System and method for recycling fly ash

Abstract

The invention relates to a fly ash recycling system and method. The system comprises a fly ash curing subsystem for curing and forming fly ash raw materials into cured ash, a water washing subsystem, a water washing liquid post-treatment system and a wet ash post-treatment subsystem, the washing subsystem comprises a washing hopper, n stages of washing liquid barrels and a pump, the washing hopper comprises a filter screen, a liquid distributor, an air pipe and a supporting plate, the liquid distributor is connected with an inlet pipe, the bottom of the washing hopper is connected with an outlet pipe, an inlet of the pump is connected with the outlet pipe and an outlet of each stage of washing liquid barrel, and an outlet of the pump is connected with the inlet pipe and an inlet of each stage of washing liquid barrel. Valves are respectively arranged on the inlet pipe and the outlet pipe, and valves are respectively arranged on pipelines of an inlet and an outlet of each stage of washing liquid bucket. According to the system and method, solid-liquid separation is easy to achieve after water washing, the water-cement ratio in the water washing process is low, water in all stages of water washing liquid buckets is recycled, and the system and method have the advantages of being good in technological process economical efficiency, more convenient to operate, low in energy consumption cost, efficient and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of waste incineration fly ash reprocessing and recycling, and in particular relates to a fly ash resource utilization system and method. Background Art

[0002] Waste incineration fly ash is produced during the incineration of municipal domestic waste. During the incineration process of waste, organic matter in the waste is mainly discharged in the form of gaseous substances; while inorganic matter mainly forms solid particles, among which larger solid particles are deposited at the bottom of the incinerator and on the grate, which is called bottom ash, and those fine particles float in the flue gas and enter the flue gas purification system with the flue gas. These particles constitute 50% of the incineration fly ash, and the remaining incineration fly ash comes from the limestone or activated carbon added during the flue gas purification process. They are captured together in the dust collector (electrostatic precipitator, bag filter, etc.), and some fine particles also settle at the bottom of the flue and chimney. These captured and settled fine particles are called incineration fly ash. Fly ash has a very low moisture content and is in the form of light grey powder. The fly ash particles are uneven in size, complex in structure, and variable in properties. They mostly exist in amorphous and polycrystalline aggregate structures. Usually, the particle size of fly ash particles is less than 100 μm, and their surface is rough, with a large specific surface area and high porosity. The chemical composition of incineration fly ash includes elements such as Cl, Ca, K, Na, Si, Al, and O, and the main chemical components are CaO, SiO2, Al2O3, and Fe2O3. In addition, since incineration fly ash often contains high concentrations of heavy metals such as Hg, Pb, Cd, Cu, Cr, and Zn, fly ash is listed as hazardous waste. However, fly ash contains rich calcium and silicon resources, and the resource utilization of fly ash is of great significance. 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 and landfill, and resource utilization has not yet reached a large scale. Fly ash water washing can wash away the soluble chloride salts in the fly ash to obtain high calcium substances with practical value, which can be used to prepare cement clinker. Chinese patent application CN202211165978.4 discloses a method for treating waste incineration fly ash in coordination with waste incineration flue gas, specifically, discloses a three-stage stirring and water-washing fly ash water washing treatment method, but the water washing process consumes a large amount of water, and the subsequent evaporation and crystallization requires a large amount of evaporation energy consumption. The reagent cost and energy consumption cost per ton of ash are high, and the economy of the entire process is poor.

[0003] In summary, it is very necessary to provide a new system and method for fly ash resource utilization. Summary of the invention

[0004] In order to solve one or more technical problems existing in the prior art, the present invention provides a system and method for fly ash resource utilization.

[0005] In a first aspect, the present invention provides a fly ash resource utilization system, the system comprising: a fly ash solidification subsystem for solidifying fly ash raw materials into solidified ash; a water washing subsystem for washing the solidified ash with water, the water washing subsystem comprising a water washing hopper, n-stage water washing liquid barrels and a pump, the water washing hopper comprising a filter screen for placing solidified ash, a liquid distributor located on the top of the filter screen, an air pipe for conveying gas into the water washing hopper and a support plate for supporting the filter screen, the liquid distributor is connected to an inlet pipe, the An outlet pipe is connected to the bottom of the washing hopper, the inlet of the pump is connected to the outlet pipe and the outlet of each stage of the washing liquid barrel, the outlet of the pump is connected to the inlet pipe and the inlet of each stage of the washing liquid barrel, the inlet pipe is provided with an inlet valve, the outlet pipe is provided with an outlet valve, and valves are provided on the inlet pipeline and the outlet pipeline of each stage of the washing liquid barrel; a washing liquid post-processing subsystem for post-processing the washing liquid obtained by the washing subsystem; and a wet ash post-processing subsystem for post-processing the wet ash obtained by the washing subsystem.

[0006] Preferably, the crystallizing agent used in the solidification molding is one or more of water glass, aluminum chloride, ferrous chloride, silicate cement, ferrous sulfate, ferric sulfate, and ferric chloride.

[0007] Preferably, the bottom of the water washing hopper is a conical bottom; n-level water washing liquid barrels are arranged in sequence, 1≤n≤15, preferably 2≤n≤15; the filter screen is a cylindrical filter screen, preferably, the mesh number of the filter screen is 20-400 meshes, the air pipe is arranged close to the bottom of the filter screen, and air holes are opened on the tube wall of the air pipe, preferably, the pore size of the air holes is 0.01-1mm, one end of the air pipe passes through the filter screen and the side wall of the water washing hopper and is connected to a gas storage tank, preferably, the gas is nitrogen, carbon dioxide, air or exhaust gas; and / or a through hole is opened in the support plate, and the pore size of the through hole is 2-20mm.

[0008] Preferably, the fly ash solidification subsystem includes, in sequence, a fly ash raw material silo, a solidification molding machine for solidifying the fly ash raw material into solidified ash, and a solidified ash silo; the water wash liquid post-processing subsystem includes, in sequence, a physical sedimentation tank, a chemical sedimentation tank, a filter, a storage tank, and an evaporation crystallizer; and / or the wet ash post-processing subsystem includes, in sequence, a wet ash dryer and a dry ash storage.

[0009] Preferably, chemical agents are added to the chemical sedimentation tank, and the chemical agents are one or more of sodium hydroxide, sodium carbonate, sodium sulfate, sodium phosphate, and sodium sulfide; and / or the evaporation crystallizer is a multiple-effect evaporation crystallizer and / or an MVR evaporation crystallizer.

[0010] Preferably, the outlet of the fly ash solidification subsystem is connected to the inlet of the water washing subsystem; the washing liquid obtained by the water washing subsystem is connected to the inlet of the water washing liquid post-treatment subsystem, the washing liquid is treated by the water washing liquid post-treatment subsystem to obtain salt and pure water, and the obtained pure water is returned to the water washing subsystem; and / or the wet ash obtained by the water washing subsystem is connected to the inlet of the wet ash post-treatment subsystem.

[0011] Preferably, when the solidified ash is washed in a washing hopper, the water-ash ratio is (0.75-2.75):1, preferably (0.75-2):1; when the solidified ash is solidified in a solidification molding machine, the amount of crystallizing agent used is 2-20% of the mass of the fly ash raw material, preferably 5-10%.

[0012] In a second aspect, the present invention provides a method for recycling fly ash, the method being performed using the fly ash recycling system of the first aspect of the present invention, and the method comprising the following steps:

[0013] (1) allowing the fly ash raw material to complete solidification and forming in the fly ash solidification subsystem to obtain solidified ash;

[0014] (2) placing the solidified ash in the washing hopper of the washing subsystem, and then performing a step-by-step washing process with water in the n-stage washing liquid barrel; in the step-by-step washing process, first washing with water in the first-stage washing liquid barrel, and then washing with water in the next-stage washing liquid barrel, until the n-stage washing process is completed, the water in the first-stage washing liquid barrel becomes washing liquid after washing; the water in the next-stage washing liquid barrel returns to the previous-stage washing liquid barrel after washing;

[0015] (3) The wet ash obtained after the step-by-step water washing process in step (2) is post-processed by a wet ash post-processing subsystem to obtain dry ash, and the washing liquid is passed into a washing liquid post-processing subsystem for post-processing of the washing liquid to obtain salt and pure water. The obtained pure water is returned to the washing liquid barrel of the washing subsystem, thereby completing the resource utilization of fly ash.

[0016] Preferably, the obtained pure water is returned to the last-stage washing liquid barrel of the washing subsystem; and / or the post-treatment of the washing liquid is: the washing liquid is first precipitated in the physical sedimentation tank, and then the upper layer liquid in the physical sedimentation tank after sedimentation is transported to the chemical sedimentation tank and chemical agents are added for stirring reaction, and then transported to the filter for solid-liquid separation, and then the filtrate is transported to the storage tank, and finally the filtrate in the storage tank is transported to the evaporation crystallizer for evaporation and crystallization to obtain salt and pure water.

[0017] Preferably, in step (1), the solidification and molding is: taking the fly ash raw material in the fly ash raw material silo and mixing it evenly with the crystallizing agent, and then solidifying and molding it in a solidification molding machine to obtain solidified ash; and / or in step (3), the post-processing performed by the wet ash post-processing subsystem is: placing the obtained wet ash in a wet ash dryer for drying to obtain dry ash.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] (1) The system of the present invention includes four parts: a fly ash solidification subsystem, a water washing subsystem, a water washing liquid post-processing subsystem, and a wet ash post-processing subsystem. The system of the present invention solidifies the fly ash raw material into a pre-polymerized crystal of fly ash through the fly ash solidification subsystem, and then washes the pre-polymerized crystal of fly ash obtained after solidification. The fly ash pre-polymerized crystal is in the form of solid particles, and solid-liquid self-separation can be easily achieved without external force in n-stage water washing, and the separation is thorough. In the prior art, the fly ash slurry needs to be centrifuged or filtered step by step in n-stage water washing, and solid-liquid separation needs to be achieved with the help of external force, which consumes a lot of energy, is cumbersome to operate, and has the problem of incomplete separation. In addition, the use of the system of the present invention is conducive to reducing the chloride ion content of the treated fly ash. The system of the present invention can make the water-to-ash ratio of the water washing process low, and the water at each stage is recycled, and the actual water consumption of water washing is low. The wet ash post-processing subsystem included in the system of the present invention is mainly used to dry the wet ash so that it can be added to the cement kiln. The washing liquid in the present invention is subjected to various water treatment processes to finally obtain industrial salts of sodium chloride and potassium chloride, and the obtained pure water can be used in the washing subsystem to realize the recycling of water.

[0020] (2) The water washing subsystem in the present invention includes a water washing hopper and an n-stage water washing liquid barrel. The water washing hopper includes a liquid distributor, an air pipe, a filter screen and a support plate. The arrangement of the liquid distributor allows water to enter the water washing hopper evenly, so that the water can more evenly contact the surface of the fly ash pre-polymerized crystals and the water washing is more thorough. There is no need to set a stirring device in the water washing hopper in the present invention. During the water washing process, no stirring device is required. The gas is introduced through the air pipe for disturbance stirring, which can save electricity and effectively save energy resources.

[0021] (3) The system and method of the present invention have the advantages of good process economy, more convenient operation, low energy consumption cost, high efficiency, etc. The salt (sodium chloride and potassium chloride) extracted by the system and method of the present invention has high purity, which can reach more than 90%, which is beneficial to the subsequent application of the salt; the chlorine content of the dry ash treated by the system and method of the present invention is less than 1%. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] 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.

[0023] Figure 1 It is a structural schematic diagram of a fly ash resource utilization system in some specific embodiments of the present invention;

[0024] Figure 2 yes Figure 1 A schematic diagram of the structure of the fly ash solidification subsystem included in the invention;

[0025] Figure 3 yes Figure 1 A schematic diagram of the structure of the water washing subsystem included in the embodiment;

[0026] Figure 4 yes Figure 3 A schematic diagram of the structure of the water washing hopper included in the embodiment;

[0027] Figure 5 yes Figure 1 A schematic diagram of the structure of the water wash liquid post-treatment subsystem included in;

[0028] Figure 6 yes Figure 1 Schematic diagram of the structure of the wet ash post-processing subsystem included in.

[0029] In the figure, 1: fly ash solidification subsystem; 11: fly ash raw material silo; 12: solidification molding machine; 13: solidified ash silo; 2: water washing subsystem; 21: water washing hopper; 211: inlet pipe; 212: inlet valve; 213: liquid distributor; 214: air pipe; 215: filter screen; 216: support plate; 217: conical bottom of water washing hopper; 218: outlet valve; 219: outlet pipe; 22: water washing liquid barrel; 221: first-stage water washing liquid barrel; 2 22: 2nd stage water washing liquid barrel; 223: 3rd stage water washing liquid barrel; 224: 4th stage water washing liquid barrel; 225: 5th stage water washing liquid barrel; 226: nth stage water washing liquid barrel; 23: Pump; 24: Valve; 3: Water washing liquid post-processing subsystem; 31: Physical sedimentation tank; 32: Chemical sedimentation tank; 33: Filter; 34: Storage tank; 35: Evaporation crystallizer; 4: Wet ash post-processing subsystem; 41: Wet ash dryer; 42: Dry ash storage; 5: Solidified ash. DETAILED DESCRIPTION

[0030] 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.

[0031] In the present invention, Figure 1It is a structural schematic diagram of a fly ash resource utilization system in some specific embodiments of the present invention; Figure 2 yes Figure 1 A schematic diagram of the structure of the fly ash solidification subsystem included in the invention; Figure 3 yes Figure 1 A schematic diagram of the structure of the water washing subsystem included in the embodiment; Figure 4 yes Figure 3 A schematic diagram of the structure of the water washing hopper included in the embodiment; Figure 5 yes Figure 1 A schematic diagram of the structure of the water wash liquid post-treatment subsystem included in; Figure 6 yes Figure 1 Schematic diagram of the structure of the wet ash post-processing subsystem included in.

[0032] In a first aspect, the present invention provides a fly ash resource recovery system, for example, Figures 1 to 6 As shown, the system includes: a fly ash solidification subsystem 1 for solidifying and molding fly ash raw materials into solidified ash 5; in the fly ash solidification subsystem 1, a pre-polymerized crystal of fly ash (solidified ash) is obtained in a solidification molding machine 12 by adding a crystallizing agent and combining with the fly ash raw materials, and then the solidified ash 5 is used as a raw material for a subsequent water washing subsystem 2; in the present invention, it is preferred that the crystallizing agent used in the fly ash solidification subsystem 1 is one or a mixture of more than one of water glass, aluminum chloride, ferrous chloride, silicate cement, ferrous sulfate, ferric sulfate, and ferric chloride; a water washing subsystem 2 for washing the solidified ash 5, for example, Figure 3 As shown, the water washing subsystem 2 includes a water washing hopper 21, an n-level water washing liquid barrel 22 and a pump 23, for example, Figure 4As shown, the washing hopper 21 includes a filter screen 215 for placing solidified ash 5, a liquid distributor 213 located on the top of the filter screen 215, an air pipe 214 for conveying gas into the washing hopper 21 and a support plate 216 for supporting the filter screen 215, wherein the air pipe 214 conveys gas to provide a disturbance effect; the liquid distributor 213 is connected to an inlet pipe 211. In the present invention, the top of the liquid distributor 213 is connected to the inlet pipe 211, so that the water (washing water) in the washing liquid barrel 22 passes through the inlet pipe 211 and then passes through the liquid distributor 213 into the filter screen 215 of the washing hopper 21; the bottom of the washing hopper 21 is connected to an outlet pipe 219, the inlet of the pump 23 is connected to the outlet pipe 219 and the outlet of each stage of the washing liquid barrel 22, the outlet of the pump 23 is connected to the inlet pipe 211 and the inlet of each stage of the washing liquid barrel 22, and the inlet pipe An inlet valve 212 is provided on 211, an outlet valve 218 is provided on the outlet pipe 219, and valves 24 are provided on the inlet pipeline and the outlet pipeline of each stage of the washing liquid barrel 22; in the present invention, the step-by-step washing process of the solidified ash 5 in the washing hopper 21 is realized by controlling the opening and closing of the inlet valve 212, the outlet valve 218 and the valve 24 provided on the inlet pipeline and the outlet pipeline of each stage of the washing liquid barrel 22; the washing process in the washing subsystem 2 of the present invention does not require mechanical stirring or external force solid-liquid separation, and the entire washing process has low energy consumption and high efficiency; a washing liquid post-processing subsystem 3 for post-processing the washing liquid obtained by the washing subsystem 2; and a wet ash post-processing subsystem 4 for post-processing the wet ash obtained by the washing subsystem 2; the present invention obtains salt and pure water after passing through the washing liquid post-processing subsystem 3, and obtains dry ash after passing through the wet ash post-processing subsystem 4.

[0033] The system of the present invention comprises four parts, namely, a fly ash solidification subsystem, a water washing subsystem, a water washing liquid post-processing subsystem, and a wet ash post-processing subsystem. The system of the present invention solidifies the fly ash raw material into solidified ash (i.e., pre-polymerized crystals of fly ash) through the fly ash solidification subsystem, and then washes with water. The fly ash pre-polymerized crystals are in the form of solid particles, and their structure is more stable, which helps to reduce the possibility of fly ash dissolution and breakage during the water washing process, and the water washing process is not loose and broken. After the fly ash prepolymer crystals are piled up, they present a non-dense accumulation, which is not compacted. In the n-stage water washing, no external force is required (i.e., no complicated external force separation step is required) to easily achieve solid-liquid self-separation, and the separation is thorough. On the one hand, it is beneficial to remove chlorine in the fly ash during the water washing process, and on the other hand, it saves energy and time costs in the water washing process. In the prior art, the fly ash slurry needs to be centrifuged or filtered step by step in the n-stage water washing, and needs to rely on external force to achieve solid-liquid separation, which consumes a lot of energy, is cumbersome to operate, and has the problem of incomplete separation. In addition, the fly ash raw material may have a bonding problem in the water washing process when it is made into a slurry, which affects the water washing effect. The present invention solidifies the fly ash raw material into a fly ash prepolymer crystal and then washes it. Compared with washing with a slurry, it can improve the water washing effect, simplify the water washing process, and help to improve the resource recovery rate, thereby better achieving the goal of fly ash resource utilization. The system in the present invention can make the water-cement ratio of the water washing process low, the water at each level is recycled, and the actual water consumption of water washing is low. The wet ash post-processing subsystem included in the system of the present invention is mainly used to dry the wet ash so as to add it to the cement kiln. The water washing liquid in the present invention passes through various water treatment processes to finally obtain sodium chloride and potassium chloride industrial salts, and the obtained pure water can be used in the water washing subsystem to achieve water recycling; and the use of the system of the present invention is conducive to reducing the chloride ion content of the treated fly ash.

[0034] The water washing subsystem 2 in the present invention comprises a water washing hopper 21 and an n-stage water washing liquid barrel 22, wherein the water washing hopper 21 comprises a liquid distributor 213, an air pipe 214, a filter screen 215 and a support plate 216. The arrangement of the liquid distributor and the air pipe plays an important role in helping to optimize the water washing effect and improve the washing efficiency of the fly ash; the arrangement of the liquid distributor allows the washing water to enter the filter screen of the water washing hopper evenly, so that the water can more evenly contact the surface of the fly ash prepolymer crystals, and the water washing is more thorough; the water washing hopper in the present invention does not need to be provided with a stirring device, and during the water washing process There is no need for stirring device during the washing process. During the water washing process, air is supplied through the air pipe to form a gas disturbance effect. This gas disturbance can make the solidified ash particles more easily contact with the washing water, thereby improving the washing efficiency. However, it is difficult to achieve the same effect by stirring water washing with a traditional agitator. The gas disturbance effect adopted by the present invention consumes less energy than mechanical stirring, because the supply and treatment of gas are relatively simple, which can reduce the energy consumption of the water washing process to a certain extent. Moreover, when using the gas disturbance effect for water washing, there are no moving parts such as mechanical agitators, which can reduce the wear of the equipment and extend the service life of the equipment.

[0035] According to some preferred embodiments, the crystallizing agent used in the solidification molding is one or more of water glass, aluminum chloride, ferrous chloride, silicate cement, ferrous sulfate, ferric sulfate, and ferric chloride; in the present invention, the water glass is an aqueous solution of sodium silicate.

[0036] According to some preferred embodiments, the bottom of the washing hopper 21 is a conical bottom 217; in the present invention, it is preferred that the bottom of the washing hopper is conical, so that the water after washing can be quickly concentrated to the tip of the cone, thereby quickly discharged from the washing hopper, and the conical bottom can reduce the residual water after washing in the washing hopper, and the washing and solid-liquid separation are more thorough and efficient.

[0037] According to some preferred embodiments, n-level washing liquid barrels 22 are arranged in sequence, 1≤n≤15, preferably 2≤n≤15 (e.g., 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15); in the present invention, for example, Figure 3As shown, the washing liquid barrel 22 includes, for example, a first-stage washing liquid barrel 221, a second-stage washing liquid barrel 222, a third-stage washing liquid barrel 223, a fourth-stage washing liquid barrel 224, a fifth-stage washing liquid barrel 225, and finally an nth-stage washing liquid barrel 226 in sequence; the filter screen 215 is a cylindrical filter screen, and preferably, the mesh number of the filter screen 215 is 20 to 400 meshes, and the air pipe 214 is arranged near the bottom of the filter screen 215, for example, it can be 0.5 to 5 cm higher than the bottom of the filter screen 215; air holes are opened on the wall of the air pipe 214, specifically, for example, a part of the air pipe 214 located in the filter screen 215 and facing away from the bottom of the filter screen (that is, the side of the tube wall facing the top of the filter screen) is evenly opened with a plurality of air holes; the support plate 216 is connected to the washing hopper 21 on the inner wall of the washing hopper, and is located at the top (top) of the conical bottom of the washing hopper. In the present invention, the conical bottom is also recorded as the hopper cone bottom, that is, the support plate 216 is located at the top of the hopper cone bottom, and the cylindrical filter screen 215 is placed on the support plate 216, and the support plate 216 is used to provide support for the cylindrical filter screen; preferably, the pore size of the air hole is 0.01-1mm, one end of the air pipe 214 passes through the filter screen 215 and the side wall of the washing hopper 21 and is connected to a gas storage tank, preferably, the gas is nitrogen, carbon dioxide, air or exhaust gas; and / or the support plate 216 is provided with a through hole (for example, a plurality of through holes are evenly provided), the through hole has a diameter of 2-20mm, and the through hole passes through the upper and lower surfaces of the support plate 216.

[0038] According to some preferred embodiments, the liquid distributor 213 is a spray-type liquid distributor, and the outer edge diameter of the liquid distributor is slightly smaller than the inner diameter of the filter screen, for example, 2 to 10 cm smaller than the inner diameter of the filter screen; the length of the portion of the air pipe located in the filter screen is slightly smaller than the inner diameter of the filter screen, for example, 1 to 5 cm smaller than the inner diameter of the filter screen, and the end of the air pipe extending into the filter screen is in a closed state.

[0039] According to some preferred embodiments, the filter screen 215 is planar, the filter screen 215 is connected to the inner wall of the water washing hopper 21, the support plate 216 is connected to the inner wall of the water washing hopper 21, and is located at the top of the conical bottom of the water washing hopper. In the present invention, the conical bottom is also recorded as the hopper cone bottom, that is, the support plate 216 is located at the top of the hopper cone bottom, the planar filter screen 215 is located above the support plate 216, and the support plate 216 is used to provide support for the filter screen 215; the air pipe 2 14 is located above the filter screen 215, the air pipe 214 is, for example, 0.5 to 5 cm higher than the filter screen, and air holes are opened on the tube wall of the air pipe 214. Specifically, one end of the air pipe 214 passes through the side wall of the water washing hopper 21 and is connected to a gas storage tank. Preferably, the gas is nitrogen, carbon dioxide, air or exhaust gas. For example, the part of the air pipe located in the water washing hopper and facing the top of the water washing hopper is evenly provided with a plurality of air holes on the tube wall; preferably, the aperture of the air hole is 0.01 to 1 mm.

[0040] The present invention does not specifically limit the size of each component included in the system, the number of air holes in the air pipe, the number of through holes in the support plate, etc., and those skilled in the art can make selections according to needs.

[0041] According to some preferred embodiments, the fly ash solidification subsystem 1 comprises, in sequence, a fly ash raw material silo 11, a solidification molding machine 12 for solidifying and molding the fly ash raw material into solidified ash, and a solidified ash silo 13, for example, Figure 2 As shown; in the present invention, the solidification of fly ash is completed in the fly ash solidification subsystem: the fly ash raw material (granulated fly ash) in the fly ash raw material silo is taken, mixed with a crystallizing agent, and solidified in a solidification molding machine to obtain pre-polymerized crystals of fly ash (solidified ash), which are then stored in the solidified ash silo.

[0042] According to some preferred embodiments, the water wash liquid post-treatment subsystem 3 includes a physical sedimentation tank 31, a chemical sedimentation tank 32, a filter 33, a storage tank 34 and an evaporation crystallizer 35 in sequence, for example, Figure 5As shown; in the present invention, the washing liquid is first precipitated in a physical sedimentation tank, for example, the upper layer of liquid in the physical sedimentation tank is transported to a chemical sedimentation tank by a pump, and after adding chemical agents for stirring reaction, it is transported to a filter by a pump for solid-liquid separation, for example, the filtrate is transported to a storage tank by a pump, and finally the water in the storage tank enters an evaporation crystallizer to obtain salt and pure water, and the pure water is reused to the washing subsystem; the washing liquid post-treatment subsystem in the present invention can realize the sedimentation of suspended matter in the washing liquid, and by adding chemical agents, the calcium and magnesium ions in the washing liquid can be removed (for example, calcium chloride and magnesium chloride can be removed), and the hardness of the washing liquid can be reduced; by filtering, the tiny suspended matter inside is removed, and finally through the evaporation crystallizer, the separation of sodium chloride and potassium chloride can be realized, and the resource utilization of salt in fly ash can be realized.

[0043] According to some preferred embodiments, the wet ash post-processing subsystem 4 includes a wet ash dryer 41 and a dry ash storage 42 in sequence, for example, Figure 6 As shown; the wet ash post-processing subsystem completes the post-processing of the wet ash: the wet ash obtained from the water washing subsystem is placed in a wet ash dryer for drying to obtain dry ash, and the dry ash is placed in a dry ash storage for storage.

[0044] According to some preferred embodiments, chemical agents are added to the chemical sedimentation tank 32, and the chemical agents are one or more of sodium hydroxide, sodium carbonate, sodium sulfate, sodium phosphate, and sodium sulfide; in the present invention, the amount of the chemical agent can be, for example, 0.1 to 10% of the mass of the upper liquid obtained after sedimentation in the physical sedimentation tank; and / or the evaporation crystallizer 35 is a multiple-effect evaporation crystallizer and / or an MVR evaporation crystallizer.

[0045] According to some preferred embodiments, the outlet of the fly ash solidification subsystem 1 is connected to the inlet of the water washing subsystem 2; the washing liquid obtained by the water washing subsystem 2 is connected to the inlet of the water washing liquid post-treatment subsystem 3, and the washing liquid is treated by the water washing liquid post-treatment subsystem 3 to obtain salt and pure water, and the obtained pure water is returned to the water washing subsystem 2; and / or the wet ash obtained by the water washing subsystem 2 is connected to the inlet of the wet ash post-treatment subsystem 4.

[0046] According to some preferred embodiments, when the solidified ash is washed in the washing hopper, the water-to-ash ratio is (0.75-2.75):1 (e.g., 0.75:1, 0.85:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.5:1 or 2.75:1), preferably (0.75-2):1; in the present invention, the water-to-ash ratio refers to the mass ratio of washing water to solidified ash of (0.75-2.75):1. , preferably (0.75~2): 1; when the curing molding machine is used for curing molding, the amount of the crystallizing agent is 2~20% (for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%) of the mass of the fly ash raw material, and preferably 5~10% (for example, 5%, 6%, 7%, 8%, 9% or 10%).

[0047] According to some specific implementation methods, a fly ash resource utilization system includes a fly ash solidification subsystem 1, a water washing subsystem 2, a water washing liquid post-processing subsystem 3, and a wet ash post-processing subsystem 4; the outlet of the fly ash solidification subsystem 1 is connected to the inlet of the water washing subsystem 2, the water washing liquid obtained by the water washing subsystem 2 is connected to the inlet of the water washing liquid post-processing subsystem 3, the wet ash obtained by the water washing subsystem 2 is connected to the inlet of the wet ash post-processing subsystem 4, and the pure water obtained by the water washing liquid post-processing subsystem 3 is used for the water washing subsystem 2; wherein the fly ash solidification subsystem 1 includes a fly ash raw material silo 11, a solidification molding machine 12, and a solidified ash silo 13; wherein the water washing subsystem 2 includes a water washing hopper 21, an n-level water washing liquid barrel 22, a pump 23, and a valve 24, wherein In the embodiment, the inlet of the pump 23 is connected to the outlet (outlet pipe) of the washing hopper 21 and the outlets of the washing liquid barrels 22 at various levels, and the outlet of the pump 23 is connected to the inlet (inlet pipe) of the washing hopper 21 and the inlet of the washing liquid barrels 22 at various levels; wherein the valve 24 is installed on the pipeline near the outlet and inlet of the washing liquid barrels 22 at various levels; wherein the washing hopper 21 is composed of an inlet pipe 211, an inlet valve 212, a liquid distributor 213, an air pipe 214, a filter screen 215, a support plate 216, an outlet pipe 219, and an outlet valve 218; the liquid distributor 213 is connected to the inlet pipe 211, the support plate 216 is located at the top of the cone bottom, the filter screen 215 is located above the support plate 216, and the air pipe 214 is located above the filter screen 215. The water washing barrel has a level of 1 to 15, the aperture of the support plate 216 is 2 mm to 20 mm, the mesh number of the filter 215 is 20 to 400 meshes, and the diameter of the surface holes (pores) of the air pipe 214 is 0.01 mm to 1 mm.

[0048] The water washing liquid post-processing subsystem 3 includes a physical sedimentation tank 31, a chemical sedimentation tank 32, a filter 33, a storage tank 34, and an evaporation crystallizer 35;

[0049] The wet ash post-processing subsystem 4 includes a wet ash dryer 41 and a dry ash storage 42 .

[0050] In a second aspect, the present invention provides a method for recycling fly ash, the method being performed using the fly ash recycling system of the first aspect of the present invention, and the method comprising the following steps:

[0051] (1) allowing the fly ash raw material to complete solidification and forming in the fly ash solidification subsystem to obtain solidified ash;

[0052] (2) placing the solidified ash in the washing hopper of the washing subsystem, and then performing a step-by-step washing process with water in the n-stage washing liquid barrel; in the step-by-step washing process, first washing with water in the first-stage washing liquid barrel, and then washing with water in the next-stage washing liquid barrel, until the n-stage washing process is completed, the water in the first-stage washing liquid barrel becomes washing liquid after washing; the water in the next-stage washing liquid barrel returns to the previous-stage washing liquid barrel after washing;

[0053] (3) The wet ash obtained after the step-by-step water washing process in step (2) is post-processed by a wet ash post-processing subsystem to obtain dry ash, and the washing liquid is passed into a washing liquid post-processing subsystem for post-processing of the washing liquid to obtain salt and pure water. The obtained pure water is returned to the washing liquid barrel of the washing subsystem, thereby completing the resource utilization of fly ash.

[0054] The system and method of the present invention have the advantages of good process economy, more convenient operation, low energy consumption cost, high efficiency, etc. The salt (sodium chloride and potassium chloride) extracted by the system and method of the present invention has high purity, which can reach more than 90%, which is beneficial to the subsequent application of the salt; the chlorine content of the dry ash treated by the system and method of the present invention is less than 1%.

[0055] According to some preferred embodiments, the obtained pure water is returned to the last-stage washing liquid barrel of the washing subsystem; and / or the post-treatment of the washing liquid is: the washing liquid is first precipitated in the physical sedimentation tank, and then the upper layer liquid in the physical sedimentation tank after sedimentation is transported to the chemical sedimentation tank and chemical agents are added for stirring reaction, and then transported to the filter for solid-liquid separation, and then the filtrate is transported to the storage tank, and finally the filtrate in the storage tank is transported to the evaporation crystallizer for evaporation and crystallization to obtain salt and pure water.

[0056] According to some preferred embodiments, in step (1), the solidification and molding is: taking the fly ash raw material in the fly ash raw material silo and mixing it evenly with the crystallizing agent, and then solidifying and molding it in a solidification molding machine to obtain solidified ash; and / or in step (3), the post-processing performed by the wet ash post-processing subsystem is: placing the obtained wet ash in a wet ash dryer for drying to obtain dry ash.

[0057] According to some specific implementations, the fly ash resource utilization method of the present invention includes the following steps: ① The solidification of fly ash is completed in the fly ash solidification subsystem: the granulated ash (fly ash raw material) in the fly ash raw material silo is taken, mixed with the crystallizing agent, and solidified in the solidification molding machine to obtain the pre-polymerized crystals of fly ash (solidified ash), which are stored in the solidified ash silo. ② The water washing of fly ash is completed in the water washing subsystem: the pre-polymerized crystals of fly ash in the solidified ash silo are placed in the water washing hopper, first washed with water in the first-stage water washing liquid barrel, the washed water is pumped to the physical sedimentation tank in the water washing liquid post-treatment subsystem, and then washed with water in the second-stage water washing liquid barrel, the washed water is pumped to the empty first-stage water washing liquid barrel, and then washed with water in the third-stage water washing liquid barrel, the washed water is pumped to the empty second-stage water washing liquid barrel, and the n-stage water washing process is completed in sequence. ③ Complete the post-processing of wet ash in the wet ash post-processing subsystem: Place the wet ash obtained from the water washing subsystem in the wet ash dryer to dry it to obtain dry ash, and store the dry ash in the dry ash storage. ④ Complete the post-processing of the water washing liquid in the water washing liquid post-processing subsystem: The water washing liquid is first settled in the physical sedimentation tank, and the upper layer of the physical sedimentation tank is pumped to the chemical sedimentation tank, and after adding chemical agents for stirring and reaction, it is pumped to the filter for solid-liquid separation, and then the filtrate is pumped to the storage tank, and finally the filtrate in the storage tank enters the evaporation crystallizer to obtain salt and pure water, and the pure water is reused to the water washing subsystem.

[0058] The present invention will be further described below by way of examples, but the protection scope of the present invention is not limited to these embodiments.

[0059] Example 1

[0060] A fly ash resource utilization system comprises a fly ash solidification subsystem, a water washing subsystem, a water washing liquid post-processing subsystem, and a wet ash post-processing subsystem.

[0061] The fly ash solidification subsystem is used to solidify the fly ash raw material into solidified ash. The fly ash solidification subsystem includes a fly ash raw material silo, a solidification molding machine, and a solidified ash silo; a water washing subsystem for washing the solidified ash, the water washing subsystem includes a water washing hopper, an n-level water washing liquid barrel and a pump, the water washing hopper includes a filter screen for placing solidified ash, a liquid distributor located on the top of the filter screen, an air pipe for conveying gas (air) into the water washing hopper, and a support plate for supporting the filter screen, the liquid distributor is connected to an inlet pipe, and the water washing hopper is connected to a liquid distributor. The bottom of the hopper is connected with an outlet pipe, the bottom of the water washing hopper is a conical bottom, the inlet of the pump is connected with the outlet pipe and the outlet of each level of water washing liquid barrel, the outlet of the pump is connected with the inlet pipe and the inlet of each level of water washing liquid barrel, the inlet pipe is provided with an inlet valve, the outlet pipe is provided with an outlet valve, the inlet pipeline and the outlet pipeline of each level of water washing liquid barrel are provided with valves, and the n-level water washing subsystem is realized by controlling the inlet valve, the outlet valve and the valves provided on the inlet pipeline and the outlet pipeline of each level of water washing liquid barrel. The filter screen is a cylindrical filter screen, the air pipe is arranged near the bottom of the filter screen, one end of the air pipe passes through the filter screen and the side wall of the water washing hopper and is connected to a gas storage tank, a plurality of air holes are evenly opened on the pipe wall of the air pipe, specifically, a portion of the air pipe located in the filter screen and a plurality of air holes are evenly opened on the pipe wall on the side away from the bottom of the filter screen, and the end of the air pipe extending into the filter screen is in a closed state; a plurality of through holes are evenly opened in the support plate; the number of stages of the water washing liquid barrel is 15, and the through holes in the support plate The aperture of the through hole is 2 mm, the mesh number of the filter is 20 meshes, the diameter of the pores of the air pipe is 0.01 mm, and in each stage of water washing, the water-ash ratio is 0.75:1; the water washing liquid post-processing subsystem includes a physical sedimentation tank, a chemical sedimentation tank, a filter, a storage tank, and an evaporation crystallizer. In the chemical sedimentation tank, sodium carbonate and sodium hydroxide with a mass ratio of 10:1 are used as chemical agents, and the amount of the chemical agent is 10% of the mass of the upper layer liquid after sedimentation in the physical sedimentation tank; the wet ash post-processing subsystem includes a wet ash dryer and a dry ash storage.

[0062] The method for utilizing the fly ash resource utilization system in this embodiment includes the following steps:

[0063] ① The solidification of fly ash is completed in the fly ash solidification subsystem: the granulated ash (fly ash raw material) in the fly ash raw material silo is taken, mixed with a crystallizing agent, and solidified in a solidification molding machine to obtain a pre-polymerized crystal of fly ash (solidified ash), which is then stored in a solidified ash silo; the crystallizing agent used in the solidification molding is water glass and aluminum chloride in a mass ratio of 1:1, and the water glass is a sodium silicate aqueous solution with a concentration of 38wt%, that is, the mass fraction of sodium silicate in the sodium silicate aqueous solution is 38%; the amount of the crystallizing agent used is 8% of the mass of the fly ash raw material; the solidification molding is solidification molding at 120°C for 20 minutes.

[0064] ② Complete the washing of fly ash in the washing subsystem: take the pre-polymerized crystals of fly ash in the solidified ash silo and place them in the washing hopper. First wash them with the water in the first-stage washing liquid barrel. The washed water (as washing liquid) is pumped to the physical sedimentation tank in the washing liquid post-treatment subsystem. Then wash them with the water in the second-stage washing liquid barrel. The washed water is pumped to the empty first-stage washing liquid barrel. Then wash them with the water in the third-stage washing liquid barrel. The washed water is pumped to the empty second-stage washing liquid barrel. The n-stage (15-stage) washing process is completed in sequence.

[0065] ③ Complete the post-processing of wet ash in the wet ash post-processing subsystem: place the wet ash obtained from the water washing subsystem in a wet ash dryer to dry it to obtain dry ash, and store the dry ash in a dry ash storage.

[0066] ④ Complete the post-treatment of the washing liquid in the washing liquid post-treatment subsystem: the washing liquid is first settled in the physical sedimentation tank, and the upper layer of the liquid in the physical sedimentation tank is pumped to the chemical sedimentation tank, and after adding chemical agents for stirring reaction, it is pumped to the filter for solid-liquid separation, and then the filtrate is pumped to the storage tank, and finally the filtrate in the storage tank enters the evaporation crystallizer to obtain salt and pure water, and the pure water is reused in the last-stage washing liquid barrel in the washing subsystem.

[0067] Example 2

[0068] A fly ash resource utilization system comprises a fly ash solidification subsystem, a water washing subsystem, a water washing liquid post-processing subsystem, and a wet ash post-processing subsystem.

[0069] The fly ash solidification subsystem is used to solidify the fly ash raw materials into solidified ash. The fly ash solidification subsystem includes a fly ash raw material silo, a solidification molding machine, and a solidified ash silo; a water washing subsystem for washing the solidified ash, the water washing subsystem includes a water washing hopper, a three-stage water washing liquid barrel and a pump, the water washing hopper includes a filter screen for placing solidified ash, a liquid distributor located on the top of the filter screen, an air pipe for conveying gas (air) into the filter screen, and a support plate for supporting the filter screen, the liquid distributor is connected to an inlet pipe, and the water washing hopper is connected to a liquid distributor. The bottom of the hopper is connected with an outlet pipe, the bottom of the water washing hopper is a conical bottom, the inlet of the pump is connected with the outlet pipe and the outlet of each level of water washing liquid barrel, the outlet of the pump is connected with the inlet pipe and the inlet of each level of water washing liquid barrel, the inlet pipe is provided with an inlet valve, the outlet pipe is provided with an outlet valve, the inlet pipeline and the outlet pipeline of each level of water washing liquid barrel are provided with valves, and the three-level water washing subsystem is realized by controlling the inlet valve, the outlet valve and the valves provided on the inlet pipeline and the outlet pipeline of each level of water washing liquid barrel. Water washing process; the filter screen is a cylindrical filter screen, the air pipe is arranged near the bottom of the filter screen, one end of the air pipe passes through the filter screen and the side wall of the water washing hopper and is connected to a gas storage tank, a plurality of air holes are evenly opened on the pipe wall of the air pipe, specifically, a portion of the air pipe located in the filter screen and a plurality of air holes are evenly opened on the pipe wall on the side away from the bottom of the filter screen, and the end of the air pipe extending into the filter screen is in a closed state; a plurality of through holes are evenly opened in the support plate; the number of stages of the water washing liquid barrel is 3, and the support plate The aperture of the through hole is 2mm, the mesh number of the filter is 20 meshes, the diameter of the pores of the air pipe is 0.01mm, and the water-ash ratio is 2:1 in each stage of water washing; the water washing liquid post-processing subsystem includes a physical sedimentation tank, a chemical sedimentation tank, a filter, a storage tank, and an evaporation crystallizer. In the chemical sedimentation tank, sodium carbonate and sodium sulfide with a mass ratio of 10:1 are used as chemical agents, and the amount of the chemical agent is 10% of the mass of the upper layer liquid after sedimentation in the physical sedimentation tank; the wet ash post-processing subsystem includes a wet ash dryer and a dry ash storage.

[0070] The method for utilizing the fly ash resource utilization system in this embodiment includes the following steps:

[0071] ① The solidification of fly ash is completed in the fly ash solidification subsystem: the granulated ash (fly ash raw material) in the fly ash raw material silo is taken, mixed with a crystallizing agent, and solidified in a solidification molding machine to obtain a pre-polymerized crystal of fly ash (solidified ash), which is then stored in a solidified ash silo; the crystallizing agent used in the solidification molding is water glass and aluminum chloride in a mass ratio of 1:1, and the water glass is a sodium silicate aqueous solution with a concentration of 38wt%, that is, the mass fraction of sodium silicate in the sodium silicate aqueous solution is 38%; the amount of the crystallizing agent used is 8% of the mass of the fly ash raw material; the solidification molding is solidification molding at 120°C for 20 minutes.

[0072] ② Complete the washing of fly ash in the washing subsystem: take the pre-polymerized crystals of fly ash in the solidified ash silo and place them in the washing hopper. First wash them with the water in the first-stage washing liquid barrel, and then pump the washed water (as washing liquid) to the physical sedimentation tank in the washing liquid post-treatment subsystem. Then wash them with the water in the second-stage washing liquid barrel, and then pump the washed water to the empty first-stage washing liquid barrel. Then wash them with the water in the third-stage washing liquid barrel, and then pump the washed water to the empty second-stage washing liquid barrel, and complete the three-stage washing process in sequence.

[0073] ③ Complete the post-processing of wet ash in the wet ash post-processing subsystem: place the wet ash obtained from the water washing subsystem in a wet ash dryer to dry it to obtain dry ash, and store the dry ash in a dry ash storage.

[0074] ④ Complete the post-treatment of the washing liquid in the washing liquid post-treatment subsystem: the washing liquid is first settled in the physical sedimentation tank, and the upper layer of the liquid in the physical sedimentation tank is pumped to the chemical sedimentation tank, and after adding chemical agents for stirring reaction, it is pumped to the filter for solid-liquid separation, and then the filtrate is pumped to the storage tank, and finally the filtrate in the storage tank enters the evaporation crystallizer to obtain salt and pure water, and the pure water is reused in the third-level washing liquid barrel in the washing subsystem.

[0075] The system and method of the present invention have the advantages of good process economy, more convenient operation, low energy consumption cost, high efficiency, etc. The salt (sodium chloride and potassium chloride) extracted by the system and method of Examples 1 and 2 of the present invention has high purity, which can reach more than 90%, which is beneficial to the subsequent application of the salt; the chlorine content of the dry ash treated by the system and method of Examples 1 and 2 of the present invention is less than 1%.

[0076] Parts of the present invention that are not described in detail are well known to those skilled in the art.

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. 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 fly ash resource system, characterized in that: The system comprises: A fly ash solidification subsystem for solidifying and shaping fly ash raw materials into solidified ash; A water washing subsystem for washing solidified ash with water, the water washing subsystem comprising a water washing hopper, n-stage water washing liquid barrels and a pump, the water washing hopper comprising a filter screen for placing solidified ash, a liquid distributor located on the top of the filter screen, an air pipe for conveying gas into the water washing hopper and a support plate for supporting the filter screen, the liquid distributor is connected to an inlet pipe, the bottom of the water washing hopper is connected to an outlet pipe, the inlet of the pump is connected to the outlet pipe and the outlet of each stage of the water washing liquid barrel, the outlet of the pump is connected to the inlet pipe and the inlet of each stage of the water washing liquid barrel, the inlet pipe is provided with an inlet valve, the outlet pipe is provided with an outlet valve, and valves are provided on the inlet pipeline and the outlet pipeline of each stage of the water washing liquid barrel; A water washing liquid post-processing subsystem for post-processing the water washing liquid obtained from the water washing subsystem; and A wet ash post-processing subsystem is used to post-process the wet ash obtained from the water washing subsystem.

2. The system according to claim 1, characterized in that: The crystallizing agent used in the solidification molding is one or more of water glass, aluminum chloride, ferrous chloride, silicate cement, ferrous sulfate, ferric sulfate, and ferric chloride.

3. The system according to claim 1, characterized in that: The bottom of the water washing hopper is a conical bottom; n-level washing liquid barrels are arranged in sequence, 1≤n≤15, preferably 2≤n≤15; The filter screen is a cylindrical filter screen, preferably, the mesh number of the filter screen is 20-400 meshes, the air pipe is arranged near the bottom of the filter screen, and air holes are opened on the wall of the air pipe, preferably, the aperture of the air holes is 0.01-1 mm, one end of the air pipe passes through the filter screen and the side wall of the washing hopper and is connected to a gas storage tank, preferably, the gas is nitrogen, carbon dioxide, air or tail gas; and / or The support plate is provided with a through hole, and the diameter of the through hole is 2 to 20 mm.

4. The system according to claim 1, characterized in that: The fly ash solidification subsystem includes, in sequence, a fly ash raw material silo, a solidification molding machine for solidifying and molding the fly ash raw material into solidified ash, and a solidified ash silo; The water washing liquid post-processing subsystem includes a physical sedimentation tank, a chemical sedimentation tank, a filter, a storage tank and an evaporation crystallizer in sequence; and / or The wet ash post-processing subsystem includes a wet ash dryer and a dry ash storage in sequence.

5. The system according to claim 4, characterized in that: Chemical agents are added to the chemical sedimentation tank, and the chemical agents are one or more of sodium hydroxide, sodium carbonate, sodium sulfate, sodium phosphate, and sodium sulfide; and / or The evaporation crystallizer is a multiple-effect evaporation crystallizer and / or an MVR evaporation crystallizer.

6. The system according to claim 1, characterized in that: The outlet of the fly ash solidification subsystem is connected to the inlet of the water washing subsystem; The washing liquid obtained by the washing subsystem is connected to the inlet of the washing liquid post-processing subsystem, and the washing liquid is processed by the washing liquid post-processing subsystem to obtain salt and pure water, and the obtained pure water is returned to the washing subsystem; and / or The wet ash obtained by the water washing subsystem is connected to the inlet of the wet ash post-processing subsystem.

7. The system according to claim 1, characterized in that: When the solidified ash is washed in the washing hopper, the water-to-ash ratio is (0.75-2.75):1, preferably (0.75-2):1; and / or When the solidification molding machine is used for solidification molding, the amount of the crystallizing agent is 2-20% of the mass of the fly ash raw material, preferably 5-10%.

8. A method for recycling fly ash, characterized in that: The method is carried out using the fly ash resource recovery system according to any one of claims 1 to 7, and the method comprises the following steps: (1) allowing the fly ash raw material to complete solidification and forming in the fly ash solidification subsystem to obtain solidified ash; (2) placing the solidified ash in the water washing hopper of the water washing subsystem, and then performing a step-by-step water washing process using water in n-level water washing liquid barrels; In the step-by-step washing process, the water in the first-stage washing liquid bucket is first used for washing, and then the water in the next-stage washing liquid bucket is used for washing, until the n-stage washing process is completed, and the water in the first-stage washing liquid bucket becomes washing liquid after washing; The water in the next level washing liquid barrel is returned to the previous level washing liquid barrel after washing; (3) The wet ash obtained after the step-by-step water washing process in step (2) is post-processed by a wet ash post-processing subsystem to obtain dry ash, and the washing liquid is passed into a washing liquid post-processing subsystem for post-processing of the washing liquid to obtain salt and pure water. The obtained pure water is returned to the washing liquid barrel of the washing subsystem, thereby completing the resource utilization of fly ash.

9. The method according to claim 8, characterized in that: The obtained pure water is returned to the last-stage water washing liquid barrel of the water washing subsystem; and / or The post-treatment of the washing liquid is as follows: the washing liquid is first precipitated in the physical sedimentation tank, and then the upper layer liquid in the physical sedimentation tank after sedimentation is transported to the chemical sedimentation tank and chemical agents are added for stirring reaction, and then transported to the filter for solid-liquid separation, and then the filtrate is transported to the storage tank, and finally the filtrate in the storage tank is transported to the evaporation crystallizer for evaporation and crystallization to obtain salt and pure water.

10. The method according to claim 8, characterized in that: In step (1), the solidification molding is: taking the fly ash raw material in the fly ash raw material bin and mixing it with the crystallizing agent evenly, and then solidifying and molding it in a solidification molding machine to obtain solidified ash; and / or In step (3), the post-processing performed by the wet ash post-processing subsystem is as follows: placing the obtained wet ash in a wet ash dryer for drying to obtain dry ash.

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