation of silicon dioxide and the formation of nanoparticles. If the reaction temperature is too low, the reaction rate will be slow, which is not conducive to the generation of highly active special silicon aggregates. If the reaction temperature is too high, the reaction will be too fast, the particles will grow rapidly, and the silicon dioxide particles may quickly aggregate and form larger agglomerates, making it difficult to control the size and uniformity of the particle size. If the reaction time is too short, the formation of special silicon aggregates of silicon dioxide is insufficient, resulting in uneven particle size and incomplete reaction. If the reaction time is too long, the special silicon aggregates may begin to re-aggregate to form larger particles, destroying the uniform nanostructure, affecting the activity of the special silicon aggregates, and further affecting the sintering activity of the waste incineration fly ash.

[0035] According to some preferred embodiments, in step (1), the base is one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0036] According to some preferred embodiments, in step (1): the dispersant is one or more of methyltriethoxysilane, propyltriethoxysilane, and sodium tripolyphosphate.

[0037] According to some preferred embodiments, in step (1): the mass ratio of the silicon powder, the alkali and the dispersant is 100:(5-15):(0.1-1.5) (for example, 100:5:0.1, 100:5:0.5, 100:5:1, 100:5:1.5, 100:10:0.1, 100:10:0.5, 100:10:1, 100:10:1.5, 100:15:0.1, 100:15:0.5, 100:15:1 or 100:15:1.5), preferably 100:(5-10):(0.1-1.5).

[0038] According to some preferred embodiments, in step (1), the mass amount of water is 3 to 6 times (eg, 3, 4, 5 or 6 times) the mass amount of silicon powder.

[0039] In the present invention, it is preferred that, in the process of preparing the special silicon aggregate solution, the mass ratio of silicon powder, alkali and dispersant is controlled to be 100: (5-15): (0.1-1.5), and the mass of water is 3-6 times the mass of silicon powder, which is helpful to generate special silicon aggregates with extremely small particle size (1nm to 10nm) and uniformity and high activity. The possible reasons are: if the amount of alkali is too little, the silicon powder cannot react fully, resulting in a large amount of silicon powder not participating in the reaction and low yield of special silicon aggregates; if the amount of alkali is too much, it will lead to the formation of irregular or larger silicon dioxide agglomerates, destroying the originally designed small particle size structure and affecting the sintering activity. The role of the dispersant is to prevent the silicon dioxide nanoparticles generated during the reaction from agglomerating. Aggregation, maintaining uniform dispersion of particles. If the amount of dispersant used is too little, the nanoparticles are prone to agglomeration, resulting in an increase in particle size and reduced sintering activity; excessive use of dispersant may affect the stability of the reaction system, making it difficult to control the reaction process, which is not conducive to the formation of small-size aggregates. An appropriate amount of dispersant can effectively prevent agglomeration and maintain stable dispersion of nanoparticles; the addition of an appropriate amount of water can ensure an appropriate reaction concentration and a good mass transfer environment, which is conducive to the formation of the desired particle size range and structure; in the present invention, it is precisely because the special silicon aggregate solution is used to sinter the waste incineration fly ash that the sintering activity is greatly improved, which is conducive to obtaining a fly ash sintered material with both heavy metal leaching toxicity and strength meeting the standards.

[0040] According to some preferred embodiments, the special silicon aggregates contained in the special silicon aggregate solution obtained in step (1) are silicon dioxide with a particle size of 1 to 10 nm.

[0041] According to some preferred embodiments, in step (2): the sintering aid is one or more of calcium fluoride, boron powder, and borax with a particle size not greater than 100 nm; in the present invention, preferably, the sintering aid is one or more of calcium fluoride, boron powder, and borax with a particle size not greater than 100 nm, which also helps to improve the sintering activity of waste incineration fly ash.

[0042] According to some preferred embodiments, the compressive strength of the fly ash sintered material with a high fly ash content obtained in step (3) is not less than 4 MPa.

[0043] According to some preferred embodiments, the molding granulation device includes a powder feeding plate 81, a liquid atomizer 82, a wet material feeding device 83 and a granulation molding machine 84, for example, Figure 2 As shown; a cavity is formed between the powder unloading plate 81, the liquid atomizer 82 and the wet material unloading device 83, the powder unloading plate 81 is located above the cavity, the liquid atomizer 82 is located in the circumference of the cavity, the liquid atomizer 82 is used to atomize the special silicon aggregate solution into droplets to form liquid droplets, the wet material unloading device 83 is located below the cavity, and the granulator 84 is located below the wet material unloading device 83; in the present invention, using Figure 2 When the molding granulation device shown is used for molding and granulation, the specific process is: the solid powder is allowed to enter the cavity through the powder discharge plate, and at the same time, the special silicon aggregate solution is atomized into liquid droplets under the action of the liquid atomizer and enters the cavity, and the liquid droplets are fully contacted and evenly mixed with the solid powder in the cavity to obtain wet material, and then the wet material enters the granulation molding machine through the wet material discharge device for molding to obtain molded particles; in the present invention, the granulation molding machine can be an extrusion granulator; the molding granulation device used in the present invention is an efficient solid-liquid mixing granulation preparation device, which greatly improves the uniformity of the molded particles, and improves the molding density and uniformity. In the present invention, the solid powder is evenly mixed with the special silicon aggregate solution and then molded, granulated and calcined, which is beneficial to improve the heavy metal stabilization and sintering uniformity of the prepared fly ash sintered material.

[0044] According to some preferred embodiments, the high temperature treatment equipment comprises a heating section cylinder at the top, a cooling section cylinder at the middle and a solid material quenching pool 5 at the bottom, which are connected in sequence. Figure 3As shown, the outside of the heating section cylinder is provided with a heat insulation layer 1, the inside of the heating section cylinder is provided with an internal heating plate 7, and the outside of the cooling section cylinder is provided with a cooling section cylinder jacket for the cooling medium to pass through; the top of the heating section cylinder is provided with an exhaust gas discharge port 8, a vacuum port 9, a gas inlet 10 and a solid material inlet 11; a porous partition plate 6 is provided between the heating section cylinder and the cooling section cylinder, and the bottom of the cooling section cylinder is a solid material outlet 4, and the solid material outlet 4 is connected to the solid material quenching pool 5; in step (3), the solid material is obtained by forming and granulating. After the shaped particles are formed, the shaped particles enter the heating section cylinder of the high-temperature treatment equipment through the solid material inlet, are heated to 600-900°C by the internal heating plate, and are calcined at 600-900°C for 0.2-1.2h, and then enter the cooling section cylinder through the porous partition to be cooled, and then enter the solid material quenching pool through the solid material outlet to be quenched, so as to obtain the fly ash sintered material with high fly ash content; in the present invention, the upper part of the cooling section cylinder jacket is also provided with a cooling medium outlet 2, and the lower part of the cooling section cylinder jacket is also provided with a cooling medium inlet 3. The present invention has adopted the cooling medium, internal heating There is no specific limitation on the plate, porous partition, etc., and those skilled in the art can make conventional selections; in the present invention, the holes in the porous partition are evenly distributed; in the present invention, the exhaust gas discharge port, vacuum port, gas inlet and solid material inlet can be arranged in sequence from left to right at the top of the heating section cylinder, for example; in the present invention, the internal heating plate can be provided with multiple internal heating plates, so that the multiple internal heating plates are evenly distributed inside the heating section cylinder, preferably, the upper end of the internal heating plate is connected to the inner top of the heating section cylinder, and the internal heating plate is also connected to the heating power supply, and the internal heating plate can realize the solid material (molded particles) from the inside Heating, improve the heating efficiency; in the present invention, the gas inlet can be used to pass nitrogen, argon, carbon dioxide and other atmospheres, can realize the atmosphere calcination function, and the high temperature treatment equipment also has a vacuum port, the vacuum port is connected to an external vacuum system, can realize the internal atmosphere control of the high temperature treatment equipment, which is very beneficial to the control of the calcination atmosphere during the calcination process; the new high temperature heat treatment equipment adopted in the present invention can effectively improve the efficiency of the heat treatment process (calcination process) and reduce the process energy consumption.

[0045] In a second aspect, the present invention provides a fly ash sintered material with a high fly ash content, which is prepared by the preparation method described in the first aspect of the present invention.

[0046] The third aspect of the present invention provides the use of fly ash sintered material with high fly ash content prepared by the preparation method described in the first aspect of the present invention as a filler in building materials; specifically, for example, it can be used as a filler for concrete materials, such as aggregate.

[0047] The present invention provides a molding granulation device in a fourth aspect, for example, Figure 2 As shown, the molding granulation device includes a powder feeding plate 81, a liquid atomizer 82, a wet material feeding device 83 and a granulation molding machine 84; a cavity is formed between the powder feeding plate 81, the liquid atomizer 82 and the wet material feeding device 83, the powder feeding plate 81 is located above the cavity, the liquid atomizer 82 is located in the circumference of the cavity, the wet material feeding device 83 is located below the cavity, and the granulation molding machine 84 is located below the wet material feeding device 83; in the present invention, the granulation molding machine can be an extrusion granulator; the present invention provides an efficient solid-liquid mixing granulation preparation device, which greatly improves the uniformity of the molded particles.

[0048] The present invention provides a high temperature processing device in a fifth aspect, for example, Figure 3 As shown, the high temperature treatment equipment includes a heating section cylinder located at the top, a cooling section cylinder located in the middle and a solid material quenching pool 5 located at the bottom, which are connected in sequence. The outside of the heating section cylinder is provided with a heat insulation layer 1, the inside of the heating section cylinder is provided with an internal heating plate 7, and the outside of the cooling section cylinder is provided with a cooling section cylinder jacket for the cooling medium to pass through; the top of the heating section cylinder is provided with an exhaust gas discharge port 8, a vacuum port 9, a gas inlet 10 and a solid material inlet 11; a porous partition plate 6 is provided between the heating section cylinder and the cooling section cylinder, and the bottom of the cooling section cylinder is a solid material outlet 4, which is connected to the solid material quenching pool 5; in the present invention, the upper part of the cooling section cylinder jacket is also provided with a cooling medium outlet 2, and the lower part of the cooling section cylinder jacket is also provided with a cooling medium outlet 10. Medium inlet 3; In the present invention, the exhaust gas discharge port, vacuum port, gas inlet and solid material inlet can be arranged in sequence from left to right at the top of the heating section cylinder, for example; In the present invention, the internal heating plate can be provided with multiple, so that the multiple internal heating plates are evenly distributed inside the heating section cylinder, preferably, the upper end of the internal heating plate is connected to the inner top of the heating section cylinder, the internal heating plate is also connected to the heating power supply, and the internal heating plate can realize solid material heating from the inside to improve heating efficiency; In the present invention, the gas inlet can be used to pass nitrogen, argon, carbon dioxide and other atmospheres, which can realize the atmosphere calcination function, and the high temperature treatment equipment also has a vacuum port, and the vacuum port is connected to an external vacuum system, which can realize the internal atmosphere control of the high temperature treatment equipment. The present invention provides a new type of high temperature heat treatment equipment, which can effectively improve the efficiency of the heat treatment process (calcination process) and reduce the process energy consumption.

[0049] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] Example 1

[0051] This embodiment provides a method for preparing a fly ash sintered material with a high fly ash content, comprising the following steps:

[0052] ① Evenly mix silicon powder, alkali, water and dispersant and stir the mixture at 85°C for 5 hours to obtain a special silicon aggregate solution; wherein the alkali is sodium hydroxide, the dispersant is methyltriethoxysilane, and the mass ratio of silicon powder, sodium hydroxide and methyltriethoxysilane is 100:8:1; the mass amount of water is 4 times the mass amount of silicon powder; the special silicon aggregate solution obtained in step ① contains silicon dioxide with a particle size (average particle size) of 1.8 nm.

[0053] ② Mix the sintering aid (boron powder with an average particle size of 100 nm) and the waste incineration fly ash (urban domestic waste incineration fly ash) to obtain a solid powder; place the solid powder together with the special silicon aggregate solution obtained in step ① in a Figure 2 The molding and granulation are carried out in the molding and granulation device shown to obtain molded particles.

[0054] ③ Place the shaped particles obtained in step ② in Figure 3 The fly ash sintered material with a high fly ash content is obtained by calcining at 600°C in a nitrogen atmosphere for 1.2 hours in the high-temperature treatment equipment shown in the figure; the fly ash sintered material contains 70wt% of waste incineration fly ash by mass, 2wt% of sintering aid by mass, and 28wt% of special silicon aggregate by mass.

[0055] Example 2

[0056] This embodiment provides a method for preparing a fly ash sintered material with a high fly ash content, comprising the following steps:

[0057] ① Evenly mix silicon powder, alkali, water and dispersant and stir the mixture at 85°C for 5 hours to obtain a special silicon aggregate solution; wherein the alkali is sodium hydroxide, the dispersant is methyltriethoxysilane, and the mass ratio of silicon powder, sodium hydroxide and methyltriethoxysilane is 100:8:1; the mass amount of water is 4 times the mass amount of silicon powder; the special silicon aggregate solution obtained in step ① contains silicon dioxide with a particle size (average particle size) of 1.8 nm.

[0058] ② Mix the sintering aid (boron powder with an average particle size of 100 nm) and the waste incineration fly ash (urban domestic waste incineration fly ash) to obtain a solid powder; place the solid powder together with the special silicon aggregate solution obtained in step ① in a Figure 2 The molding and granulation are carried out in the molding and granulation device shown to obtain molded particles.

[0059] ③ Place the shaped particles obtained in step ② in Figure 3 The fly ash sintered material with a high fly ash content is obtained by calcining at 750°C in a nitrogen atmosphere for 1 hour in the high-temperature treatment equipment shown in the figure; the fly ash sintered material contains 78wt% of waste incineration fly ash by mass, 4wt% of sintering aid by mass, and 18wt% of special silicon aggregate by mass.

[0060] Example 3

[0061] This embodiment provides a method for preparing a fly ash sintered material with a high fly ash content, comprising the following steps:

[0062] ① Evenly mix silicon powder, alkali, water and dispersant and stir the mixture at 85°C for 5 hours to obtain a special silicon aggregate solution; wherein the alkali is sodium hydroxide, the dispersant is methyltriethoxysilane, and the mass ratio of silicon powder, sodium hydroxide and methyltriethoxysilane is 100:8:1; the mass amount of water is 4 times the mass amount of silicon powder; the special silicon aggregate solution obtained in step ① contains silicon dioxide with a particle size (average particle size) of 1.8 nm.

[0063] ② Mix the sintering aid (boron powder with an average particle size of 100 nm) and the waste incineration fly ash (urban domestic waste incineration fly ash) to obtain a solid powder; place the solid powder together with the special silicon aggregate solution obtained in step ① in a Figure 2 The molding and granulation are carried out in the molding and granulation device shown to obtain molded particles.

[0064] ③ Place the shaped particles obtained in step ② in Figure 3 The fly ash sintered material with a high fly ash content is obtained by calcining in a nitrogen atmosphere at 900°C for 1 hour in the high-temperature treatment equipment shown in the figure; the fly ash sintered material contains 85wt% of waste incineration fly ash by mass, 5wt% of sintering aid by mass, and 10wt% of special silicon aggregate by mass.

[0065] Comparative Example 1

[0066] ① Evenly mix a sintering aid (boron powder with an average particle size of 100 nm), waste incineration fly ash (urban domestic waste incineration fly ash) and silicon powder to obtain a solid powder; shape and granulate the solid powder in a common extrusion granulator to obtain molded particles.

[0067] ② The formed particles are calcined in a common rotary kiln at 750° C. in a nitrogen atmosphere for 1 hour to obtain a fly ash sintered material; the fly ash sintered material contains 78wt% of waste incineration fly ash, 4wt% of sintering aid, and 18wt% of silicon micropowder.

[0068] Comparative Example 2

[0069] ① Evenly mix a sintering aid (boron powder with an average particle size of 100 nm), waste incineration fly ash (urban domestic waste incineration fly ash) and silicon dioxide nanoparticles (average particle size of 50 nm) to obtain a solid powder; shape and granulate the solid powder in a common extrusion granulator to obtain molded particles.

[0070] ② The formed particles are calcined in a common rotary kiln at 750° C. in a nitrogen atmosphere for 1 hour to obtain a fly ash sintered material; the fly ash sintered material contains 78wt% of waste incineration fly ash, 4wt% of sintering aid, and 18wt% of silica nanoparticles.

[0071] Comparative Example 3

[0072] ① Evenly mix a sintering aid (boron powder with an average particle size of 100 nm) and waste incineration fly ash (urban domestic waste incineration fly ash) to obtain a solid powder; shape and granulate the solid powder in a common extrusion granulator to obtain molded particles; in the molded particles, the mass ratio of the waste incineration fly ash to the sintering aid is 78:4.

[0073] ② The formed particles were calcined in a common rotary kiln at 750°C in a nitrogen atmosphere for 1 hour to obtain fly ash sintered material.

[0074] The present invention tests the heavy metal leaching value concentration (mg / mL) and compressive strength (MPa) of the fly ash sintered materials obtained by the waste incineration fly ash, Examples 1 to 3 and Comparative Examples 1 to 3, and the results are shown in Table 1; wherein the heavy metal leaching value concentration is tested according to the provisions of the solid waste leaching toxicity leaching method - acetic acid buffer solution method HJ / T300-2007 in accordance with the provisions of the standard GB16889-2008.

[0075] Table 1

[0076]

[0077]

[0078] In Table 1, the symbol “ / ” indicates that the indicator does not exist or cannot be measured.

[0079] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0080] It should be noted that the terms "upper", "lower", "bottom", "top", "inner", "outer" and the like indicate directions or positional relationships based on the attached Figure 2 and attached Figure 3 The orientation or positional relationship shown is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or a communicating connection, etc. For those of ordinary skill in the art, the specific meaning of the term in the present invention can be understood according to the specific circumstances.

[0081] Finally, it should be noted that: the fly ash sintered material with high fly ash content, preparation method and application thereof disclosed in the embodiments of the present invention are introduced in detail above. Specific examples are used in this article to illustrate the implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing fly ash sintered material with high fly ash content, characterized in that: The method comprises the following steps: (1) mixing silicon powder, alkali, water and dispersant uniformly and stirring at 75 to 95° C. for 4 to 12 hours to obtain a special silicon aggregate solution; (2) mixing the sintering aid and the waste incineration fly ash uniformly to obtain a solid powder, and then placing the solid powder and the special silicon aggregate solution in a molding and granulating device for molding and granulating to obtain molded particles; (3) calcining the formed particles in a high temperature treatment device at 600-900° C. for 0.2-1.2 h to obtain a fly ash sintered material with a high fly ash content; the fly ash sintered material contains 70-85wt% of waste incineration fly ash by weight and 2-5wt% of a sintering aid by weight.

2. The preparation method according to claim 1, characterized in that: In step (1): The alkali is one or more of sodium hydroxide, potassium hydroxide and lithium hydroxide; The dispersant is one or more of methyltriethoxysilane, propyltriethoxysilane and sodium tripolyphosphate; The mass ratio of the silicon powder, the alkali and the dispersant is 100:(5-15):(0.1-1.5); The mass amount of water is 3 to 6 times the mass amount of silicon powder; and / or The special silicon aggregates contained in the special silicon aggregate solution obtained in step (1) are silicon dioxide with a particle size of 1 to 10 nm.

3. The preparation method according to claim 1, characterized in that: In step (2): The sintering aid is one or more of calcium fluoride, boron powder and borax with a particle size not greater than 100 nm.

4. The preparation method according to claim 1, characterized in that: The compressive strength of the fly ash sintered material with high fly ash content obtained in step (3) is not less than 4 MPa.

5. The preparation method according to claim 1, characterized in that: The molding and granulating device comprises a powder feeding plate, a liquid atomizer, a wet material feeding device and a granulating molding machine; A cavity is formed between the powder unloading plate, the liquid atomizer and the wet material unloading device, the powder unloading plate is located above the cavity, the liquid atomizer is located in the circumference of the cavity, the wet material unloading device is located below the cavity, and the granulating molding machine is located below the wet material unloading device; When the molding and granulation device is used for molding and granulation, the solid powder enters the cavity through the powder discharge plate, and at the same time, the special silicon aggregate solution is atomized into liquid droplets under the action of the liquid atomizer and enters the cavity. In the cavity, the liquid droplets are fully in contact with and evenly mixed with the solid powder to obtain wet material, and then the wet material enters the granulation molding machine through the wet material discharge device for molding to obtain molded particles.

6. The preparation method according to claim 1, characterized in that: The high temperature treatment equipment comprises a heating section cylinder located at the top, a cooling section cylinder located in the middle and a solid material quenching pool located at the bottom, which are connected in sequence. The outside of the heating section cylinder is provided with a heat insulation layer, the inside of the heating section cylinder is provided with an internal heating plate, and the outside of the cooling section cylinder is provided with a cooling section cylinder jacket for the cooling medium to pass through; the top of the heating section cylinder is provided with an exhaust gas discharge port, a vacuum port, a gas inlet and a solid material inlet; a porous partition is provided between the heating section cylinder and the cooling section cylinder, and the bottom of the cooling section cylinder is a solid material outlet, which is connected to the solid material quenching pool; In step (3), after the shaped particles are obtained through forming and granulation, the shaped particles are allowed to enter the heating section cylinder of the high-temperature treatment equipment through the solid material inlet, are heated to 600-900° C. by the internal heating plate, and are calcined at 600-900° C. for 0.2-1.2 h. Then, the shaped particles are allowed to enter the cooling section cylinder through the porous partition plate for cooling, and then enter the solid material quenching pool through the solid material outlet for quenching to obtain fly ash sintered material with a high fly ash content.

7. A fly ash sintered material with a high fly ash content prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the fly ash sintered material with high fly ash content prepared by the preparation method according to any one of claims 1 to 6 as filler in building materials.

9. A forming and granulating device, characterized in that: The molding and granulating device comprises a powder feeding plate, a liquid atomizer, a wet material feeding device and a granulating molding machine; A cavity is formed between the powder feeding plate, the liquid atomizer and the wet material feeding device. The powder feeding plate is located above the cavity, the liquid atomizer is located around the cavity, the wet material feeding device is located below the cavity, and the granulation molding machine is located below the wet material feeding device.

10. A high temperature processing equipment, characterized in that: The high-temperature treatment equipment includes a heating section cylinder located at the top, a cooling section cylinder located in the middle and a solid material quenching pool located at the bottom, which are connected in sequence. The outside of the heating section cylinder is provided with a heat insulation layer, the inside of the heating section cylinder is provided with an internal heating plate, and the outside of the cooling section cylinder is provided with a cooling section cylinder jacket for the cooling medium to pass through; the top of the heating section cylinder is provided with an exhaust gas discharge port, a vacuum port, a gas inlet and a solid material inlet; a porous partition is provided between the heating section cylinder and the cooling section cylinder, and the bottom of the cooling section cylinder is a solid material outlet, which is connected to the solid material quenching pool.

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