Industrial waste salt treatment method

Abstract

The invention relates to a treatment method of industrial waste salt. The treatment method comprises the steps that S1, a first mixed solution containing industrial waste salt and an acid solution of a precipitator are mixed, a second mixed solution is obtained, the molar ratio of M < 2 + > to Al < 3 + > is 6: (1-4), M is selected from Ca and / or Mg, and the industrial waste salt is selected from industrial waste sulfate and / or industrial waste impurity salt containing sulfate; s2, adjusting the pH value of the second mixed solution to 7.5-14 by adopting alkali liquor, and enabling the second mixed solution to react to obtain a reaction product; and S3, filtering the reaction product to obtain a solid-phase product and a liquid-phase product. The precipitant is prepared from the solid waste as the raw material, calcium, magnesium and heavy metal in the waste sulfate solution are precipitated, the hardness of the waste sulfate solution is reduced, the waste sulfate solution is purified, the content of the heavy metal in the obtained crystalline salt meets the national requirement, and the purpose of treating waste with waste can be achieved; and a new direction is provided for waste sulfate recycling and solid waste synergistic utilization.

Description

Technical Field

[0001] This application relates to the field of solid waste resource utilization, and in particular to a method for treating industrial waste salt. Background Technology

[0002] my country produces approximately 20 million tons of industrial waste salt annually. The large volume, diverse types, and complex processing methods make it unsuitable for direct reuse in the chemical industry. Currently, landfill disposal is the primary method for industrial waste salt treatment, but this is costly, requires significant land use, and is prone to leaching pollution. Therefore, the resource utilization of industrial waste salt has become a key focus for the industry.

[0003] The main challenges in the resource utilization of waste salt are the separation of organic matter, heavy metals, and mixed salts.

[0004] Incineration, pyrolysis, and advanced oxidation are the main methods for removing organic matter from industrial waste salt. However, incineration and advanced oxidation consume too much energy and have poor removal efficiency for organic pollutants, making it difficult to directly meet the relevant indicators of "Industrial Salt" and pollution control limits for specific industries.

[0005] Activated carbon adsorption and chelating resin adsorption are commonly used for heavy metal adsorption and also have a certain effect on the removal of organic matter. However, as the equipment operates for a long time, the adsorbent tends to become saturated, the adsorbent regeneration process is complicated, and there is secondary pollution.

[0006] Membrane separation and evaporation crystallization are two typical salt separation processes, which utilize the selective permeability and solubility of different ions to separate and recycle different salt components. However, concentrated brine often contains calcium and magnesium ions, which easily form calcium carbonate and magnesium carbonate precipitates, leading to hard scaling on membrane equipment and evaporators. Severe scaling can affect evaporator efficiency and even cause the membrane equipment and evaporator to malfunction, resulting in high operation and maintenance costs.

[0007] Current hardening removal processes for waste salt solutions include using reagents such as sodium carbonate, lime, polyaluminum chloride, and polyacrylamide to complex and precipitate calcium and magnesium ions. However, these reagents are expensive, and the resulting precipitates are difficult to utilize, increasing disposal costs.

[0008] Therefore, it is necessary to provide an efficient and low-cost method for the resource recovery of industrial waste salt. Summary of the Invention

[0009] To address the aforementioned technical problems in the existing technology, this application provides a method for treating industrial waste salt. This application uses solid waste as raw material to prepare a precipitant, which precipitates calcium, magnesium, and heavy metals from the waste salt solution, reducing the hardness of the waste salt solution and purifying it. The resulting crystalline salt has a heavy metal content that meets national requirements, achieving the goal of treating waste with waste and providing a new direction for the resource utilization of waste salt and the co-utilization of solid waste.

[0010] In a first aspect, this application provides a method for treating industrial waste salt, which includes the following steps:

[0011] S1: A first mixture containing industrial waste salt is mixed with an acidic solution of a precipitant to obtain a second mixture. In the second mixture, M... 2+ And Al 3+ The molar ratio is 6:(1-4), M is selected from Ca and / or Mg, and the industrial waste salt is selected from industrial waste sulfate and / or industrial waste miscellaneous salt containing sulfate;

[0012] S2: The pH of the second mixture from step S1 is adjusted to 7.5-14 using an alkaline solution to allow the second mixture to react and obtain the reaction product;

[0013] S3: Filter the reaction product of step S3 to obtain a solid product and a liquid product.

[0014] Industrial waste salt has a wide range of sources and complex composition, often containing heavy metals. Without pretreatment, it is difficult to reuse directly, making treatment and disposal challenging. Industrial waste salt, especially industrial waste sulfate, is often recovered through evaporation and crystallization processes. However, concentrated brine often contains calcium and magnesium ions, which easily form calcium carbonate and magnesium carbonate precipitates, leading to hard scaling on membrane equipment and evaporators. Severe scaling can affect evaporator efficiency and even cause the membrane equipment and evaporators to malfunction, resulting in high maintenance costs. Furthermore, since waste salt solutions usually contain heavy metals, these heavy metals accumulate in the regenerated salt after evaporation and crystallization, making it difficult to meet reuse standards. This application uses aluminum-containing solid waste as a raw material to prepare a precipitant. Industrial solid waste contains silicon and aluminum elements, which can dissolve under certain conditions. It combines with sulfate and calcium in the waste sulfate solution to form calcium sulfoaluminate and calcium aluminosilicate precipitates. Magnesium forms magnesium-containing calcium sulfoaluminate and a small amount of magnesium hydroxide. Simultaneously, heavy metal ions can be solidified in the precipitate products, effectively reducing disposal costs and achieving the goal of treating waste with waste.

[0015] In some embodiments, in step S1, the amount of precipitant is adjusted to adjust the concentration of M in the second mixture. 2+ And Al 3+ The molar ratio is 6:(1-4), for example 6:1.5, 6:2, 6:2.3, 6:2.5, 6:2.7, 6:3, 6:3.3, 6:3.5, or 6:3.7. In some embodiments, M 2+ And Al 3+ The molar ratio is 6:(1-3). In some embodiments, M 2+ And Al 3+ The molar ratio is 6:(2.5-3.5).

[0016] In some embodiments, the pH of the second mixture is 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, or any value between them. In some embodiments, the pH of the second mixture is 8-12. In some embodiments, the pH of the second mixture is 8-10.

[0017] In some embodiments, the sulfate content in the industrial waste salt is 10%-90% by mass, for example, 20%, 30%, 40%, 50%, 60%, 70%, 80% or any value between them.

[0018] In some embodiments, the precipitant is selected from one or more aluminosilicate solid wastes.

[0019] In some embodiments, the precipitant is selected from one or more of fly ash, gasification slag, lithium slag, red mud, silica fume, and aluminum ash.

[0020] In some embodiments, the acid solution of the precipitant is selected from a hydrochloric acid solution of the precipitant and / or an industrial waste acid solution of the precipitant. In some embodiments, the acid solution of the precipitant is selected from an industrial waste sulfuric acid solution of the precipitant.

[0021] In some embodiments, the COD of the industrial waste sulfuric acid solution is less than or equal to 2500 mg / L. In some embodiments, the sulfuric acid content in the industrial waste sulfuric acid solution is greater than or equal to 4%.

[0022] In some implementations, the amount of precipitant (solid waste) in the acidic solution of the precipitant is determined based on the calcium and magnesium content in the salt solution and the solid phase composition of the solid waste: first, the content of Si and Al elements in the solid waste is detected, and then the amount of silicon and aluminum required to generate calcium sulfoaluminate and calcium aluminosilicate is determined based on the calcium and magnesium content in the waste salt solution. The amount of solid waste can be confirmed by the amount of silicon and aluminum used.

[0023] In some embodiments, the industrial waste salt solution is subjected to adsorption treatment or advanced oxidation treatment to remove organic matter, resulting in a first mixture containing industrial waste salt.

[0024] In some embodiments, the adsorption treatment is selected from activated carbon adsorption treatment.

[0025] In some embodiments, the advanced oxidation treatment is selected from ultraviolet ozone oxidation treatment.

[0026] In some embodiments, solid industrial waste salt is pyrolyzed to remove organic matter, yielding pyrolysis products. The pyrolysis products are then mixed with water to obtain a first mixture containing industrial waste salt.

[0027] In some embodiments, the pyrolysis temperature is 300°C-700°C, for example, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, or any value between them. In some embodiments, the pyrolysis temperature is 400°C-600°C.

[0028] In some embodiments, the liquid-to-solid ratio of the pyrolysis product to water is 3:1 to 15:1, for example, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, or any value between them. In some embodiments, the liquid-to-solid ratio of the pyrolysis product to water is 5:1 to 10:1.

[0029] In some embodiments, the TOC of the pyrolysis product is less than or equal to 50 mg / g.

[0030] In some embodiments, the TOC of the first mixture containing industrial waste salt is less than or equal to 500 mg / L.

[0031] In some embodiments, in step S2, the temperature of the reaction is 25°C-95°C, for example 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C or any value between them.

[0032] In some embodiments, the reaction time in step S2 is 3h-48h, for example, 4h, 6h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, 32h, 34h, 36h, 38h, 40h, 42h, 44h, 46h or any value between them.

[0033] In some embodiments, in step S2, the alkaline solution is selected from one or more of saturated NaOH solution, saturated KOH solution, ammonia water, and industrial waste alkaline solution.

[0034] In some embodiments, in step S3, the total content of calcium and magnesium in the liquid product is less than or equal to 10 mg / L.

[0035] In some embodiments, in step S3, the heavy metal content of the solid salt after the liquid phase product is evaporated and crystallized meets the requirements of GB18598-2019 "Standard for Pollution Control of Hazardous Waste Landfill".

[0036] In some embodiments, the processing method includes the following specific steps:

[0037] 1) After removing organic matter from waste salt particles using a preferred pyrolysis process, the waste salt particles are mixed with water to obtain a mixture containing industrial waste salt; or the waste brine is treated by activated carbon adsorption or advanced oxidation to remove organic matter, thereby obtaining a mixture containing industrial waste salt. Preferably, the TOC of the waste salt particles after pyrolysis is <0.5 mg / g, and the TOC of the waste brine after activated carbon adsorption or advanced oxidation is <500 mg / L.

[0038] 2) Dissolve solid waste in an acid solution to prepare a solution containing a precipitant, and mix the solution containing the precipitant with a mixture containing industrial waste salt to obtain a mixture;

[0039] After adjusting the pH of the mixture and performing a precipitation reaction, solid-liquid separation is obtained to obtain a liquid phase and a solid phase. The solid phase contains ettringite, hydrated calcium silicate, and hydrated calcium aluminosilicate, and the liquid phase includes a purified salt solution.

[0040] 3) The purified salt solution can be fed into an evaporation device for salt separation and crystallization recovery.

[0041] Secondly, this application provides the application of the treatment method described in the first aspect in waste brine evaporation crystallization or ultrafiltration reverse osmosis pretreatment.

[0042] (1) The treatment method of this application can be used in the pretreatment industry of waste brine evaporation crystallization or ultrafiltration reverse osmosis to reduce the hardness and heavy metal content of waste brine, achieve the purpose of treating waste with waste, reduce disposal costs, improve resource utilization rate, and provide a new direction for waste salt resource utilization and solid waste co-utilization.

[0043] (2) The treatment method of this application precipitates calcium, magnesium and heavy metals in the waste salt solution, reduces the hardness of the waste salt solution, purifies the waste salt solution, and the heavy metal content in the crystalline salt meets the national requirements. The calcium and magnesium ions in the waste salt solution are reduced to ≤10mg / L. Attached Figure Description

[0044] Figure 1 This is an SEM image of the precipitated and solidified product in Example 1. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application in any way.

[0046] Example 1

[0047] Step (1) Solid waste salt 1 (a mixed salt mainly composed of sulfates, with a sulfate content of 10%) in a coal chemical industrial park in Ningxia Hui Autonomous Region was pyrolyzed at 500℃ for 1 hour to obtain pyrolysis products. The TOC content of the pyrolysis products was measured to be 0.293 mg / L after being dissolved in an aqueous solution at a liquid-to-solid ratio of 5:1.

[0048] Step (2) Dissolve the solid waste red mud in 1 mol / L hydrochloric acid solution to obtain a precipitant solution. The amount of solid waste used is determined based on the calcium and magnesium content in the waste salt solution and the solid phase composition of the solid waste. Specifically, the content of Si and Al elements in the solid waste is first detected, and then the amount of silicon and aluminum required to generate calcium sulfoaluminate and calcium aluminosilicate is determined based on the calcium and magnesium content in the waste salt solution. The amount of solid waste used can be confirmed by the amount of silicon and aluminum used.

[0049] Step (3) involves mixing an aqueous solution of solid waste salt pyrolysis products at a liquid-to-solid ratio of 10:1 into the above precipitant solution to obtain a mixed solution. The Ca content in the mixed solution is controlled. 2+ +Mg 2+ And Al 3+ The molar ratio was 6:3, and the pH of the mixed solution was adjusted to 8 using ammonia.

[0050] Step (4) The above mixed solution is subjected to precipitation reaction at 25°C for 48 hours. The product obtained from the precipitation reaction is filtered. The solid phase obtained is the precipitated solidified product of calcium and magnesium ions and heavy metals, and the liquid phase is the purified salt solution.

[0051] from Figure 1 The SEM images of the precipitated and solidified products show that they include calcium sulfoaluminate and calcium aluminosilicate.

[0052] The elements in the original solid waste salt from ICP, the pyrolysis products, and the purified salt solution were tested, and the specific results are shown in Table 1. Table 1 shows that, through precipitation, the contents of Ca and Mg in the salt solution were both below 10 mg / L.

[0053] The purified salt solution was evaporated and crystallized to obtain pyrolysis-precipitation evaporation crystallized salt 1. The final heavy metal content met the requirements of GB18598-2019 "Standard for Pollution Control of Hazardous Waste Landfill" (see Table 2).

[0054] Table 1

[0055]

[0056] Table 2

[0057]

[0058] Example 2

[0059] Step (1) Solid waste salt 2 (a mixed salt mainly composed of sulfates, with a sulfate content of 35%) in a coal chemical industrial park in Ningxia Hui Autonomous Region was pyrolyzed at 500℃ for 1 hour to obtain pyrolysis products. The TOC content of the pyrolysis products was measured to be 0.255 mg / L after being dissolved in an aqueous solution at a liquid-to-solid ratio of 10:1.

[0060] The solid waste gasification slag was dissolved in 2 mol / L hydrochloric acid solution to obtain a precipitant solution. The method for determining the amount of solid waste used was the same as in Example 1.

[0061] Step (2) Add an aqueous solution of solid waste salt pyrolysis products at a liquid-to-solid ratio of 5:1 to the above precipitant solution to obtain a mixed solution. Control the Ca content in the mixed solution. 2+ +Mg 2+ And Al 3+ The molar ratio was 6:3, and the pH of the mixed solution was adjusted to 10 using industrial waste alkaline solution.

[0062] Step (3) The above mixed solution is subjected to precipitation reaction at 50°C for 24 hours. The product obtained from the precipitation reaction is filtered. The solid phase obtained is the precipitated solidified product of calcium and magnesium ions and heavy metals, and the liquid phase is the purified salt solution.

[0063] Step (4) uses ICP to test the elements in solid waste salt 2, pyrolysis products, and purified salt solution. The specific results are shown in Table 3. As can be seen from Table 3, the Ca and Mg content in the salt solution is less than 10 mg / L through precipitation.

[0064] The purified salt solution was evaporated and crystallized to obtain pyrolysis-precipitation evaporation crystallized salt 2. The heavy metal content of the final crystallized salt met the requirements of GB18598-2019 "Standard for Pollution Control of Hazardous Waste Landfill" (see Table 4).

[0065] Table 3

[0066]

[0067] Table 4

[0068]

[0069] Example 3

[0070] Step (1) Solid waste salt 3 (a mixed salt mainly composed of sulfates, with a sulfate content of 50%) from a coal chemical industrial park in Ningxia Hui Autonomous Region was pyrolyzed at 500℃ for 1 hour to obtain pyrolysis products. The TOC content of the pyrolysis products was measured to be 0.247 mg / L after being dissolved in an aqueous solution at a liquid-to-solid ratio of 10:1.

[0071] Solid waste fly ash was dissolved in 1 mol / L hydrochloric acid solution to obtain a precipitant solution. The method for determining the amount of solid waste used was the same as in Example 1.

[0072] Step (2) Add water, the pyrolysis product of solid waste salt solution at a liquid-to-solid ratio of 10:1, to the above precipitant solution to obtain a mixed solution. Control the Ca content in the mixed solution. 2+ +Mg 2+ And Al 3+ The molar ratio was 6:1, and the pH of the mixed solution was adjusted to 12 using a saturated potassium hydroxide solution.

[0073] Step (3) The above mixed solution is subjected to precipitation reaction at 75°C for 12 hours. The product obtained from the precipitation reaction is filtered. The solid phase obtained is the precipitated solidified product of calcium and magnesium ions and heavy metals, and the liquid phase is the purified salt solution.

[0074] Step (4) involves testing each element using ICP, and the specific results are shown in Table 5. Table 5 shows that, through precipitation, the Ca and Mg content in the salt solution is below 10 mg / L.

[0075] The purified salt solution was evaporated and crystallized to obtain pyrolysis-precipitation evaporation crystallized salt 3. The heavy metal content of the final crystallized salt met the requirements of GB18598-2019 "Standard for Pollution Control of Hazardous Waste Landfill" (see Table 6).

[0076] Table 5

[0077]

[0078] Table 6

[0079]

[0080] Example 4

[0081] Step (1) Waste salt solution 4 (a mixed salt of sodium sulfate and sodium chloride, mainly sulfate, in a coal chemical industrial park in Ningxia Hui Autonomous Region, with a sulfate content of 70%) was adsorbed by activated carbon to obtain an adsorbed waste salt solution with a TOC content of 277 mg / L.

[0082] Solid waste lithium slag was dissolved in 1 mol / L hydrochloric acid solution to obtain a precipitant solution. The method for determining the amount of solid waste used was the same as in Example 1.

[0083] Step (2) Add the above-mentioned adsorbed waste salt solution at a liquid-to-solid ratio of 10:1 to the above-mentioned precipitant solution to obtain a mixed solution. Control the Ca content in the mixed solution. 2+ +Mg 2+ And Al 3+The molar ratio was 6:1, and the pH of the mixed solution was adjusted to 14 using a saturated sodium hydroxide solution.

[0084] Step (3) The above mixed solution is subjected to precipitation reaction at 75°C for 6 hours. The product obtained from the precipitation reaction is filtered. The solid phase obtained is the precipitated solidified product of calcium and magnesium ions and heavy metals, and the liquid phase is the purified salt solution.

[0085] Step (4) uses ICP to test the elements in waste salt solution 4, the waste salt solution after adsorption, and the purified salt solution. The specific results are shown in Table 7. As can be seen from Table 7, through precipitation, the content of Ca and Mg elements in the salt solution is less than 10 mg / L.

[0086] The purified salt solution was evaporated and crystallized to obtain adsorption-precipitation evaporation crystallized salt 4. The heavy metal content of the final crystallized salt met the requirements of GB18598-2019 "Standard for Pollution Control of Hazardous Waste Landfill" (see Table 8).

[0087] Table 7

[0088]

[0089] Table 8

[0090]

[0091] Example 5

[0092] Step (1) Waste salt solution 5 (waste sulfate from a coal chemical industrial park in Ningxia Hui Autonomous Region) was subjected to advanced oxidation treatment to obtain an oxidized waste salt solution with a TOC content of 439 mg / L. The advanced oxidation treatment adopted ultraviolet ozone oxidation process, with an ozone dosage of 50 mg / L and a residence time of 30 min.

[0093] Step (2) Dissolve the solid waste silica fume and aluminum ash in a 1 mol / L industrial waste sulfuric acid solution to obtain a precipitant solution. The method for determining the amount of solid waste is the same as in Example 1, and the industrial waste sulfuric acid solution meets the requirements of Table 9.

[0094] Step (3) Add the above-mentioned oxidized waste salt solution at a liquid-to-solid ratio of 10:1 to the above-mentioned precipitant solution to obtain a mixed solution. Control the Ca content in the mixed solution. 2+ +Mg 2+ And Al 3+ The molar ratio was 6:3, and the pH of the mixed solution was adjusted to 14 using a saturated sodium hydroxide solution.

[0095] Step (4) The above mixed solution is subjected to precipitation reaction at 95°C for 3 hours. The product obtained from the precipitation reaction is filtered. The solid phase obtained is the precipitated solidified product of calcium and magnesium ions and heavy metals, and the liquid phase is the purified salt solution.

[0096] ICP was used to test the elements in waste salt solution 5, the oxidized waste salt solution, and the purified salt solution. The specific results are shown in Table 10. As can be seen from Table 10, the Ca and Mg content in the waste salt solution was less than 10 mg / L through precipitation.

[0097] The purified salt solution was evaporated and crystallized to obtain oxidation-precipitation evaporation crystallized salt 5. The heavy metal content of the final crystallized salt met the requirements of GB18598-2019 "Standard for Pollution Control of Hazardous Waste Landfill" (see Table 11).

[0098] Table 9 Waste Acid Requirements

[0099] COD (mg / L) ≤2500 Appearance colorless sulfuric acid content ≥4％

[0100] Table 10

[0101]

[0102] Table 11

[0103]

[0104]

[0105] The technical solutions of this application are not limited to the specific embodiments described above. Any technical modifications made based on the technical solutions of this application shall fall within the protection scope of this application.

Claims

1. A method for treating industrial waste salt, comprising the following steps: S1: A first mixture containing industrial waste salt is mixed with an acidic solution of a precipitant to obtain a second mixture. In the second mixture, M... 2+ And Al 3+ The molar ratio is 6:(1-4), M is selected from Ca and / or Mg, and the industrial waste salt is selected from industrial waste sulfate and / or industrial waste miscellaneous salt containing sulfate; S2: The pH of the second mixture from step S1 is adjusted to 7.5-14 using an alkaline solution to allow the second mixture to react and obtain the reaction product; S3: Filter the reaction product of step S3 to obtain a solid product and a liquid product.

2. The processing method according to claim 1, characterized in that, In step S1, by adjusting the amount of precipitant, the concentration of M in the second mixture is adjusted. 2+ And Al 3+ The molar ratio is 6:(1-4), preferably M 2+ And Al 3+ The molar ratio is 6:(1-3), and more preferably M 2+ And Al 3+ The molar ratio is 6:(2.5-3.5); and / or The pH of the second mixture is 8-12, preferably 8-10.

3. The processing method according to claim 1 or 2, characterized in that, The industrial waste salts contain 10%-90% sulfate by mass.

4. The processing method according to any one of claims 1-3, characterized in that, The precipitant is selected from one or more aluminosilicate solid wastes, preferably from one or more of fly ash, gasification slag, lithium slag, red mud, silica fume, and aluminum ash; and / or The acid solution of the precipitant is selected from the hydrochloric acid solution of the precipitant and / or the industrial waste acid solution of the precipitant, preferably the industrial waste sulfuric acid solution.

5. The processing method according to any one of claims 1-4, characterized in that, After removing organic matter from the industrial waste salt solution through adsorption or advanced oxidation treatment, a first mixture containing industrial waste salt is obtained; or Solid industrial waste salt is pyrolyzed to remove organic matter, yielding pyrolysis products. These products are then mixed with water to obtain a first mixture containing industrial waste salt.

6. The processing method according to claim 5, characterized in that, The adsorption treatment is selected from activated carbon adsorption treatment; and / or The advanced oxidation treatment is selected from ultraviolet ozone oxidation treatment; and / or The pyrolysis temperature is 300℃-700℃, preferably 400℃-600℃; and / or The liquid-to-solid ratio of the pyrolysis products to water is 3:1-15:1, preferably 5:1-10:

1.

7. The processing method according to any one of claims 1-6, characterized in that, The TOC of the first mixture containing industrial waste salt is less than or equal to 500 mg / L; The TOC of the pyrolysis product is less than or equal to 50 mg / g.

8. The processing method according to any one of claims 1-7, characterized in that, In step S2, the reaction temperature is 25℃-95℃; and / or In step S2, the reaction time is 3h-48h; In step S2, the alkaline solution is selected from one or more of saturated NaOH solution, saturated KOH solution, ammonia water, and industrial waste alkaline solution.

9. The processing method according to any one of claims 1-8, characterized in that, In step S3, the total content of calcium and magnesium in the liquid product is less than or equal to 10 mg / L; and / or In step S3, the solid products include calcium sulfoaluminate and calcium aluminosilicate.

10. The application of the treatment method according to claims 1-9 in waste brine evaporation crystallization or ultrafiltration reverse osmosis pretreatment.

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