Ash dealkalization device and method based on sub-molten salt method

Abstract

The invention provides an ash dealkalization device based on a sub-molten salt method. The ash dealkalization device comprises a reaction cavity, an inner wall and a shell, wherein the reaction cavity comprises a flushing pipe, a flushing head, a rotating rod, a stirring rod, a scraping plate and a filter plug, the rotating rod is driven by a driving motor, a convex disc is arranged at the lower part of the rotating rod, and a cavity is formed in the filter plug and is matched with the convex disc at the lower part of the rotating rod; an ash feeding hole, a water inlet, a steam outlet and a discharging hole are formed in the top of the inner wall; and a heating resistance wire is arranged between the inner wall and the shell. The device can be used for sub-molten salt treatment, water washing, acid pickling, solid-liquid separation and drying of raw materials, and is suitable for dealkalization of ash. The invention further provides an ash dealkalization method based on the sub-molten salt method, the method can effectively reduce the alkali content of ash, and generated waste liquid can be used for producing potash fertilizer.

Description

Technical Field

[0001] The invention belongs to the technical field of power plant ash treatment, and in particular relates to an ash dealkalization device and method based on a sub-molten salt method. Background Art

[0002] Coal-fired power generation is the main source of electricity in my country. It also plays an important role in frequency regulation and peak regulation of the power grid system. In the long run, coal-fired power generation will still be the main source of electricity in my country. However, carbon emissions from coal-fired power generation account for about 40% of the country's carbon emissions and are the main source of carbon emissions in China. Therefore, reducing carbon emissions in the process of coal-fired power generation is a top priority. Biomass energy is a renewable energy source based on photosynthesis and has the characteristics of zero carbon emissions throughout its life cycle. Blending coal with biomass can not only reduce coal consumption and carbon emissions, but also can be transformed based on existing coal-fired power equipment with less capital investment. It is an effective measure to reduce carbon emissions from coal-fired power plants.

[0003] Clinker production is the main carbon emission link in the cement production process. Using the ash produced during coal-fired power generation for cement production can reduce the demand for clinker and has great carbon emission reduction potential. However, some biomass ash has a high alkali content. If this ash is directly used in cement production, it will not only reduce the strength of the cement, but also cause serious alkali-aggregate reaction problems.

[0004] There are two main types of alkali in blended ash: water-soluble and water-insoluble. Commonly used de-alkali methods such as water washing can remove most of the water-soluble alkali in blended ash, but the effect on water-insoluble alkali is poor. Calcination can remove some water-soluble and water-insoluble alkali in blended ash, but the effect needs to be improved. Summary of the invention

[0005] In order to solve the problem that ash cannot be directly used for cement production due to its high alkali content, the present invention provides an ash dealkalization method based on a sub-molten salt method to address the shortcomings of the prior art. The method can not only effectively remove water-insoluble alkali metals in ash, but also requires a lower temperature and has a good removal effect on chloride ions in ash.

[0006] In addition, the present invention also provides an ash dealkalization device based on the sub-molten salt method, which can be used for the sub-molten salt reaction, water washing, acid washing, solid-liquid separation and raw material drying required for ash dealkalization, and has good integration.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present application provides an ash dealkalization device based on a sub-molten salt method, comprising a reaction chamber, an inner wall and an outer shell; wherein:

[0009] The reaction chamber includes a flushing pipe, a flushing head, a rotating rod, a stirring rod, a scraper and a filter plug. The rotating rod is driven by a driving motor and has a convex plate at the bottom. The filter plug has a cavity. The top of the inner wall has an ash feed port, a water inlet, and a steam outlet. The bottom of the inner wall has an ash feed port and a discharge port. A heating resistance wire is provided between the inner wall and the outer shell.

[0010] The filter plug is a porous structure that can separate solids from liquids. There is a cavity inside the filter plug, which cooperates with the convex disk at the bottom of the rotating rod. When solids are not allowed to pass through, the rotating rod moves downward under the drive of the driving motor and pushes the filter plug to fit tightly with the lower part of the inner wall of the device. The solid raw materials cannot be discharged through the discharge port due to the obstruction of the filter plug. When solids need to pass through, the driving motor rotates in the opposite direction to lift the rotating rod upward, and the filter plug is lifted up driven by the convex disk, and the solid raw materials pass through the gap between the filter plug and the inner wall.

[0011] The angle between the lower part of the inner wall and the horizontal line is greater than 50 degrees, so that the solid raw material falls under the action of gravity.

[0012] The top of the inner wall is provided with an ash feed inlet, a water inlet and a steam outlet to facilitate feeding and recovery of steam heat.

[0013] The inner wall should be selected according to needs. For the ash dealkalization method based on the sub-molten salt method, acid-resistant steel with strong acid corrosion resistance or polytetrafluoroethylene material is used as the lining. For general water washing and drying, ordinary stainless steel material is used.

[0014] The shell has a thermal insulation material as an inner lining, such as ceramic fiber, rock wool, etc.

[0015] The stirring rod has a convex structure to enhance the stirring ability. The stirring rod is connected to a scraper to scrape off the raw materials attached to the inner wall while stirring, so as to enhance the stirring ability.

[0016] Based on the same inventive concept, the present application also provides an ash de-alkali method based on the sub-molten salt method, which reduces the alkali content of the ash through sub-molten salt treatment, alcohol washing, acid washing and drying, and the generated waste liquid can be used to produce potash fertilizer.

[0017] The hot steam generated during the sub-molten salt treatment process is used for distillation of the alcohol washing filtrate obtained by alcohol washing, that is, the alkali-containing fertilizer solution.

[0018] The drying temperature to be adopted in the drying process is 150° C. to ensure the decomposition of the silicate generated during the pickling process.

[0019] One or more technical solutions in the present invention have at least the following technical effects or advantages:

[0020] 1. The present invention provides an ash dealkalization device based on a sub-molten salt method, wherein a porous filter plug is provided inside a reaction chamber, and the shape of the filter plug can be closely fitted with the lower part of the inner wall of the device to achieve solid-liquid separation. There is a cavity inside the filter plug that can cooperate with the lower convex disc of the rotating rod. Driven by a driving motor, the filter plug can move up and down with the rotating rod to control the entry and exit of solid raw materials. The device integrates the functions of a sub-molten salt reactor, water washing, acid washing, solid-liquid separation, and raw material drying, and is suitable for an ash dealkalization method based on a sub-molten salt method. In addition, by rationally arranging pipelines and heat exchangers, the recovery of alkali solution, ethanol, water vapor, and waste heat can also be achieved.

[0021] 2. The present invention provides a slag dealkalization method based on a sub-molten salt method,

[0022] This method is suitable for reducing the alkali content of power plant ash, especially for the non-water-soluble alkali metals in the ash. After treatment by this method, the alkali content of the ash is below 3wt.%. The reaction temperature required by this method is relatively low, at 200-300°C, and the heat carried by the required alkali solution, ethanol and steam can be recovered during the treatment process. The pickling filtrate produced by the pickling treatment can be used to make potash fertilizer.

[0023] 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 according to 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 listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of ash dealkalization device based on sub-molten salt method

[0025] Figure 2 Schematic diagram of the use of the ash dealkalization device based on the sub-molten salt method

[0026] Markings in the figure: 1-inner wall, 2-outer shell, 3-reaction chamber, 4-ash feed port, 5-flushing pipe, 6-driving motor, 7-water inlet, 8-steam outlet, 9-flushing head, 10-heating resistance wire, 11-rotating rod, 12-stirring rod, 13-scraper, 14-cavity, 15-convex disc, 16-filter plug, 17-discharge port DETAILED DESCRIPTION

[0027] The technical solution provided by this application is to solve the above technical problems, and the overall idea is as follows:

[0028] According to a typical embodiment of the present invention, a slag dealkalization device and method based on a sub-molten salt method are provided, the device comprising a reaction chamber 3, an inner wall 1 and an outer shell 2; the reaction chamber comprises a flushing pipe 5, a flushing head 9, a rotating rod 11, a stirring rod 12, a scraper 13 and a filter plug 16, the rotating rod 11 is driven by a driving motor 6 and has a convex plate 15 at the bottom; the top of the inner wall 1 has an ash feed port 4, a water inlet 7, a steam outlet 8, and the bottom of the inner wall 1 has an ash discharge port 17; a heating resistor wire 10 is provided between the inner wall 1 and the outer shell 2, the filter plug 16 is a porous structure, and a cavity 14 is provided in the filter plug 16, which cooperates with the convex plate 15 at the bottom of the rotating rod 11. When solids are not allowed to pass through, the rotating rod 11 moves downward under the drive of the driving motor 6 and pushes the filter plug 16 to fit closely with the lower part of the inner wall 1 of the device, and the solid raw materials cannot be discharged through the discharge port 17 under the obstruction of the filter plug 16. When solids need to pass through, the driving motor 6 rotates in the opposite direction to lift the rotating rod 11 upward, and the filter plug 16 is lifted up under the drive of the convex plate 15, and the solid raw materials pass through the gap between the filter plug 16 and the inner wall 1.

[0029] The angle between the lower part of the inner wall 1 and the horizontal line is greater than 50 degrees. The top of the inner wall 1 has an ash feed port 4, a water inlet 7, and a steam outlet 8. The inner wall 1 should be selected according to needs. For the ash dealkalization method based on the sub-molten salt method, acid-resistant steel with strong acid corrosion resistance or polytetrafluoroethylene material is used as the lining. The outer shell 2 has a material with heat preservation ability as the lining, such as ceramic fiber, rock wool, etc. The stirring rod 12 has a convex structure, and the stirring rod 12 is connected to the scraper 13.

[0030] The following is a detailed description of an ash dealkalization device based on a sub-molten salt method of the present application in conjunction with an embodiment.

[0031] Example 1

[0032] This embodiment provides an ash dealkalization device and method based on a sub-molten salt method, such as Figure 1-2 As shown in the figure, the operation method of the ash dealkalization device based on the sub-molten salt method can be divided into four major processes:

[0033] (1) Sub-molten salt treatment; (2) Alcohol washing; (3) Acid washing; (4) Drying.

[0034] The four major processes include the following detailed steps:

[0035] (1) Before feeding, close the valve of the discharge port 17, start the drive motor 6, rotate the rotating rod 11, drive the stirring rod 12 to stir, and ensure that the rotating rod 11 has moved downward so that the filter plug 16 is closely attached to the inner wall 1 of the device.

[0036] (2) Solid KOH enters the reaction chamber 3 from the ash feed port 4, and water as a solvent enters from the water inlet 7 and enters the reaction chamber 3 through the flushing pipe 5 and the flushing head 9. The mass ratio of KOH to water is 4:1.

[0037] (3) The heating resistor 10 is energized to heat KOH and water to form a sub-molten salt. During the heating process and the subsequent reaction process, water will leave the reaction chamber 3 from the steam outlet 8 due to evaporation due to heat. Water should be introduced through the water inlet 7 and a condensing device should be installed at the steam outlet 8 to maintain the water volume in the reaction chamber 3. During operation, the temperature in the reaction chamber 3 should be maintained at 200-300°C. If the inner wall 1 of the device is lined with polytetrafluoroethylene, the temperature in the reaction chamber 3 should be less than 250°C to prevent damage to the polytetrafluoroethylene lining; the stirring rate is not less than 100rpm, and the generated hot steam can be used for the subsequent distillation of the alcohol washing filtrate, i.e., the alkali-containing waste liquid, through an indirect heat exchanger, and the hot steam is condensed into condensed water. The ethanol obtained after distillation enters the reaction chamber 3 through the water inlet 7 for alcohol washing in step (6), and the alkali solution obtained after distillation enters the reaction chamber 3 through the water inlet 7 for step (2). The shell 2 of the ash dealkalization device based on the sub-molten salt method should be made of insulation materials, such as ceramic fiber, rock wool, etc.

[0038] (4) The ash to be treated enters the ash dealkalization device based on the sub-molten salt method from the ash feed port 4, reacts with the sub-molten salt, and the relatively stable non-water-soluble alkali metal compounds in the ash are converted into unstable non-water-soluble alkali metal compounds. The reactions occurring in the process are as follows:

[0039] 2KAlSi3O8+2KOH→K2Si4O9+2KAlSiO4+H2O

[0040] NaAlSi3O8+8KOH+8Na + →2Na4SiO4+NaAlSiO4+4H2O+8K +

[0041] The mass ratio of the ash input to the KOH input is less than 1:4, and the reaction time is not less than 3 hours.

[0042] (5) After the reaction is completed, the power supply to the heating resistor 10 is stopped, and cold water is introduced into the reaction chamber 3 to accelerate the cooling of the device. The mass ratio of the introduced cold water to the mass ratio of the KOH already introduced is greater than 2:1.

[0043] (6) After the ash dealkalization device based on the sub-molten salt method is cooled, ethanol is introduced into the reaction chamber 3 through the water inlet 7 for alcohol washing to reduce the dissolution of silicates. When ethanol is introduced, the temperature of the ash dealkalization device based on the sub-molten salt method should be lower than 50°C, and the mass ratio of the introduced ethanol to the mass ratio of the water in the reaction chamber 3 should be greater than 1:1.

[0044] (7) After stirring for a period of time, the valve of the discharge port 17 is opened. Under the action of the filter plug 16, the ash is retained in the reaction chamber 3, and the ethanol solution containing KOH is discharged from the discharge port 17 through the filter plug 16 to become an alkali-containing waste liquid and enter the indirect heat exchanger to complete heat exchange distillation. In this step, the water-soluble alkali metal in the ash is removed. The filter plug 16 should be made of porous material, or a filter screen should be used to achieve solid-liquid separation. The stirring time in this step should be greater than 15 minutes. After draining, the valve at the discharge port 17 can be closed, and water and ethanol can be introduced again. Steps (6) and (7) are repeated to achieve a better dealkalization effect. The alcohol wash filtrate, that is, the alkali-containing waste liquid, can be distilled to recover ethanol. If the mass ratio of the alkali metal salt in the alcohol wash filtrate to the mass ratio of (KOH+NaOH) is less than 1:1, it can enter the reaction chamber 3 from the water inlet 7 in the form of alkali liquid to replace the KOH solid in step (2).

[0045] (8) The valve of the discharge port 17 is closed, and sulfuric acid is introduced into the alcohol-washed residue in the reaction chamber 3 for acid washing, so that the unstable water-insoluble alkali metal compounds in the ash are converted into water-soluble alkali metal compounds. The reactions occurring in this process are as follows:

[0046]

[0047] K2Si4O9+H2SO4→K2SO4+4SiO2+H2O

[0048] Na4SiO4+2H2SO4→2Na2SO4+SiO2+2H2O

[0049] The concentration of the sulfuric acid introduced is 2 mol / L, the ratio of the volume of sulfuric acid introduced to the mass of the ash added is 10L:1kg, and the pickling time should be greater than 1h;

[0050] (9) After the pickling is completed, the valve of the discharge port 17 is opened to discharge the pickling filtrate, and after the discharge, an appropriate amount of water is introduced to rinse the pickling residue. The pickling filtrate produced in this step can be used to produce potash fertilizer;

[0051] (10) Stop the water supply, and after the water in the reaction chamber 3 is completely drained, close the valve of the discharge port 17, supply power to the heating resistance wire 10, dry the pickling residue, and decompose the silicic acid. The reaction that occurs is as follows:

[0052] H2SiO3→SiO2+H2O

[0053] The drying temperature is not lower than 150°C and the time is not less than 2 hours. The acid-washed filter residue becomes dealkalized ash after drying.

[0054] (11) Stop heating, and the driving motor 6 causes the rotating rod 11 to rise, and the filter plug 16 to rise through the cooperation between the lower convex plate 15 of the rotating rod 11 and the filter plug cavity 14, and the dealkalized ash is discharged from the discharge port 17 under the action of gravity so as to be used as a raw material for cement production. The angle between the lower part of the inner wall of the ash dealkalization device based on the sub-molten salt method and the horizontal line is not less than 50 degrees.

[0055] One or more technical solutions in this application also have at least the following technical effects or advantages:

[0056] (1) The present invention provides an ash dealkalization device based on a sub-molten salt method,

[0057] The device integrates the functions of reactor, water washing, acid washing, solid-liquid separation and drying, and is suitable for an ash dealkalization method based on a sub-molten salt method proposed in the present invention. By reasonably arranging heat exchangers and pipelines, it can also realize the recovery of alkali solution, ethanol and steam waste heat.

[0058] (2) The present invention provides a slag dealkalization method based on a sub-molten salt method,

[0059] This method can effectively reduce the alkali content in power plant ash, which is conducive to increasing the amount of ash added in the cement production process, thereby promoting the resource utilization of ash, ensuring the sustainability of coal and biomass blending, and helping to achieve carbon emissions in coal-fired power plants and the cement industry. This method can also be used for the dealkalization treatment of other alkali-containing substances.

Claims

1. An ash dealkalization device based on a sub-molten salt method, characterized in that: It includes a reaction chamber 3, an inner wall 1 and an outer shell 2; wherein, The reaction chamber comprises a flushing pipe 5, a flushing head 9, a rotating rod 11, a stirring rod 12, a scraper 13 and a filter plug 16, wherein the rotating rod 11 is driven by a driving motor 6 and has a convex plate 15 at the bottom; an ash feed port 4, a water inlet 7, a steam outlet 8 are provided at the top of the inner wall 1, and an ash discharge port 17 is provided at the bottom of the inner wall 1; a heating resistor 10 is provided between the inner wall 1 and the outer shell 2; the filter plug 16 is a porous structure, and a cavity 14 is provided in the filter plug 16, which cooperates with the convex plate 15 at the bottom of the rotating rod 11; when solids are not allowed to pass through, the rotating rod 11 moves downward under the drive of the driving motor 6 and pushes the filter plug 16 to fit tightly with the lower part of the inner wall 1 of the device, and the solid raw materials cannot be discharged through the discharge port 17 under the obstruction of the filter plug 16; when solids need to pass through, the driving motor 6 rotates in the opposite direction to lift the rotating rod 11 upward, and the filter plug 16 is lifted up under the drive of the convex plate 15, and the solid raw materials pass through the gap between the filter plug 16 and the inner wall 1.

2. The ash dealkalization device based on the sub-molten salt method according to claim 1 is characterized in that: The angle between the lower part of the inner wall 1 and the horizontal line is greater than 50 degrees, so that the solid raw material can fall under the action of gravity.

3. The ash dealkalization device based on the sub-molten salt method according to claim 1, characterized in that: A condensing device or the like is installed at the steam outlet 8 to maintain the water level in the reaction chamber 3 .

4. The ash dealkalization device based on the sub-molten salt method according to claim 1, characterized in that The inner wall 1 should be selected according to needs. For the ash dealkalization method based on the sub-molten salt method, acid-resistant steel with strong acid corrosion resistance can be used, or polytetrafluoroethylene material can be used as the lining. For general water washing and drying, ordinary stainless steel material can be used.

5. The ash dealkalization device based on the sub-molten salt method according to claim 1, characterized in that The outer shell 2 may be lined with a material having heat-insulating properties, such as ceramic fiber, rock wool, etc.

6. The ash dealkalization device based on the sub-molten salt method according to claim 1, characterized in that: The stirring rod 12 has a convex structure to enhance the stirring ability; the stirring rod 12 is connected to a scraper 13 to scrape off the raw materials attached to the inner wall 1 while stirring, so as to enhance the stirring ability.

7. The method for operating an ash dealkalization device based on a sub-molten salt method according to claim 1, characterized in that: It includes the following four major processes: (1) Sub-molten salt treatment; (2) Alcohol washing; (3) Acid washing; (4) Drying.

8. The method for operating an ash dealkalization device based on a sub-molten salt method according to claim 7, characterized in that: The detailed steps are as follows: (1) Before feeding, close the valve of the discharge port 17, start the drive motor 6, rotate the rotating rod 11, drive the stirring rod 12 to stir, and ensure that the rotating rod 11 has moved downward so that the filter plug 16 is tightly attached to the inner wall 1 of the device; (2) Solid KOH enters the reaction chamber 3 from the ash feed port 4, and water as a solvent enters from the water inlet 7 and enters the reaction chamber 3 through the flushing pipe 5 and the flushing head 9. The mass ratio of KOH to water is 4:1; (3) The heating resistor 10 is energized to heat KOH and water to form a sub-molten salt. During the heating process and the subsequent reaction process, water will leave the reaction chamber 3 from the steam outlet 8 due to evaporation. Water should be introduced through the water inlet 7 and a condensing device should be installed at the steam outlet 8 to maintain the water level in the reaction chamber 3. During operation, the temperature in the reaction chamber 3 should be maintained at 200-300°C. If the inner wall 1 of the device is lined with polytetrafluoroethylene, the temperature in the reaction chamber 3 should be less than 250°C to prevent damage to the polytetrafluoroethylene lining. The stirring rate is not less than 100 rpm. The generated hot steam can be used for the subsequent distillation of the alcohol washing filtrate, i.e., the alkali-containing waste liquid, through an indirect heat exchanger, and the hot steam is condensed into condensed water. The ethanol obtained after distillation enters the reaction chamber 3 through the water inlet 7 for alcohol washing in step (6), and the alkali solution obtained after distillation enters the reaction chamber 3 through the water inlet 7 for step (2). (4) The ash to be treated enters the ash dealkalization device based on the sub-molten salt method from the ash feed port 4, reacts with the sub-molten salt, and the relatively stable non-water-soluble alkali metal compounds in the ash are converted into unstable non-water-soluble alkali metal compounds. The reactions occurring in the process are as follows: 2KAlSi3O8+2KOH→K2Si4O9+2KAlSiO4+H2O NaAlSi3O8+8KOH+8Na + →2Na4SiO4+NaAlSiO4+4H2O+8K + The mass ratio of the ash added to the KOH added is less than 1:4, and the reaction time is not less than 3 hours; (5) After the reaction is completed, the power supply to the heating resistor 10 is stopped, and cold water is introduced into the reaction chamber 3 to accelerate the cooling of the device. The mass ratio of the introduced cold water to the mass ratio of the KOH introduced is greater than 2:1; (6) After the ash dealkalization device based on the sub-molten salt method is cooled, ethanol is introduced into the reaction chamber 3 through the water inlet 7 for alcohol washing to reduce the dissolution of silicates. When the ethanol is introduced, the temperature of the ash dealkalization device based on the sub-molten salt method should be lower than 50° C., and the mass ratio of the introduced ethanol to the mass ratio of the water in the reaction chamber 3 should be greater than 1:1; (7) After stirring for a period of time, the valve of the discharge port 17 is opened. Under the action of the filter plug 16, the ash is retained in the reaction chamber 3, and the ethanol solution containing KOH is discharged from the discharge port 17 through the filter plug 16 to become an alkaline waste liquid and enter the indirect heat exchanger to complete heat exchange distillation. In this step, the water-soluble alkali metal in the ash is removed; the filter plug 16 should be made of porous material, or a filter screen should be used to achieve solid-liquid separation; the stirring time in this step should be greater than 15 minutes. After draining, the valve at the discharge port 17 can be closed, and water and ethanol can be introduced again, and steps (6) and (7) are repeated to achieve a better dealkalization effect; the alcohol wash filtrate, i.e. the alkaline waste liquid, can be distilled to recover ethanol. If the mass ratio of the alkali metal salt in the alcohol wash filtrate to the mass ratio of (KOH+NaOH) is less than 1:1, it can enter the reaction chamber 3 from the water inlet 7 in the form of alkaline solution to replace the KOH solid in step (2); (8) The valve of the discharge port 17 is closed, and sulfuric acid is introduced into the alcohol-washed residue in the reaction chamber 3 for acid washing, so that the unstable water-insoluble alkali metal compounds in the ash are converted into water-soluble alkali metal compounds. The reactions occurring in this process are as follows: K2Si4O9+H2SO4→K2SO4+4SiO2+H2O Na4SiO4+2H2SO4→2Na2SO4+SiO2+2H2O The concentration of the sulfuric acid introduced is 2 mol / L, the ratio of the volume of sulfuric acid introduced to the mass of the ash added is 10L:1kg, and the pickling time should be greater than 1h; (9) After the pickling is completed, the valve of the discharge port 17 is opened to discharge the pickling filtrate, and after the discharge, an appropriate amount of water is introduced to rinse the pickling residue. The pickling filtrate produced in this step can be used to produce potash fertilizer; (10) Stop the water supply, and after the water in the reaction chamber 3 is completely drained, close the valve of the discharge port 17, supply power to the heating resistance wire 10, dry the pickling residue, and decompose the silicic acid. The reaction that occurs is as follows: H2SiO3→SiO2+H2O The drying temperature is not less than 150℃ and the drying time is not less than 2h. The acid-washed filter residue becomes dealkalized ash after drying; (11) Stop heating, and the driving motor 6 causes the rotating rod 11 to rise. The filter plug 16 rises through the cooperation between the lower convex plate 15 of the rotating rod 11 and the filter plug cavity 14. The dealkalized ash is discharged from the discharge port 17 under the action of gravity so as to be used as a raw material for cement production.

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