A method for comprehensive treatment of alkaline waste liquid and waste solid

Abstract

The present invention discloses a comprehensive treatment method for alkaline waste liquid and solid waste: the fallen alkali is alkali-treated with fresh water, filtered through a microporous filter, and then sent to an alkali buffer tank. The filtered slurry is sent to a salt mud filter press process for combined treatment with the salt mud; heavy ash mother liquor and baking soda mother liquor are respectively added to the alkali buffer tank, and fresh water is added thereto to dilute the alkali liquor; the required alkali liquor and acetic acid are sent to a reactor for reaction, and fresh water is added to adjust the solution specific gravity; the acidic tail gas generated during the reaction is passed to a tail gas scrubber, where it is circulated and washed with fresh water as washing water. Based on the pH change of the washing water, part of the acidic waste water is returned to the reactor for recycling, and a corresponding amount of fresh water is added as washing water; the washed carbon dioxide tail gas is sent to a joint alkali production system for recycling; and after the reaction, the reactor effluent is pumped to a sodium acetate solution finished product tank. The present invention solves the environmental problems caused by alkaline waste liquid and solid waste.

Description

Technical Field

[0001] The present invention relates to the field of environmental protection management, and more particularly to a method for comprehensive management of alkaline waste liquid and waste solid. Background Art

[0002] In the process of combined alkali production, in order to maintain the balance of mother liquor and prevent the salt content in the mother liquor from exceeding the standard and affecting the product quality, it is necessary to discharge the mother liquor regularly, such as heavy ash mother liquor, baking soda mother liquor, etc. Under normal circumstances, for every ton of heavy ash or baking soda product produced, the mother liquor to be discharged is approximately 0.05 to 0.08 m3. 3 In addition, the company's combined alkali production unit requires regular dust removal and equipment cleaning, generating over 1,000 tons of alkali waste annually that requires targeted treatment. Directly discharging these alkali-containing waste liquids and solids not only results in raw material loss and resource waste, but also poses serious environmental risks.

[0003] Sodium acetate solution is the preferred carbon source for most sewage treatment plants. Currently, the main production method uses finished acetic acid and sodium hydroxide (or sodium carbonate or sodium bicarbonate) as raw materials. The process involves reaction, concentration, crystallization, purification, and dissolution (adding water to dissolve the solution into sodium acetate solutions of varying concentrations). This method consumes a lot of raw materials, is costly, and involves a complex process.

[0004] The main components of the waste liquids and solids discharged from the combined alkali unit, such as heavy ash mother liquor, baking soda mother liquor, and ground alkali, are sodium carbonate or sodium bicarbonate. If they can react with acetic acid to directly obtain sodium acetate solution that meets the carbon source requirements, the steps of concentration, crystallization, purification, and dissolution can be omitted. While achieving comprehensive waste management, it can also simplify the process and reduce costs, which is of great significance. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the existing technology and propose an industrially scalable method for the comprehensive treatment of alkaline waste liquids and solids. Using heavy ash mother liquor, baking soda mother liquor, and ground caustic soda discharged from the company's alkali-containing waste liquid and solids as raw materials, they react with acetic acid to produce sodium acetate solution, which is sold as a microbial carbon source. This not only effectively solves the environmental problems caused by alkaline waste liquids and solids, but also avoids resource waste, turning waste into valuable resources, enriching the company's product range, and significantly improving the company's economic benefits and environmental protection level.

[0006] The objectives of the present invention are achieved through the following technical solutions.

[0007] The method for comprehensive treatment of alkaline waste liquid and waste solid of the present invention comprises the following steps:

[0008] Step 1: Send the fallen alkali into the alkali tank and add fresh water to the alkali tank for alkali treatment;

[0009] Step 2: Start the alkali liquid pump to extract the alkali liquid from the alkali liquid tank, filter it through a microporous filter, and then send it to the alkali liquid buffer tank. The mud flows into the mud tank; start the heavy ash mother liquor pump to pump the heavy ash mother liquor in the heavy ash mother liquor tank to the alkali liquid buffer tank; start the baking soda mother liquor pump to pump the baking soda mother liquor in the baking soda mother liquor tank to the alkali liquid buffer tank;

[0010] Step 3: Add fresh water to the alkali solution buffer tank to dilute the alkali solution to a total alkalinity of 150-170 g / L, where the total alkalinity is calculated as sodium carbonate and sodium bicarbonate;

[0011] Step 4: Start the alkali solution delivery pump to pump a certain amount of alkali solution into the reactor; start the acetic acid pump to pump a certain amount of acetic acid from the acetic acid tank into the reactor; after reacting for 0.5 to 1.5 hours, add fresh water to the reactor to adjust the solution specific gravity to 1.12 to 1.14, and continue the reaction for 10 to 30 minutes;

[0012] Step 5: Add fresh water to the washing water circulation tank until its liquid level reaches 60-80%, start the washing water circulation pump, and pump the washing water to the top of the tail gas washing tower to wash the acidic tail gas entering the tail gas washing tower through the tail gas pipeline in a spraying manner. The carbon dioxide after the tail gas washing is sent to the alkali system for recycling, and the acetic acid in it is washed out and flows into the washing water circulation tank, and the washing cycle is repeated; when the pH of the washing water is 5-6, 20-30% of it is returned to the reactor through the acidic wastewater pipeline for recycling; at the same time, a corresponding amount of fresh water is added to the washing water circulation tank;

[0013] Step 6: After the reaction is completed, the reaction liquid discharge pump is started to pump the sodium acetate solution in the reactor into the sodium acetate solution finished product tank, wherein the mass fraction of sodium acetate is 25-28%, the COD is 200000-210000 mg / L, the pH is 7.5-8.5, and the specific gravity is 1.12-1.14.

[0014] In the second step, when the mud stored in the mud tank reaches 60-70% of the effective volume of the tank, the mud pump is started to send the mud to the combined alkali salt mud filter press process for combined treatment.

[0015] In the fourth step, the reaction is carried out according to a volume ratio of the diluted alkali solution to acetic acid of 3.2 to 3.8:1, and the required amounts of alkali solution and acetic acid are calculated based on 70 to 80% of the effective volume of the reactor.

[0016] In the fourth step, during the reaction of alkali solution and acetic acid in the reactor, the reaction heat is removed by circulating water, and the reaction temperature is controlled at 40-60°C.

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0018] (1) The present invention can effectively solve the environmental problems caused by the alkaline waste liquids and solids such as heavy ash mother liquor, baking soda mother liquor, and ground alkali discharged during the production process of combined alkali, save treatment costs, avoid waste of resources, and significantly improve the environmental protection level of the enterprise.

[0019] (2) The present invention uses alkaline waste liquids and solids such as heavy ash mother liquor, baking soda mother liquor, and ground alkali as raw materials to produce high-value-added sodium acetate solution, which can be sold as a microbial carbon source. Key indicators such as the mass fraction of sodium acetate is 25-28%, COD is 200,000-210,000 mg / L, pH is 7.5-8.5, and specific gravity is 1.12-1.14, which meet the requirements of first-class products in relevant standards, realize the transformation of waste into treasure, and enrich the company's product variety; in addition, compared with the traditional production process of sodium acetate solution, the present invention uses alkaline waste liquid and solid as raw materials, and directly reacts to obtain sodium acetate solution that meets the carbon source requirements, eliminating the steps of concentration, crystallization, purification, and dissolution, simplifying the process, reducing costs, and can bring considerable economic benefits to the company.

[0020] (3) The present invention does not generate any new "three wastes" in the process of achieving comprehensive treatment of alkaline waste liquids and solids such as heavy ash mother liquor, baking soda mother liquor, and ground alkali and producing sodium acetate solution. The tail gas of the reactor is mainly carbon dioxide and a small amount of unreacted acetic acid. The acetic acid can be washed out by spraying and circulating with fresh water, and the acid-containing waste water can be returned to the reactor for continued use, which not only improves the utilization rate of acetic acid, reduces raw material consumption, but also avoids the generation of waste liquid; the washed carbon dioxide tail gas is sent to the joint alkali production system for recycling, avoiding the generation of waste gas; when ground alkali is used as raw material, a small amount of insoluble matter such as mud and sand in the alkali solution (whose composition is similar to that of salt mud) is intercepted by a microporous filter and sent to the salt mud filter press process in the form of mud for combined disposal, avoiding the generation of solid waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a schematic diagram of the process flow of the method for comprehensive treatment of alkaline waste liquid and waste solid of the present invention.

[0022] Figure 1: 1-alkali tank, 2-alkali liquid pump, 3-microporous filter, 4-mud tank, 5-mud pump, 6-heavy ash mother liquor tank, 7-heavy ash mother liquor pump, 8-baking soda mother liquor tank, 9-baking soda mother liquor pump, 10 alkali liquid buffer tank, 11-alkali liquid delivery pump, 12-reactor, 13-acetic acid pump, 14-acetic acid tank, 15-tail gas scrubber, 16-washing water circulation pump, 17-washing water circulation tank, 18-reaction liquid discharge pump, 19-sodium acetate solution finished product tank, 20-finished product loading pump, 21-fresh water main, 22-alkali tank water inlet pipeline, 23-alkali liquid buffer tank water inlet pipeline, 24-reactor water inlet pipeline, 25-tail gas pipeline, 26-acid wastewater pipeline. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, the system for comprehensive treatment of alkaline waste liquid and solid waste of the present invention includes an alkali tank 1, an alkali liquid pump 2, a microporous filter 3, a mud tank 4, a mud pump 5, a heavy ash mother liquor tank 6, a heavy ash mother liquor pump 7, a baking soda mother liquor tank 8, a baking soda mother liquor pump 9, an alkali liquid buffer tank 10, an alkali liquid delivery pump 11, a reactor 12, an acetic acid pump 13, an acetic acid tank 14, an exhaust gas scrubber 15, a washing water circulation pump 16, a washing water circulation tank 17, a reaction liquid discharge pump 18, a sodium acetate solution finished product tank 19, a finished product loading pump 20 and related connecting pipelines.

[0025] The water inlet of the alkali tank 1 is connected to the fresh water main 21 through the alkali tank water inlet pipeline 22, and the alkali liquid pump 2 is connected between the discharge port of the alkali tank 1 and the feed port of the microporous filter 3 through a pipeline; the filtrate outlet of the microporous filter 3 is connected to the feed port of the alkali liquid buffer tank 10 through a pipeline, and the mud outlet at the bottom of the microporous filter 3 is connected to the feed port of the mud tank 4 through a pipeline; the discharge port of the mud tank 4 is connected to the mud pump 5 through a pipeline; the discharge port of the heavy ash mother liquor tank 6 and the feed port of the alkali liquid buffer tank 10 are connected to the heavy ash mother liquor pump 7 through a pipeline; the discharge port of the baking soda mother liquor tank 8 and the feed port of the alkali liquid buffer tank 10 are connected to the baking soda mother liquor pump 9 through a pipeline; the water inlet of the alkali liquid buffer tank 10 is connected to the fresh water main 21 through the alkali liquid buffer tank water inlet pipeline 23, and the discharge port of the alkali liquid buffer tank 10 is connected to the reactor 12 The alkali liquor feed port is connected to the alkali liquor delivery pump 11 through a pipeline; the water inlet of the reactor 12 is connected to the fresh water main 21 through the reactor water inlet pipeline 24, the tail gas outlet of the reactor 12 and the air inlet of the tail gas scrubber are connected through the tail gas pipeline 25, the acetic acid feed port of the reactor 12 and the discharge port of the acetic acid tank 14 are connected to the acetic acid pump 13 through a pipeline, and the reaction liquid discharge port of the reactor 12 and the feed port of the sodium acetate solution finished product tank 19 are connected through a pipeline to the reaction liquid discharge pump 18; the water inlet of the washing water circulation tank 17 is connected to the fresh water main 21, the water outlet of the washing water circulation tank 17 and the liquid inlet of the tail gas scrubber 15 are connected through a pipeline to the washing water circulation pump 16, and the circulating washing water feed port of the washing water circulation tank 17 is connected to the liquid outlet of the tail gas scrubber 15 through a pipeline; the outlet of the washing water circulation pump 16 is connected to the acid wastewater pipeline 26 The outlet of the sodium acetate solution finished product tank 19 is connected to the finished product loading pump 20 through a pipeline.

[0026] In the above system, the reactor 12 contains a jacket, and circulating water enters from the upper water inlet of the jacket and exits from the return water outlet of the jacket, and the reaction heat is removed by the circulating water.

[0027] In the above system, the pipelines between the acetic acid tank 14, the acetic acid pump 13 and the reactor 12 are provided with heating pipelines to prevent the acetic acid from freezing.

[0028] In the above system, the carbon dioxide tail gas washed by the tail gas washing tower 15 is returned to the combined alkali production system for recycling.

[0029] In the above system, the mud in the mud tank 4 is sent to the combined alkali salt mud filter press process through the mud pump 5 for combined treatment.

[0030] Based on the above-mentioned system for comprehensive treatment of alkaline waste liquid and waste solid, the present invention proposes a method for comprehensive treatment of alkaline waste liquid and waste solid, and the specific implementation process is as follows:

[0031] The first step is to send the ground alkali into the alkali tank 1, and at the same time add fresh water to the alkali tank 1 through the alkali tank water inlet pipeline 22 to carry out alkali treatment.

[0032] Step 2: Start the alkali liquid pump 2 to extract the alkali liquid from the alkali liquid tank 1, filter it through the microporous filter 3 (filtration accuracy of 0.5-1μm), and then send it to the alkali liquid buffer tank 10. The filtered mud flows into the mud tank 4; start the heavy ash mother liquor pump 7 to pump the heavy ash mother liquor in the heavy ash mother liquor tank 6 to the alkali liquid buffer tank 10; start the baking soda mother liquor pump 9 to pump the baking soda mother liquor in the baking soda mother liquor tank 8 to the alkali liquid buffer tank 10. When the mud stored in the mud tank 4 reaches 60-70% of the effective volume of the tank, start the mud pump 5 to send the mud to the combined alkali salt mud filter press process for combined treatment.

[0033] Step 3: Add fresh water to the alkali solution buffer tank 10 through the alkali solution buffer tank water inlet pipeline 23 to dilute the alkali solution therein to a total alkalinity (calculated as sodium carbonate and sodium bicarbonate) of 150-170 g / L.

[0034] Step 4: React the diluted alkali solution with acetic acid (99.8% by mass) in a volume ratio of 3.2-3.8:1. Calculate the required amounts of alkali solution and acetic acid based on 70-80% of the effective volume of reactor 12. Start the alkali solution pump 11 to pump the required alkali solution into reactor 12. Start the acetic acid pump 13 to pump the required acetic acid from the acetic acid tank 14 into reactor 12 (at a temperature below 20°C, with heating). After 0.5-1.5 hours of reaction, add fresh water to reactor 12 through reactor water inlet line 24 to adjust the solution specific gravity to 1.12-1.14. Continue the reaction for 10-30 minutes. Acidic exhaust gas generated during the reaction enters exhaust gas scrubber 15 via exhaust gas line 25. Circulating water removes the heat of reaction during the alkali solution and acetic acid reaction in reactor 12, maintaining the reaction temperature at 40-60°C.

[0035] Step 5: Fresh water is added to the wash water circulation tank 17 through the fresh water main 21 to a level of 60-80%. The wash water circulation pump 16 is started and pumped to the top of the tail gas scrubber 15. The wash water is then sprayed to scrub the acidic tail gas entering the scrubber 15 through the tail gas line 25. The carbon dioxide from the scrubbed tail gas is then recycled to the combined alkali system, where the acetic acid is washed away and then returned to the wash water circulation tank 17 for multiple wash cycles. When the wash water pH reaches 5-6, 20-30% of the water is returned to the reactor 12 through the acidic wastewater line 26 for recycling. Simultaneously, a corresponding amount of fresh water is added to the wash water circulation tank 17.

[0036] Step 6: After the reaction is completed, the reaction liquid discharge pump 18 is started to pump the sodium acetate solution in the reactor 12 into the sodium acetate solution finished product tank 19. The sodium acetate mass fraction is 25-28%, the COD is 200,000-210,000 mg / L, the pH is 7.5-8.5, and the specific gravity is 1.12-1.14. When loading, the finished product loading pump 20 is started to load the truck.

[0037] Example 1

[0038] The method for comprehensive treatment of alkaline waste liquid and waste solid in this embodiment is specifically implemented as follows:

[0039] The first step is to send the ground alkali into the alkali tank 1, and add fresh water to the alkali tank 1 through the alkali tank water inlet pipeline 22 to carry out alkali treatment.

[0040] Step 2: Start the alkali liquid pump 2 to extract the alkali liquid from the alkali liquid tank 1, filter it through the microporous filter 3 (filtration accuracy of 0.5μm), and then send it to the alkali liquid buffer tank 10. The mud flows into the mud tank 4; start the heavy ash mother liquor pump 7 to pump the heavy ash mother liquor in the heavy ash mother liquor tank 6 to the alkali liquid buffer tank 10; start the baking soda mother liquor pump 9 to pump the baking soda mother liquor in the baking soda mother liquor tank 8 to the alkali liquid buffer tank 10. When the mud stored in the mud tank 4 reaches 65% of the effective volume of the tank, start the mud pump 5 to send the mud to the combined alkali salt mud filter press process for combined treatment.

[0041] Step 3: Add fresh water to the alkali solution buffer tank 10 through the alkali solution buffer tank water inlet pipeline 23 to dilute the alkali solution therein to a total alkalinity (in terms of sodium carbonate and sodium bicarbonate) of 160 g / L.

[0042] Step 4: React with a volume ratio of 3.5:1 between the diluted alkali solution and acetic acid (99.8% by mass). Calculate the required amounts of alkali solution and acetic acid based on 80% of the effective volume of reactor 12. Start the alkali solution delivery pump 11 and pump the required alkali solution into reactor 12. Start the acetic acid pump 13 and pump the required acetic acid from the acetic acid tank 14 into reactor 12 (if the temperature is below 20°C, start heating). After 1 hour of reaction, add fresh water to reactor 12 through reactor water inlet line 24 to adjust the solution specific gravity to 1.12. Continue the reaction for 10 minutes. The acidic exhaust gas generated during the reaction enters exhaust gas scrubber 15 through exhaust gas line 25. The heat of reaction during the alkali solution and acetic acid reaction in reactor 12 is removed by circulating water, maintaining the reaction temperature at 50°C.

[0043] Step 5: Fresh water is added to the wash water circulation tank 17 through the fresh water main 21 to an 80% liquid level. The wash water circulation pump 16 is activated, pumping the wash water to the top of the tail gas scrubber 15. It is then sprayed to scrub the acidic tail gas entering the scrubber 15 through the tail gas line 25. The carbon dioxide from the scrubbed tail gas is then recycled to the combined alkali system, where the acetic acid is washed away and then returned to the wash water circulation tank 17 for multiple wash cycles. When the pH of the wash water reaches 5, 30% of the water is returned to the reactor 12 through the acidic wastewater line 26 for recycling. Simultaneously, a corresponding amount of fresh water is added to the wash water circulation tank 17.

[0044] Step 6: After the reaction is completed, the reaction liquid discharge pump 18 is started to pump the sodium acetate solution into the sodium acetate solution finished product tank 19, wherein the sodium acetate mass fraction is 25%, the COD is 210,000 mg / L, the pH is 8.5, and the specific gravity is 1.12. When loading, the finished product loading pump 20 is started to load the truck.

[0045] Example 2

[0046] The method for comprehensive treatment of alkaline waste liquid and waste solid in this embodiment is specifically implemented as follows:

[0047] The first step is to send the ground alkali into the alkali tank 1, and add fresh water to the alkali tank 1 through the alkali tank water inlet pipeline 22 to carry out alkali treatment.

[0048] Step 2: Start the alkali liquid pump 2 to extract the alkali liquid from the alkali liquid tank 1, filter it through the microporous filter 3 (filtration accuracy of 0.75μm), and then send it to the alkali liquid buffer tank 10. The mud flows into the mud tank 4; start the heavy ash mother liquor pump 7 to pump the heavy ash mother liquor from the heavy ash mother liquor tank 6 to the alkali liquid buffer tank 10; start the baking soda mother liquor pump 9 to pump the baking soda mother liquor from the baking soda mother liquor tank 8 to the alkali liquid buffer tank 10. When the mud stored in the mud tank 4 reaches 60% of the effective volume of the tank, start the mud pump 5 to send the mud to the combined alkali salt mud filter press process for combined treatment.

[0049] Step 3: Add fresh water to the alkali solution buffer tank 10 through the alkali solution buffer tank water inlet pipeline 23 to dilute the alkali solution therein to a total alkalinity (in terms of sodium carbonate and sodium bicarbonate) of 150 g / L.

[0050] Step 4: The reaction is carried out in a volume ratio of 3.8:1 between the diluted alkali solution and acetic acid (mass fraction 99.8%). The required amount of alkali solution and acetic acid is calculated based on 70% of the effective volume of the reactor 12. Start the alkali solution delivery pump 11 and pump the required alkali solution into the reactor 12. Start the acetic acid pump 13 and pump the required acetic acid from the acetic acid tank 14 into the reactor 12 (the temperature is below 20°C and heating is started). After 1.5 hours of reaction, fresh water is added through the reactor water inlet line 24 to adjust the solution specific gravity to 1.13. Thereafter, the reaction is continued for 20 minutes. The acidic tail gas generated during the reaction enters the tail gas scrubber 15 through the tail gas line 25. The reaction heat of the alkali solution and acetic acid reaction in the reactor 12 is removed by circulating water, and the reaction temperature is controlled at 40°C.

[0051] Step 5: Fresh water is added to the wash water circulation tank 17 through the fresh water main 21 to a level of 70%. The wash water circulation pump 16 is started, pumping the wash water to the top of the tail gas scrubber 15. It is then sprayed to scrub the acidic tail gas entering the tail gas scrubber 15 through the tail gas line 25. The carbon dioxide from the scrubbed tail gas is then recycled to the combined alkali system, where the acetic acid is washed away and then returned to the wash water circulation tank 17 for multiple washing cycles. When the wash water reaches a pH of 6, 20% of the water is returned to the reactor 12 through the acidic wastewater line 26 for recycling. Simultaneously, a corresponding amount of fresh water is added to the wash water circulation tank 17.

[0052] Step 6: After the reaction is completed, the reaction liquid discharge pump 18 is started to pump the sodium acetate solution in the reactor 12 into the sodium acetate solution finished product tank 19. The sodium acetate mass fraction is 28%, the COD is 200,000 mg / L, the pH is 8, and the specific gravity is 1.13. When loading, the finished product loading pump 20 is started to load the truck.

[0053] Example 3

[0054] The method for comprehensive treatment of alkaline waste liquid and waste solid in this embodiment is specifically implemented as follows:

[0055] The first step is to send the ground alkali into the alkali tank 1, and add fresh water to the alkali tank 1 through the alkali tank water inlet pipeline 22 to carry out alkali treatment.

[0056] Step 2: Start the alkali liquid pump 2 to extract the alkali liquid from the alkali liquid tank 1, filter it through the microporous filter 3 (filtration accuracy of 1μm), and then send it to the alkali liquid buffer tank 10. The mud flows into the mud tank 4; start the heavy ash mother liquor pump 7 to pump the heavy ash mother liquor from the heavy ash mother liquor tank 6 to the alkali liquid buffer tank 10; start the baking soda mother liquor pump 9 to pump the baking soda mother liquor from the baking soda mother liquor tank 8 to the alkali liquid buffer tank 10. When the mud stored in the mud tank 4 reaches 70% of the effective volume of the tank, start the mud pump 5 to send the mud to the combined alkali salt mud filter press process for combined treatment.

[0057] Step 3: Add fresh water to the alkali solution buffer tank 10 through the alkali solution buffer tank water inlet pipeline 23 to dilute the alkali solution therein to a total alkalinity (in terms of sodium carbonate and sodium bicarbonate) of 170 g / L.

[0058] Step 4: React according to a volume ratio of 3.2:1 between the diluted alkali solution and acetic acid (mass fraction 99.8%). Calculate the required amount of alkali solution and acetic acid based on 75% of the effective volume of the reactor 12. Start the alkali solution delivery pump 11 and pump the required alkali solution into the reactor 12. Start the acetic acid pump 13 and pump the required acetic acid from the acetic acid tank 14 into the reactor 12 (the temperature is below 20°C and heating is started). After 0.5 hours of reaction, add fresh water through the reactor water inlet line 24 to adjust the solution specific gravity to 1.14. Then, continue the reaction for 30 minutes. The acidic tail gas generated during the reaction enters the tail gas scrubber 15 through the tail gas line 25. The reaction heat of the alkali solution and acetic acid reaction in the reactor 12 is removed by circulating water, and the reaction temperature is controlled at 60°C.

[0059] Step 5: Fresh water is added to the wash water circulation tank 17 through the fresh water main 21 to a level of 60%. The wash water circulation pump 16 is started, pumping the wash water to the top of the tail gas scrubber 15. It is then sprayed to scrub the acidic tail gas entering the tail gas scrubber 15 through the tail gas line 25. The carbon dioxide from the scrubbed tail gas is then recycled to the combined alkali system, where the acetic acid is washed away and then returned to the wash water circulation tank 17 for multiple wash cycles. When the pH of the wash water reaches 5.5, 25% of the water is returned to the reactor 12 through the acidic wastewater line 26 for recycling. Simultaneously, a corresponding amount of fresh water is added to the wash water circulation tank 17.

[0060] Step 6: After the reaction is complete, the reaction liquid discharge pump 18 is started to pump the sodium acetate solution in the reactor 12 into the sodium acetate solution finished product tank 19. The sodium acetate mass fraction is 26.5%, the COD is 205,000 mg / L, the pH is 7.5, and the specific gravity is 1.14. When loading, the finished product loading pump 20 is started to load the truck.

[0061] Although the functions and working processes of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific functions and working processes. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all protected by the present invention.

Claims

1. A method for comprehensive treatment of alkaline waste liquid and waste solid, characterized in that: The method comprehensively utilizes three alkali-containing waste materials, namely, ground alkali, heavy ash mother liquor, and baking soda mother liquor, and specifically includes the following processes: The first step is to send the fallen alkali into the alkali tank (1) and add fresh water to the alkali tank (1) to alkali; Step 2: Start the alkali liquid pump (2) to extract the alkali liquid from the alkali liquid tank (1), filter it through the microporous filter (3) and send it to the alkali liquid buffer tank (10), and the mud flows into the mud tank (4); start the heavy ash mother liquor pump (7) to pump the heavy ash mother liquor in the heavy ash mother liquor tank (6) to the alkali liquid buffer tank (10); start the baking soda mother liquor pump (9) to pump the baking soda mother liquor in the baking soda mother liquor tank (8) to the alkali liquid buffer tank (10); wherein the filtration accuracy of the microporous filter (3) is 0.5~1μm; Step 3: Add fresh water to the alkali solution buffer tank (10) to dilute the alkali solution therein to a total alkalinity of 150-170 g / L, where the total alkalinity is calculated as sodium carbonate and sodium bicarbonate; Step 4: Start the alkali solution delivery pump (11) to pump a certain amount of alkali solution into the reactor (12); start the acetic acid pump (13) to pump a certain amount of acetic acid from the acetic acid tank (14) into the reactor (12); after reacting for 0.5 to 1.5 hours, add fresh water to the reactor (12) to adjust the solution specific gravity to 1.12 to 1.14, and continue the reaction for 10 to 30 minutes; the acid-containing tail gas generated during the reaction enters the tail gas scrubber (15) through the tail gas pipeline (25); Step 5: Add fresh water to the washing water circulation tank (17) until the liquid level is 60-80%, start the washing water circulation pump (16), and pump the washing water to the top of the tail gas washing tower (15), and wash the acidic tail gas entering the tail gas washing tower (15) through the tail gas pipeline (25) in a spraying manner. The carbon dioxide after the tail gas washing is sent to the joint alkali system for recycling, and the acetic acid therein is washed out and flows into the washing water circulation tank (17), and the washing is repeated in a cycle; when the pH of the washing water is 5-6, 20-30% of it is returned to the reactor (12) through the acidic wastewater pipeline (26) for recycling; at the same time, a corresponding amount of fresh water is added to the washing water circulation tank (17); Step 6: After the reaction is completed, the reaction liquid discharge pump (18) is started to pump the sodium acetate solution in the reactor (12) into the sodium acetate solution finished product tank (19), wherein the mass fraction of sodium acetate is 25-28%, the COD is 200,000-210,000 mg / L, the pH is 7.5-8.5, and the specific gravity is 1.12-1.

14.

2. The method for comprehensive treatment of alkaline waste liquid and waste solid according to claim 1, characterized in that: In the second step, when the mud stored in the mud tank (4) reaches 60-70% of the effective volume of the tank, the mud pump (5) is started to send the mud to the combined alkali salt mud filter press process for combined treatment.

3. The method for comprehensive treatment of alkaline waste liquid and waste solid according to claim 1, characterized in that: In the fourth step, the reaction is carried out according to a volume ratio of the diluted alkali solution to acetic acid of 3.2 to 3.8:1, and the amount of alkali solution and acetic acid required is calculated based on 70 to 80% of the effective volume of the reactor (12).

4. The method for comprehensive treatment of alkaline waste liquid and waste solid according to claim 1, characterized in that: In the fourth step, during the reaction of alkali solution and acetic acid in the reactor (12), the reaction heat is removed by circulating water, and the reaction temperature is controlled to be 40-60°C.

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