Method for regulating and controlling crystallization process of first-stage reaction salty mud by lime-flue gas method

Abstract

The invention belongs to the technical field of brine purification, and discloses a regulation and control method for a lime-flue gas method primary reaction salty mud crystallization process. The method comprises the following steps: firstly, controlling the pH value to be 12.4-12.6 by using caustic soda to remove impurity components in original brine, then dropwise adding Ca (OH) 2 to carry out primary causticization reaction with the brine, after reaction crystallization is finished, carrying out separation treatment on bottom slurry, taking small particles as seed crystals to cyclically participate in the reaction again, and finally washing and dehydrating the slurry to obtain a primary salty mud finished product. According to the method, impurities influencing the reaction crystallization process in the brine are removed, first-stage salty mud particles are increased, the salty mud settling time is shortened, the dosage of a flocculating agent is reduced, and compared with a traditional process, the whole process is short in reaction period, lower in energy consumption, easy and convenient to operate and lower in production cost; a material basis is provided for the subsequent comprehensive utilization of the salty mud, and the high-valued application of the salty mud in the downstream field can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of salt-making brine purification, and particularly relates to a method for regulating a salt mud crystallization process in a primary reaction of a lime flue gas method. Background Art

[0002] Brine purification, also known as brine pretreatment, is one of the key processes in the salt production process. 2+ Mg 2+ The ions are separated before entering the heating chamber. Salt mud is the general name for various inorganic salts discharged in this process.

[0003] The lime flue gas method is a process for purifying brine in salt chemical industry. It is also a fast-growing energy-saving and consumption-reducing reaction process. Its core is the causticization reaction between calcium hydroxide and sodium sulfate. The lime water reacts with the Mg in the brine. 2+ The reaction produces magnesium hydroxide precipitate, while the lime emulsion (Ca(OH)2) reacts with the sodium sulfate (Na2SO4) in the brine to produce calcium sulfate (CaSO4), precipitating the calcium ions that part of the lime emulsion added to the brine, and producing sodium hydroxide (NaOH).

[0004] The causticizing reaction will produce primary salt mud, the main components of which are CaSO4, Mg(OH)2 and unreacted Ca(OH)2. Since the causticizing reaction is a reversible reaction, the causticizing reaction rate will change with time and the concentration of various ions. 2+ 、SO4 2- The increase of is beneficial to the causticization reaction, and the product OH - The increase will prevent the causticizing reaction from proceeding. During the generation of primary salt mud, the growth of calcium sulfate crystals is affected by the efficiency of the causticizing reaction, raw materials, reaction conditions, etc. At the same time, Mg(OH)2 is a flocculent precipitate with small particles and poor rheological properties, which is wrapped on the surface of calcium sulfate crystals. This will lead to high fine powder salt mud particles in the salt mud slurry and slow sedimentation. The supernatant obtained by sedimentation contains fine powder salt mud particles. The recovery of brine for purification affects the clarity and quality of the preparation of refined brine. In addition, the clarity of the washing water for washing salt mud is low. Transporting it to the return water pool will cause salt mud to settle at the bottom. Pipeline transportation of return water back to the mine pipe for a long time will cause salt mud accumulation and serious pipe blockage. In addition, the excessively fine particles of salt mud products during sales, transportation and use will cause dust, which will have an adverse impact on the environment.

[0005] The first-stage salt mud crystallization process of the lime flue gas method is a typical reaction crystallization. How to optimize the first-stage reaction crystallization process of the lime flue gas method based on the existing process, balance the influence of impurities, and achieve the improvement of the particle size of the salt mud product has become an urgent problem to be solved. Summary of the invention

[0006] In order to solve the problems existing in the existing lime flue gas method first-stage reaction crystallization process, the purpose of the present invention is to provide a method for regulating the first-stage reaction salt mud crystallization process of the lime flue gas method, which not only effectively avoids the influence of impurities in the salt mud on the salt mud crystallization process, but also uses its own components as crystal seeds to increase the particle size of the salt mud particles. In addition, the regulation and treatment method can greatly reduce the amount of quicklime, reduce the enrichment of impurity components in the brine, and improve the quality of the brine. The method of the present invention improves the quality of salt mud products and reduces the production cost of brine purification, and plays a positive role in pollutant control, energy conservation and emission reduction, and environmental protection.

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

[0008] S2: The brine preheated in step S1 is transferred to reaction barrel 1, and the NaOH solution in batching barrel 1 is added to adjust the pH of the reaction system to between 12.4 and 12.6. The reaction is stirred for 0.5 h, and then the reaction system is filtered by a ceramic membrane, and the filter residue is discharged to mud barrel 1; the brine obtained after filtration is transferred to reaction barrel 2.

[0009] S3: Add the saturated Ca(OH)2 solution in the batching barrel 2 to the reaction barrel 2, stir and react for 3 hours, add 1-1.2 mg / L of flocculant, flocculate for 0.5 hours, and let it stand for 0.5 hours after the reaction is completed.

[0010] S4: After the aging in step S3 is completed, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, the slurry at the bottom is pumped out by a mud pump and enters the sorting cyclone, the overflow slurry is re-added to reaction barrel 2, and the bottom slurry is discharged to mud barrel 2.

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

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

[0013] Optionally, in step S1, the salt-making raw brine comprises at least the following components, and the components are respectively, measured by mass concentration: 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 a small amount of Fe and Al impurities.

[0014] Optionally, in step S1, 60° C. condensate water is heated using a plate heat exchanger.

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

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

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

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

[0019] Optionally, in step S4, the primary refined halogen comprises at least the following components, and the components are respectively, measured by mass concentration: 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 in the present invention is a by-product of salt production, wherein the median particle size Dv50 is 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) The present invention proposes for the first time a control method for the primary salt mud crystallization process using lime flue gas, which first removes Mg 2+ , Fe 3+ 、Al 3+ Impurities such as NaOH can be removed to reduce the impact of impurities on the crystallization process and reduce the inclusion rate of salt mud. The pH value is adjusted by NaOH during the impurity removal process, and NaOH is generated in the subsequent reaction. 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 sludge by the lime flue gas method. The method can increase the particle size of salt sludge particles, reduce the sedimentation time of salt sludge, and reduce the amount of flocculant used, thereby producing primary salt sludge with better chemical properties such as high purity, low fine particles, and good sedimentation performance. This method provides a material basis for the subsequent comprehensive utilization of salt sludge and can realize the high-value application of salt sludge in downstream fields.

[0023] (3) The present invention makes full use of the sorting cyclone technology to grade and screen the salt mud particles. The small-particle salt mud is recycled as a crystal seed, turning the poor and inconsistent crystallization process into a repeatable process, improving the dispersion and particle size of the salt mud particles while increasing the purity of the salt mud.

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

[0025] Figure 1 The present invention is a process flow chart of a control method for a primary salt mud crystallization process using a lime flue gas method.

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

[0027] Figure 3 The microscopic microscope photographs of primary salt mud produced by the lime flue gas process according to the exemplary embodiments of the present invention and the comparative examples are shown. DETAILED DESCRIPTION

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

[0029] S2: The brine preheated in step S1 is transferred to reaction barrel 1, and the NaOH solution in batching barrel 1 is added to adjust the pH of the reaction system to between 12.4 and 12.6. The reaction is stirred for 0.5 h, and then the reaction system is filtered by a ceramic membrane, and the filter residue is discharged to mud barrel 1; the brine obtained after filtration is transferred to reaction barrel 2.

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

[0031] S4: After the aging in step S3, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, the slurry at the bottom is pumped out by a mud pump and enters the sorting cyclone, and the overflow slurry is re-added to reaction barrel 2 after sorting, and the bottom slurry is discharged to mud barrel 2.

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

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

[0034] The first-order reaction of brine purification lime flue gas method is causticization reaction. The main reaction equation is Ca(OH)2+Na2SO4→CaSO4+2NaOH. The target products are calcium sulfate, Mg 2+ , Fe 3+ 、Al 3+ Impurities such as precipitates are deposited into the salt mud during the brine purification process, especially under alkaline conditions, to form hydroxide flocculent precipitates with small particles and poor rheological properties, which are wrapped on the surface of calcium sulfate crystals, greatly affecting the quality of the salt mud. At the same time, the reaction efficiency of the causticizing reaction is low. Due to insufficient reaction, there are problems such as waste of raw materials and formation of small calcium sulfate crystals. Therefore, the method provided by the present 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 salt-making 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 raw brine barrel is preheated to 40~45℃. Under this temperature condition, the soluble salt in the raw brine will not precipitate, and the temperature of the reaction system is suitable for the subsequent causticization reaction.

[0036] Compared with the traditional lime flue gas method, the S2 added in the present invention is to reduce the impurities that may cover the surface of the causticization reaction product CaSO4 as much as possible. Step S2 adjusts the pH to between 12.4 and 12.6 by adding 20% ​​to 30% NaOH solution to the raw brine. According to the precipitation equilibrium constant Ksp, the precipitation pH values ​​of Mg(OH)2, Fe(OH)3, Al(OH)3, and Ca(OH)2 at room temperature are 10.4 to 12.4, 1.5 to 4.1, 3.3 to 5.2, and 12.7 to 14.4, respectively. The present invention controls the pH between 12.4 and 12.6 to ensure that Mg 2+ , Fe 3+ 、Al 3+ Impurities such as Ca 2+ It will not precipitate. In addition, since the reaction is often very rapid during the reaction crystallization, the impurities produced may wrap around the reactants and prevent the reaction from proceeding. Reasonable control methods can reduce the inclusion of impurity ions in the target products of subsequent reactions.

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

[0038] Step S4, the aged bottom slurry is sorted by a sorting cyclone, and the small particles in the overflow slurry are used as seeds to re-react, optimize the crystallization behavior, and repeat the cycle to ensure that the final crystal size is increased. Finally, most of the soluble impurities are removed by water washing to obtain the regulated salt mud. The characteristics of the salt mud components are used to control the impurity ion content and the main component particle morphology through sorting technology to exert their synergistic effect.

[0039] The control method of the lime flue gas method salt mud crystallization process of the specific embodiment of the present invention, the first-level 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 lime flue gas method of the present invention is a control method for the crystallization process of primary salt mud. The lime flue gas method primary salt mud is a by-product of salt production, 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.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. Example 1

[0042] After testing, the raw halogen composition of this embodiment is calculated by mass concentration as follows: NaCl 297g / L; Ca 2+ 0.52g / L; Mg 2+ 0.02g / L; SO4 2- 16.0g / L and a small amount of Fe and Al impurities.

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

[0044] S2: The brine preheated in step S1 is transferred to reaction barrel 1, and the NaOH solution in batching barrel 1 is added to adjust the pH of the reaction system to 12.5, and the reaction is stirred for 0.5h. The reaction system is then filtered through a ceramic membrane, and the filter residue is discharged to mud barrel 1; the brine obtained after filtration is transferred to reaction barrel 2.

[0045] S3: Add the saturated Ca(OH)2 solution in batching barrel 2 to reaction barrel 2, stir and react for 3 hours, add 1.2 mg / L polyacrylamide flocculant, flocculate for 0.5 hours, and let stand and age for 0.5 hours after the reaction is completed.

[0046] S4: After the aging in step S3, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, the slurry at the bottom is pumped out by a mud pump and enters the sorting cyclone, and the overflow slurry is re-added to reaction barrel 2 after sorting, and the bottom slurry is discharged to mud barrel 2.

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

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

[0049] After testing, the raw halogen composition of this embodiment is calculated by mass concentration as follows: NaCl 297g / L; Ca 2+ 0.60g / L; Mg 2+ 0.05g / L; SO4 2- 18.0g / L and a small amount of Fe and Al impurities.

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

[0051] S2: The brine preheated in step S1 is transferred to reaction barrel 1, and the NaOH solution in batching barrel 1 is added to adjust the pH of the reaction system to 12.6. The reaction is stirred for 0.5h, and then the reaction system is filtered by a ceramic membrane, and the filter residue is discharged to mud barrel 1; the brine obtained after filtration is transferred to reaction barrel 2.

[0052] S3: Add the saturated Ca(OH)2 solution in the batching barrel 2 to the reaction barrel 2, stir and react for 3 hours, add 1.2 mg / L polyacrylamide flocculant, flocculate for 0.5 hours, and after the reaction is completed, let it stand and age for 0.5 hours.

[0053] S4: After the aging in step S3, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, the slurry at the bottom is pumped out by a mud pump and enters the sorting cyclone, and the overflow slurry is re-added to reaction barrel 2 after sorting, and the bottom slurry is discharged to mud barrel 2.

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

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

[0056] The raw halogen composition of this comparative example is the same as that of Example 1. Step S2 of the control method of Example 1 is eliminated, and the specific steps are as follows: S1: Preheat the brine in the original brine barrel to 40°C; prepare a saturated Ca(OH)2 solution in the batching barrel 2.

[0057] S2: The brine preheated in step S1 is directly transferred to reaction barrel 2, and the saturated Ca(OH)2 solution in batching barrel 2 is added dropwise, stirred for reaction for 3 hours, 1.2 mg / L polyacrylamide flocculant is added, and the flocculation reaction is carried out for 0.5 hours. After the reaction is completed, it is allowed to stand and age for 0.5 hours.

[0058] S3: After the aging of step S3 is completed, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, and the slurry at the bottom is pumped out by a mud pump and enters the sorting cyclone. After sorting, the overflow slurry is re-added to reaction barrel 2, and the bottom slurry is discharged to mud barrel 2.

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

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

[0061] The raw brine composition of this comparative example is the same as that of Example 2. The mud separation step S4 and the repetition process of S5 in the control method of Example 2 are eliminated, and the specific steps are as follows: S1: Preheat the brine in the original brine barrel to 45℃; prepare 30% NaOH solution and saturated Ca(OH)2 solution in batching barrel 1 and batching barrel 2 respectively.

[0062] S2: The brine preheated in step S1 is transferred to reaction barrel 1, and the NaOH solution in batching barrel 1 is added to adjust the pH of the reaction system to 12.6, and the reaction is stirred for 0.5h. The reaction system is then filtered through a ceramic membrane, and the filter residue is discharged to mud barrel 1; the brine obtained after filtration is transferred to reaction barrel 2.

[0063] S3: Add the saturated Ca(OH)2 solution in the batching barrel 2 to the reaction barrel 2, stir and react for 3 hours, add 1.2 mg / L polyacrylamide flocculant, flocculate for 0.5 hours, and after the reaction is completed, let it stand and age for 0.5 hours.

[0064] S4: After the aging in step S3 is completed, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, and the bottom slurry is discharged to the mud barrel 2.

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

[0066] The composition of the raw brine in this comparative example is the same as that in Example 2. In the salt mud regulation step, step S2 of adjusting the pH of the reaction system is eliminated, and the remaining steps are the same as those in Example 2. Comparative Example 4

[0067] The composition of the raw brine in this comparative example is the same as that in Example 2. In the salt mud adjustment step, the static aging process after the reaction in step S3 is eliminated, and the remaining steps are the same as those in Example 2.

[0068] Detection of salt mud particle size before and after regulation: The samples prepared in the above embodiments and comparative examples were ultrasonically dispersed in a dispersion medium (water) at room temperature, and the particle size of the first-level salt mud sample obtained by the lime flue gas method was detected using a Malvern laser particle size analyzer. Table 1 shows the median particle size Dv50 of the salt mud in the comparative examples and embodiments. Figure 2 The particle size distribution curves of the salt mud of the comparative example and the embodiment are shown in Table 1 and Figure 1 It can be seen that the particle size of the embodiment is larger than that of the comparative example, and the particle size distribution is uniform.

[0069] Electron microscope morphology characterization: According to the national standard GB / Z21738-2008, a high-resolution transmission electron microscope was used to ultrasonically disperse the prepared whisker sample in a dispersion medium (ethanol) at room temperature and then drop it on a transmission electron microscope microgrid with a carbon film. The morphology of the salt mud was then observed under 50 times magnification. Figure 3 The following are microscopic microscope photos (200 μm) of the salt mud after purification in the comparative example and the embodiment. Figure 3 It can be seen that the particles of the examples are larger than those of the comparative examples.

[0070] Turbidity detection of the supernatant liquid in the mud bucket: According to the standard HJ 1075-2019 "Determination of turbidity of water quality-turbidimeter method", the turbidity of the supernatant liquid in the mud bucket is detected by a turbidimeter. The turbidity of the supernatant liquid in the mud bucket of the comparative example and the embodiment is shown in Table 1.

[0071] Analysis of salt mud particle storage rate:

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

[0073] Table 1 Salt mud median particle size Dv50, mud barrel supernatant turbidity, salt mud particle inclusion rate

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling the crystallization process of salt mud in the first-order reaction of lime flue gas method, characterized in that: The following steps are involved: S1: Preheat the brine in the original brine barrel to 40-45°C; prepare a 20%-30% NaOH solution in batching barrel 1, and prepare a saturated Ca(OH)2 solution in batching barrel 2; S2: The brine preheated in step S1 is transferred to reaction barrel 1, and the NaOH solution in batching barrel 1 is added to adjust the pH of the reaction system to between 12.4 and 12.6, and the reaction is stirred for 0.5h, and then the reaction system is filtered by a ceramic membrane, and the filter residue is discharged to mud barrel 1; the brine obtained after filtration is transferred to reaction barrel 2; S3: Add the saturated Ca(OH)2 solution in the batching barrel 2 to the reaction barrel 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 completed; S4: After the aging in step S3 is completed, the brine in reaction barrel 2 is transferred to the first-level refined brine barrel, the slurry at the bottom is pumped out by a mud pump and enters the sorting cyclone, the overflow slurry is re-added to reaction barrel 2, and the bottom slurry is discharged to mud barrel 2; S5: After sorting is completed, repeat steps S3 and S4; S6: When the solid-liquid ratio of the slurry in the mud barrel reaches 5:1, washing water is used at a mass ratio of 1:10 to obtain lime flue gas method first-grade salt mud through dehydration; the median particle size Dv50 of the lime flue gas method first-grade salt mud is between 70-80 μm.

2. The control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: In step S1, the raw halogen includes 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 control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: The pore size of the ceramic membrane described in step S2 is 30 to 50 nm.

4. The control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: In step S3, the amount of saturated Ca(OH)2 solution added is controlled to account for 1% of the volume of the brine in reaction tank 2, and the addition time is controlled within 30 minutes.

5. The control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: The flocculant described in step S3 is any one of polyacrylamide, sodium polyacrylate, and polyaluminium chloride.

6. The control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: The taper ratio of the separation cyclone in step S4 is controlled between 0.75 and 0.

8.

7. The control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: In step S4, the brine in the first-level refined brine barrel includes 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.

8. The control method for the primary reaction salt mud crystallization process of the lime flue gas method according to claim 1, characterized in that: In step S6, the lime flue gas method primary salt mud has the following components by weight percentage: CaSO4 74.0-76.0%, Ca(OH)2 20.0-22.0%, NaCl 0.5-1.0%; and impurities 0.5-1.0%.

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