Resource utilization system for preparing gypsum by pickling waste incineration fly ash

Abstract

The utility model discloses a resource utilization system for preparing gypsum by pickling waste incineration fly ash. The resource utilization system comprises a raw ash bin, a pickling tank, a plate-and-frame filter press I, a washing tank A, a plate-and-frame filter press II and a pickling gypsum temporary storage bin, the pickling tank is communicated with an external waste sulfuric acid box body; the raw ash bin, the pickling tank, the plate-and-frame filter press I, the washing tank A and the plate-and-frame filter press II are sequentially communicated through a conveying mechanism; and a washing-separating system is also arranged between the plate-and-frame filter press II and the pickling gypsum temporary storage bin. According to the method, heavy metals in the fly ash can be effectively removed, the leaching risk of the heavy metals in the fly ash building material products is reduced, calcium ions in the fly ash can be fixed in the form of gypsum, the cost of subsequent wastewater treatment is reduced, meanwhile, the cost of preparing the fly ash recycling gypsum is also reduced, and the method is suitable for industrial production. Therefore, low-cost resource utilization of the household garbage incineration fly ash is realized.

Description

Technical Field

[0001] The present application relates to the technical field of waste incineration fly ash treatment, and in particular to a resource utilization system for producing gypsum by acid washing of waste incineration fly ash. Background Art

[0002] Numerous studies have shown that waste incineration fly ash primarily contains SiO2, Al2O3, CaO, Fe2O3, and other substances, similar in composition to certain construction materials. Therefore, fly ash can be used as a resource in place of certain building materials. In particular, the calcium content in fly ash, as high as 30% to 40%, makes it an ideal raw material for the production of building plaster. However, waste incineration fly ash is a hazardous waste rich in heavy metals and chlorides. The heavy metals in fly ash can have significant impacts on both humans and plants. The high chlorine content, which can reach as high as 30%, is a key characteristic of fly ash in my country, complicating its resource utilization. Currently, the most commonly used fly ash recovery technology primarily involves washing the chlorides from the fly ash with water, followed by co-disposal in cement kilns.

[0003] Cement kiln co-processing technology, a related technology, relies on the availability of cement kilns near the project site. This makes it difficult to promote in areas without cement kilns and is also impacted by policies such as staggered cement production and kiln shutdowns. Furthermore, traditional water-washing dechlorination processes only remove soluble chloride salts from fly ash, leaving heavy metals in the fly ash largely untreated and untreated, increasing the environmental risks of its use in building materials. Calcium in the fly ash is also washed out as chloride salts, increasing subsequent wastewater treatment costs and wasting active ingredients in building materials. Utility Model Content

[0004] The purpose of this application is to provide a resource utilization system for acid-washing gypsum from waste incineration fly ash. This system addresses the problem that traditional water-washing dechlorination processes only remove soluble chloride salts from fly ash, leaving heavy metals in the fly ash largely untreated and increasing the environmental risks of building material utilization. Calcium in the fly ash is also washed out as chloride salts, increasing the cost of subsequent wastewater treatment and wasting active ingredients in building materials.

[0005] The present application provides a waste incineration fly ash pickling gypsum resource utilization system adopts the following technical solutions:

[0006] A resource utilization system for producing gypsum by pickling fly ash from garbage incineration, comprising a raw ash bin, a pickling tank, a plate and frame filter press 1, a water washing tank A, a plate and frame filter press 2, and a temporary storage bin for pickled gypsum;

[0007] The pickling tank is connected to an external waste sulfuric acid box;

[0008] The raw ash bin, the pickling tank, the plate-frame filter press 1, the water washing tank A and the plate-frame filter press 2 are sequentially connected through a conveying mechanism;

[0009] A water washing and separation system is also provided between the second plate and frame filter press and the pickled gypsum temporary storage bin.

[0010] Furthermore, the water washing-separation system includes a water washing tank B and a plate and frame filter press three, the water washing tank B is connected to the plate and frame filter press two through a conveying mechanism, the plate and frame filter press three is connected to the water washing tank B through a conveying mechanism, and the plate and frame filter press three is connected to the pickling gypsum temporary storage bin through a conveying mechanism.

[0011] Furthermore, the plate and frame filter press 3 is connected to the water washing tank A through a conveying mechanism.

[0012] Furthermore, the plate and frame filter press three is connected to an external water tank.

[0013] Furthermore, the resource utilization system also includes a wastewater treatment unit, and the wastewater treatment unit is connected to the plate and frame filter press through a conveying mechanism.

[0014] Furthermore, the second plate and frame filter press is connected to the pickling tank through a conveying mechanism.

[0015] Furthermore, the delivery mechanism includes a delivery pump, and the input end and the output end of the delivery pump are respectively connected to an input pipe and an output pipe.

[0016] Furthermore, control equipment is provided on the output end of the waste sulfuric acid tank and the output end of the water tank.

[0017] Compared with the prior art, the beneficial effect of the present application is that by setting up a structure in which raw ash bin, pickling tank, plate and frame filter press 1, water washing tank A, plate and frame filter press 2, pickling gypsum temporary storage bin and water washing-separation system cooperate with each other, not only can the heavy metals in fly ash be effectively removed and the risk of heavy metal leaching in fly ash building material products be reduced, but the calcium ions in fly ash can be fixed in the form of gypsum, thereby reducing the cost of subsequent wastewater treatment, and at the same time reducing the cost of preparing fly ash resource gypsum, thereby realizing low-cost resource utilization of fly ash from domestic waste incineration.

[0018] At the same time, this system effectively reduces the heavy metal and chloride ion content in fly ash resource gypsum through one-stage acid washing and two-stage water washing, and completes the conversion process of most calcium-containing compounds into gypsum during acid washing. By coordinating waste sulfuric acid, it reduces the cost of preparing fly ash resource gypsum, realizing low-cost resource utilization of fly ash from municipal solid waste incineration. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of a resource utilization system for producing gypsum by pickling fly ash from waste incineration in an embodiment of the present application.

[0020] Description of reference numerals:

[0021] 1. Raw ash silo; 2. Pickling tank; 3. Plate and frame filter press 1; 4. Water washing tank A; 5. Plate and frame filter press 2; 6. Pickling gypsum temporary storage silo; 7. Waste sulfuric acid tank; 8. Wastewater treatment unit; 9. Water washing tank B; 10. Plate and frame filter press 3; 11. Water tank. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1 This application is described in further detail.

[0023] The present application discloses a resource utilization system for producing gypsum by pickling fly ash from garbage incineration. Figure 1 In this embodiment, the resource utilization system includes a raw ash bin 1, a pickling tank 2, a plate and frame filter press 1 3, a water washing tank A4, a plate and frame filter press 2 5, and a temporary storage bin for pickled gypsum 6. The raw ash bin 1 stores a large amount of waste incineration fly ash. The pickling tank 2 is connected to the discharge end of the raw ash bin 1 via a conveying mechanism, which can transport the waste incineration fly ash in the raw ash bin 1 to the pickling tank 2. The feed end of the pickling tank 2 is also connected to an external waste sulfuric acid tank 7 via a conveying mechanism. The external waste sulfuric acid tank 7 stores waste sulfuric acid with a concentration of 98%.

[0024] The waste sulfuric acid in the waste sulfuric acid tank 7 is transported by a conveying mechanism to the pickling tank 2 for pickling the waste incineration fly ash. The waste sulfuric acid reacts with the waste incineration fly ash to form gypsum, thereby producing a mud-water mixture A. Simultaneously, heavy metals in the waste incineration fly ash are leached by the waste sulfuric acid and mixed with the mud-water mixture A.

[0025] Preferably, a control device is installed at the output end of the waste sulfuric acid tank 7. This control device is configured to effectively regulate the amount of waste sulfuric acid added during the pickling process, thereby facilitating the pH of the solid-liquid mixture in the pickling tank 2 to be stabilized between 7 and 8 and allowing it to fully react for at least 2 hours, thereby further enhancing the reaction between the waste sulfuric acid and the waste incineration fly ash. Furthermore, the control device can be any instrument capable of regulating the flow rate of the liquid, and will not be further described here.

[0026] At the same time, refer to Figure 1In this embodiment, the feed end of the plate-and-frame filter press 3 is connected to the discharge end of the pickling tank 2 via a conveying mechanism. The conveying mechanism transports the muddy-water mixture a obtained by the reaction in the pickling tank 2 to the interior of the plate-and-frame filter press 3. The plate-and-frame filter press 3 then performs solid-liquid separation on the muddy-water mixture a to produce filtrate a and filter cake a. Specifically, filter cake a is pickled gypsum, while the leached heavy metals are mixed in the filtrate a.

[0027] Preferably, in this embodiment, the resource utilization system also includes a wastewater treatment unit 8, the liquid inlet end of the wastewater treatment unit 8 is interconnected with the liquid outlet end of the plate and frame filter press 3 through a conveying mechanism. Under the action of the conveying mechanism, the filtrate a inside the plate and frame filter press 3 is uniformly conveyed to the wastewater treatment unit 8, so that the filtrate a and heavy metals can be effectively stored and treated, so as to reduce the risk of heavy metal leaching in the fly ash building material product.

[0028] The feed end of the water washing tank A4 is connected to the discharge end of the plate and frame filter press 3 through a conveying mechanism. Under the action of the conveying mechanism, the filter cake a inside the plate and frame filter press 3 can be conveyed to the water washing tank A4 to achieve the first water washing treatment of the filter cake a, thereby removing the salt in the pickled gypsum to form a mud-water mixture b.

[0029] In addition, refer to Figure 1 In this embodiment, the feed end of the plate-and-frame filter press 2 5 is connected to the discharge end of the water washing tank A4 via a conveying mechanism. The conveying mechanism uniformly transports the muddy-water mixture b formed after the first water washing in the water washing tank A4 to the interior of the plate-and-frame filter press 2 5 . The plate-and-frame filter press 2 5 then performs solid-liquid separation on the muddy-water mixture b to produce filtrate b and filter cake b. Specifically, the filter cake b is desalinated acid-washed gypsum.

[0030] Preferably, in this embodiment, the liquid outlet end of the plate and frame filter press 2 5 is connected to the liquid inlet end of the pickling tank 2 through a conveying mechanism. Under the action of the conveying mechanism, the filtrate b inside the plate and frame filter press 2 5 is uniformly transported back to the interior of the pickling tank 2, which can not only serve as supplementary water for the pickling tank 2 during the pickling process, but also facilitates the circulation reaction of the filtrate b, thereby further effectively reducing the heavy metal and chloride ion content in the filter cake b.

[0031] In addition, refer to Figure 1 In this embodiment, a water washing and separation system is further installed between the plate and frame filter press 2 5 and the pickled gypsum temporary storage bin 6. The water washing and separation system can perform a second water washing process and solid-liquid separation process on the filter cake b, thereby obtaining a filter cake c. The filter cake c can be used as a raw material for building gypsum and transported and stored in the pickled gypsum temporary storage bin 6, thereby realizing its utilization as a building material.

[0032] Specifically, the water washing and separation system includes a water washing tank B9 and a plate and frame filter press 3 10. The feed end of the water washing tank B9 is connected to the discharge end of the plate and frame filter press 2 via a conveying mechanism. This conveying mechanism transports the filter cake b from the plate and frame filter press 2 5 to the water washing tank B9 for a second water washing of the filter cake b, further removing salt from the first water washing gypsum to form a mud-water mixture c.

[0033] The feed end of the plate and frame filter press 3 10 is connected to the discharge end of the water washing tank B9 through a conveying mechanism. Under the action of the conveying mechanism, the mud-water mixture c formed after the second water washing in the water washing tank B9 is uniformly transported to the interior of the plate and frame filter press 3 10. The plate and frame filter press 3 10 then performs solid-liquid separation on the mud-water mixture c to obtain filtrate c and filter cake c.

[0034] Preferably, in this embodiment, the liquid inlet of the plate-and-frame filter press (3) 10 is connected to an external water tank (11) via a conveying mechanism. Water tank (11) stores a large amount of water. The conveying mechanism delivers the water from tank (11) to the interior of the plate-and-frame filter press (3), thereby replenishing the mud-water mixture (C). A control device is also installed at the output end of the water tank (11), effectively regulating the amount of water added to the water tank (11).

[0035] At the same time, the discharge end of the plate and frame filter press three 10 is connected to the feed end of the pickling gypsum temporary storage bin 6 through a conveying mechanism. Under the action of the conveying mechanism, the filter cake c obtained in the plate and frame filter press three 10 is uniformly conveyed to the pickling gypsum temporary storage bin 6 for storage. The filter cake c can be used as a raw material for building gypsum and used in the subsequent production of gypsum, thereby reducing the cost of preparing fly ash resource gypsum and realizing the low-cost resource utilization of fly ash from the incineration of domestic waste.

[0036] Moreover, the gypsum sample prepared using filter cake c has a chloride ion content of less than 1%, and the leaching concentration of heavy metals should not exceed the maximum allowable emission concentration limit specified in GB8978 (the maximum allowable emission concentration of Class II pollutants shall be implemented in accordance with the first-level standard); at the same time, its calcium sulfate content is greater than 60%.

[0037] Better, refer to Figure 1In this embodiment, the liquid outlet of the plate and frame filter press 3 10 is also interconnected with the liquid inlet of the water washing tank A4 through a conveying mechanism. Under the action of the conveying mechanism, the filtrate c inside the plate and frame filter press 3 10 is uniformly conveyed back to the interior of the water washing tank A4. It can not only serve as supplementary water for the water washing tank A4 during the water washing process, but also facilitate the recycling of the filtrate c, thereby further effectively reducing the heavy metal and chloride ion content in the filter cake c, and further effectively reducing the heavy metal and chloride ion content in the filter cake C.

[0038] Secondly, in this embodiment, the structure of the conveying mechanism described above is the same; specifically, the conveying mechanism includes a conveying pump, an input pipe, and an output pipe. The input pipe and the output pipe are fixedly connected to the input and output ends of the conveying pump, respectively. When the conveying pump is activated, the input pipe conveys the mud-water mixture, filtrate, or filter cake into the output pipe, and then transports it along the output pipe to the next-level processing equipment.

[0039] Preferably, a one-way valve is also installed on the output pipe. By setting the one-way valve, it can be ensured that the mud-water mixture, filtrate or filter cake only flows from the upper-level processing equipment to the lower-level processing equipment, thereby avoiding the backflow of the mud-water mixture, filtrate or filter cake.

[0040] Therefore, this system effectively reduces the heavy metal and chloride ion content in fly ash resource gypsum through one-stage acid washing and two-stage water washing, and completes the conversion process of most calcium-containing compounds into gypsum during acid washing. By coordinating waste sulfuric acid, the cost of preparing fly ash resource gypsum is reduced, realizing the low-cost resource utilization of fly ash from municipal solid waste incineration.

[0041] The implementation principle of a resource utilization system for producing gypsum by pickling fly ash from waste incineration in an embodiment of the present application is as follows: first, the waste incineration fly ash in the original ash bin 1 is transported to the pickling tank 2, and then the waste sulfuric acid in the waste sulfuric acid box 7 is transported to the pickling tank 2 to pickle the waste incineration fly ash, so that the waste sulfuric acid reacts with the waste incineration fly ash to generate gypsum, thereby obtaining a mud-water mixture a; the mud-water mixture a is then transported to the interior of a plate and frame filter press 3 to perform solid-liquid separation on the mud-water mixture a to obtain a filtrate a and a filter cake a; and the heavy metals in the waste incineration fly ash are leached under the action of the waste sulfuric acid and mixed in the mud-water mixture a.

[0042] The filtrate a and the leached heavy metals are then transported to the wastewater treatment unit 8 to effectively store and treat the filtrate a and the heavy metals; at the same time, the filter cake a is transported to the water washing tank A4 to perform the first water washing treatment on the filter cake a, thereby removing the salt in the pickled gypsum to form a mud-water mixture b, and then the mud-water mixture b is transported to the interior of the plate and frame filter press 2 5 to perform solid-liquid separation on the mud-water mixture b, thereby obtaining the filtrate b and the filter cake b.

[0043] At this time, the filtrate b is transported back to the pickling tank 2, and the filter cake b is transported to the water washing tank B9 to achieve a second water washing treatment on the filter cake b, so as to further remove the salt in the first water washing gypsum to form a mud-water mixture c, and then the mud-water mixture c is transported to the interior of the plate and frame filter press 3 10 to perform solid-liquid separation on the mud-water mixture c, thereby obtaining a filtrate c and a filter cake c.

[0044] At this time, the filtrate c is transported back to the water washing tank A4, and the filter cake c is transported to the pickling gypsum temporary storage bin 6 for storage. The filter cake c can be used as a raw material for building gypsum and used in the subsequent production of gypsum, thus completing the resource utilization process of waste incineration fly ash pickling gypsum.

[0045] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A resource utilization system for producing gypsum by pickling fly ash from waste incineration, characterized by: It includes a raw ash bin (1), a pickling tank (2), a plate and frame filter press 1 (3), a water washing tank A (4), a plate and frame filter press 2 (5) and a temporary storage bin for pickled gypsum (6); The pickling tank (2) is connected to an external waste sulfuric acid tank (7); The raw ash bin (1), the pickling tank (2), the plate-frame filter press 1 (3), the water washing tank A (4) and the plate-frame filter press 2 (5) are sequentially connected via a conveying mechanism; A water washing and separation system is also provided between the second plate and frame filter press (5) and the temporary storage bin for pickled gypsum (6).

2. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 1, characterized in that: The water washing-separation system includes a water washing tank B (9) and a plate-frame filter press three (10), wherein the water washing tank B (9) is connected to the plate-frame filter press two (5) via a conveying mechanism, and the plate-frame filter press three (10) is connected to the water washing tank B (9) via a conveying mechanism, and the plate-frame filter press three (10) is connected to the pickling gypsum temporary storage bin (6) via a conveying mechanism.

3. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 2, characterized in that: The plate and frame filter press three (10) is connected to the water washing tank A (4) through a conveying mechanism.

4. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 3, characterized in that: The plate and frame filter press three (10) is connected to an external water tank (11).

5. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 1, characterized in that: The resource utilization system further comprises a wastewater treatment unit (8), and the wastewater treatment unit (8) is connected to the plate and frame filter press (3) via a conveying mechanism.

6. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 1, characterized in that: The plate and frame filter press 2 (5) is connected to the pickling tank (2) through a conveying mechanism.

7. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 1, characterized in that: The delivery mechanism includes a delivery pump, and the input end and the output end of the delivery pump are respectively connected to an input pipe and an output pipe.

8. The resource utilization system for producing gypsum by pickling fly ash from waste incineration according to claim 4, characterized in that: The output end of the waste sulfuric acid tank (7) and the output end of the water tank (11) are both provided with control equipment.

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