Multi-stage countercurrent washing device for fly ash

Abstract

The utility model discloses a fly ash multistage countercurrent washing device, which relates to the technical field of garbage fly ash incineration dechlorination, and is characterized in that the whole device is positioned in a buffer chamber, an upper-stage washing chamber and a lower-stage washing chamber are connected through an inclined plate, a slurry collecting port of the inclined plate is connected with the upper-stage washing chamber, and a slurry outlet of the inclined plate is connected with the lower-stage washing chamber. The washing chamber is internally divided into a leachate chamber, a filter cloth layer and a spiral propelling chamber from top to bottom, and fly ash enters from a slurry inlet of the spiral propelling chamber, is conveyed to a slurry outlet by a spiral propeller, flows to an inclined plate and enters the next washing chamber. The fly ash countercurrent washing device solves the problems that an existing integrated fly ash countercurrent washing device is inconvenient to maintain, disassemble and assemble, and the washing stage number cannot be selected, and achieves the purposes of being easy to disassemble and assemble, convenient to maintain and capable of improving the washing efficiency.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of washing device, can be used to solid particle containing soluble material, especially fly ash after garbage incineration is carried out countercurrent water washing. BACKGROUND

[0002] Incineration as a kind of garbage disposal technology, with high reduction, large processing capacity, small secondary pollution and other advantages, in nearly ten years, it is popular, and develops rapidly. Therefore, for most of the waste, will be incinerated, but incineration can also lead to part of the garbage to produce toxic flue gas. Incineration cannot completely consume solid waste, and fly ash will be produced. Fly ash, as a secondary pollutant produced in the flue gas treatment process section of garbage incineration, accounts for about 3% to 5% of the total amount of incinerated garbage, which contains a large amount of dioxins, heavy metals and chlorides, and is a dangerous solid waste. And washing as a very common and convenient treatment method, can effectively remove more than 98% of chlorides and chlorine-containing substances in fly ash, and is simple and stable, and can be used as an effective means for fly ash harmless treatment.

[0003] The fly ash multistage countercurrent washing device currently used, such as the "incineration fly ash washing equipment and its use method" disclosed in application publication No. CN116967200A, adopts an integrated multistage countercurrent washing, installs a conveying mechanism in a shell, and the shell is processed with multiple bent pipes. Because the conveying mechanism is entirely installed on the shell, and the bent pipe is a cavity structure inside the shell, there is only one feeding port and one liquid outlet. There are disadvantages such as fixed washing stages, unguaranteed washing efficiency, inconvenience for cleaning the inside of the shell, high requirement for the structural strength of the shell, the need to replace the shell when the shell is damaged, affecting production efficiency, inconvenient installation and disassembly, possible backflow of slurry after washing, and inefficient collection of fly ash after washing. UTILITY MODEL CONTENTS

[0004] In view of the deficiencies of the prior art, the utility model provides a fly ash multistage countercurrent washing device. The washing device transports the slurry after washing between the washing chambers by using the inclined plate connected with the upper and lower washing chambers. The content of chlorides and chlorine-containing substances in fly ash can be connected and washed with a proper number of washing chambers, and such device has good fly ash washing effect, high water resource utilization rate, convenient disassembly, simple maintenance, and relatively convenient equipment movement.

[0005] The utility model achieves the above technical purposes through the following technical means.

[0006] The device is located in the buffer chamber, and is composed of a plurality of washing chambers and a plurality of inclined plates. The washing chambers are divided into upper and lower washing chambers according to the slurry flow direction. The slurry collecting port of the inclined plate is connected with the upper washing chamber, and the slurry outlet of the inclined plate is connected with the lower washing chamber. The inclined plate is detachably installed with the washing chamber.

[0007] Further, the slurry collecting port of the inclined plate has an inclined surface, which is installed below the upper washing chamber and away from the slurry outlet side. The slurry outlet of the inclined plate is an inclined narrow port, which is installed at the slurry inlet of the lower washing chamber.

[0008] In some embodiments, the inclined plate is made of pp material, and one side has an inclined angle, which facilitates the rolling and collection of fly ash particles into the slurry inlet of the next stage.

[0009] Further, the washing chambers are arranged in a left-right column according to the relationship between the upper and lower washing chambers, and are arranged in a gradient. The upper and lower washing chambers are connected through the inclined plate.

[0010] Further, the bottom of the leachate chamber of the washing chamber is fixedly installed with a filter cloth layer, and the spiral propelling chamber is arranged below the filter cloth layer. The leachate chamber is installed with a water pump.

[0011] In some embodiments, the water pump is installed at the slurry inlet of the spiral propelling chamber of the washing chamber.

[0012] The water inlet pipe of the water pump is connected with the leachate chamber.

[0013] In some embodiments, the water inlet pipe can be a U-shaped pipe.

[0014] The water outlet pipe of the water pump is connected with the back flushing pipe port of the upper washing chamber. The spiral propelling chamber is installed with a fly ash feeding port. The bottom of the spiral propelling chamber is installed with an inclined plate. One end of the spiral propelling chamber is installed with a slurry inlet, and the other end is installed with a slurry outlet. The slurry outlet is inclined downwardly and has a back flushing pipe port.

[0015] As preferred, the installation position of the slurry inlet is below the central rotating shaft of the spiral propelling chamber.

[0016] As preferred, the horizontal height of the fly ash feeding port is higher than the height of the overflow port of the leachate chamber.

[0017] In some embodiments, the fly ash feeding port is connected with a fly ash hopper through a flange port, and the middle part is controlled by an electric valve.

[0018] In some embodiments, only the initial washing chamber is provided with a fly ash feeding port.

[0019] In some embodiments, the initial water washing chamber is not provided with a water pump.

[0020] In some embodiments, the water pump is connected with the water outlet pipe by a flange.

[0021] The spiral propelling chamber is provided with a spiral propeller, hinged rods are installed at the central rotating shafts at both ends of the spiral propeller, and hinges are installed at the other ends of the hinged rods.

[0022] The central rotating shafts of the spiral propeller are provided with a plurality of scoops that can rotate with the spiral propeller.

[0023] Further, the scoops are installed in an inclined manner on the central rotating shafts of the spiral propeller, the inclination direction is consistent with the propelling direction of the spiral propeller, the scoops can be used to control the speed of the pulp propelling, prolong the residence time of the pulp in the water washing chamber, and improve the percolation efficiency.

[0024] Preferably, the inclination angle of the scoops is preferably 10° to 30°.

[0025] The filtration of the filtrate and the pulp between the percolate chamber and the spiral propelling chamber is realized by a filter cloth layer, the uppermost layer of the filter cloth layer is a fixed layer, the middle layer is a filter membrane, and the bottom is a filter cloth, the fixed layer is fixedly connected with the bottom of the percolate chamber, a plurality of percolation holes are distributed on the fixed layer, the middle layer is a filter membrane, the filter cloth is a detachable filter cloth, and the filter cloth layer is located above the spiral propelling chamber and connected with the spiral propelling chamber.

[0026] Preferably, the fixed layer is made of an alloy material and is welded with the lower part of the percolate chamber.

[0027] Preferably, the middle layer is a filter membrane, and the pore size is preferably between 0.3 μm and 0.6 μm.

[0028] The utility model has the following gain effects:

[0029] The overall equipment is operated in a pressurized state, the number of water washing chambers is added or reduced according to the chlorine content of the fly ash, the equipment unit is concentrated, and the land occupation space is small. Compared with the multi-stage water washing tank process, the construction, land, and labor costs are saved, and the equipment is more economical. For the multi-stage countercurrent sedimentation tank type equipment, the utility model adopts a spiral propeller, the speed of the spiral propelling is controlled by a scoop, the fly ash can be efficiently dissolved and the pulp can be preliminarily concentrated in the pipe, the salt content is not released to the environment, the high-salt-content mother liquor is separated by the pressure difference between the spiral propeller and the percolate chamber, and then extracted for flushing the upper propeller, achieving the countercurrent effect. The fly ash is washed by the percolate of the next stage into the buffer chamber at the outlet of the propeller, reacts and dissolves with the mother liquor in the buffer chamber during the free-fall process, and then collects on the inclined plate and enters the next propeller. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0031] Figure 1 It is a schematic diagram of the device of the present application.

[0032] Figure 2 It is a lateral schematic diagram of a single washing chamber.

[0033] Reference signs:

[0034] 1: washing chamber; 11: spiral propelling chamber; 111: spiral propeller; 1111: central rotating shaft; 112: slurry inlet; 113: slurry outlet; 114: backflush pipe opening; 115: hinge rod; 116: hinge; 12: percolate chamber; 121: percolate chamber overflow opening; 13: water pump; 131: water inlet pipe; 132: water outlet pipe; 14: dipper; 15: filter cloth layer; 151: fixed layer; 152: filter membrane; 153: filter cloth; 2: fly ash inlet; 3: inclined plate; 31: slurry collection opening; 32: slurry conveying plate; 33: slurry outlet; 34: inclined surface; 4: buffer chamber. DETAILED DESCRIPTION

[0035] The present application will be further described below in conjunction with the drawings and specific embodiments, but the scope of protection of the present application is not limited thereto.

[0036] In the description of the present application, it should be understood that the directions or position relationships indicated by the terms "upper", "lower", "left", "right" and the like are based on the directions or position relationships shown in the drawings, and are only for the convenience of describing the present application, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. The terms "mounting", "connecting", "fixing" and the like should be understood broadly, for example, they can be fixed connection, or detachable connection, or integral connection, can be direct connection, or indirect connection through intermediate medium, or internal communication of two elements; for those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0037] As Figure 1 and Figure 2As shown, the embodiment provides a fly ash multi-stage countercurrent water washing chlorine removal device, comprising a water washing chamber 1, a fly ash feeding port 2, an inclined plate 3, and a buffer chamber 4.

[0038] One primary water washing chamber is fixedly connected with the fly ash feeding port 2 by flanges; the height of the fly ash feeding port is higher than that of the percolate overflow port 121 of the percolate chamber 12 in the water washing chamber 1; the primary water washing chamber is connected with the next stage water washing chamber through the inclined plate 3.

[0039] After the fly ash enters the spiral propulsion chamber 11 of the primary water washing chamber from the fly ash feeding port 2, it is fully dissolved and filtered, flows out from the slurry outlet 113 of the primary water washing chamber, flows into the slurry collection port 31 of the inclined plate 3, and then flows to the slurry flow outlet 33 of the inclined plate 3 along the slurry conveying plate 32 by gravity.

[0040] After multiple water washing, the slurry meeting the requirements is finally collected for subsequent secondary use. After the fly ash is completely washed, the fly ash feeding port 2 stops feeding. The concentrated mother liquor in the primary water washing chamber is extracted and used later. Fresh water is injected into the buffer chamber 4 and the water washing chamber 1 to flush the entire device, flush out the residual slurry in the device, protect the device, and avoid damage caused by residual particles when the device is next used for water washing.

[0041] In actual use, the fly ash sample is fully dissolved by sampling, the approximate chlorine content of the batch of fly ash is measured, and the number of water washing chambers required is selected according to the chlorine content and the mass of the fly ash of the batch that needs to be washed.

[0042] After determining the number of water washing chambers 1 required, the backflush port of the last stage water washing chamber at the bottom is connected, and fresh water without chlorine ions is injected into the water washing chamber 1 and the buffer chamber 4. After the device is filled with water, the pressure value inside the device is set to pressurize the entire device.

[0043] During pressurization, the contact between water molecules and fly ash particles is more frequent and close under the pressurized condition, increasing the opportunity for dissolution reaction and making the soluble substances such as chlorides in the fly ash dissolve faster into water. The increase in pressure can strengthen the mass transfer process, i.e. the process of transferring substances from the surface of fly ash particles to the solution. This helps to improve the removal rate of harmful substances in the water washing process. Due to the improvement of dissolution and mass transfer rates, the entire washing process can be completed in a shorter time, improving the water washing efficiency. Due to the improvement of washing efficiency, the energy consumption of the entire washing process can be reduced, making the entire water washing process more environmentally friendly.

[0044] At the same time, the pressurization can promote the mutual coagulation of the small fly ash in suspension in water, so as to sink faster, and then pass through the inclined plate 3 into the next water washing chamber for water washing, thereby improving the water washing efficiency of the fly ash.

[0045] After the pressurization process is completed, the valve between the fly ash feeding port 2 (where the fly ash has been completely fed and the upper part is closed, and the internal pressure is the same as the pressure in the equipment) and the slurry inlet 112 of the first-stage water washing chamber is opened. The fly ash is fed into the spiral propelling chamber 11 of the first-stage water washing chamber, the spiral propeller 111 is started, and the water pump 13 is started in reverse order from the last-stage water washing chamber to the second-stage water washing chamber.

[0046] The two ends of the central rotating shaft of the spiral propeller are welded with a plurality of hinge rods, the other ends of the hinge rods are welded with hinges, and the hinge rods are hollow.

[0047] The water in the percolate chamber 12 of the second-stage water washing chamber is connected with the back flushing pipe port 114 of the first-stage water washing chamber through the water outlet pipe 132, and is pumped into the spiral propelling chamber 11 of the first-stage water washing chamber. The slurry advancing direction is the same as the propelling direction of the spiral propelling chamber 11, and the water flow pumped out of the back flushing pipe port 114 flows in the opposite direction of the slurry advancing direction. Therefore, the countercurrent water washing process of the fly ash is realized.

[0048] During the propelling process of the spiral propeller 111, the slurry is affected by the centrifugal force and is thrown on the filter cloth 153 at the bottom of the filter cloth layer 15. However, since the fly ash is a solid particle and is coagulated into a group under high pressure, the fly ash cannot pass through the filter cloth layer 15.

[0049] However, a small part of the fine fly ash particles can pass through the filter cloth 153, and therefore the filter membrane 152 plays a role in completely separating the fly ash in the slurry and the solution.

[0050] During the cleaning process in the water washing chamber 1, the solution in the spiral propelling chamber 11 has a high concentration of chloride ions, and first penetrates the filter membrane 152 in the filter cloth layer 15 to transfer to the percolate chamber 12.

[0051] Since the filtrate in the spiral propelling chamber 11 comes from the percolate chamber 12 of the lower-stage water washing chamber, the concentration of the filtrate in the percolate chamber 12 of the water washing chamber is reversely distributed along with the number of stages of the water washing chamber 1. Generally, the concentration of the filtrate in the first-stage water washing chamber is the highest, and the concentration of the filtrate in the last-stage water washing chamber is the lowest, which is consistent with the principle of countercurrent water washing.

[0052] In this embodiment, three inclined angle 10° paddles 14 are welded on the central rotating shaft 1111 of the screw propeller 111 of the screw propelling chamber 11 in the water washing chamber 1, and the inclined direction is the same as the propelling direction of the screw propeller 111.

[0053] The paddle 14 can adjust the propelling speed of the slurry in the screw propelling chamber 11, adjust the residence time of the slurry in the water washing chamber, and improve the dissolution efficiency.

[0054] However, the residence time of the slurry in the single water washing chamber is limited, and the solubility of the soluble substances in the fly ash in water has an upper limit.

[0055] Therefore, as the soluble substances in the water continue to dissolve, the ion concentration of the solution becomes larger and larger, and the dissolution rate of the remaining soluble substances in the fly ash becomes slower. At this time, it is obvious that the fly ash is transported to the next water washing chamber 1 with lower solution concentration to better dissolve the remaining soluble substances in the fly ash slurry.

[0056] Generally speaking, the more the number of water washing chambers 1, the less the remaining soluble substances in the fly ash, and the better the water washing effect. However, in engineering practice, it is obviously impractical to increase the number of water washing chambers 1 without limit, because after the water-cement ratio reaches a certain proportion, the effect of fly ash water washing will not increase significantly. However, the utilization rate of water resources will be greatly reduced, which does not meet the production demand for efficiency. Therefore, the number of fly ash water washing stages in industry is generally 2-4, that is, 2-4 water washing chambers 1 are used to wash the fly ash.

[0057] Therefore, when the fly ash flows into the first water washing chamber from the fly ash feeding port 2, it needs to flow into several water washing chambers set according to the content of chlorides in the fly ash sample in the preparation link.

[0058] For convenience of description, the number of water washing chambers in this embodiment is selected to be three.

[0059] The three water washing chambers 1 are selected to be arranged in left and right columns and in echelon. After the slurry outlet 113 of the water washing chamber 1 is connected with the next water washing chamber through the inclined plate 3, and the slurry inlet 112 is connected with the previous water washing chamber through the inclined plate 3, the water washing chamber 1 is placed in the buffer chamber 4.

[0060] After the preparation is completed, the feeding can be started, and the fly ash is water washed. The fly ash feeding port 2 connected with the slurry inlet 112 of the first water washing chamber is opened, and the fly ash is mixed with the solution in the screw propelling chamber 11 to form the slurry for water washing.

[0061] In the spiral propulsion chamber 11, the fly ash will be slow due to multiple collisions with the scraper 14, resulting in slow fly ash propulsion, which can be fully mixed with the solution in the spiral propulsion chamber 11, fully dissolved, and the fly ash just enters, mixed with air, and some fly ash may be attached to small bubbles and float, but due to the presence of filter cloth 153 and filter membrane 152, this part of fly ash will not enter the percolate chamber 12, and will not pollute the solution.

[0062] When the slurry flows out of the slurry outlet 113 of the first-stage washing chamber, it falls freely under the action of gravity into the slurry collection port 31 of the inclined plate 3. Because of the existence of the inclined surface 34, even if the position of part of the slurry flow deviates greatly, it will flow into the slurry collection port 31 of the inclined plate 3 due to falling on the inclined surface 34.

[0063] The slurry collection port 31 of the inclined plate 3 also has a certain downward inclination angle, and the slurry flows to the slurry conveying plate 32 through the inclined angle of the inclined plate, and finally moves to the slurry outlet 33 of the inclined plate 3, and flows into the slurry inlet 112 of the second-stage washing chamber, starting the countercurrent washing in the second-stage washing chamber.

[0064] In the second-stage washing chamber, the slurry outlet 33 of the inclined plate 3 is connected with the slurry inlet 112 of the spiral propulsion chamber 11, and the slurry inlet 112 is generally selected to be above the central rotating shaft 1111 of the spiral propeller 111. In this way, on the one hand, the slurry can quickly enter the spiral propulsion chamber 11 under the action of gravitational potential energy because of the high position, and on the other hand, the falling particles will not accumulate at the bottom of the spiral propulsion chamber 11, slowing down or even blocking the inflow of the slurry behind.

[0065] After passing through the spiral propulsion chamber 11, the slurry repeats the above steps to flow into the third-stage washing chamber through the inclined plate 3, and then repeats the washing steps.

[0066] When the washing process is completed, the washed slurry will flow out of the slurry outlet of the last-stage washing chamber and enter the collection device, and the concentrated mother liquor with the highest concentration will be extracted from the percolate chamber of the first-stage washing chamber.

[0067] Meanwhile, in the previous washing equipment, a special pipeline and chamber for countercurrent washing are also needed, which often belongs to non-standard design and needs to be customized by manufacturers, which takes a long time and costs a lot. The product designed and produced also needs to be verified through simulation, and it also needs to prevent the backflow of slurry during countercurrent washing.

[0068] Through the inclined plate 3 and the left-right arrangement and gradient arrangement of the washing chamber 1, a one-way slurry flow channel is formed.

[0069] In another embodiment, the buffer chamber 4 can not be filled with water, but the inclined plate 3 is changed into an inclined pipe with the same function as the inclined plate 3, which has higher requirements for sealing and pressure resistance.

[0070] The inclined pipe can be made of 316 stainless steel, alloy steel, titanium alloy, light high-strength ceramic material, nickel-based alloy, and aluminum alloy, which have excellent high-pressure corrosion resistance. In addition, according to the practicality and economy, the material with lighter weight and more convenient disassembly can be selected to make the inclined pipe, which is more expensive, or more economical but heavier, which requires additional support to fix the inclined pipe and is relatively inconvenient to disassemble.

[0071] The above-mentioned inclined pipe material can not only be used to make the inclined pipe, but also be used to make the inclined plate 3. Compared with the high requirements for sealing and pressure resistance of the inclined pipe, the inclined plate 3 has lower requirements for sealing and pressure resistance, but like the inclined pipe, the inclined plate 3 also has high requirements for corrosion resistance of these materials.

[0072] Because the fly ash washing liquid is generally a high-concentration salt solution, the ions in the liquid can accelerate the corrosion and oxidation of the material, so the material needs to have strong corrosion resistance. There may be an electrochemical reaction between some parts of the equipment, which greatly accelerates the oxidation and corrosion of the equipment, so insulation protection or other protective measures need to be taken between different metal material parts. The use of an inclined pipe can better avoid the electrochemical reaction of the equipment in the solution.

[0073] The inclined pipe can be realized by adding a sealing cover on the top of the inclined plate 3.

[0074] The connection between the upper and lower washing chambers adopts a connection method with higher sealing requirements, and the corresponding inclined pipe material is thickened to withstand greater pressure.

[0075] The advantage of this embodiment is that the buffer chamber 4 does not need to be filled with liquid, and the washing chamber 1 is not completely immersed in water, which reduces the waterproofness requirement of the washing chamber 1.

[0076] Without filling water in the buffer chamber 1, the equipment can be well protected, which is also conducive to equipment maintenance. Only during the disassembly of the equipment, especially the disassembly of the inclined pipe, the sealing of the equipment needs to be checked by water before the installation is completed, and then the fly ash can be washed by pressurized water.

[0077] The device is realized by separating the integrated washing chamber of the same kind of product into independent multiple washing chambers 1, connecting the inclined plate 3 between the washing chambers to transport the slurry, and making the countercurrent washing device from the original fixed number of devices into the corresponding washing chamber 1 number according to the production needs, so that the fly ash washing efficiency is higher, and the future equipment is more convenient to disassemble when moving, and more convenient to maintain when overhauling. When a component of a washing chamber in the device is damaged, the time and cost required for maintenance and replacement are also reduced, which can effectively improve the production efficiency and economic benefit.

[0078] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fly ash multi-stage countercurrent water washing device comprising a buffer chamber (4), characterized in that, The fly ash multi-stage countercurrent water washing device is composed of a plurality of washing chambers (1) and a plurality of inclined plates (3), the washing chambers (1) are divided into upper and lower washing chambers, the upper and lower washing chambers are connected through the inclined plates, the bottom of the percolate chamber (12) of the washing chamber (1) is provided with a filter cloth layer (15), a spiral propelling chamber (11) is arranged below the filter cloth layer (15), the spiral propelling chamber (11) is provided with a fly ash feeding port (2), and the inclined plate (3) is installed at the bottom of the spiral propelling chamber (11); The slurry collecting port (31) of the inclined plate is connected with the slurry outlet (113) of the upper washing chamber; The slurry outlet (33) of the inclined plate is connected with the slurry inlet (112) of the lower washing chamber.

2. A fly ash multi-stage countercurrent water washing device according to claim 1, characterized in that, The slurry collecting port (31) of the inclined plate (3) has an inclined surface (34), the inclined surface (34) is installed below the upper washing chamber and away from one side of the slurry outlet (113); The slurry outlet (33) of the inclined plate is an inclined narrow port, which is installed at the slurry inlet (112) of the lower washing chamber.

3. A fly ash multi-stage countercurrent water washing device according to claim 1 or 2, characterized in that, The washing chambers (1) are arranged in left and right columns according to the relationship between the upper and lower washing chambers.

4. A multi-stage counter-current fly ash water scrubbing apparatus according to claim 1, wherein, The percolate chamber (12) is provided with a water pump (13), the water inlet pipe (131) of the water pump (13) is connected with the percolate chamber (12), and the water outlet pipe (132) of the water pump (13) is connected with the back flushing pipe port (114) of the upper washing chamber.

5. A fly ash multi-stage countercurrent water washing apparatus according to claim 4, characterized in that, The uppermost layer of the filter cloth layer is a fixed layer (151), the middle layer is a filter membrane (152), and the bottom is a filter cloth (153); The fixed layer (151) is fixedly connected with the bottom of the percolate chamber (12), and the filter cloth (153) is located above the spiral propelling chamber (11) and connected with the spiral propelling chamber (11).

6. A multi-stage counter-current fly ash water scrubbing apparatus according to claim 4, wherein, One end of the spiral propelling chamber (11) close to the percolate chamber overflow port (121) of the percolate chamber (12) is provided with a slurry inlet (112), the other end of the spiral propelling chamber (11) is provided with a slurry outlet (113), and the slurry outlet (113) is provided with a back flushing pipe port (114) obliquely below; The slurry inlet (112) is arranged above the central rotating shaft (1111) of the spiral propelling chamber (11), and the spiral propelling chamber (11) is provided with a spiral propeller (111).

7. A fly ash multi-stage countercurrent water washing apparatus according to claim 6, characterized in that, A plurality of scoops (14) that can rotate with the spiral propeller (111) are arranged at the central rotating shaft (1111) of the spiral propeller (111).

8. A fly ash multi-stage countercurrent water washing apparatus according to claim 7, characterized in that, The scoops (14) are arranged obliquely on the central rotating shaft (1111) of the spiral propeller (111), and the oblique direction is consistent with the propelling direction of the spiral propeller (111).

9. A fly ash multi-stage counter-current water washing apparatus according to claim 6 or 7 or 8, characterized in that, Hinge rods (115) are arranged at the central rotating shaft (1111) of both ends of the spiral propeller (111), and hinges (116) are arranged at the other ends of the hinge rods (115).

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