Device and method for resource utilization of caustic soda ammonia distillation waste liquid

Abstract

The application aims to provide a device and method for resource utilization of alkali production ammonia evaporation waste liquid, belonging to the technical field of industrial waste liquid comprehensive utilization. 2+ The application evaporates and concentrates the ammonia evaporation waste liquid by using flue gas waste heat, realizes flue gas desulfurization, obtains CaSO4 by-product, uses the ammonia evaporation waste liquid to absorb CO2 to prepare special CaCO3 hollow microspheres, uses the carbonate precipitation method to convert the remaining Ca + The application converts Na The application converts the remaining NH4Cl concentrated solution into a raw material of liquid fertilizer and commercializes it. The application has the characteristics of simple process flow, good technical economy, strong practicability, complete treatment of the ammonia evaporation waste liquid, complete resource utilization of the main inorganic salt resources in the ammonia evaporation waste liquid, and high-value products such as CaCO3 hollow microspheres and phosphorus sodium ammonium stone.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization technology of industrial waste liquid, specifically relating to an apparatus and method for the resource utilization of waste liquid from alkali production and ammonia stripping. Background Technology

[0002] Ammonia stripping wastewater is a persistent source of mother liquor in the ammonia-soda industry, and the amount generated annually in my country is enormous. In 2020, over 177 million tons of ammonia stripping wastewater were generated nationwide, containing a total of 23.01-31.86 million tons of inorganic salts such as CaCl2 and NaCl. Therefore, to alleviate the frictional contradiction between environmental threats and resource loss caused by ammonia stripping wastewater discharge, the treatment and resource utilization of ammonia stripping wastewater have a profound impact on the alkali industry, regional economic development and environmental protection, and even the stability of the global ecosystem.

[0003] Currently, the main methods for treating ammonia-containing wastewater both domestically and internationally involve solid-liquid separation through natural sedimentation and evaporation. The solid waste is used for land reclamation, production of flue gas desulfurization agents, and building materials, while the supernatant is treated before discharge, recovering the inorganic salts CaCl2 and NaCl, or removing Ca... 2+ The ammonia is converted into hydroxyapatite, CaSO4, and CaCO3 products. Patent (CN115215364A) synthesizes aragonite-type CaCO3 using ammonia waste liquid as raw material; patent (CN115304091A) prepares aragonite-type CaCO3 using ammonia waste liquid; patent (CN113104876A) produces CaCO3 and HCl gas using ammonia waste liquid; and patent (CN112877780A) synthesizes CaSO4·0.5H2O whiskers using a hydrothermal method. Some cases involve ammonia waste liquid treatment technologies and devices. Patent (CN111559753A) adds Na2SO4 to ammonia waste liquid to obtain CaSO4, simultaneously producing a solution rich in NaCl; and patent (CN113387409A) uses a circulation device to reduce the ash milk content of ammonia waste liquid, achieving internal recycling of ammonia waste liquid resources. However, due to the low added value of the aforementioned products and the incomplete treatment of ammonia-containing wastewater by the aforementioned equipment and processes, the technical and economic limitations of efficient treatment and utilization of ammonia-containing wastewater have not yet been overcome. Therefore, if high-value products can be produced, the technical and economic efficiency of the process can be significantly improved. For example, the economic value of some special types of calcium carbonate is significantly higher than that of light calcium carbonate products from ordinary carbonation reactions, and the market price of special sodium salt crystal products is much higher than that of ordinary inorganic sodium salts. The synthesis of these products will significantly improve the technical and economic efficiency of the process. In summary, developing a high-efficiency and high-value ammonia-containing wastewater treatment process has become a key issue for the green development of the soda ash industry. Summary of the Invention

[0004] The purpose of this invention is to provide an apparatus and method for the resource utilization of ammonia stripping waste liquid in alkali production, breaking through the bottleneck of high-value utilization of ammonia stripping waste liquid.

[0005] The present invention adopts the following technical solution:

[0006] A device for the resource utilization of waste liquid from alkali production and ammonia distillation includes a gas-liquid reactor, a solid-liquid separation device 1, a gas-liquid heating reactor, a two-stage heat exchange device, a gas-liquid separation device, a spray evaporation device, a solid-liquid separation device 2, a stirred reactor, a solid-liquid separation device 3, a solid-liquid heating reactor, a forced cooling device, and a solid-liquid separation device 4.

[0007] The gas-liquid reactor has an air inlet at the lower end of one side, a liquid inlet at the upper end of the other side, an outlet at the bottom, and a tail gas outlet at the top.

[0008] The solid-liquid separation device has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the upper side.

[0009] The gas-liquid heating reactor has an outlet at the top and an inlet at the bottom.

[0010] The two-stage heat exchanger has an inlet at the top and an outlet and a liquid inlet at the bottom.

[0011] The gas-liquid separator has a liquid inlet at the top, a liquid outlet at the bottom, and a gas outlet at the upper side.

[0012] The spray evaporation device has a liquid inlet at the top, an outlet at the bottom, an air outlet at the upper end of one side, and an air inlet at the lower end of the other side.

[0013] The solid-liquid separation device 2 has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the upper side.

[0014] The stirred reactor has a liquid phase inlet on one upper side, a solid phase inlet on the other upper side, and an outlet at the bottom.

[0015] The solid-liquid separation device 3 has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the upper side.

[0016] The solid-liquid heating reactor has a liquid inlet at the upper end of one side, a solid phase inlet at the upper end of the other side, and an outlet at the bottom.

[0017] The forced cooling device has an inlet at the top and an outlet at the bottom.

[0018] The solid-liquid separation device 4 has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the upper side.

[0019] The inlet of the gas-liquid reactor is connected to the outlet of the gas-liquid heating reactor; the outlet of the gas-liquid reactor is connected to the inlet of the first solid-liquid separation device; the liquid inlet of the gas-liquid reactor is connected to the liquid inlet of the spray evaporator; the liquid phase outlet of the first solid-liquid separation device is connected to the liquid inlet of the spray evaporator; the inlet of the gas-liquid heating reactor is connected to the outlet of the gas-liquid separation device; the inlet of the two-stage heat exchanger is connected to the outlet of the spray evaporator; the outlet is connected to the liquid inlet of the gas-liquid separation device; the liquid inlet is connected to the liquid outlet of the gas-liquid separation device; the outlet of the spray evaporator is connected to the inlet of the second solid-liquid separation device; the liquid phase outlet of the second solid-liquid separation device is connected to the liquid phase inlet of the stirred reactor; the outlet of the stirred reactor is connected to the inlet of the third solid-liquid separation device; the liquid phase outlet of the third solid-liquid separation device is connected to the liquid inlet of the solid-liquid heating reactor; the outlet of the solid-liquid heating reactor is connected to the inlet of the forced cooling device; and the outlet of the forced cooling device is connected to the inlet of the fourth solid-liquid separation device.

[0020] A method for resource utilization of waste liquid from ammonia distillation in alkali production includes the following steps:

[0021] The first step is to pass the ammonia-steamed waste liquid into the gas-liquid reactor, and then pass CO2 from the gas-liquid heating reactor into the gas-liquid reactor to react with the ammonia-steamed waste liquid to undergo a carbonation reaction. The reaction time is 20-60 minutes. The solid phase obtained after passing through the solid-liquid separation device is CaCO3 hollow microspheres, and the liquid phase 1 is obtained.

[0022] The second step is to pass the separated liquid phase 1 into a spray evaporation device for concentration. The high-temperature flue gas of 200~300℃ introduced from below provides a heat source for evaporation. At the same time, SO2 in the flue gas reacts with the ammonia stripping waste liquid to achieve flue gas desulfurization. The system after evaporation and concentration is passed into the solid-liquid separation device 2 to obtain solid CaSO4 byproduct and liquid phase 2.

[0023] The third step involves cooling the exhaust gas discharged from the spray evaporator through a two-stage heat exchanger, then passing it through a gas-liquid separation device. The resulting liquid H2O is recycled back to the two-stage heat exchanger. The separated gas is then introduced into a gas-liquid heating reactor containing ethanolamine solution and reacted for 30-60 minutes. The reactor is then heated to 60-110°C to release a high concentration of CO2. The enriched CO2 gas is then introduced into the gas-liquid reactor to react with the ammonia stripping waste liquid.

[0024] The fourth step is to pass the separated liquid phase 2 into a stirred reactor, and add solid Na2CO3 while stirring. After reacting for 20 to 60 minutes, the mixture is passed into the solid-liquid separation device 3 to obtain micron-sized CaCO3 and liquid phase 3.

[0025] Fifth step: Liquid phase 3 is passed into a solid-liquid heating reactor for evaporation and concentration to obtain liquid phase 4. (NH4)2HPO4 is added to the solid-liquid heating reactor at 60~100℃ to dissolve and react for 10~60 minutes. Then it is passed into a forced cooling device for cooling and crystallization at a cooling temperature of -10~20℃ for 10~60 minutes. Then it is passed into a solid-liquid separation device four to obtain solid sodium ammonium phosphate. The remaining liquid phase 5, which is rich in NH4Cl, is retained.

[0026] Furthermore, the separation method of the solid-liquid separation device is centrifugal separation or natural sedimentation. The centrifugal separation speed is 1000~10000 rpm. The CaCO3 hollow microspheres obtained by separation are washed with ultrapure water and dried to obtain CaCO3 hollow microsphere products.

[0027] Furthermore, the separation method of the solid-liquid separation device three is filtration separation or vacuum filtration separation. The separated micron-sized CaCO3 is washed with ultrapure water and dried to obtain micron-sized CaCO3 product.

[0028] Furthermore, the separation method of the solid-liquid separation device four is vacuum filtration or natural sedimentation. The separated sodium phosphate ammonium stone is dried by natural air drying to obtain sodium phosphate ammonium stone product with the chemical formula H(NH4)Na(PO4)·4H2O.

[0029] Furthermore, the flow rate of enriched CO2 introduced into the gas-liquid reactor is 0.5-5 L / (min·L). 蒸氨废液 ).

[0030] Furthermore, ammonia water needs to be added to the ammonia-containing waste liquid added to the gas-liquid reactor, with a total ammonia concentration of 0.057~1.430 mol / L.

[0031] Furthermore, the ammonia solution can also be NaOH solution, lime milk, or waste alkali solution, and the corresponding product obtained is aragonite-type CaCO3 product or massive calcite-type CaCO3 product.

[0032] Furthermore, in the liquid phase 1 separated in the solid-liquid separation device 1, lime slurry needs to be continuously added to maintain its concentration in the solution at 1~10 g / L.

[0033] Further, the separated liquid phase 2 is passed into a stirred reactor, and solid Na2CO3 is added while stirring. The Na in the reaction solution... + : Ca 2+ The molar ratio of the substances is (0.5~5):1.

[0034] Furthermore, liquid phase 3 is passed into a heated reactor for evaporation and concentration to obtain liquid phase 4, with a volume ratio of liquid phase 4 to liquid phase 3 of 1:(2~10).

[0035] Furthermore, (NH4)2HPO4 is added to the solid-liquid heating reactor, and the molar ratio of (NH4)2HPO4 to NaCl in the reaction solution is (0.5~5):1.

[0036] Furthermore, the (NH4)2HPO4 can also be (NH4)H2PO4, or NH3·H2O and H3PO4 can be added successively, and the corresponding products can also be H(NH4)Na(PO4) or (NH4)H2PO4.

[0037] The beneficial effects of this invention are as follows:

[0038] In terms of process: (1) A device for the resource utilization of ammonia stripping waste liquid was developed to thoroughly treat ammonia stripping waste liquid, while realizing flue gas desulfurization and making full use of flue gas waste heat. The treatment process was optimized, and the inorganic salt resources in ammonia stripping waste liquid were converted into high-value products without causing excessive energy and material consumption.

[0039] In terms of technology: (2) A method for the resource utilization of ammonia stripping waste liquid was developed, which specifically addresses the practical problems of incomplete resource utilization and poor economic benefits of ammonia stripping waste liquid, and realizes the high-value utilization and resource utilization of low-value waste liquid.

[0040] In terms of products: (1) For the first time, hollow calcite microspheres were synthesized by absorbing CO2 from ammonia stripping waste liquid;

[0041] In terms of products: (2) For the first time, we explored the synthesis of sodium ammonium phosphate rock using ammonia stripping waste liquid as raw material;

[0042] Among the two high-value products mentioned above, the price of hollow CaCO3 spheres is higher than that of light CaCO3 products produced by ordinary carbonation reactions. Sodium phosphate ammonium stone can be used in the titration and detection of uranium, magnesium, zinc and manganese elements. The market price of high-quality sodium phosphate ammonium stone products is as high as 10,000 to 30,000 yuan / ton. The synthesis of these products provides a guarantee for the good technical and economic benefits of this invention, and is expected to solve the "bottleneck" problem in the ammonia-soda industry, and has the potential to further promote the development of the soda ash industry. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the device structure of the present invention;

[0044] In the diagram: 1-Gas-liquid reactor; 2-Solid-liquid separation device one; 3-Gas-liquid heating reactor; 4-Two-stage heat exchange device; 5-Gas-liquid separation device; 6-Spray evaporation device; 7-Solid-liquid separation device two; 8-Stirred reactor; 9-Solid-liquid separation device three; 10-Solid-liquid heating reactor; 11-Forced cooling device; 12-Solid-liquid separation device four.

[0045] Figure 2 Scanning electron microscope (SEM) image of the CaCO3 hollow microsphere product prepared in Example 1 of this invention.

[0046] Figure 3 The scanning electron microscope (SEM) image and X-ray diffraction (XRD) spectrum of the sodium phosphate ammonium stone product prepared in Example 1 of this invention. Detailed Implementation

[0047] In the embodiments, the device employs, for example... Figure 1 The device shown.

[0048] Example 1

[0049] The main components and characteristics of ammonia stripping waste liquid are shown in Table 1.

[0050] Table 1. Main components and characteristics of ammonia stripping waste liquid

[0051]

[0052] This embodiment provides a device for the resource utilization of waste liquid from alkali production and ammonia stripping, including a gas-liquid reactor 1. The gas-liquid reactor 1 has an air inlet at its lower left end, a liquid inlet at its upper end, and an outlet at its lower right end, connected to the inlet of a solid-liquid separation device 2. The solid-liquid separation device 2 has a solid phase outlet at its lower end and a liquid phase outlet at its upper end, connected to the liquid inlets of the gas-liquid reactor 1 and a spray evaporation device 6. A gas-liquid heating reactor 3 has an air inlet at its lower end and an air outlet at its upper end, connected to the gas-liquid reactor 1 and a spray evaporation device 6. The inlet of the liquid reactor 1 is connected; the upper end of the two-stage heat exchanger 4 has an inlet connected to the spray evaporator 6, the lower left end has an outlet connected to the inlet of the gas-liquid separator 5, and the lower right end has a liquid inlet connected to the liquid outlet of the gas-liquid separator 5; the upper end of the gas-liquid separator 5 has a liquid inlet connected to the liquid outlet of the two-stage heat exchanger 4, the upper left end has an outlet connected to the inlet of the gas-liquid heating reactor 3, and the lower end has a liquid outlet connected to the gas-liquid separator 4. The spray evaporator 6 has an inlet at its upper end, which connects to the outlet of the solid-liquid separation device 1 2. It also has an outlet at its upper left end, which connects to the inlet of the two-stage heat exchanger 4. The lower right end has an inlet, and the lower end has an outlet, which connects to the solid-liquid separation device 2 7. The solid-liquid separation device 2 7 has a solid phase outlet at its lower end and a liquid phase outlet at its upper end, which connects to the liquid phase inlet of the stirred reactor 8. The stirred reactor 8 has a solid phase inlet at its upper right end and an outlet at its lower end, which connects to the inlet of the solid-liquid separation device 3 9. The solid-liquid separation device 3 9 has a solid phase outlet at its lower end and a liquid phase outlet at its upper end, which connects to the inlet of the solid-liquid heating reactor 10. The solid-liquid heating reactor 10 has a solid phase inlet at its upper right end and an outlet at its lower end, which connects to the inlet of the forced cooling device 11. The forced cooling device 11 has an outlet at its lower end, which connects to the inlet of the solid-liquid separation device 4 12. The solid-liquid separation device 4 12 has a solid phase outlet at its lower end and a liquid phase outlet at its upper end.

[0053] This embodiment provides a method for the resource utilization of waste liquid from ammonia stripping during alkali production, including the following steps:

[0054] a) First, the ammonia-steaming waste liquid is fed into the gas-liquid reactor 1. The high-concentration CO2 in the gas-liquid heating reactor 3 is fed into the reactor to react with the ammonia-steaming waste liquid to undergo a carbonation reaction. The reaction time is 20 minutes. The solid phase obtained after passing through the solid-liquid separation device 2 is CaCO3 hollow microspheres, and the liquid phase is liquid phase 1.

[0055] b) The solid-liquid separation device 2 uses centrifugal separation at a speed of 10,000 rpm. The separated CaCO3 hollow microspheres are washed with ultrapure water and dried to obtain the CaCO3 hollow microsphere product, such as... Figure 2 As shown, the yield is 18.01 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 20.0%;

[0056] c) The separated liquid phase 1 is passed into the spray evaporator 6 for concentration. The 300°C high-temperature flue gas introduced from below provides a heat source for evaporation, while the SO2 in the flue gas reacts with the ammonia stripping waste liquid to achieve flue gas desulfurization. The concentrated system is then passed into the solid-liquid separation device 7 to obtain solid CaSO4 byproduct and liquid phase 2.

[0057] d) The exhaust gas discharged from the spray evaporator 6 is cooled in the two-stage heat exchanger 4 and then passed through the gas-liquid separation device 5. The liquid phase H2O is recycled back to the two-stage heat exchanger 4. The separated gas (low concentration CO2) is introduced into the gas-liquid heating reactor 3 containing ethanolamine solution and reacted for 30 minutes. Then it is heated to 110°C to release high concentration CO2. The enriched CO2 gas is introduced into the gas-liquid reactor 1 to react with the ammonia stripping waste liquid.

[0058] e) The separated liquid phase 2 is introduced into the stirred reactor 8, and Na2CO3 solid is added while stirring. After reacting for 20-60 minutes, it is introduced into the solid-liquid separation device 9 to obtain micron CaCO3, and the liquid phase is liquid phase 3.

[0059] f) The solid-liquid separation unit 39 uses filtration separation. The separated micron-sized CaCO3 is washed with ultrapure water and dried to obtain the micron-sized CaCO3 product, with a yield of 72.07 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 80.0%;

[0060] g) Liquid phase 3 is passed into solid-liquid heating reactor 10 for evaporation and concentration to obtain liquid phase 4. (NH4)2HPO4 is added to solid-liquid heating reactor 10 at 80°C to dissolve and react for 20 minutes. Then, it is passed into forced cooling device 11 for cooling and crystallization at 0°C for 30 minutes. Then, it is passed into solid-liquid separation device 12 to obtain solid sodium ammonium phosphate. The remaining liquid phase 5, which is rich in NH4Cl, is retained.

[0061] h) The solid-liquid separation device 412 uses vacuum filtration. The separated sodium phosphate ammonium stone is dried by natural air drying. The SEM image and XRD pattern of the obtained product are shown below. Figure 3 As shown in the XRD pattern, the peaks of the product are basically consistent with those on the standard card for sodium phosphate ammonium stone, confirming that the product is sodium phosphate ammonium stone. The yield of sodium phosphate ammonium stone is 396.5 kg / t. 蒸氨废液 Na in ammonia stripping waste liquid + The conversion rate was 93.0%.

[0062] Further, as described in a), the flow rate of enriched CO2 introduced into the gas-liquid reactor 1 is 2.5 L / (min·L). 蒸氨废液 ).

[0063] Furthermore, as described in a), ammonia water needs to be added to the ammonia-containing waste liquid added to the gas-liquid reactor 1, with a total ammonia concentration of 0.286 mol / L.

[0064] Furthermore, as described in c), a small amount of lime slurry needs to be continuously added to the liquid phase 1 separated in the solid-liquid separation device 2 to maintain its concentration in the solution at 4.76 g / L.

[0065] Further, as described in e), the separated liquid phase 2 is introduced into the stirred reactor 8, and solid Na2CO3 is added while stirring. The Na in the reaction solution... + : Ca 2+ The molar ratio of the substances is 1:1.

[0066] Further, as described in g), the liquid phase 3 is passed into the solid-liquid heating reactor 10 for evaporation and concentration to obtain the liquid phase 4, the volume ratio of the liquid phase 4 to the liquid phase 3 being 1:2.5.

[0067] Further, as described in g), (NH4)2HPO4 is added to the solid-liquid heating reactor 10 at 80°C to dissolve and react for 20 minutes, with the molar ratio of (NH4)2HPO4 to NaCl in the reaction solution being 1:1.

[0068] Example 2

[0069] The apparatus and method are the same as in Example 1, except that the ammonia water added to the ammonia stripping waste liquid is replaced with lime slurry, making the alkalinity of the ammonia stripping waste liquid 11.40. Accordingly, the carbonation product obtained in step a) is a CaCO3 product doped with aragonite and calcite or a massive calcite-type CaCO3 product, with a yield of 15.38 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 17.1%. The micron-sized CaCO3 separated in the solid-liquid separation unit 3.9 was washed with ultrapure water and dried to obtain the micron-sized CaCO3 product, with a yield of 74.68 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 82.9%.

[0070] Example 3

[0071] The apparatus and method are the same as in Example 1, except that the carbonation reaction is carried out in the gas-liquid reactor 1 for 60 minutes with CO2 introduced, a saturated Na2CO3 solution is added to the liquid phase 2, and the concentrated liquid phase 3 is liquid phase 4, with a volume ratio of 1:5. After washing and drying, micron-sized CaCO3 is obtained, with a yield of 71.88 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 79.8%.

[0072] Example 4

[0073] The apparatus and method are the same as in Example 1, except that the solid-liquid separation device 2 uses natural sedimentation for separation, with a sedimentation time of 0-48 hours. After washing and drying, CaCO3 hollow microspheres are obtained, with a yield of 16.48 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 18.3%. The solid-liquid separation unit 39 used vacuum filtration for separation, followed by washing and drying to obtain micron-sized CaCO3 product, with a yield of 73.61 kg / t. 蒸氨废液 Ca in ammonia stripping waste liquid 2+ The conversion rate was 81.7%.

[0074] Example 5

[0075] The apparatus and method are the same as in Example 1, except that (NH4)2HPO4 is added to the solid-liquid heating reactor 10 to dissolve and react while the liquid phase 4 is maintained at 90°C. Then, the mixture is passed through a forced cooling device 11 for cooling and crystallization at a temperature of 10°C. The solid-liquid separation device 12 uses natural sedimentation for separation. The separated sodium phosphate ammonium stone is dried naturally to obtain the sodium phosphate ammonium stone product, with a yield of 383.7 kg / t. 蒸氨废液 Na in ammonia stripping waste liquid +The conversion rate was 90.0%.

Claims

1. A device for the resource utilization of waste liquid from alkali production and ammonia distillation, characterized in that: It includes a gas-liquid reactor (1), a solid-liquid separation device one (2), a gas-liquid heating reactor (3), a two-stage heat exchange device (4), a gas-liquid separation device (5), a spray evaporation device (6), a solid-liquid separation device two (7), a stirred reactor (8), a solid-liquid separation device three (9), a solid-liquid heating reactor (10), a forced cooling device (11), and a solid-liquid separation device four (12); The gas-liquid reactor (1) has an air inlet at the lower end of one side, a liquid inlet at the upper end of the other side, an outlet at the bottom, and a tail gas outlet at the top. The solid-liquid separation device (2) has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the top of one side; the gas-liquid heating reactor (3) has an outlet at the top and an inlet at the bottom. The two-stage heat exchanger (4) has an inlet at the top and an outlet and a liquid inlet at the bottom; The gas-liquid separator (5) has a liquid inlet at the top, a liquid outlet at the bottom, and a gas outlet at the top of one side. The spray evaporation device (6) has a liquid inlet at the top, an outlet at the bottom, an air outlet at the top of one side, and an air inlet at the bottom of the other side. The solid-liquid separation device 2 (7) has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the top of one side; The stirred reactor (8) has a liquid phase inlet on one side and a solid phase inlet on the other side, and an outlet at the bottom. The top of the solid-liquid separation device 3 (9) is provided with an inlet, the bottom is provided with a solid phase outlet, and the upper side is provided with a liquid phase outlet; The solid-liquid heating reactor (10) has a liquid inlet at the upper end of one side, a solid phase inlet at the upper end of the other side, and an outlet at the bottom; the forced cooling device (11) has an inlet at the top and an outlet at the bottom. The solid-liquid separation device four (12) has an inlet at the top, a solid phase outlet at the bottom, and a liquid phase outlet at the top of one side; The inlet of the gas-liquid reactor (1) is connected to the outlet of the gas-liquid heating reactor (3), the outlet of the gas-liquid reactor (1) is connected to the inlet of the solid-liquid separation device (2), the liquid inlet of the gas-liquid reactor (1) is connected to the liquid inlet of the spray evaporator (6), the liquid phase outlet of the solid-liquid separation device (2) is connected to the liquid inlet of the spray evaporator (6), the inlet of the gas-liquid heating reactor (3) is connected to the outlet of the gas-liquid separation device (5), the inlet of the two-stage heat exchange device (4) is connected to the outlet of the spray evaporator (6), and the outlet is connected to the liquid inlet of the gas-liquid separation device (5). The outlet of the gas-liquid separator (5) is connected to the outlet of the spray evaporator (6), the outlet of the spray evaporator (6) is connected to the inlet of the solid-liquid separator (7), the liquid phase outlet of the solid-liquid separator (7) is connected to the liquid phase inlet of the stirred reactor (8), the outlet of the stirred reactor (8) is connected to the inlet of the solid-liquid separator (9), the liquid phase outlet of the solid-liquid separator (9) is connected to the inlet of the solid-liquid heating reactor (10), the outlet of the solid-liquid heating reactor (10) is connected to the inlet of the forced cooling device (11), and the outlet of the forced cooling device (11) is connected to the inlet of the solid-liquid separator (12). A method for resource utilization of waste liquid from ammonia distillation in alkali production, using the aforementioned apparatus, includes the following steps: The first step involves passing the ammonia-containing waste liquid into a gas-liquid reactor. CO2 from the gas-liquid heating reactor is then introduced into the gas-liquid reactor to react with the ammonia-containing waste liquid in a carbonation reaction for 20-60 minutes. The solid phase obtained after passing through the solid-liquid separation device is CaCO3 hollow microspheres, and liquid phase 1 is obtained. In the liquid phase 1 separated in the solid-liquid separation device, lime milk needs to be continuously added to maintain its concentration in the solution at 1-10 g / L. The second step is to pass the separated liquid phase 1 into a spray evaporation device for concentration. The high-temperature flue gas of 200~300℃ introduced from below provides a heat source for evaporation. At the same time, SO2 in the flue gas reacts with the ammonia stripping waste liquid to achieve flue gas desulfurization. The system after evaporation and concentration is passed into the solid-liquid separation device 2 to obtain solid CaSO4 byproduct and liquid phase 2. The third step involves cooling the exhaust gas from the spray evaporator through a two-stage heat exchanger, then passing it through a gas-liquid separator. The resulting liquid H2O is recycled back to the two-stage heat exchanger. The separated gas is then introduced into a gas-liquid heating reactor containing ethanolamine solution and reacted for 30-60 minutes. The reactor is then heated to 60-110°C to release a high concentration of CO2. The enriched CO2 gas is then introduced into the gas-liquid reactor to react with the ammonia stripping waste liquid. The fourth step involves introducing the separated liquid phase 2 into a stirred reactor while simultaneously adding solid Na₂CO₃ through stirring. The Na₂CO₃ in the reaction solution... + :Ca 2+ The molar ratio of the substances is (0.5~5):

1. After reacting for 20~60 minutes, the mixture is introduced into a solid-liquid separation device to obtain micron-sized CaCO3 and liquid phase 3. Fifth step: Liquid phase 3 is passed into a solid-liquid heating reactor for evaporation and concentration to obtain liquid phase 4. The volume ratio of liquid phase 4 to liquid phase 3 is 1:(2~10). Under the condition of 60~100℃, (NH4)2HPO4 is added to the solid-liquid heating reactor to dissolve and react for 10~60 minutes. The molar ratio of (NH4)2HPO4:NaCl in the reaction solution is (0.5~5):

1. Then, it is passed into a forced cooling device for cooling and crystallization. The cooling temperature is -10~20℃ and the cooling time is 10~60 minutes. Then, it is passed into a solid-liquid separation device four to obtain solid sodium ammonium phosphate. The remaining liquid phase 5 rich in NH4Cl is retained. The (NH4)2HPO4 can also be (NH4)H2PO4, or NH3·H2O and H3PO4 can be added successively. The corresponding products can also be H(NH4)Na(PO4) or (NH4)H2PO4. Ammonia water needs to be added to the ammonia-containing waste liquid added to the gas-liquid reactor, with a total ammonia concentration of 0.057~1.430 mol / L; The ammonia solution can also be NaOH solution, lime milk, or waste alkali solution, and the corresponding product is aragonite-type CaCO3 or massive calcite-type CaCO3.

2. The apparatus for resource utilization of alkali-making ammonia distillation waste liquid according to claim 1, characterized in that: The separation method of the solid-liquid separation device is centrifugal separation or natural sedimentation. The centrifugal separation speed is 1000~10000 rpm. The CaCO3 hollow microspheres obtained by separation are washed with ultrapure water and dried to obtain CaCO3 hollow microsphere products. The separation method of the solid-liquid separation device three is filtration separation or vacuum filtration separation. The separated micron CaCO3 is washed with ultrapure water and dried to obtain micron CaCO3 product. The separation method of the solid-liquid separation device four is vacuum filtration or natural sedimentation. The separated sodium phosphate rock is dried by natural air drying to obtain sodium phosphate rock product with the chemical formula H(NH4)Na(PO4)·4H2O.

3. The apparatus for resource utilization of alkali-making ammonia distillation waste liquid according to claim 1, characterized in that: The flow rate of enriched CO2 introduced into the gas-liquid reactor is 0.5-5 L / (min·L). 蒸氨废液 ).

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