Process for realizing sodium potassium salt separation from carnallite

Abstract

The invention relates to a process for separating sodium sylvite from carnallite, which comprises the following steps: 1) pretreatment: filtering salt-containing wastewater to obtain filtrate a, and filtering the filtrate a through an MBR (Membrane Bioreactor) membrane to obtain filtrate b; adding an adsorbent into the filtrate b, uniformly stirring, adjusting the pH value of the filtrate b to 9.5-11, adding soluble phosphate, uniformly mixing, settling, and extracting supernatant to obtain a pretreatment solution; 2) ion exchange: carrying out ion exchange treatment on the pretreatment liquid for 20-30 minutes to obtain ion exchange particles; 3) ion elution: carrying out backwashing, regeneration and cleaning on the ion exchange particles to obtain a salt solution and regenerated particle size exchange resin; and 4) crystallization: carrying out evaporative crystallization on the salt solution to obtain crystals, and drying the crystals to obtain the sodium sylvite. Pure sodium sylvite is obtained through the technological processes of pretreatment, ion exchange, ion elution and evaporative crystallization, and the purity and the extraction amount of the final product are ensured.

Description

Technical Field

[0001] The present application relates to the technical field of salt extraction, and more specifically, to a process for separating sodium and potassium salts from miscellaneous salts. Background Art

[0002] In the chemical industry, especially in the salt chemical industry, extracting various high-purity salts from complex mixed salts is a crucial link. This not only helps to improve product quality, but also is conducive to environmental protection and the effective use of resources. With the continuous deepening of industrialization, the market demand for salt products is growing, and the continuous advancement of purification technology has greatly promoted the progress and development of the entire chemical industry. However, how to ensure the purification rate while maintaining high efficiency has always been one of the challenges faced in this field.

[0003] In order to solve the problem of extracting a variety of salt products from saline wastewater, the methods currently commonly used in the industry include but are not limited to: 1) Direct evaporation crystallization after pretreatment, and separation of different salts by adjusting the crystallization conditions; 2) Adopting selective precipitation technology, selective precipitation is achieved by adding specific precipitants, thereby separating the target salts; 3) Using the freeze crystallization method, by adjusting the temperature and time, different salts are crystallized step by step at different temperatures. In addition, there are methods that use salt solvent extraction or countercurrent crystallization. Although these methods have their own characteristics, they are all for the purpose of efficiently purifying various salts from mixed salts.

[0004] However, the above method still has certain limitations in practical application, especially when faced with the purification of complex salts of different concentrations, the problems of low purification rate and low extraction efficiency are particularly prominent. Summary of the invention

[0005] In order to further improve the extraction efficiency of sodium-potassium salt, the present application provides a process for separating sodium-potassium salt from miscellaneous salts.

[0006] The present application provides a process for separating sodium and potassium salts from miscellaneous salts, which is prepared by the following method: 1) Pretreatment: Filter the salt-containing wastewater through a 100-300 mesh filter screen, and then filter the obtained filtrate a through an MBR membrane to obtain a filtrate b; add an adsorbent to the filtrate b and stir evenly, adjust the pH value of the filtrate b to 9.5-11, settle, extract the supernatant, and obtain a pretreatment liquid; 2) Ion exchange: subjecting the pretreatment liquid to ion exchange treatment for 20-30 minutes to obtain ion exchange particles; 3) Ion dewashing: backwashing, regenerating and cleaning the ion exchange particles to obtain a salt solution and a regenerated particle size exchange resin; 4) Crystallization: Evaporate and crystallize the salt solution, and then dry the obtained crystals to obtain sodium potassium salt.

[0007] The above process has high production efficiency, and the salt purity is above 96%, and it can be used for wastewater with different salinity levels. Specifically, in the pretreatment process, the filtering effect of the filter net can remove large particles, stones, etc., and the filtering effect of the MBR membrane can effectively remove pollutants such as suspended matter, microorganisms and organic matter, further improving the water quality; and adding adsorbents and adjusting to alkalinity can further remove metal ions and other ions, further improving the water quality and reducing the impact on the later ion exchange.

[0008] In steps 2)-3), the ion exchange method can selectively adsorb the desired ions, further improving the purification efficiency of sodium potassium salt. Moreover, the ion exchange time of the present application can more effectively and to a greater extent exchange the desired ions, thereby further improving the extraction amount and extraction purity.

[0009] In step 4), sodium potassium salt is effectively extracted by evaporation and crystallization to improve the extraction purity.

[0010] In summary, the pretreatment step effectively removes impurities in the wastewater through multi-stage filtration, adding specific adsorbents and adjusting the pH value, thereby improving the efficiency of subsequent ion exchange; the ion exchange step uses cation exchange resins and chloride-type anion exchange resins under specific conditions to further remove impurities and improve the separation effect; the ion dewashing step de-washes the ion exchange resin to effectively obtain the corresponding sodium ions, potassium ions and chloride ions; and pure sodium-potassium salts are obtained through evaporation and crystallization, ensuring the purity and extraction amount of the final product.

[0011] Preferably, the adsorbent is composed of the following raw materials in parts by weight: Activated carbon 10-20 parts Expanded graphite 1-3 parts 2-5 parts of magnesium silicate 1-3 parts of porous silica microspheres 0.5-3 parts of organic bentonite.

[0012] Activated carbon, expanded graphite, magnesium silicate, and porous silica microspheres can significantly adsorb metal ions, sulfate ions, carbonate ions, small particles, suspended matter, etc., and can play a better role in removing impurities.

[0013] When activated carbon, expanded graphite, magnesium silicate, porous silica microspheres and organic bentonite are compounded, the synergistic effect obtained, combined with the pretreatment process of the present application, can enhance the ion adsorption and sediment adsorption in the wastewater, and further improve the extraction amount and extraction purity of potassium and sodium salts.

[0014] Preferably, the amount of the adsorbent is 1-5 g / L; the amount of the soluble phosphate is 10-30 g / L, the stirring rate is 60-80 r / min, the stirring time is 20-30 min, and the sedimentation time is 2-3 h.

[0015] By adopting the above technical scheme, the dosage of the adsorbent, the stirring rate and the sedimentation time are optimized, so that impurities can be removed more effectively during the pretreatment process, the efficiency of the subsequent ion exchange and crystallization steps is improved, and the purification rate and extraction efficiency of the sodium potassium salt are thereby improved.

[0016] Preferably, the specific steps of step 2) ion exchange are as follows: The pH value of the pretreatment liquid is adjusted to 6-7, and heated to 38-45°C, and then 150-210g / m3 of cation exchange resin and 183-250g / m3 of chloride-type anion exchange resin are added, and the mixture is stirred at a speed of 80-120r / min for 20-30min, filtered, and ion exchange particles are obtained.

[0017] In the above scheme, the pH value of the pretreatment liquid is adjusted to 6-7, and heated to 38-45°C, and the corresponding amount of cation exchange resin and chloride-type anion exchange resin is added, and stirred at a speed of 80-120r / min for 20-30min, which can adsorb a large amount of chloride ions, sodium ions and potassium ions. After de-washing and recrystallization, the extraction purity and extraction amount of sodium potassium salt can be further improved.

[0018] Preferably, the particle size of the cation exchange resin is 0.3-1.2 mm; the particle size of the chloride-type anion exchange resin is 0.4-0.9 mm.

[0019] The particle size of the cation exchange resin is 0.3-1.2 mm, and the particle size of the chloride-type anion exchange resin is 0.4-0.9 mm, which allows the resin to be in more complete contact with the solution during the ion exchange process, thereby improving the ion exchange efficiency and thereby increasing the separation purity of the sodium-potassium salt.

[0020] Preferably, the method further comprises adding 10-22 g / m3 of an activation stabilizer in step 2) and mixing the activated stabilizer uniformly with the pretreatment liquid.

[0021] The separation process of the present application is to extract from saline wastewater. Usually, the saline wastewater is large in volume and contains many impurities during the treatment process, which affects the extraction effect. In addition, long-term extraction can easily lead to instability and uneven dispersion of ion exchange resins during the exchange process.

[0022] Therefore, the present application adds 10-22g / m3 of activation stabilizer and mixes it evenly with the pretreatment liquid, which can effectively improve the stability of the pretreatment liquid and activate the ions, so that the ion exchange resin can fully contact with the required ions, thereby achieving the adsorption effect of the required ions. Further improve the separation efficiency of sodium potassium salt, enhance the ion exchange effect, and thus improve the purity and extraction amount of sodium potassium salt.

[0023] Preferably, the activated stabilizer is composed of the following raw materials in parts by weight: Sodium hexametaphosphate 1-8 parts 0.5-1.8 parts of sodium aminoalginate 1-3 parts of methacryloylethyl sulfobetaine Polyamide modified hydrogenated castor oil derivative 3-8 Potassium peroxymonosulfate complex salt 0.2-0.8 parts Cetyl alcohol 0.3-1 part.

[0024] In the above scheme, cetyl alcohol can promote the fluidity and wettability of the exchange resin, interact with methacryloylethyl sulfobetaine and methacryloylethyl sulfobetaine, and further improve the dispersion uniformity and stability of the exchange resin in the pretreatment solution. The polyamide-modified hydrogenated castor oil derivative can improve the fluidity and stability, and further synergize with cetyl alcohol, methacryloylethyl sulfobetaine and methacryloylethyl sulfobetaine to ensure the stability and activity of the ion exchange resin during the exchange process.

[0025] The molecular formula of potassium permonosulfate complex salt is KHSO5·0.5KHSO4·0.5K2SO4. It is a non-chlorine oxidant. In the process of extracting chloride ions or sodium ions with ion exchange resin, its oxidizing property can promote or enhance the ion exchange efficiency.

[0026] It may work synergistically with other chemical reagents or additives to promote the adsorption of chloride ions, potassium ions and sodium ions. For example, it can affect the adsorption and exchange behavior of ions on the resin surface by changing the surface tension, charge distribution and other characteristics of the solution.

[0027] Solution environment regulation: In a solution containing SBMA, the ion exchange performance of the resin may be affected by the solution environment (such as pH value, ionic strength, etc.), and the presence of SBMA may indirectly affect the exchange behavior of the resin by changing these environmental parameters.

[0028] Sodium aminoalginate plays an adsorption role, reduces the concentration of free ions in the pretreatment solution, and interacts with cetyl alcohol, methacryloylethyl sulfobetaine, methacryloylethyl sulfobetaine, potassium persulfate complex salt, thereby promoting the activity of sodium, potassium, and rate ions in the pretreatment solution, while improving the activation stability of the ion exchange resin for selective exchange of ions. Sodium hexametaphosphate can control the pH stability of the ion exchange environment, thereby cooperating with other raw materials to achieve better control of its ion exchange and selection, so as to improve the exchange efficiency and extraction purity.

[0029] In summary, the present application is compounded by cetyl alcohol, methacryloylethyl sulfobetaine, methacryloylethyl sulfobetaine, potassium permonosulfate complex salt, and sodium hexametaphosphate to achieve a better synergistic effect, improve the ion activity of sodium, potassium, and chlorine, and make them easily exchanged by ion exchange resins. At the same time, it can ensure the stability of the pretreatment liquid during the ion exchange process, make the ion exchange resin easy to disperse and exchange and adsorb, and further improve the extraction purity and extraction efficiency of sodium potassium salts.

[0030] Preferably, the step 2) further comprises treating the cation exchange resin and the chloride-type anion exchange resin with a regeneration agent, and the regeneration process is as follows: The cation exchange resin and the chloride-type anion exchange resin are completely immersed in an alkaline regeneration agent, filtered, and the obtained solid is then immersed in an acidic regeneration agent, filtered, and the solid is dried to obtain ion exchange particles.

[0031] The ion exchange particles are backwashed, immersed in an alkaline regeneration agent, filtered, immersed again in an acidic regeneration agent, and finally dried, which effectively improves the regeneration efficiency of the ion exchange resin, ensures the continued effectiveness of the ion exchange process, and thereby improves the extraction purity and efficiency of the sodium-potassium salt.

[0032] Preferably, the alkaline regeneration agent is composed of the following raw materials in weight percentage: 0.1-0.5% isothiazolinone, 0.2-0.5% hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 1-2% sodium chloride, 3-5% sodium hydroxide, 0.1-0.3% potassium permonosulfate complex salt, and the balance is water.

[0033] Isothiazolinone, hexadecanoylamidopropyl hydroxypropyl sulfobetaine, sodium chloride, potassium permonosulfate complex salt and sodium hydroxide in the alkaline regeneration agent act synergistically at a specific weight percentage, effectively improving the regeneration efficiency and stability of the ion exchange resin after regeneration, thereby improving the overall efficiency and purification rate of the sodium-potassium salt separation process.

[0034] In addition, potassium peroxymonosulfate complex salt and thiazolinone play a synergistic cleaning and stabilizing role, further improving the dewashing efficiency and dewashing effect of the exchange resin.

[0035] Preferably, the acidic regeneration agent is composed of 0.1-0.5% isothiazolinone, 0.2-0.5% hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 3-5% hydrochloric acid, and the balance is water.

[0036] The acidic regenerant formula can effectively improve the regeneration effect of ion exchange resin, enhance the stability and reusability of the resin, and thus improve the separation purity and efficiency of sodium-potassium salts. Specifically, the addition of isothiazolinone and hexadecanoylamidopropyl hydroxypropyl sulfobetaine improves the sterilization and washing effects during the regeneration process, sodium chloride assists in adjusting the solution environment, and hydrochloric acid helps the regeneration process under acidic conditions, ultimately achieving efficient regeneration and stable operation.

[0037] Preferably, the step 4) further comprises dissolving the sodium potassium salt, followed by freeze crystallization and centrifugation to obtain a mother liquor and potassium salt; and then evaporating the mother liquor and drying the obtained solid to obtain the sodium salt.

[0038] By dissolving the sodium potassium salt and controlling the freezing temperature, corresponding salt crystals are produced to improve the extraction efficiency and purity.

[0039] In summary, this application has the following beneficial effects: 1. The pretreatment step effectively removes impurities in the wastewater through multi-stage filtration, adding specific adsorbents and adjusting the pH value, thereby improving the efficiency of subsequent ion exchange; the ion exchange step uses cation exchange resins and chloride-type anion exchange resins under specific conditions to further remove impurities and improve the separation effect; the ion dewashing step de-washes the ion exchange resin to effectively obtain the corresponding sodium ions, potassium ions and chloride ions; and then pure sodium potassium salts are obtained through evaporation and crystallization, ensuring the purity and extraction amount of the final product.

[0040] 2. The present application is compounded with cetyl alcohol, methacryloylethyl sulfobetaine, methacryloylethyl sulfobetaine, potassium permonosulfate complex salt, and sodium hexametaphosphate to achieve a better synergistic effect, thereby increasing the ion activity of sodium, potassium, and chlorine, making them easily exchanged by ion exchange resins. At the same time, it can ensure the stability of the pretreatment liquid during the ion exchange process, making it easy for the ion exchange resin to disperse and exchange and adsorb, thereby further improving the extraction purity and extraction efficiency of sodium-potassium salts. DETAILED DESCRIPTION

[0041] The present application is further described in detail below with reference to the embodiments.

[0042] Introduction of some raw materials: The brand model of polyamide-modified hydrogenated castor oil derivative is THIXATROL ST; Porous silica microspheres, porosity 85%-95%, specific surface area 350-500m 2 / g, pore size range is 10-20μm; The cation exchange resin is preferably from Langfang New Era Chemical Building Materials Co., Ltd., brand 001*7, specification 0.3-1.2mm; The chlorine-type anion exchange resin is preferably from Guangzhou Yuanteng Environmental Protection Technology Co., Ltd., brand A600MB, specification 0.4-0.9mm; the molecular structure of amino sodium alginate is as follows: Example

[0043] Example 1 A process for separating sodium and potassium salts from miscellaneous salts comprises the following steps: According to weight parts, 10 parts of activated carbon, 3 parts of expanded graphite, 5 parts of magnesium silicate, 3 parts of porous silica microspheres, and 0.5 parts of organic bentonite were weighed and mixed evenly to obtain an adsorbent.

[0044] The activated carbon can be wood activated carbon or coconut shell activated carbon. In this embodiment, coconut shell activated carbon is preferred, with a mesh size of 300 meshes; the expansion multiple of expanded graphite is 250, and the specific surface area is 400-500m 2 / g; these materials have good adsorption properties and stability; organic bentonite helps to improve fluidity and uniformity during pretreatment.

[0045] The alkaline regeneration agent is composed of the following raw materials in percentage by weight: 0.1% of isothiazolinone, 0.5% of hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 2% of sodium chloride, 3% of sodium hydroxide, 0.5% of potassium permonosulfate complex salt, and the balance is water; the acidic regeneration agent is composed of 0.5% of isothiazolinone, 0.1% of hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 5% of hydrochloric acid, and the balance is water.

[0046] 1) Pretreatment: Pump the salt-containing wastewater into the filter tank, connect and filter the salt-containing wastewater through a 100-mesh filter screen, intercept stones, garbage and other materials, and then transfer the obtained filtrate a to the MBR membrane tank, and then filter through the MBR membrane to obtain the filtrate b; transfer the filtrate b to the sedimentation tank, add 1g / L of adsorbent to the filtrate b, stir at a rate of 60r / min, stir for 30min, then add sodium hydroxide, adjust the pH value of the filtrate b to 9.5, then add 30g / L of soluble phosphate, mix well, stop stirring, let it settle, the sedimentation time is 2h, extract the supernatant, and obtain the pretreatment liquid.

[0047] 2) Ion exchange: The pretreatment liquid is transferred to the ion exchange device, the pH value of the pretreatment liquid is adjusted to 6, and heated to 38°C, and then 210g / m 3 Cation exchange resin and 183g / m 3 The chloride-type anion exchange resin was stirred at a rotation speed of 80 r / min for 30 min and filtered to obtain ion exchange particles.

[0048] 3) Ion dewashing: The ion exchange particles are backwashed at a backwash flow rate of 8 BV / h, and passed through an alkaline regeneration agent 5 times the volume of the ion exchange particles at a flow rate of 5 m / h for regeneration for 30 min, and then filtered. The obtained solid is then passed through an acidic regeneration agent 5 times the volume of the ion exchange particles at a flow rate of 5 m / h for regeneration, filtered, and the solid is dried. In this process, all the filtrate is mixed evenly and recorded as a salt solution. The obtained particles are regenerated ion exchange resin.

[0049] 4) Crystallization: Place the salt solution in an evaporation crystallization device, heat it to 100°C, and concentrate it until the solution is completely evaporated. The obtained crystals are then placed in a 50°C oven and dried for 2 hours to obtain sodium potassium salt.

[0050] Sodium potassium salt is dissolved in water to prepare a salt solution with a mass fraction of 30%, cooled to 19°C, and then cooled to 10°C at a rate of 1°C / min, and allowed to stand for 20 minutes. The solid produced in this process is potassium chloride, which is then centrifuged and dried to obtain potassium chloride; the mother liquor obtained by centrifugation is heated to 100°C to completely evaporate the water, and the obtained solid is dried to obtain sodium chloride, wherein the drying temperature is 50°C and the drying time is 30 minutes.

[0051] The MBR membrane is preferably a hollow fiber membrane-Japan Mitsubishi Chemical MBR membrane-PVDF membrane-ultrafiltration membrane, with an operating pressure of 100 MPa, a thickness of 30 mm, and a flux of 25 L / min. The average particle size of the cation exchange resin is 0.3 mm, the average particle size of the chloride-type anion exchange resin is 0.9 mm, and the soluble phosphate is tetrapotassium phosphate.

[0052] Example 2 The difference between Example 2 and Example 1 is that the process parameters are different, as follows: In step 1), 3.8 g / L of adsorbent was added to the filtrate b at a stirring rate of 65 r / min for 25 min, and then sodium hydroxide was added to adjust the pH value of the filtrate b to 10.5, and then 20 g / L of soluble phosphate was added, mixed evenly, and stirring was stopped to allow the mixture to settle for 2.5 h.

[0053] In step 2), the pretreatment solution was adjusted to a pH of 6, heated to 40°C, and then 188 g / m3 Cation exchange resin and 203g / m 3 Chloride anion exchange resin was stirred at a speed of 70 r / min for 30 min.

[0054] The alkaline regeneration agent is composed of the following raw materials in percentage by weight: 0.2% of isothiazolinone, 0.3% of hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 2% of sodium chloride, 4% of sodium hydroxide, 0.3% of potassium permonosulfate complex salt, and the balance is water; the acidic regeneration agent is composed of 0.2% of isothiazolinone, 0.4% of hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 4% of hydrochloric acid, and the balance is water.

[0055] The average particle size of the cation exchange resin is 0.8 mm; the average particle size of the chloride type anion exchange resin is 0.5 mm.

[0056] Example 3 The difference between Example 3 and Example 1 is that the process parameters are different, as follows: In step 1), 1 g / L of adsorbent is added to the filtrate b at a stirring rate of 60 r / min and a stirring time of 30 min, and then sodium hydroxide is added to adjust the pH value of the filtrate b to 11, and then 10 g / L of soluble phosphate is added, mixed evenly, and stirring is stopped to allow it to settle for 2 h.

[0057] In step 2), the pretreatment solution was adjusted to a pH of 6, heated to 38°C, and then 210 g / m 3 Cation exchange resin and 183g / m 3 Chloride anion exchange resin was stirred at a speed of 80 r / min for 30 min.

[0058] The alkaline regeneration agent is composed of the following raw materials in percentage by weight: 0.5% of isothiazolinone, 0.2% of hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 1% of sodium chloride, 5% of sodium hydroxide, 0.1% of potassium permonosulfate complex salt, and the balance is water; the acidic regeneration agent is composed of 0.1% of isothiazolinone, 0.5% of hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 3% of hydrochloric acid, and the balance is water.

[0059] The average particle size of the cation exchange resin is 1.2 mm; the average particle size of the chloride type anion exchange resin is 0.4 mm.

[0060] Example 4 The difference between Example 4 and Example 2 is that the amount of adsorbent used is different as follows: According to weight parts, 15 parts of activated carbon, 2 parts of expanded graphite, 4 parts of magnesium silicate, 2 parts of porous silica microspheres, and 0.6 parts of organic bentonite were weighed and mixed evenly to obtain an adsorbent.

[0061] Example 5 The difference between Example 5 and Example 2 is that the amount of adsorbent used is different as follows: According to weight, 20 parts of activated carbon, 1 part of expanded graphite, 2 parts of magnesium silicate, 1 part of porous silica microspheres, and 3 parts of organic bentonite were weighed and mixed evenly to obtain an adsorbent.

[0062] Example 6 The difference between Example 6 and Example 2 is that the expanded graphite is replaced by activated carbon in equal amount.

[0063] Example 7 The difference between Example 7 and Example 2 is that the porous silica microspheres are replaced by activated carbon in equal amounts.

[0064] Example 8 The difference between Example 8 and Example 2 is that an equal amount of magnesium silicate is replaced by activated carbon.

[0065] Example 9 The difference between Example 9 and Example 4 is that: 10 g / m 3 The activated stabilizer is mixed evenly with the pretreatment liquid. The specific process is as follows: 8 parts of polyamide-modified hydrogenated castor oil derivative, 0.8 parts of potassium permonosulfate complex salt, 1 part of methacryloylethyl sulfobetaine, 0.5 parts of sodium aminoalginate, 1 part of sodium hexametaphosphate, and 0.3 parts of cetyl alcohol were weighed and mixed evenly according to weight to obtain an activated stabilizer.

[0066] Step 2): Adjust the pH value of the pretreatment solution to 6, heat it to 40°C, and then add 188g / m 3 Cation exchange resin, 203g / m 3 Chloride anion exchange resin and 10g / m 3 of activated stabilizer and stirred at a speed of 70r / min for 30min.

[0067] Example 10 The difference between Example 10 and Example 9 is that the dosage is 17g / m 3 Activated stabilizer.

[0068] Embodiment 11 The difference between Example 11 and Example 9 is that the dosage is 22g / m 3 Activated stabilizer.

[0069] Example 12 The difference between Example 12 and Example 10 is that the amount of raw materials used for the activated stabilizer is different, as follows: 5 parts of polyamide-modified hydrogenated castor oil derivative, 0.5 parts of potassium permonosulfate complex salt, 2 parts of methacryloylethyl sulfobetaine, 1.3 parts of sodium aminoalginate, 3.5 parts of sodium hexametaphosphate, and 0.5 parts of cetyl alcohol were weighed according to weight and mixed evenly to obtain an activated stabilizer.

[0070] Embodiment 13 The difference between Example 13 and Example 10 is that the amount of raw materials used for the activation stabilizer is different, as follows: 3 parts of polyamide-modified hydrogenated castor oil derivative, 0.2 parts of potassium permonosulfate complex salt, 1 part of methacryloylethyl sulfobetaine, 1.8 parts of sodium aminoalginate, 8 parts of sodium hexametaphosphate, and 0.3 parts of cetyl alcohol were weighed and mixed evenly according to weight to obtain an activated stabilizer.

[0071] Embodiment 14 The difference between Example 14 and Example 9 is that the potassium peroxymonosulfate complex salt is replaced by an equal amount of a polyamide-modified hydrogenated castor oil derivative.

[0072] Embodiment 15 The difference between Example 15 and Example 9 is that the amino sodium alginate is replaced by an equal amount of a polyamide-modified hydrogenated castor oil derivative. Example 16 The difference between Example 16 and Example 9 is that cetyl alcohol is replaced by an equal amount of a polyamide-modified hydrogenated castor oil derivative.

[0073] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that: Step 1 does not use MBR membrane filtration, and the specific steps are as follows: 1) Pretreatment: Pump the salt-containing wastewater into the filter tank, connect and filter the salt-containing wastewater through a 100-mesh filter screen, intercept stones, garbage and other materials, and transfer the filtrate b to the sedimentation tank. Add 1g / L of adsorbent to the filtrate b at a stirring rate of 60r / min and a stirring time of 30min. Then add sodium hydroxide and adjust the pH value of the filtrate b to 9.5. Then add 30g / L of soluble phosphate, mix well, stop stirring, and allow it to settle for 2h. Extract the supernatant to obtain a pretreated liquid.

[0074] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that no adsorbent is added.

[0075] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the ion exchange method is replaced by evaporative crystallization.

[0076] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that the stirring time of the ion exchange in step 2) is 50 min.

[0077] Performance testing Detection method / test method The saline wastewater in the examples of the present application was tested and the following test results were obtained: Table 1 Ionic composition of the slightly saline wastewater of this application The processes of Examples 1-16 and Comparative Examples 1-3 were used to treat the above lightly saline wastewater, moderately saline wastewater, and heavily saline wastewater, respectively, with a treatment capacity of 1 ton; the purity of sodium chloride and potassium chloride was then tested, with light pollution being recorded as A, moderate pollution being recorded as B, and heavy pollution being recorded as C. When calculating the purity reduction, the reduction a1=AB, and the reduction a2=AC; the amount of potassium chloride and sodium chloride finally obtained from the moderately saline wastewater was then weighed.

[0078] The above specific data are shown in Table 1; Table 2 Experimental data of Examples 1-16 and Comparative Examples 1-3 Combining Example 1 and Comparative Examples 1-3, it can be seen that the change rates of Comparative Examples 1-3 are all higher than those of Example 1, while the purity and extraction amount are all lower than those of Example 1, indicating that the preparation method of the present application can obtain sodium chloride and potassium chloride with higher purity and extraction amount, and has better extraction effect for heavily saline wastewater.

[0079] By comparing Comparative Example 4 and Example 1 and combining with Table 1, it can be seen that the data of Example 1 and Comparative Example 1 do not change much, indicating that the ion exchange of the present application can complete adsorption in a relatively short time.

[0080] By comparing Example 4 and Example 9 and combining with Table 2, it can be seen that the change in Example 9 is less than that in Example 4, and the purity and extraction amount of Example 9 are greater than the extraction amount and purity of Example 4, indicating that after the addition of the active stabilizer in the present application, the exchange of potassium ions and sodium ions by the cation exchange resin can be promoted; at the same time, the exchange of chloride ions by the chlorine-type anion exchange resin is promoted, and the exchange rate is accelerated and the stability of adsorption is ensured, so that the purity and extraction amount of potassium chloride and sodium chloride are higher.

[0081] By comparing Example 9 with Examples 14-16 and combining with Table 2, it can be seen that the change in Example 9 is less than the change in Examples 14-16, and the purity and extraction amount of Example 9 are greater than the extraction amount and purity of Examples 14-16, indicating that the activation stabilizer obtained by using the polyamide-modified hydrogenated castor oil derivative, potassium permonosulfate composite salt, methacryloylethyl sulfobetaine, sodium aminoalginate, sodium hexametaphosphate, and cetyl alcohol in the present application has better activation and stabilization effects, and can better promote the selective absorption of chloride ions, sodium ions and potassium ions by the ion exchange resin, thereby obtaining potassium chloride and sodium chloride with higher purity and extraction amount.

[0082] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A process for separating sodium and potassium salts from miscellaneous salts, characterized in that: Prepared by the following method: 1) Pretreatment: Filter the salt-containing wastewater through a 100-300 mesh filter, and then filter the obtained filtrate a through an MBR membrane to obtain a filtrate b; add an adsorbent to the filtrate b and stir evenly, adjust the pH value of the filtrate b to 9.5-11, then add soluble phosphate, mix evenly, settle, extract the supernatant, and obtain a pretreatment liquid; 2) Ion exchange: The pretreatment liquid is subjected to ion exchange treatment for 20-30 minutes to obtain ion exchange particles; 3) Ion dewashing: backwash, regenerate and clean the ion exchange particles to obtain salt solution and regenerated particle exchange resin; 4) Crystallization: Evaporate the salt solution and crystallize it, then dry the crystals to obtain sodium potassium salt.

2. A process for separating sodium and potassium salts from miscellaneous salts according to claim 1, characterized in that: The adsorbent is composed of the following raw materials in parts by weight: Activated carbon 10-20 parts Expanded graphite 1-3 parts 2-5 parts of magnesium silicate 1-3 parts of porous silica microspheres 0.5-3 parts of organic bentonite.

3. A process for separating sodium and potassium salts from miscellaneous salts according to claim 1, characterized in that: The dosage of the adsorbent is 1-5 g / L; the dosage of the soluble phosphate is 10-30 g / L, the stirring rate is 60-80 r / min, the stirring time is 20-30 min, and the sedimentation time is 2-3 h.

4. A process for separating sodium and potassium salts from miscellaneous salts according to claim 1, characterized in that: The specific steps of step 2) ion exchange are as follows: Adjust the pH value of the pretreatment liquid to 6-7, heat it to 38-45℃, and then add 150-210g / m 3 Cation exchange resin and 183-250g / m 3 The chloride type anion exchange resin is stirred at a rotation speed of 80-120 r / min for 20-30 min and filtered to obtain ion exchange particles.

5. A process for separating sodium and potassium salts from miscellaneous salts according to claim 4, characterized in that: The particle size of the cation exchange resin is 0.3-1.2 mm; the particle size of the chloride-type anion exchange resin is 0.4-0.9 mm.

6. A process for separating sodium and potassium salts from miscellaneous salts according to claim 4, characterized in that: Also includes adding 10-22g / m 3 The activated stabilizer is mixed evenly with the pretreatment liquid.

7. A process for separating sodium and potassium salts from miscellaneous salts according to claim 6, characterized in that: The activated stabilizer is composed of the following raw materials in parts by weight: Polyamide modified hydrogenated castor oil derivative 3-8 parts Potassium peroxymonosulfate complex salt 0.2-0.8 parts 1-3 parts of methacryloylethyl sulfobetaine 0.5-1.8 parts of amino sodium alginate Sodium hexametaphosphate 1-8 parts Cetyl alcohol 0.3-1 part.

8. A process for separating sodium and potassium salts from miscellaneous salts according to claim 1, characterized in that: In the step 3), the ion removal is specifically as follows: The ion exchange particles are backwashed, and then completely immersed in an alkaline regeneration agent, filtered, and the obtained solid is then immersed in an acidic regeneration agent, filtered, and the solid is dried to obtain a salt solution and a regenerated particle size exchange resin.

9. A process for separating sodium and potassium salts from miscellaneous salts according to claim 8, characterized in that: The alkaline regeneration agent is composed of the following raw materials in weight percentage: 0.1-0.5% isothiazolinone, 0.2-0.5% hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 1-2% sodium chloride, 3-5% sodium hydroxide, 0.1-0.3% potassium permonosulfate complex salt, and the balance is water; the acidic regeneration agent is composed of 0.1-0.5% isothiazolinone, 0.2-0.5% hexadecanoylamidopropyl hydroxypropyl sulfobetaine, 3-5% hydrochloric acid, and the balance is water.

10. A process for separating sodium and potassium salts from miscellaneous salts according to claim 8, characterized in that: The step 4) further comprises dissolving the sodium potassium salt, and then sequentially performing freeze crystallization and centrifugation to obtain a mother liquor and potassium salt; and then evaporating the mother liquor and drying the obtained solid to obtain the sodium salt.

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