Control methods for the first-stage reaction salt mud crystallization process using lime flue gas method

Abstract

This invention belongs to the field of brine purification technology and discloses a method for controlling the crystallization process of primary reaction salt mud using lime flue gas. First, caustic soda is used to control the pH to 12.4–12.6 to remove impurities from the original brine. Then, Ca(OH)₂ is added dropwise to the brine for a primary causticization reaction. After crystallization, the bottom slurry is sorted, with smaller particles used as seed crystals for recirculation. Finally, the slurry is washed and dewatered to obtain the final primary salt mud product. This invention removes impurities from the brine that affect the crystallization process, utilizes sorting technology to increase the size of the primary salt mud particles, reduce the settling time, and decrease the amount of flocculant used. The overall process has a shorter reaction cycle, lower energy consumption, simpler operation, and lower production cost compared to traditional processes, providing a material basis for the comprehensive utilization of salt mud and enabling its high-value application in downstream fields.

Description

Technical Field

[0001] This invention belongs to the field of brine purification technology, and specifically relates to a method for controlling the crystallization process of primary reaction salt mud using lime flue gas. Background Technology

[0002] Brine purification, also known as brine pretreatment, is a key step in the salt-making process. Its purpose is to remove calcium from the raw brine. 2+ Mg 2+ Ions are separated before entering the heating chamber. Salt mud is the general term for all kinds of inorganic salts discharged during this process.

[0003] The lime flue gas process, a method for purifying brine in salt chemical industries, is also a rapidly developing energy-saving and consumption-reducing reaction process. Its core involves the causticization reaction between calcium hydroxide and sodium sulfate, and the reaction of lime water with Mg in the brine. 2+ The reaction produces magnesium hydroxide precipitate, while the lime slurry (Ca(OH)2) reacts with sodium sulfate (Na2SO4) in the brine to produce calcium sulfate (CaSO4). The precipitated lime slurry is added to the calcium ions in the brine, and sodium hydroxide (NaOH) is also produced.

[0004] The causticization reaction produces primary salt mud, whose main components are CaSO4, Mg(OH)2, and unreacted Ca(OH)2. Since the causticization reaction is reversible, its rate varies with time and the concentration of each ion. 2+ SO4 2- The increase of OH is beneficial to the causticization reaction, while the product OH - The increase of Mg(OH)2 will hinder the causticization reaction. During the formation of primary salt mud, the growth of calcium sulfate crystals is affected by the efficiency of the causticization reaction, raw materials, and reaction conditions. At the same time, Mg(OH)2 is a flocculent precipitate with small particles and poor rheological properties, which coats the surface of calcium sulfate crystals. This results in a high concentration of fine powder salt mud particles in the salt mud slurry and slow sedimentation. The supernatant obtained after sedimentation contains fine powder salt mud particles, which affects the clarity and quality of the refined brine to be prepared when the brine is recycled and purified. In addition, the washing water of the salt mud has low clarity, and when it is transported to the return water tank, it causes salt mud to settle at the bottom. Long-term pipeline transportation of return water to the mine pipe will cause salt mud to accumulate and seriously block the pipe. Furthermore, the excessively fine particles of salt mud products will cause dust during sales, transportation, and use, which will have an adverse impact on the environment.

[0005] The primary salt mud crystallization process using lime flue gas is a typical reaction crystallization process. How to optimize the primary reaction crystallization process using lime flue gas based on the existing technology, balance the influence of impurities, and improve the particle size of the salt mud product has become an urgent problem to be solved. Summary of the Invention

[0006] To address the problems existing in the current lime flue gas method for primary reaction crystallization, this invention provides a method for controlling the crystallization process of salt mud in the lime flue gas method. This method not only effectively avoids the influence of impurities in the salt mud on the crystallization process, but also utilizes its own components as seed crystals to increase the particle size of the salt mud. Furthermore, this control method can significantly reduce the amount of quicklime used, reduce the enrichment of impurities in the brine, and improve the quality of the brine. This invention improves the quality of salt mud products and reduces the production cost of brine purification, playing a positive role in pollutant control, energy conservation and emission reduction, and environmental protection.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: A method for controlling the crystallization process of primary salt mud using lime flue gas, wherein the method can control impurities in the brine and improve the particle size of the salt mud, comprising the following steps: S1: Preheat the brine in the original brine tank to 40-45℃; prepare a 20%-30% NaOH solution in ingredient tank 1 and a saturated Ca(OH)2 solution in ingredient tank 2.

[0008] S2: Transfer the preheated brine from step S1 to reaction tank 1, add NaOH solution from ingredient tank 1, adjust the pH of the reaction system to between 12.4 and 12.6, stir the reaction for 0.5 hours, then filter the reaction system through a ceramic membrane, and discharge the filter residue to mud tank 1; transfer the brine obtained after filtration to reaction tank 2.

[0009] S3: Add the saturated Ca(OH)2 solution from the mixing tank 2 to the reaction tank 2, stir and react for 3 hours, add 1-1.2 mg / L of flocculant, and flocculate for 0.5 hours. After the reaction is complete, let it stand and age for 0.5 hours.

[0010] S4: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank. The slurry at the bottom is pumped out by a mud pump and enters the sorting hydrocyclone. The overflow slurry is added back to reaction tank 2, and the bottom slurry is discharged to mud tank 2.

[0011] S5: After sorting is complete, repeat steps S3 and S4.

[0012] S6: When the solid-liquid ratio of the slurry in the mud bucket reaches 5:1, wash with washing water at a mass ratio of 1:10 to obtain first-grade salt mud by lime flue gas method.

[0013] Optionally, in step S1, the raw brine for salt production includes at least the following components, each component being, by mass concentration, as follows: NaCl 297~300g / L; Ca 2+0.52~0.66g / L; Mg 2+ 0.02~0.07g / L; SO4 2- 16.0~18.0g / L, and small amounts of Fe and Al impurities.

[0014] Optionally, in step S1, a plate heat exchanger is used to heat the condensate at 60°C.

[0015] Optionally, the pore size of the ceramic membrane described in step S2 is 30–50 nm.

[0016] Optionally, in step S3, the amount of saturated Ca(OH)2 solution added is controlled to be 1% of the volume of brine in reaction tank 2, and the dripping time is controlled to be within 30 minutes.

[0017] Optionally, in step S3, the flocculant is any one of polyacrylamide, sodium polyacrylate, and polyaluminum chloride.

[0018] Optionally, in step S4, the taper ratio of the sorting hydrocyclone is controlled between 0.75 and 0.8.

[0019] Optionally, in step S4, the primary refined brine includes at least the following components, each component being, by mass concentration, as follows: NaCl 292~295g / L; Ca 2+ 0.76~0.88g / L; SO4 2- 14.0~15.0g / L.

[0020] Optionally, the lime flue gas method primary salt mud obtained by the present invention is a salt production by-product, with a mean particle size Dv50 between 70-80 μm, and its main components are: CaSO4 74.0-76.0 parts by weight; Ca(OH)2 20.0-22.0 parts by weight; NaCl 0.5-1.0 parts by weight; and other impurities 0.5-1.0 parts by weight.

[0021] The present invention has at least the following beneficial effects: (1) This invention proposes for the first time a method for controlling the crystallization process of primary salt mud using lime flue gas method. This method first removes Mg during the reaction crystallization process. 2+ Fe 3+ Al 3+ Impurities are removed to reduce their impact on the crystallization process and decrease the inclusion rate of salt mud. The pH is adjusted using NaOH during the impurity removal process, and since the NaOH is generated in subsequent reactions, the residual NaOH will not affect the reaction system.

[0022] (2) The present invention proposes a method for regulating the crystallization process of primary salt mud using lime flue gas method. This regulation method can increase the particle size of salt mud, reduce the settling time of salt mud, reduce the amount of flocculant used, and produce primary salt mud with better chemical properties such as high purity, low particle size, and good settling performance. This provides a material basis for the comprehensive utilization of salt mud in the future and enables the high-value application of salt mud in downstream fields.

[0023] (3) This invention makes full use of the sorting cyclone technology to classify and screen the salt mud particles. The small salt mud particles are recycled as seed crystals, which transforms the poor and inconsistent crystallization process into a repeatable process. This improves the dispersibility and particle size of the salt mud particles while increasing the purity of the salt mud.

[0024] (4) The process of this invention is simple, green and environmentally friendly, and does not require complex and expensive equipment. The improved process has a shorter reaction cycle, lower energy consumption, simpler operation and lower production cost than the traditional process. It has made a beneficial attempt for energy conservation, emission reduction and resource recycling and has good promotion and application value. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of a method for controlling the crystallization process of primary salt mud using lime flue gas according to the present invention.

[0026] Figure 2 The particle size distribution diagram of primary salt mud prepared by the lime flue gas method is shown in the exemplary embodiment and comparative example of the present invention.

[0027] Figure 3 Microscopic images of primary salt mud prepared by the lime flue gas method, which are exemplary embodiments and comparative examples of the present invention. Detailed Implementation

[0028] The method for controlling the crystallization process of salt mud using lime flue gas according to a specific embodiment of the present invention can reduce the impurity content of the salt mud and control the particle size of the salt mud: S1: Preheat the brine in the original brine tank (heat the 60℃ condensate with a plate heat exchanger) to 40-45℃; prepare 20%-30% NaOH solution and saturated Ca(OH)2 solution in batching tank 1 and batching tank 2 respectively.

[0029] S2: Transfer the preheated brine from step S1 to reaction tank 1, add NaOH solution from ingredient tank 1, adjust the pH of the reaction system to between 12.4 and 12.6, stir the reaction for 0.5 hours, then filter the reaction system through a ceramic membrane, and discharge the filter residue to mud tank 1; transfer the brine obtained after filtration to reaction tank 2.

[0030] S3: Add saturated Ca(OH)2 solution from mixing tank 2 dropwise into reaction tank 2 (the amount added is 1% of the brine volume, and the addition is completed in 30 minutes), stir and react for 3 hours, add 1-1.2 mg / L of flocculant, and flocculate for 0.5 hours. After the reaction is completed, let it stand and age for 0.5 hours.

[0031] S4: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank. The slurry at the bottom is pumped out by a mud pump and enters the sorting hydrocyclone. After sorting, the overflow slurry is added back to reaction tank 2, and the bottom slurry is discharged to mud tank 2.

[0032] S5: After sorting is complete, repeat steps S3 and S4.

[0033] S6: When the solid-liquid ratio of the slurry in the mud bucket reaches 5:1, wash with washing water at a mass ratio of 1:10 to obtain first-grade salt mud by lime flue gas method.

[0034] The first-order reaction in the brine purification of lime flue gas is a causticization reaction. The main reaction equation is Ca(OH)₂ + Na₂SO₄ → CaSO₄ + 2NaOH, and the target product is calcium sulfate and Mg. 2+ Fe 3+ Al 3+ Impurities are deposited into the salt mud during the brine purification process, especially under alkaline conditions, forming flocculent hydroxide precipitates with small particles and poor rheological properties. These precipitates coat the surface of calcium sulfate crystals, greatly affecting the quality of the salt mud. At the same time, the causticization reaction has low efficiency, resulting in incomplete reaction, raw material waste, and the formation of fine calcium sulfate crystals. Therefore, the method provided by this invention can effectively control the influence of impurities on the reaction crystallization process, while increasing the particle size of the target product and improving the reaction efficiency.

[0035] The main components of the raw brine used in the following specific embodiments of the present invention are NaCl 297-300 g / L; Ca 2+ 0.52~0.66g / L; Mg 2+ 0.02~0.07g / L; SO4 2- 16.0~18.0g / L and a small amount of Fe and Al impurities. In step S1, the brine in the original brine tank is preheated to 40~45℃. Under this temperature condition, soluble salts in the original brine will not precipitate, and the temperature of the reaction system is suitable for the subsequent causticization reaction.

[0036] Compared to the traditional lime flue gas method, this invention adds step S2 to minimize impurities that may coat the surface of the causticization reaction product CaSO4. Step S2 involves adjusting the pH to between 12.4 and 12.6 by adding 20%–30% NaOH solution to the original brine. Based on the precipitation equilibrium constant Ksp, the pH ranges for precipitation of Mg(OH)2, Fe(OH)3, Al(OH)3, and Ca(OH)2 at room temperature are calculated to be 10.4–12.4, 1.5–4.1, 3.3–5.2, and 12.7–14.4, respectively. This invention controls the pH between 12.4 and 12.6 to ensure that Mg… 2+ Fe 3+ Al 3+ Impurities precipitate fully in the form of hydroxides, Ca 2+ No precipitation will occur. Furthermore, since the reaction is often very rapid during crystallization, the impurities produced may encapsulate the reactants and prevent the reaction from proceeding. Reasonable control methods can reduce the encapsulation of impurity ions on the target product of the subsequent reaction.

[0037] In step S3, adding Ca(OH)2 by dripping can prevent excessive local concentration during the causticization reaction, maintain uniform reaction, and improve reaction efficiency. The flocculant bridging effect causes the CaSO4 crystals generated in the reaction to aggregate together, forming larger flocs, making them easier to settle. After the reaction is completed, aging will allow the precipitated crystals to grow, increase the crystal size, and make the particle size distribution more uniform.

[0038] Step S4 involves separating the aged bottom slurry using a hydrocyclone separator. Small particles in the overflow slurry are used as seed crystals to re-participate in the reaction, optimizing crystallization behavior. This process is repeated to ensure an increase in the final crystal particle size. Finally, water washing removes most soluble impurities, resulting in the regulated salt mud. By utilizing the inherent characteristics of the salt mud's components and employing separation technology to control the impurity ion content and the morphology of the main component particles, their synergistic effects are maximized.

[0039] The method for controlling the crystallization process of salt mud using lime flue gas according to a specific embodiment of the present invention, wherein the primary refined brine components after control by this method are: NaCl 292~295g / L; Ca 2+ 0.76~0.88g / L; SO4 2- 14.0~15.0g / L.

[0040] The present invention discloses a method for controlling the crystallization process of primary salt mud using the lime flue gas method. The primary salt mud is a by-product of salt production, and its main components are: 74.0-76.0 parts by weight of CaSO4; 20.0-22.0 parts by weight of Ca(OH)2; 0.5-1.0 parts by weight of NaCl; and 0.5-1.0 parts by weight of other impurities.

[0041] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below. Example 1

[0042] After testing, the composition of the original halogen in this embodiment, based on mass concentration, was: NaCl 297 g / L; Ca... 2+ 0.52 g / L; Mg 2+ 0.02 g / L; SO4 2- 16.0 g / L and trace amounts of Fe and Al impurities.

[0043] S1: Preheat the brine in the original brine tank to 40℃; prepare a 20% NaOH solution and a saturated Ca(OH)2 solution in ingredient tank 1 and ingredient tank 2 respectively.

[0044] S2: Transfer the preheated brine from step S1 to reaction tank 1, add NaOH solution from mixing tank 1, adjust the pH of the reaction system to 12.5, stir the reaction for 0.5 hours, then filter the reaction system through a ceramic membrane, and discharge the filter residue to mud tank 1; transfer the brine obtained after filtration to reaction tank 2.

[0045] S3: Add the saturated Ca(OH)2 solution from the mixing tank 2 to the reaction tank 2, stir and react for 3 hours, add 1.2 mg / L of polyacrylamide flocculant, and flocculate for 0.5 hours. After the reaction is complete, let it stand and age for 0.5 hours.

[0046] S4: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank. The slurry at the bottom is pumped out by a mud pump and enters the sorting hydrocyclone. After sorting, the overflow slurry is added back to reaction tank 2, and the bottom slurry is discharged to mud tank 2.

[0047] S5: After sorting is complete, repeat steps S3 and S4.

[0048] S6: When the solid-liquid ratio of the slurry in the mud bucket reaches 5:1, wash with washing water at a mass ratio of 1:10 to obtain first-grade salt mud by lime flue gas method. Example 2

[0049] After testing, the composition of the original halogen in this embodiment, based on mass concentration, was: NaCl 297 g / L; Ca... 2+ 0.60 g / L; Mg 2+ 0.05 g / L; SO4 2- 18.0 g / L and trace amounts of Fe and Al impurities.

[0050] S1: Preheat the brine in the original brine tank to 45℃; prepare a 30% NaOH solution and a saturated Ca(OH)2 solution in ingredient tank 1 and ingredient tank 2 respectively.

[0051] S2: Transfer the preheated brine from step S1 to reaction tank 1, add NaOH solution from mixing tank 1, adjust the pH of the reaction system to 12.6, stir the reaction for 0.5 hours, then filter the reaction system through a ceramic membrane, and discharge the filter residue to mud tank 1; transfer the brine obtained after filtration to reaction tank 2.

[0052] S3: Add the saturated Ca(OH)2 solution from the mixing tank 2 to the reaction tank 2, stir and react for 3 hours, add 1.2 mg / L of polyacrylamide flocculant, and flocculate for 0.5 hours. After the reaction is complete, let it stand and age for 0.5 hours.

[0053] S4: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank. The slurry at the bottom is pumped out by a mud pump and enters the sorting hydrocyclone. After sorting, the overflow slurry is added back to reaction tank 2, and the bottom slurry is discharged to mud tank 2.

[0054] S5: After sorting is complete, repeat steps S3 and S4.

[0055] S6: When the solid-liquid ratio of the slurry in the mud bucket reaches 5:1, wash with washing water at a mass ratio of 1:10 to obtain first-grade salt mud by lime flue gas method. Comparative Example 1

[0056] The original halogen composition of this comparative example is the same as that of Example 1. Step S2 of the control method in Example 1 is omitted. The specific steps are as follows: S1: Preheat the brine in the original brine tank to 40℃; prepare a saturated Ca(OH)2 solution in the ingredient tank 2.

[0057] S2: Transfer the preheated brine from step S1 directly to reaction tank 2, add the saturated Ca(OH)2 solution from mixing tank 2, stir and react for 3 hours, add 1.2 mg / L of polyacrylamide flocculant, and flocculate for 0.5 hours. After the reaction is complete, let it stand and age for 0.5 hours.

[0058] S3: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank. The slurry at the bottom is pumped out by a mud pump and enters a sorting hydrocyclone. After sorting, the overflow slurry is added back to reaction tank 2, and the bottom slurry is discharged to mud tank 2.

[0059] S4: After sorting is complete, repeat steps S2 and S3.

[0060] S5: When the solid-liquid ratio of the slurry in the mud bucket reaches 5:1, wash with washing water at a mass ratio of 1:10 to obtain first-grade salt mud by lime flue gas method. Comparative Example 2

[0061] The original brine composition of this comparative example is the same as that of Example 2. The mud sorting process in step S4 and the repeating process in step S5 of the control method in Example 2 are omitted. The specific steps are as follows: S1: Preheat the brine in the original brine tank to 45℃; prepare a 30% NaOH solution and a saturated Ca(OH)2 solution in ingredient tank 1 and ingredient tank 2 respectively.

[0062] S2: Transfer the preheated brine from step S1 to reaction tank 1, add NaOH solution from ingredient tank 1, adjust the pH of the reaction system to 12.6, stir the reaction for 0.5 hours, then filter the reaction system through a ceramic membrane, and discharge the filter residue to mud tank 1; transfer the brine obtained after filtration to reaction tank 2.

[0063] S3: Add the saturated Ca(OH)2 solution from the mixing tank 2 to the reaction tank 2, stir and react for 3 hours, add 1.2 mg / L of polyacrylamide flocculant, and flocculate for 0.5 hours. After the reaction is complete, let it stand and age for 0.5 hours.

[0064] S4: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank, and the bottom slurry is discharged to mud tank 2.

[0065] S5: When the solid-liquid ratio of the slurry in the mud bucket reaches 5:1, wash with washing water at a mass ratio of 1:10 to obtain first-grade salt mud by lime flue gas method. Comparative Example 3

[0066] The original brine composition of this comparative example is the same as in Example 2. In the salt mud control step, step S2, which adjusts the pH of the reaction system, is omitted; the remaining steps are the same as in Example 2. Comparative Example 4

[0067] The original brine composition of this comparative example is the same as that of Example 2. In the salt mud conditioning step, the post-reaction aging process in step S3 is omitted, and the remaining steps are the same as in Example 2.

[0068] Particle size detection of salt mud before and after adjustment: The samples prepared in the above examples and comparative examples were ultrasonically dispersed in a dispersion medium (water) at room temperature, and the particle size of the primary salt mud samples obtained by the lime flue gas method was detected using a Malvern laser particle size analyzer. Table 1 shows the median particle size Dv50 values ​​of the salt mud in the comparative and examples. Figure 2 The table shows the particle size distribution curves of the salt mud in the comparative and example cases. (From Table 1 and...) Figure 1 It can be seen that the particle size of the embodiment is larger and the particle size distribution is more uniform compared to the comparative example.

[0069] Electron microscopy morphology characterization: According to the national standard GB / Z21738-2008, a high-resolution transmission electron microscope was used. The prepared whisker samples were ultrasonically dispersed in a dispersion medium (ethanol) at room temperature and then dropped onto a transmission electron microscope grating with a carbon film. The morphology of the salt mud was then observed under 50x magnification. Figure 3 These are microscopic images (200 μm) of the purified salt mud from the comparative and example samples. From Figure 3 It can be seen that the particles in the example are larger than those in the comparative example.

[0070] Turbidity detection of mud tank supernatant: The turbidity of the mud tank supernatant was detected using a turbidimeter according to standard HJ 1075-2019 "Determination of Turbidity in Water - Turbidimeter Method". The turbidity of the mud tank supernatant in the comparative and example cases is shown in Table 1.

[0071] Analysis of the inclusion rate of salt mud particles:

[0072] Wherein, ω represents the inclusion rate; M0 represents the total mass of the salt mud, in g; and M1 represents the total mass of calcium sulfate and calcium hydroxide, in g. The inclusion rates of the salt mud particles in the comparative examples and embodiments are shown in Table 1.

[0073] Table 1. Median particle size (Dv50) of salt mud, turbidity of supernatant in mud bucket, and particle inclusion rate of salt mud.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling the crystallization process of primary reactive salt mud using lime flue gas, characterized in that, Includes the following steps: S1: Preheat the brine in the original brine tank to 40-45℃; prepare a 20%-30% NaOH solution in ingredient tank 1 and a saturated Ca(OH)2 solution in ingredient tank 2. S2: Transfer the preheated brine from step S1 to reaction tank 1, add NaOH solution from ingredient tank 1, adjust the pH of the reaction system to between 12.4 and 12.6, stir the reaction for 0.5 hours, then filter the reaction system through a ceramic membrane, and discharge the filter residue to mud tank 1; transfer the brine obtained after filtration to reaction tank 2. S3: Add the saturated Ca(OH)2 solution from the mixing tank 2 to the reaction tank 2, stir and react for 3 hours, add 1-1.2 mg / L of flocculant, flocculate for 0.5 hours, and let stand and age for 0.5 hours after the reaction is complete. S4: After the aging process in step S3 is completed, the brine in reaction tank 2 is transferred to the primary refined brine tank. The slurry at the bottom is pumped out by a mud pump and enters the sorting hydrocyclone. The overflow slurry is added back to reaction tank 2, and the bottom slurry is discharged to mud tank 2. S5: After sorting is complete, repeat steps S3 and S4. S6: When the solid-liquid ratio of the slurry in mud bucket 1 or mud bucket 2 reaches 5:1, it is washed with washing water at a mass ratio of 1:10 and dehydrated to obtain primary salt mud by lime flue gas method; the median particle size Dv50 of the primary salt mud by lime flue gas method is between 70-80μm.

2. The method for controlling the crystallization process of primary reactive salt mud using the lime flue gas method as described in claim 1, characterized in that, In step S1, the brine in the original brine tank contains at least the following components by mass concentration: NaCl 297-300 g / L; Ca 2+ 0.52~0.66g / L; Mg 2+ 0.02~0.07g / L; SO4 2- 16.0~18.0g / L.

3. The method for controlling the crystallization process of primary reactive salt mud using the lime flue gas method as described in claim 1, characterized in that, The pore size of the ceramic membrane mentioned in step S2 is 30-50 nm.

4. The method for controlling the crystallization process of primary reactive salt mud using the lime flue gas method as described in claim 1, characterized in that, In step S3, the amount of saturated Ca(OH)2 solution added is controlled to be 1% of the volume of brine in reaction tank 2, and the adding time is controlled to be within 30 minutes.

5. The method for controlling the crystallization process of primary reactive salt mud using the lime flue gas method as described in claim 1, characterized in that, The flocculant mentioned in step S3 is any one of polyacrylamide, sodium polyacrylate, and polyaluminum chloride.

6. The method for controlling the crystallization process of primary reactive salt mud using the lime flue gas method as described in claim 1, characterized in that, The taper ratio of the sorting hydrocyclone mentioned in step S4 is controlled between 0.75 and 0.

8.

7. The method for controlling the crystallization process of primary reactive salt mud using the lime flue gas method as described in claim 1, characterized in that, In step S4, the brine in the primary brine tank contains at least the following components by mass concentration: NaCl 292-295 g / L; Ca 2+ 0.76~0.88g / L; SO4 2- 14.0~15.0g / L.

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