Fly ash washing and comprehensive resource utilization system

Abstract

The embodiment of the present invention relates to a fly ash water washing and desalination treatment technology, and discloses a fly ash water washing and resource comprehensive utilization system. The filter press residue outlet of the fly ash calcium and heavy metal solidification unit is connected to the inlet of the cascade backwash dechlorination unit, and the filter press outlet is connected to the inlet of the filter press desulfurization unit; the eluent outlet of the cascade backwash dechlorination unit is connected to the inlet of the fly ash calcium and heavy metal coordinated solidification unit, and the backwash dechlorination residue washing outlet is connected to the inlet of the drying unit; the liquid outlet of the filter press desulfurization unit is connected to the inlet of the evaporation salt production unit, and the eluent desulfurization residue outlet is connected to the inlet of the fly ash calcium and heavy metal coordinated solidification unit; condensed water returns to the cascade backwash dechlorination unit for reuse; the residue washing and drying unit outlet is connected to the cement kiln inlet, the chlorine content in the fly ash is less than 1%, and can be directly used as a cement raw material. Various indicators of the eluent meet the GB8978 emission standard, and can be directly fed into an industrial sewage treatment plant or evaporated to produce salt to obtain potassium and sodium salt products, thereby realizing the "three-transformation" treatment of fly ash.

Description

Technical Field

[0001] The embodiments of the present invention relate to a fly ash water washing and desalination treatment technology, and in particular to a fly ash water washing and resource comprehensive utilization system. Background Art

[0002] Fly ash harmless treatment. Waste incineration fly ash is collected in heat recovery and flue gas purification systems after waste incineration. Industrial waste incinerators typically use Ca(OH)2 bag filters to remove dust. Fly ash contains heavy metals such as lead, zinc, and copper, dioxins, and a large amount of soluble chloride salts. If improperly handled, heavy metals and brine can migrate and contaminate groundwater, soil, and air. Therefore, it must be treated. Common treatment methods include: 1. Landfill as hazardous waste after appropriate treatment. However, this treatment is costly; 2. Solidification and stabilization methods, including cement solidification, asphalt solidification, melt solidification, and chemical solidification and stabilization. Solidified fly ash that meets leaching toxicity standards can be landfilled as ordinary waste. Its main function is to render the heavy metals and other pollutants in fly ash chemically inert or contain them for easier transportation and disposal, while also reducing the toxicity of pollutants and their migration into the ecosystem. Thirdly, fly ash is washed and dechlorinated, and then used directly as a cement additive. Heavy metals are dispersed in cement clinker, meeting safety standards, and dioxins are harmlessly decomposed during kiln calcination. The third method, which utilizes pollutants in fly ash as a resource, offers significant economic benefits and avoids secondary pollution from fly ash pollutants, presenting a distinct advantage.

[0003] Washing and dechlorinating fly ash after incineration for use as a raw material in building materials such as cement is an important and economical approach to harmless fly ash disposal. A common method in the market is to remove chloride ions from fly ash through washing, thereby meeting the standards for cement raw materials. Excessive chloride ions in cement-reinforced concrete systems can accelerate corrosion of materials such as rebar. The cement quality standard GB175-2007 requires a chloride ion content of <0.06%, and as a raw material for cement, the chloride content should be <1%.

[0004] The inventors of the present invention have discovered the following problems with the existing technology: Current equipment and processes for harmlessly treating fly ash for use as a cement raw material suffer from high residual chlorine content, high residual moisture content, high energy and water consumption, and the resulting secondary environmental pollution. There is an urgent need for a fly ash harmless treatment device that can effectively remove chloride ions while conserving energy and water resources. Summary of the Invention

[0005] The purpose of the embodiment of the present invention is to provide a fly ash washing and resource comprehensive utilization system, which can effectively remove chloride ions and save energy and water resources for fly ash harmless treatment equipment.

[0006] To solve the above technical problems, the embodiments of the present invention provide a fly ash washing and resource comprehensive utilization system, comprising: a fly ash silo, a fly ash calcium and heavy metal synergistic solidification unit, a cascade backwash dechlorination unit, a drying unit, a filter press desulfurization unit, an evaporation salt production unit, and a cement kiln unit;

[0007] Wherein, the fly ash calcium and heavy metal collaborative solidification unit is provided with a filter press residue outlet and a filter press liquid outlet, the filter press residue outlet is connected to the inlet of the cascade backwash dechlorination unit, and the filter press liquid outlet is connected to the inlet of the filter press liquid desulfurization unit; the eluent outlet of the cascade backwash dechlorination unit is connected to the inlet of the fly ash calcium and heavy metal collaborative solidification unit, and the slag washing outlet of the backwash dechlorination is connected to the inlet of the drying unit; the liquid outlet of the filter press liquid desulfurization unit is connected to the inlet of the evaporation salt production unit, and the eluent desulfurization residue outlet of the filter press liquid desulfurization unit is connected to the inlet of the fly ash calcium and heavy metal collaborative solidification unit; the condensed water generated by the evaporation salt production unit is returned to the cascade backwash dechlorination unit for reuse; the slag washing and drying unit outlet is connected to the inlet of the cement kiln.

[0008] Further optionally, the fly ash calcium and heavy metal synergistic solidification unit includes a high-efficiency premixer, a calcium and heavy metal solidification reactor, a solidifying agent silo, an extrusion filter press and an ammonia absorption tower;

[0009] The inlet of the high-efficiency premixer is respectively connected to the outlet of the fly ash metering device, the outlet of the water distribution metering device, the outlet of the curing agent silo, and the desulfurization residue outlet of the filter press desulfurization unit; the outlet of the high-efficiency premixer is connected to the inlet of the calcium and heavy metal solidification reactor; the material outlet of the calcium and heavy metal solidification reactor is connected to the inlet of the squeeze filter press; the filter press outlet of the squeeze filter press is connected to the inlet of the eluent desulfurization unit; the filter press residue outlet is connected to the inlet of the cascade backwash dechlorination unit; and the gas outlet of the calcium and heavy metal solidification reactor is connected to the inlet of the ammonia absorption tower.

[0010] Further optionally, the cascade backwash dechlorination unit includes a high-efficiency water washing tank and a backwash filter press or a belt filter, the inlet of the high-efficiency water washing tank is connected to the outlet of the filter press residue, the outlet of the high-efficiency water washing tank is connected to the inlet of the backwash filter press or the belt filter, the backwash liquid of the backwash filter press or the belt filter is connected to the inlet of the water distribution metering device of the fly ash calcium and heavy metal collaborative solidification unit, and the filter residue of the backwash filter press or the belt filter is connected to the inlet of the drying unit.

[0011] Further optionally, the eluent desulfurization unit includes a solid sulfur reactor, a solid-liquid separation and concentration device, a desulfurizer silo, and an acid storage tank. The inlet of the solid sulfur reactor is respectively connected to the filtrate outlet of the fly ash calcium and heavy metal collaborative solidification unit filter press, the outlet of the acid metering device, and the outlet of the desulfurizer silo. The inlet of the solid sulfur reactor is connected to the inlet of the solid-liquid separation and concentration device. The filtrate outlet of the third filter press or precision filter is connected to the inlet of the evaporation salt production unit. The residue or concentrated phase of the third filter press or precision filter is connected to the inlet of the high-efficiency premixer.

[0012] Further optionally, the drying unit includes a conveyor belt, a dryer, and a dry fly ash silo, the outlet of the conveyor belt is connected to the inlet of the dryer, the outlet of the dryer is connected to the inlet of the dry fly ash silo, and the outlet of the dry fly ash silo is connected to the kiln calcination unit.

[0013] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0015] Figure 1 This is a schematic diagram of the structure of the fly ash washing and resource comprehensive utilization system in an embodiment of the present invention;

[0016] Figure 2 yes Figure 1 The system shown is a schematic structural diagram of a specific example.

[0017] Fly ash calcium and heavy metal synergistic solidification unit 1, cascade backwash dechlorination unit 2, filter press desulfurization unit 3, drying unit 4, evaporation salt production unit 5, cement kiln unit 6;

[0018] High-efficiency premixer 11, curing reactor 12, curing agent silo 13, (primary) press 14 and ammonia absorption tower 15, fly ash silo 16, (secondary) high-efficiency water washing tank 17, secondary backwash filter press or belt filter 18, tertiary backwash filter press or belt filter 19, (tertiary) high-efficiency water washing tank 20, desulfurization and calcium solidification reactor 21, filter 22, desulfurizer silo 23, heavy metal curing agent silo 24. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, each embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be understood by those skilled in the art that in each embodiment of the present invention, many technical details are provided to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with each other and referenced to each other under the premise that there is no contradiction.

[0020] The first embodiment of the present invention relates to a fly ash washing and resource comprehensive utilization system, as shown in the figure, comprising: a fly ash silo 16, a fly ash calcium and heavy metal synergistic solidification unit 1, a cascade backwash dechlorination unit 2, a press filtrate desulfurization unit 3, a drying unit 4, an evaporation salt production unit 5 and a cement kiln unit 6;

[0021] Among them, the fly ash calcium and heavy metal synergistic solidification unit is provided with a filter press residue outlet and a filter press liquid outlet, the filter press residue outlet is connected to the inlet of the cascade backwash dechlorination unit, and the filter press liquid outlet is connected to the inlet of the filter press liquid desulfurization unit; the eluent outlet of the cascade backwash dechlorination unit is connected to the inlet of the fly ash calcium and heavy metal synergistic solidification unit, and the slag washing outlet of the backwash dechlorination is connected to the inlet of the drying unit; the liquid outlet of the filter press liquid desulfurization unit is connected to the inlet of the evaporation salt making unit, and the eluent desulfurization slag outlet of the filter press liquid desulfurization unit is connected to the inlet of the fly ash calcium and heavy metal synergistic solidification unit; the condensed water generated by the evaporation salt making unit is returned to the cascade backwash dechlorination unit for reuse; the slag washing and drying unit outlet is connected to the cement kiln inlet.

[0022] Further optionally, the fly ash calcium and heavy metal synergistic solidification unit includes a high-efficiency premixer 11, a solidification reactor 12, a solidifying agent silo 13, a (primary) press 14 and an ammonia absorption tower 15;

[0023] The inlet of the high-efficiency premixer 11 is respectively connected to the outlet of the fly ash metering device, the outlet of the water distribution metering device, the outlet of the curing agent silo 13, and the desulfurization residue outlet of the filter press desulfurization unit; the outlet of the high-efficiency premixer 11 is connected to the inlet of the curing reactor 12; the material outlet of the curing reactor 12 is connected to the inlet of the (first-level) press 14; the filter press outlet of the (first-level) press 14 is connected to the inlet of the eluent desulfurization unit; the filter press residue outlet is connected to the inlet of the cascade backwash dechlorination unit; the gas outlet of the curing reactor 12 is connected to the inlet of the ammonia absorption tower 15; the (first-level) press 14 can be an extrusion filter press.

[0024] like Figure 2As shown, the fly ash calcium and heavy metal synergistic solidification unit may include: a fly ash silo 16, a high-efficiency premixer 11, a (primary) press 14, a solidifying agent silo 13, an ammonia absorption tower 15, a solidification reactor 12 and a water supply device.

[0025] The high-efficiency premixer 11 pre-treats the fly ash, pre-mixing the solidifying agent silo 13 with the fly ash. The solidifying agent solidifies the calcium and heavy metals in the fly ash. The solidifying agent is composed of one or more of ferrous sulfate heptahydrate, aluminum sulfate, potassium sulfate, sodium sulfate, ferric sulfate, sodium carbonate, sodium bisulfate, potassium bisulfate, and magnesium sulfate. The high-efficiency premixer 11 is equipped with a gas inlet, a liquid inlet, a material inlet, a gas outlet, and a mixture outlet.

[0026] The fly ash silo 16 is used to carry and transport fly ash. The outlet of the fly ash silo 16 is connected to the gas inlet of the high-efficiency premixer 11. The fly ash silo 16 blows the fly ash into the high-efficiency premixer 11 in the form of gas through air pressure transportation.

[0027] The inlet of the ammonia absorption tower 15 is connected to the gas outlet of the high-efficiency premixer 11; the ammonia absorption tower 15 is used to absorb ammonia in the fly ash, thereby reducing the ammonia nitrogen content in the fly ash. Distilled water or weak hydrochloric acid is used as the absorption liquid inside the ammonia absorption tower 15.

[0028] The outlet of the curing agent silo 13 is connected to the material inlet of the high-efficiency premixer 11. The curing agent silo 13 carries curing agent, and is transported and replenished when the curing agent content in the high-efficiency premixer 11 is reduced.

[0029] The outlet of the water supply device is connected to the liquid inlet of the high-efficiency premixer 11. The water supply inlet of the water supply device is provided with a water metering device. The water supply device is used to add liquid water to the curing reactor and calculate the amount of water to be added through the water metering device.

[0030] The mixture outlet of the high-efficiency premixer 11 is connected to the inlet of the curing reactor 12, which is a vertical or horizontal agitator. The mixture conveyed by the high-efficiency premixer 11 undergoes a thorough contact reaction in the curing reactor 12. The outlet of the curing reactor 12 is connected to the inlet of a (primary) press 14; the (primary) press 14 filters the mixture discharged from the curing reactor 12. The filtrate from the (primary) press 14 enters the water purification system, and the filter residue enters the water washing and dechlorination reactor. The (primary) press 14 is selected from a filter press, a belt filter, a horizontal spiral centrifuge, and a disc centrifuge.

[0031] Further optionally, the cascade backwash dechlorination unit includes a high-efficiency water washing tank and a backwash filter press or a belt filter, the inlet of the high-efficiency water washing tank is connected to the outlet of the filter press residue, the outlet of the high-efficiency water washing tank is connected to the inlet of the backwash filter press or the belt filter, the backwash liquid of the backwash filter press or the belt filter is connected to the inlet of the water distribution metering device of the fly ash calcium and heavy metal collaborative solidification unit, and the filter residue of the backwash filter press or the belt filter is connected to the inlet of the drying unit.

[0032] like Figure 2 As shown, in some embodiments, the cascade backwash dechlorination unit mainly includes: a fly ash silo 16, a high-efficiency premixer 11, a (primary) press 14, a (secondary) high-efficiency water washing tank 17, a secondary backwash filter press or belt filter 18, a (tertiary) high-efficiency water washing tank 20, a tertiary backwash filter press or belt filter 19, a curing agent silo 13, an ammonia absorption tower 15, and a high-efficiency premixer 11.

[0033] During the first startup, the fly ash in the fly ash silo 16 enters the high-efficiency premixer 11 along with the conveying system, and the fly ash and water premix is ​​completed through the water inlet of the high-efficiency premixer 11, and enters the ammonia absorption tower 15 through the pipeline; the fly ash and water premix enters the high-efficiency premixer 11, and the calcium element and heavy metal in the fly ash are synergistically solidified under the action of the solidifying agent added in the solidifying agent silo 13, and the chloride ions are preliminarily dissolved in the water; the fly ash, chloride ions and solidified mixture are separated from the heavy metal solidified matter, part of the chloride ions and the fly ash under the action of the (primary) press 14; the eluent of the (primary) press 14 is processed separately; the solid matter filtered by the (primary) press 14 enters the (secondary) high-efficiency water washing The mixture enters the secondary backwash filter press or belt filter 18, where the chloride-containing filtrate and the fly ash-containing solids are separated, further reducing the chlorine content in the solids. The fly ash-containing solids from the secondary filter press enter the (tertiary) high-efficiency water washing tank 20 and are mixed with the make-up water and enter the tertiary backwash filter press or belt filter. The filtrate generated by the secondary filter press flows back to the high-efficiency premixer 11. The tertiary backwash filter press or belt filter 19 separates the chloride-containing filtrate and the fly ash-containing solids, where the filtrate flows back to the (secondary) high-efficiency water washing tank 17, where the solids are dehydrated and washed to obtain a fly ash concentrated product.

[0034] The high-efficiency premixer 11 is provided with a water supply port, and the outlet of the fly ash silo 16 is connected to the feed port of the high-efficiency premixer 11; the outlets of the filtration liquid and backwash liquid of the high-efficiency premixer 11, the curing agent silo 13, the secondary backwash filter press or the belt filter 18 are connected to the inlet of the high-efficiency premixer 11; the gas outlet of the high-efficiency premixer 11 is connected to the inlet of the ammonia absorption tower 15; after washing is completed, the slurry outlet of the high-efficiency premixer 11 is connected to the inlet of the (primary) press 14 for solid-liquid separation; the filtrate outlet of the (primary) press 14 is connected to the eluent purification system, and the dehydrated slag outlet enters the (secondary) high-efficiency water washing tank 17 through a conveyor belt.

[0035] At the same time, when the second and third-stage backwash filter presses or belt filters in the system run for a certain period, the filtration pressure is too high and the liquid output is small, and a backwash operation is required: the third-stage backwash filter press or belt filter 19 is replenished with water to generate a third-stage backwash eluent, which passes through the second-stage backwash filter press or belt filter 18 and is backwashed, and the generated second-stage backwash eluent is merged into the (first-stage) press.

[0036] In some optional embodiments, the liquid-to-solid ratio can be set to 1:1-2:1, the amount of eluent to be purified is only 50%-150% of the fly ash mass, and the chlorine content in the washed fly ash is <1%, which can be directly used as cement raw material.

[0037] Based on the previously disclosed embodiments, this document preferably discloses an embodiment of a fly ash washing and resource comprehensive utilization system. The system primarily comprises: a fly ash silo 16, a high-efficiency premixer 11, a (primary) press 14, a (secondary) high-efficiency water washing tank 17, a secondary backwash filter press or belt filter 18, a (tertiary) high-efficiency water washing tank 20, a tertiary backwash filter press or belt filter 19, a curing agent silo 13, an ammonia absorption tower 15, and a high-efficiency premixer 11.

[0038] In the stable operation state, the fly ash in the fly ash silo 16 enters the high-efficiency premixer 11 along with the conveying system, and is closed through the water supply port of the high-efficiency premixer 11. The fly ash and water premix is ​​completed by the secondary backwash filter press or the belt filter 18. The filtrate is partially filled with water to complete the fly ash and water premix, and enters the ammonia absorption tower 15 through the pipeline; the fly ash and water premix enters the high-efficiency premixer 11, and under the action of the curing agent added in the curing agent silo 13, the calcium element and heavy metal in the fly ash are synergistically solidified, and the chloride ions are preliminarily dissolved in the water; the fly ash, chloride ions and solidified mixture are separated from the heavy metal solidified material, part of the chloride ions and the fly ash under the action of the (primary) press 14; the eluent of the (primary) press 14 is processed separately; the (primary) press 14 filter solid The solid matter enters the (secondary) high-efficiency water washing tank 17 and is mixed with the filtrate of the tertiary backwash filter press or belt filter 19; the mixture enters the secondary backwash filter press or belt filter 18, and the chloride ion filtrate and the solid matter containing fly ash are separated, further reducing the chlorine content in the solid matter; the solid matter containing fly ash from the secondary filter press enters the (tertiary) high-efficiency water washing tank 20 and is mixed with the replenishing water and enters the tertiary backwash filter press or belt filter; the filtrate generated by the secondary filter press is refluxed to the high-efficiency premixer 11; the tertiary backwash filter press or belt filter 19 completes the separation of the chlorine-containing filtrate and the solid matter containing fly ash, wherein the filtrate is refluxed to the (secondary) high-efficiency water washing tank 17, and the solid matter is dehydrated and washed to obtain a fly ash concentrated product.

[0039] In some optional embodiments, the liquid-to-solid ratio can be set to 1:1-2:1, the amount of eluent to be purified is only 50%-150% of the fly ash mass, and the chlorine content in the washed fly ash is <1%, which can be directly used as cement raw material.

[0040] Based on the disclosed embodiments, in some embodiments, the specific parameters of the cascade backwash dechlorination unit are as follows:

[0041] Liquid-to-solid ratio of 2:1, the volume of eluent to be purified is only 120% of the fly ash mass; fly ash feed rate is 15 t / h; high-efficiency premixer water inlet during system startup is 30 t / h; high-efficiency premixer filtrate and backwash return volume is 30 t / h; first-stage high-efficiency water washing tank volume is 10 cubic meters; (first-stage) press processing capacity is 45 t / h; second-stage high-efficiency water washing tank volume is 5 cubic meters; second-stage backwash filter press or belt filter processing capacity is 45 t / h; third-stage high-efficiency water washing tank volume is 5 cubic meters; third-stage backwash filter press or belt filter processing capacity is 45 t / h; third-stage high-efficiency water washing tank water replenishment volume is 15 t / h;

[0042] Backwash water supply volume is 15t / h.

[0043] The test results show that the fly ash output after treatment is 12t / h, and the residual chlorine in the fly ash after washing is 0.5%.

[0044] Based on the disclosed embodiments, in some embodiments, the specific parameters of the cascade backwash dechlorination unit are as follows:

[0045] Liquid-to-solid ratio of 1:1, the volume of eluent to be purified is only 50% of the fly ash mass; fly ash feed rate is 10 t / h; water inlet to the high-efficiency premixer at system startup is 10 t / h; filtrate and backwash return volume to the high-efficiency premixer is 10 t / h; first-stage high-efficiency water washing tank volume is 5 cubic meters; (first-stage) press processing capacity is 20 t / h; second-stage high-efficiency water washing tank volume is 3 cubic meters; second-stage backwash filter press or belt filter processing capacity is 20 t / h; third-stage high-efficiency water washing tank volume is 3 cubic meters; third-stage backwash filter press or belt filter processing capacity is 20 t / h; third-stage high-efficiency water washing tank water replenishment is 6 t / h;

[0046] Backwash water supply volume 4t / h.

[0047] The test results show that the fly ash output after treatment is 8t / h, and the residual chlorine in the fly ash after washing is 0.98%.

[0048] Further optionally, the eluent desulfurization unit includes a solid sulfur reactor, a solid-liquid separation and concentration device, a desulfurizer silo, and an acid storage tank. The inlet of the solid sulfur reactor is respectively connected to the filtrate outlet of the fly ash calcium and heavy metal collaborative solidification unit filter press, the outlet of the acid metering device, and the outlet of the desulfurizer silo. The inlet of the solid sulfur reactor is connected to the inlet of the solid-liquid separation and concentration device, the filtrate outlet of the third filter press or precision filter is connected to the inlet of the evaporation salt production unit, and the filter residue or concentrated phase of the third filter press or precision filter is connected to the inlet of the high-efficiency premixer 11.

[0049] like Figure 2 As shown, in some optional embodiments, the filter press desulfurization unit includes: a fly ash water washing liquid storage tank, a desulfurization and calcium solidification reactor 21, a filter 22, a desulfurizer silo 23, and a heavy metal solidifying agent silo 24.

[0050] The desulfurization and calcium solidification reactor 21 carries a heavy metal solidifying agent and a desulfurizing agent, which solidify the sulfur, calcium, and heavy metals in the fly ash. The heavy metal solidifying agent comprises one or more of sodium sulfide, micro-nano zero-valent iron, polyaluminum chloride, PAM, and polyferric sulfate; the desulfurizing agent comprises one or more of hydrotalcite, witherite, barium chloride, barium carbonate, and sodium aluminate. The solidification reactor is equipped with a gas inlet, a liquid inlet, a material inlet, a gas outlet, and a slurry outlet.

[0051] The fly ash water washing liquid storage tank is used to carry and transport the fly ash water washing liquid, and the outlet of the fly ash water washing liquid storage tank is connected to the inlet of the desulfurization and calcium fixation reactor 21.

[0052] The outlet of the desulfurizer silo 23 is connected to the inlet of the desulfurization and calcium solidification reactor 21 ; the desulfurizer silo 23 is provided with a weight metering device, which can measure the weight of the desulfurizer input from the desulfurizer silo 23 to the desulfurization and calcium solidification reactor 21 .

[0053] The outlet of the heavy metal curing agent silo 24 is connected to the inlet of the desulfurization and calcium consolidation reactor 21. The heavy metal curing agent silo 24 carries a heavy metal curing agent. A weight metering device is provided on the heavy metal curing agent silo 24 to measure the weight of the desulfurization agent input from the heavy metal curing agent silo 24 to the desulfurization and calcium consolidation reactor 21. The weight metering devices of the heavy metal curing agent silo 24 and the desulfurization agent silo 23 can accurately calculate the weight ratio of the heavy metal curing agent and the desulfurization agent, thereby improving the desulfurization and heavy metal curing effects.

[0054] The outlet of the desulfurization and decalcification reactor 21 is connected to the inlet of a filtering machine. Filter 22 filters the liquid discharged from the desulfurization and decalcification reactor 21. The filtrate from filter 22 enters an evaporation and crystallization system or a sewage treatment system. The filtered concentrated phase liquid is returned to the fly ash washing process section, that is, to the desulfurization and decalcification reactor 21 for further desulfurization and decalcification to remove solids. Filter 22 is selected from a precision filter, a horizontal spiral centrifuge, a disc centrifuge, or a filter press.

[0055] Further optionally, the drying unit includes a conveyor belt, a dryer, and a dry fly ash silo, the outlet of the conveyor belt is connected to the inlet of the dryer, the outlet of the dryer is connected to the inlet of the dry fly ash silo, and the outlet of the dry fly ash silo is connected to the kiln calcining unit.

[0056] The above description is merely a preferred embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also encompasses other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A fly ash washing and resource comprehensive utilization system, characterized in that: include: Fly ash silo, fly ash calcium and heavy metal co-solidification unit, cascade backwash dechlorination unit, filter press desulfurization unit, drying unit, evaporation salt production unit and cement kiln unit; Wherein, the fly ash calcium and heavy metal collaborative solidification unit is provided with a filter press residue outlet and a filter press liquid outlet, the filter press residue outlet is connected to the inlet of the cascade backwash dechlorination unit, and the filter press liquid outlet is connected to the inlet of the filter press liquid desulfurization unit; the eluent outlet of the cascade backwash dechlorination unit is connected to the inlet of the fly ash calcium and heavy metal collaborative solidification unit, and the backwash dechlorination slag outlet is connected to the inlet of the drying unit; the liquid outlet of the filter press liquid desulfurization unit is connected to the inlet of the evaporation salt making unit, and the eluent desulfurization residue outlet of the filter press liquid desulfurization unit is connected to the inlet of the fly ash calcium and heavy metal collaborative solidification unit; the condensed water generated by the evaporation salt making unit is returned to the cascade backwash dechlorination unit for reuse; the slag washing and drying unit outlet is connected to the inlet of the cement kiln; The fly ash calcium and heavy metal synergistic solidification unit includes a high-efficiency premixer, a calcium and heavy metal solidification reactor, a solidifying agent silo, a filter press and an ammonia absorption tower; The inlet of the high-efficiency premixer is respectively connected to the outlet of the fly ash metering device, the outlet of the water distribution metering device, the outlet of the curing agent silo, and the desulfurization residue outlet of the filter press desulfurization unit; the outlet of the high-efficiency premixer is connected to the inlet of the calcium and heavy metal solidification reaction kettle; the material outlet of the calcium and heavy metal solidification reaction kettle is connected to the inlet of the filter press; the filter press filtrate outlet is connected to the inlet of the eluent desulfurization unit; the filter press residue outlet is connected to the inlet of the cascade backwash dechlorination unit; and the gas outlet of the calcium and heavy metal solidification reaction kettle is connected to the inlet of the ammonia absorption tower; The cascade backwash dechlorination unit includes a high-efficiency water washing tank and a backwash filter press or a belt filter. The inlet of the high-efficiency water washing tank is connected to the outlet of the fly ash and calcium solidification unit filter press residue, the outlet of the high-efficiency water washing tank is connected to the inlet of the backwash filter press or the belt filter, the backwash liquid and the filtrate of the backwash filter press or the belt filter are connected to the inlet of the water distribution metering device of the fly ash calcium and heavy metal coordinated solidification unit, and the filter residue of the backwash filter press or the belt filter is connected to the inlet of the drying unit.

2. The system according to claim 1, wherein: The eluent desulfurization unit includes a solid sulfur reactor, a solid-liquid separation and concentration device, a desulfurizer silo, and an acid storage tank. The inlet of the solid sulfur reactor is respectively connected to the filtrate outlet of the fly ash calcium and heavy metal collaborative solidification unit filter press, the outlet of the acid metering device, and the outlet of the desulfurizer silo. The outlet of the solid sulfur reactor is connected to the inlet of the solid-liquid separation and concentration device. The filtrate outlet of the third filter press or precision filter is connected to the inlet of the evaporation salt production unit. The residue or concentrated phase of the third filter press or precision filter is connected to the inlet of the high-efficiency premixer.

3. The system according to claim 1, wherein: The drying unit includes a conveyor belt, a dryer, and a dry fly ash silo. The outlet of the conveyor belt is connected to the inlet of the dryer, the outlet of the dryer is connected to the inlet of the dry fly ash silo, and the outlet of the dry fly ash silo is connected to the kiln calcining unit.

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