Method for preparing calcium lactate from corn soaking water

Abstract

The invention discloses a method for preparing calcium lactate from corn soaking water, and belongs to the technical field of corn deep processing. The method comprises the following steps: sedimentation, phytic acid adsorption, ceramic membrane filtration, first reverse osmosis membrane concentration, simulated moving bed chromatography separation of an organic phase and a salt phase, second reverse osmosis membrane concentration, simulated moving bed chromatography separation of a lactic acid phase and a protein phase, third reverse osmosis membrane concentration, thermal concentration, filtration, pH adjustment, cooling crystallization and calcium lactate precipitation. According to the method, the high-quality calcium lactate product can be prepared from the corn soaking water, and the content of calcium lactate in the product is greater than or equal to 95wt%.

Description

Technical Field

[0001] The invention relates to the technical field of corn deep processing, and in particular to a method for preparing calcium lactate by using corn soaking water. Background Art

[0002] Corn soaking water is an organic wastewater produced in the process of producing corn starch, which contains multiple components such as protein, sugar, organic acid, etc. If it is discharged directly, not only will the nutrients in it not be fully utilized, but it will also cause environmental pollution. At present, the main use of corn soaking water is as a nutrient source for the fermentation industry, and its application range is relatively single. In addition, since the components in corn soaking water are very complex and the physical and chemical properties of different components vary greatly, it is difficult to extract multiple components simultaneously and efficiently during the extraction process, resulting in a low comprehensive utilization rate of corn soaking water.

[0003] Calcium lactate is a good calcium source and is widely used in the food and pharmaceutical industries. Currently, the production of calcium lactate is one of the series of derivatives produced by lactic acid. In the prior art, the preparation of calcium lactate with corn soaking water has the problems of low extraction efficiency, great separation difficulty, and low purity of the prepared calcium lactate. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for preparing calcium lactate using corn soaking water, so as to overcome the problems in the prior art that the comprehensive utilization rate of corn soaking water is low and the purity of calcium lactate prepared therefrom is not high.

[0005] In a first aspect, the present invention provides a method for preparing calcium lactate using corn soaking water, comprising the following steps:

[0006] (1) Sedimentation: Soak the corn in water and let it settle for 3 to 6 hours, then take the supernatant;

[0007] (2) Phytic acid adsorption: the supernatant is passed into an anion exchange resin for phytic acid adsorption, and the effluent is collected; after the adsorption is completed, the resin is rinsed with pure water, and the rinse is collected and merged into the effluent;

[0008] (3) Ceramic membrane filtration: filtering the combined effluent through a ceramic membrane and collecting the ceramic membrane filtrate;

[0009] (4) First reverse osmosis membrane concentration: the ceramic membrane filtrate is concentrated to a solid content of 20 to 40 wt % using a reverse osmosis membrane, and the concentrated liquid is collected;

[0010] (5) separating the organic phase and the salt phase by simulated moving bed chromatography: taking the concentrated solution, separating the organic phase and the salt phase of the concentrated solution by simulated moving bed chromatography separation technology, and collecting the organic phase and the salt phase respectively;

[0011] (6) Second reverse osmosis membrane concentration: the organic phase is concentrated to a solid content of 25 to 45 wt % using a reverse osmosis membrane, and the organic phase concentrate is collected;

[0012] (7) separating the lactic acid phase and the protein phase by simulated moving bed chromatography: taking the organic phase concentrate, separating the lactic acid phase and the protein phase by simulated moving bed chromatography, and collecting the lactic acid phase and the protein phase separately;

[0013] (8) Third reverse osmosis membrane concentration: the lactic acid phase is concentrated to a solid content of 20-30 wt % using a reverse osmosis membrane, and the lactic acid phase concentrate is collected; the lactic acid phase concentrate is thermally concentrated to a solid content of 60-75 wt % at 90° C. to 100° C., filtered, and the filtrate is collected;

[0014] (9) Adjusting pH: adding calcium oxide or calcium hydroxide to the filtrate at 90° C. to 100° C. to adjust the pH value of the filtrate to 6 to 8, stirring the reaction for at least 1 hour, cooling the mixture to 35° C. to 50° C. and filtering the mixture, drying the filter cake obtained by filtration to obtain a calcium lactate product.

[0015] Compared with the prior art, the present invention first performs ceramic membrane filtration and then performs the first reverse osmosis membrane concentration, which is equivalent to using a ceramic membrane for pretreatment first, which can not only fully remove impurities in the solution, but also avoid fouling of the reverse osmosis membrane during the first reverse osmosis membrane concentration. After the first reverse osmosis membrane concentration, the concentrate contains a suitable solid content, which can improve the separation efficiency of the subsequent simulated moving bed chromatography for the organic phase and the salt phase in the concentrate and reduce the operating cost. Then, the obtained organic phase is subjected to a second reverse osmosis membrane concentration, concentrated to a suitable solid content, and the separation efficiency of the simulated moving bed chromatography for the lactic acid phase and the protein phase is improved. Due to the limited concentration capacity of the reverse osmosis membrane, the present invention first performs a third reverse osmosis membrane concentration on the lactic acid phase after separating the lactic acid phase, and then performs thermal concentration. By using two different concentration methods for concentration, the solid content in the lactic acid phase can reach 60-75wt%, further improving the concentration of lactic acid in the lactic acid phase. Further, the above-obtained hot concentrated liquid is filtered to remove solid impurities in the filtrate. Finally, the filtrate is reacted with calcium oxide or calcium hydroxide at a temperature of 90°C to 100°C, and the pH value at the end of the reaction is controlled to be 6 to 8. After the reaction is completed, the temperature is lowered to 35°C to 50°C for crystallization to obtain a calcium lactate product. Among them, the high temperature of 90°C to 100°C helps to ensure the fluidity of the material, dissolve calcium oxide or calcium hydroxide, and promote the chemical reaction between lactic acid and calcium ions. At the same time, the pH value range of 6 to 8 can not only ensure the effective formation of calcium lactate, but also avoid unnecessary side reactions. Cooling to 35°C to 50°C can promote further precipitation and crystallization of calcium lactate, while increasing the output of calcium lactate products and ensuring a high content of calcium lactate in the product.

[0016] The invention can prepare a high-quality calcium lactate product from the corn soaking water through the following preparation processes: sedimentation of corn soaking water, phytic acid adsorption, ceramic membrane filtration, first reverse osmosis membrane concentration, simulated moving bed chromatography separation of an organic phase and a salt phase, second reverse osmosis membrane concentration of the organic phase, simulated moving bed chromatography separation of a lactic acid phase and a protein phase, third reverse osmosis membrane concentration of the lactic acid phase, thermal concentration, filtration, and the use of calcium oxide or calcium hydroxide at high temperature to adjust the pH of the filtrate, stirring the reaction, and cooling and crystallizing. The calcium lactate content in the product is ≥95wt%.

[0017] Furthermore, in step (2), based on the volume of the anion exchange resin, the sample loading flow rate of the supernatant is 1 to 4 BV / h, and the sample loading amount is 7 to 12 BV of the resin volume; the sample loading flow rate of pure water is 2 to 4 BV / h, and the sample loading amount is 1.5 to 3 BV of the resin volume.

[0018] The above technical scheme further limits the loading flow rate and loading amount of the supernatant and pure water when phytic acid is adsorbed on the supernatant. Under the above conditions, the phytic acid in the supernatant can be fully adsorbed on the anion exchange resin, and the pure water rinse can further rinse off the residual protein and lactic acid on the anion exchange resin, thereby improving the protein and lactic acid yields and better restoring the exchange capacity of the resin.

[0019] Furthermore, step (2) further comprises: after the rinsing is completed, using 8-15 wt% potassium chloride solution to parse the resin, collecting the parsed liquid, concentrating it, and obtaining a potassium phytate product;

[0020] Based on the volume of the anion exchange resin, the loading flow rate of the potassium chloride solution is 1 to 2 BV / h, and the loading amount is 2 to 3 BV of the resin volume.

[0021] The above technical solution limits the use of potassium chloride solution to analyze the resin and concentrate the analyzed solution to obtain the potassium phytate product, and further limits the loading flow rate and loading amount of the potassium chloride solution. Under the above conditions, the potassium chloride solution can fully analyze the phytic acid adsorbed on the anion exchange resin to obtain the potassium phytate product, thereby improving the comprehensive utilization rate of the product.

[0022] Furthermore, in step (3), the pressure is controlled to be 0.3-0.6 MPa during ceramic membrane filtration, and the pore size of the ceramic membrane is 5-50 nm.

[0023] The above technical solution further limits the pressure and pore size during ceramic membrane filtration. Under the above conditions, insoluble impurities in the effluent can be fully removed, while avoiding fouling of the reverse osmosis membrane during subsequent reverse osmosis membrane concentration.

[0024] Furthermore, during the first reverse osmosis membrane concentration in step (4), the operating temperature is 40-60° C. and the membrane pressure is 3.0-6.0 MPa.

[0025] The above technical scheme further limits the operating temperature and membrane pressure of the first reverse osmosis membrane concentration, which can effectively concentrate the ceramic membrane filtrate, increase the concentration of the solution, reduce the subsequent processing volume of simulated moving bed chromatography separation technology, and improve the separation efficiency of the organic phase and the salt phase.

[0026] Furthermore, in step (5), the stationary phase in the simulated moving bed chromatography separation technology is a homogeneous gel cationic resin with an average particle size of 220 to 320 um, and the mobile phase is water.

[0027] The above technical solution defines the specific types of stationary phase and mobile phase in the simulated moving bed chromatography separation technology, and the stationary phase and mobile phase can fully separate the organic phase and the salt phase in the concentrated solution.

[0028] Further, the method further comprises: concentrating the salt phase obtained in step (5) using a nanofiltration membrane with a pore size of 200 to 400 Da to 1 / 8 to 1 / 4 of the original volume, and using the obtained permeate to prepare a potassium chloride solution; or,

[0029] The protein phase in step (7) is concentrated to a solid content of 40 to 50 wt% by reverse osmosis membrane, and the obtained protein phase concentrate is dried to obtain a protein product; the operating temperature of the reverse osmosis membrane during concentration is 40 to 60° C., and the membrane pressure is 4.0 to 6.0 MPa.

[0030] The above technical solution defines a method for treating the salt phase separated by simulated moving bed chromatography separation technology. After being concentrated by a nanofiltration membrane with a specific pore size, the permeate obtained contains more than 80% potassium chloride and can be used for the preparation of the potassium chloride solution in step (2).

[0031] The above technical scheme also defines a method for processing the protein phase separated by simulated moving bed chromatography separation technology. After the protein phase is concentrated and dried by a reverse osmosis membrane, the protein content in the obtained protein product is ≥70wt%, further improving the comprehensive utilization rate of the product.

[0032] Furthermore, during the second reverse osmosis membrane concentration in step (6), the operating temperature is 40-60° C. and the membrane pressure is 4.0-6.0 MPa.

[0033] The above technical scheme further limits the operating temperature and membrane pressure of the second reverse osmosis membrane concentration, which can effectively concentrate the organic phase, increase the concentration, reduce the processing volume of the subsequent separation of the organic phase using simulated moving bed chromatography separation technology, and improve the separation efficiency of the lactic acid phase and the protein phase in the organic phase.

[0034] Furthermore, in step (7), the stationary phase in the simulated moving bed chromatography separation technology is a homogeneous gel-type styrene resin with an average particle size of 320 to 420 μm, and the mobile phase is water.

[0035] The above technical solution further defines the specific types of the stationary phase and the mobile phase in the simulated moving bed chromatography separation technology, and can fully separate the lactic acid phase and the protein phase in the organic phase.

[0036] Furthermore, during the third reverse osmosis membrane concentration in step (8), the operating temperature is 45-55° C. and the membrane pressure is 4.5-6.0 MPa.

[0037] The above technical solution further defines the operating temperature and membrane pressure of the third reverse osmosis membrane concentration, which can preliminarily concentrate the lactic acid phase and increase the concentration of lactic acid. DETAILED DESCRIPTION

[0038] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] In a first aspect, an embodiment of the present invention provides a method for preparing calcium lactate using corn soaking water, comprising the following steps:

[0040] S1. Sedimentation: Soak the corn in water and let it settle for 3 to 6 hours, then take the supernatant.

[0041] The precipitate obtained after the corn soaking water is precipitated in the above step contains a large amount of corn starch, which can be used as a feed additive.

[0042] S2. Phytic acid adsorption: the above supernatant is passed through an anion exchange resin for phytic acid adsorption, and the effluent is collected; after the adsorption is completed, the resin is rinsed with pure water, and the rinse is collected and merged into the effluent.

[0043] The anion exchange resin can be specifically selected as Hebei Lijiang 201×7 resin, Xi'an Lanxiao LX-360 resin or Purolite A600MB resin. Based on the volume of the anion exchange resin, the sample loading flow rate of the supernatant is 1 to 4 BV / h, and the sample loading amount is 7 to 12 BV of the resin volume; the sample loading flow rate of pure water is 2 to 4 BV / h, and the sample loading amount is 1.5 to 3 BV of the resin volume.

[0044] For example, the loading flow rate of the supernatant can be 1BV / h, 2BV / h, 3BV / h or 4BV / h; the loading amount can be 7BV, 8BV, 9BV, 10BV, 11BV or 12BV of the resin volume, preferably 8-10BV.

[0045] The loading flow rate of pure water can be 2BV / h, 3BV / h or 4BV / h; the loading volume can be 1.5BV, 2BV, 2.5BV or 3BV of the resin volume.

[0046] In the above steps, the supernatant flows into the anion exchange resin, and the phytic acid in the supernatant is adsorbed on the anion exchange resin, thereby achieving the purpose of adsorbing the phytic acid in the supernatant. Then, the resin is rinsed with pure water to reduce the residue of protein and lactic acid on the anion exchange resin, improve the protein and lactic acid yields in the subsequent steps, and better restore the exchange capacity of the resin. In addition, the content of potassium phytate in the potassium phytate product can also be increased by rinsing the resin with pure water.

[0047] Optionally, the above steps further include: after the rinsing is completed, using 8-15wt% potassium chloride solution to resolve the resin, collecting the resolved solution, and concentrating it to obtain a potassium phytate product. For example, the potassium chloride content in the potassium chloride solution can be 8wt%, 10wt%, 12wt% or 15wt%.

[0048] Based on the volume of the anion exchange resin, the loading flow rate of the potassium chloride solution is 1 to 2 BV / h, and the loading amount is 2 to 3 BV of the resin volume. For example, the loading flow rate can be 1 BV / h, 1.5 BV / h or 2 BV / h; the loading amount can be 2 BV, 2.5 BV or 3 BV of the resin volume.

[0049] In the above step, 8-15 wt % potassium chloride solution is used to decompose the anion exchange resin, so that the phytic acid adsorbed on the resin can be fully decomposed and potassium phytate is formed in the decomposition solution.

[0050] For example, during concentration, the collected analytical solution can be concentrated to 1 / 6 to 1 / 4 of the original volume to obtain a potassium phytate product. The potassium phytate product can be used as a raw material for producing inositol, preparing high value-added products, and improving the comprehensive utilization rate of corn soaking water.

[0051] S3, ceramic membrane filtration: The combined effluent is filtered through a ceramic membrane, and the ceramic membrane filtrate is collected. The pressure is controlled to be 0.3-0.6MPa during the ceramic membrane filtration, and the pore size of the ceramic membrane is 5-50nm. For example, the pressure can be controlled to be 0.3MPa, 0.4MPa, 0.5MPa or 0.6MPa; the pore size of the ceramic membrane can be 5nm, 10nm, 20nm, 30nm, 40nm or 50nm, preferably 10-30nm.

[0052] The above step uses a ceramic membrane to filter the effluent after phytic acid adsorption, and the obtained ceramic membrane filtrate removes insoluble impurities, which is equivalent to the pretreatment of the subsequent reverse osmosis membrane concentration step, reducing the fouling of the reverse osmosis membrane by the solution. The retentate obtained after the ceramic membrane filtration can be combined with the precipitation in step S1 for further utilization.

[0053] S4, first reverse osmosis membrane concentration: the ceramic membrane filtrate is concentrated by reverse osmosis membrane to a solid content of 20-40 wt%, and the concentrated liquid is collected. For example, the solid content may be 20 wt%, 30 wt% or 40 wt%.

[0054] The operating temperature during the first reverse osmosis membrane concentration is 40-60°C, and the membrane pressure is 3.0-6.0 MPa. For example, the operating temperature may be 40°C, 50°C or 60°C; and the membrane pressure may be 3.0 MPa, 4.0 MPa, 5.0 MPa or 6.0 MPa.

[0055] The above steps use a reverse osmosis membrane to concentrate the ceramic membrane filtrate, and the obtained concentrated solution has a higher concentration, which is convenient for subsequent separation. The permeate concentrated by the reverse osmosis membrane is composed of water and can be used for simulated moving bed chromatography separation in the subsequent steps.

[0056] S5. Separating the organic phase and the salt phase by simulated moving bed chromatography: taking the above concentrate, separating the organic phase and the salt phase of the concentrate by simulated moving bed chromatography separation technology, and collecting the organic phase and the salt phase separately.

[0057] The stationary phase in the simulated moving bed chromatography separation technology is a homogeneous gel cationic resin with an average particle size of 220 to 320 um, and the mobile phase is water. For example, the homogeneous gel cationic resin can be selected from S1850 K type resin of Lanxiao Technology; the average particle size of the resin can be 220 um, 240 um, 260 um, 280 um, 300 um or 320 um, preferably 240 to 300 um.

[0058] For example, the specific process of separating the organic phase and the salt phase using simulated moving bed chromatography can be referred to as follows:

[0059] The simulated moving bed separation system is a series of six chromatographic columns connected end to end. The separation process includes a circulation flushing (Va step), a water flushing (Vb step), a water analysis (Vc step) and a feeding (Vd step) process, wherein the water analysis and the feeding are carried out simultaneously, and inorganic salts are enriched in the water flushing and feeding processes, and the organic phase is recovered in the water analysis process. In one circulation process, the flushing amount of the circulating liquid is 30-32 v / v% of the volume of the single column chromatographic column, the water flushing amount is 13-15 v / v% of the volume of the single column chromatographic column, the water analysis amount is 25-30 v / v% of the volume of the single column chromatographic column, and the feeding amount of the first reverse osmosis membrane concentrate is 12-14 v / v% of the volume of the single column chromatographic column. The flow rates of the Va step, the Vb step, and the Vc step are all 1.5-2.5 BV / h of the volume of the single column resin, and the flow rate of the Vd step is 0.6-1.4 BV / h of the volume of the single column resin, and then switch to the next circulation.

[0060] Optionally, the salt phase obtained in the above step is concentrated by a nanofiltration membrane with a pore size of 200 to 400 Da to 1 / 8 to 1 / 4 of the original volume, and the obtained permeate is used to prepare the potassium chloride solution. After the salt phase is concentrated by the nanofiltration membrane, the obtained permeate contains more than 80% potassium chloride, which can be used for the preparation of the potassium chloride solution in step S2.

[0061] S6, second reverse osmosis membrane concentration: the organic phase is concentrated by reverse osmosis membrane to a solid content of 25-45wt%, and the organic phase concentrate is collected. For example, the solid content can be 25wt%, 30wt%, 35wt%, 40wt% or 45wt%.

[0062] The operating temperature of the reverse osmosis membrane concentration is 40-60°C, and the membrane pressure is 4.0-6.0 MPa. For example, the operating temperature can be 40°C, 50°C or 60°C; the membrane pressure can be 4.0 MPa, 5.0 MPa or 6.0 MPa.

[0063] After the organic phase is concentrated in the above steps, the concentrations of lactic acid and protein in the concentrated solution are increased, which facilitates the subsequent separation of the lactic acid phase and the protein phase. The permeate concentrated by the reverse osmosis membrane is water and can be used to simulate moving bed chromatography separation.

[0064] S7. Separating the lactic acid phase and the protein phase by simulated moving bed chromatography: taking the above organic phase concentrate, separating the lactic acid phase and the protein phase by simulated moving bed chromatography separation technology, and collecting the lactic acid phase and the protein phase separately.

[0065] The stationary phase in the simulated moving bed chromatography separation technology is a homogeneous gel-type styrene resin with an average particle size of 320 to 420 um, and the mobile phase is water. For example, the homogeneous gel-type styrene resin can be selected from S4850 resin of Lanxiao Technology; the average particle size of the resin can be 320 um, 340 um, 360 um, 380 um, 400 um or 420 um, preferably 340 to 380 um.

[0066] For example, the specific process of separating the organic phase and the salt phase using simulated moving bed chromatography can be referred to as follows:

[0067] The simulated moving bed separation system is composed of eight chromatographic columns connected in series, and connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step). Water analysis and feeding are carried out simultaneously. Lactic acid is enriched in the water flushing process and the feeding process, and protein is recovered in the water analysis process. The flushing volume of the circulating liquid is 38-40v / v% of the volume of the single column chromatographic column, the water flushing volume is 15-17v / v% of the volume of the single column chromatographic column, the water analysis volume is 20-22v / v% of the volume of the single column chromatographic column, and the feeding volume of the organic phase concentrate is 10-12v / v% of the volume of the single column chromatographic column. The flow rates of the Va step, Vb step, and Vc step are all 1.0-1.5BV / h of the volume of the single column resin, and the flow rate of the Vd step is 0.4-0.9BV / h of the volume of the single column resin, and then switch to the next cycle.

[0068] Optionally, the protein phase obtained in the above step is concentrated to a solid content of 40-50wt% by reverse osmosis membrane, and then the obtained protein phase concentrate is dried to obtain a protein product. The operating temperature of the reverse osmosis membrane during concentration is 40-60°C, and the membrane pressure is 4.0-6.0Mpa. For example, the operating temperature can be 40°C, 50°C or 60°C; the membrane pressure can be 4.0Mpa, 5.0Mpa or 6.0Mpa.

[0069] After the protein phase is concentrated and dried, a protein product with a protein content of ≥70wt% can be obtained, thereby improving the comprehensive utilization rate of corn soaking water.

[0070] S8, third reverse osmosis membrane concentration: the lactic acid phase is concentrated by reverse osmosis membrane to a solid content of 20-30 wt%, and the lactic acid phase concentrate is collected. For example, the solid content may be 20 wt%, 25 wt% or 30 wt%.

[0071] The lactic acid phase concentrate is heat concentrated at 90°C to 100°C to a solid content of 60 to 75 wt%, filtered, and the filtrate is collected. For example, the temperature may be 90°C, 95°C, or 100°C; the solid content may be 60 wt%, 65 wt%, 70 wt%, or 75 wt%.

[0072] In the above steps, the reverse osmosis membrane is concentrated at an operating temperature of 45-55°C and a membrane pressure of 4.5-6.0 MPa. After the hot concentration is completed, hot filtration is required, and the filtration pore size can be 300-400 mesh. For example, the operating temperature can be 45°C, 50°C or 55°C; the membrane pressure can be 4.5 MPa, 5.0 MPa, 5.5 MPa or 6.0 MPa.

[0073] In the above step, after the lactic acid phase is concentrated to a solid content of 20-30 wt% by using a reverse osmosis membrane, further heat concentration is performed to make the solid content in the concentrated solution reach 60-75 wt%, which effectively increases the concentration of lactic acid in the lactic acid phase. High-concentration lactic acid is conducive to fully reacting with calcium oxide or calcium hydroxide to obtain calcium lactate in the subsequent step. In addition, the hot concentrated solution is filtered to further remove solid impurities in the concentrated solution.

[0074] In addition, the permeate obtained by the third reverse osmosis membrane concentration is water, which can be used for simulated moving bed chromatography separation. The filter cake obtained after filtration can be used as a protein feed additive after drying.

[0075] S9, adjusting pH: adding calcium oxide or calcium hydroxide to the filtrate at 90°C to 100°C to adjust the pH value of the filtrate to 6-8, stirring the reaction for at least 1 hour, cooling to 35°C to 50°C for filtration, and drying the filter cake obtained by filtration to obtain a calcium lactate product. The filtration pore size can be 300-400. For example, the temperature can be reduced to 35°C, 40°C, 45°C or 50°C.

[0076] The high temperature of 90°C to 100°C in the above steps can ensure the fluidity of the material, further dissolve calcium oxide or calcium hydroxide, and synergize with sufficient stirring for at least 1h to promote the chemical reaction between lactic acid and calcium ions, and convert the lactic acid reaction into calcium lactate. The pH value of the reaction end point is controlled to be 6 to 8, while ensuring the effective formation of calcium lactate, avoiding unnecessary side reactions. After the reaction is completed, the temperature is lowered to 35°C to 50°C, at which the solubility of calcium lactate is low, prompting calcium lactate to crystallize out of the solution. After filtration, the solid filter cake obtained is dried to obtain a calcium lactate product, wherein the content of calcium lactate is ≥95wt%. The filtered filtrate can be merged into the concentrated solution obtained in step S4 for further use.

[0077] It should be understood that the raw materials used in the following examples are all commercially available raw materials unless otherwise specified.

[0078] Example 1

[0079] This embodiment provides a method for preparing calcium lactate using corn soaking water, comprising the following steps:

[0080] S1. Sedimentation: Soak the corn in water and let it settle for 4 hours, then take the supernatant.

[0081] S2. Phytic acid adsorption: the above supernatant is flowed into Hebei Lijiang 201×7 anion exchange resin for phytic acid adsorption, and the effluent is collected; after the adsorption is completed, the resin is rinsed with pure water, and the rinse liquid is collected and merged into the effluent.

[0082] Among them, based on the volume of the anion exchange resin, the sample loading flow rate of the supernatant is 2BV / h, and the sample loading amount is 10BV of the resin volume; the sample loading flow rate of pure water is 3BV / h, and the sample loading amount is 2BV of the resin volume.

[0083] S3, ceramic membrane filtration: the combined effluent is filtered through a ceramic membrane, and the filtrate of the ceramic membrane is collected. The pressure during the ceramic membrane filtration is controlled to be 0.4 MPa, and the pore size of the ceramic membrane is 20 nm.

[0084] S4, first reverse osmosis membrane concentration: the ceramic membrane filtrate is concentrated to a solid content of 30 wt% by reverse osmosis membrane, and the concentrated liquid is collected. The first reverse osmosis membrane concentration is performed at an operating temperature of 50°C and a membrane pressure of 4.0 MPa.

[0085] S5. Separation of organic phase and salt phase by simulated moving bed chromatography: Take the above concentrate, separate the organic phase and salt phase of the concentrate by simulated moving bed chromatography, and collect the organic phase and salt phase respectively. The stationary phase in the simulated moving bed chromatography separation technology is S1850 K type resin of Lanxiao Technology with an average particle size of 270um, and the mobile phase is water.

[0086] Wherein, the simulated moving bed separation system is six chromatographic columns in series, and is connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step) process, wherein water analysis and feeding are carried out simultaneously, inorganic salts are enriched in water flushing and feeding process, and organic phase is recovered in water analysis process simultaneously. In one circulation process, the flushing amount of the circulating liquid is 30v / v% of the volume of the single column chromatographic column, the water flushing amount is 14v / v% of the volume of the single column chromatographic column, the water analysis amount is 27v / v% of the volume of the single column chromatographic column, and the feed amount of the first reverse osmosis membrane concentrate is 13v / v% of the volume of the single column chromatographic column. The flow rates of Va step, Vb step and Vc step are 2BV / h of the volume of the single column resin, and the flow rate of Vd step is 1BV / h of the volume of the single column resin, and then switch to the next circulation.

[0087] S6, second reverse osmosis membrane concentration: the organic phase is concentrated to a solid content of 35 wt% by using a reverse osmosis membrane, and the organic phase concentrate is collected. The reverse osmosis membrane concentration is operated at a temperature of 50°C and a membrane pressure of 5.0 MPa.

[0088] S7, simulated moving bed chromatography separation of lactic acid phase and protein phase: take the above organic phase concentrate, use simulated moving bed chromatography separation technology to separate lactic acid phase and protein phase, and collect lactic acid phase and protein phase respectively. The stationary phase in the simulated moving bed chromatography separation technology is S4850 resin of Lanxiao Technology with an average particle size of 370um, and the mobile phase is water.

[0089] The simulated moving bed separation system is composed of eight chromatographic columns connected in series, and connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step) processes. Water analysis and feeding are carried out simultaneously. Lactic acid is enriched in the water flushing process and the feeding process, and protein is recovered in the water analysis process. The circulating liquid flushing volume is 40v / v% of the volume of the single column chromatographic column, the water flushing volume is 16v / v% of the volume of the single column chromatographic column, the water analysis volume is 20v / v% of the volume of the single column chromatographic column, and the feeding volume of the organic phase concentrate is 10v / v% of the volume of the single column chromatographic column. The flow rates of Va step, Vb step and Vc step are all 1.2BV / h of the volume of the single column resin, and the flow rate of Vd step is 0.6BV / h of the volume of the single column resin, and then switch to the next cycle.

[0090] S8. The third reverse osmosis membrane concentration: the lactic acid phase is concentrated to a solid content of 25 wt % by using a reverse osmosis membrane, and the lactic acid phase concentrate is collected. The reverse osmosis membrane is operated at a temperature of 50° C. and a membrane pressure of 5.0 MPa during the concentration.

[0091] The lactic acid phase concentrate was heat concentrated at 100° C. to a solid content of 65 wt %, and filtered while hot to collect the filtrate, with a filtration pore size of 400 meshes.

[0092] S9, adjusting pH: adding calcium oxide to the above filtrate at 95°C to adjust the pH value of the filtrate to 7, stirring and reacting for 1.5 hours, cooling to 40°C for filtration, and drying the filter cake obtained by filtration to obtain a calcium lactate product with a filtration pore size of 400 mesh.

[0093] Example 2

[0094] This embodiment provides a method for preparing calcium lactate using corn soaking water, comprising the following steps:

[0095] S1. Sedimentation: Soak the corn in water and let it settle for 3 hours, then take the supernatant.

[0096] S2. Phytic acid adsorption: the supernatant is flowed into Xi'an Lanxiao LX-360 anion exchange resin for phytic acid adsorption, and the effluent is collected; after the adsorption is completed, the resin is rinsed with pure water, the rinse liquid is collected and merged with the effluent, and the resin is analyzed with 8wt% potassium chloride solution, the analyzed liquid is collected and concentrated to 1 / 5 of the original volume to obtain a potassium phytate product.

[0097] Among them, based on the volume of the anion exchange resin, the loading flow rate of the supernatant is 1BV / h, and the loading amount is 7BV of the resin volume; the loading flow rate of pure water is 2BV / h, and the loading amount is 1.5BV of the resin volume; the loading flow rate of potassium chloride solution is 1BV / h, and the loading amount is 2BV of the resin volume.

[0098] S3, ceramic membrane filtration: the combined effluent is filtered through a ceramic membrane, and the filtrate of the ceramic membrane is collected. The pressure during the ceramic membrane filtration is controlled to be 0.3 MPa, and the pore size of the ceramic membrane is 5 nm.

[0099] S4, first reverse osmosis membrane concentration: the ceramic membrane filtrate is concentrated to a solid content of 20wt% by reverse osmosis membrane, and the concentrated liquid is collected. The first reverse osmosis membrane concentration is performed at an operating temperature of 40°C and a membrane pressure of 3.0Mpa.

[0100] S5. Separation of organic phase and salt phase by simulated moving bed chromatography: Take the above concentrate, separate the organic phase and salt phase of the concentrate by simulated moving bed chromatography, and collect the organic phase and salt phase respectively. The stationary phase in the simulated moving bed chromatography separation technology is S1850 K type resin of Lanxiao Technology with an average particle size of 220um, and the mobile phase is water.

[0101] Wherein, the simulated moving bed separation system is six chromatographic columns in series, and is connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step) process, wherein water analysis and feeding are carried out simultaneously, inorganic salts are enriched in water flushing and feeding process, and organic phase is recovered in water analysis process simultaneously. In one circulation process, the flushing amount of the circulating liquid is 30v / v% of the volume of the single column chromatographic column, the water flushing amount is 14v / v% of the volume of the single column chromatographic column, the water analysis amount is 27v / v% of the volume of the single column chromatographic column, and the feed amount of the first reverse osmosis membrane concentrate is 13v / v% of the volume of the single column chromatographic column. The flow rates of Va step, Vb step and Vc step are 2BV / h of the volume of the single column resin, and the flow rate of Vd step is 1BV / h of the volume of the single column resin, and then switch to the next circulation.

[0102] The salt phase is concentrated using a nanofiltration membrane with a pore size of 200 Da to 1 / 8 of the original volume, and the obtained permeate is used to prepare the potassium chloride solution in step S2.

[0103] S6, second reverse osmosis membrane concentration: the organic phase is concentrated to a solid content of 25 wt% by using a reverse osmosis membrane, and the organic phase concentrate is collected. The reverse osmosis membrane concentration is operated at a temperature of 40°C and a membrane pressure of 4.0 MPa.

[0104] S7, simulated moving bed chromatography separation of lactic acid phase and protein phase: take the above organic phase concentrate, separate the lactic acid phase and protein phase by simulated moving bed chromatography separation technology, and collect the lactic acid phase and protein phase respectively. The stationary phase in the simulated moving bed chromatography separation technology is S4850 resin of Lanxiao Technology with an average particle size of 320um, and the mobile phase is water.

[0105] The simulated moving bed separation system is eight chromatographic columns connected in series, and connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step) processes. Water analysis and feeding are carried out simultaneously. Lactic acid is enriched in the water flushing process and the feeding process, and protein is recovered in the water analysis process. The circulating liquid flushing volume is 40v / v% of the volume of the single column chromatographic column, the water flushing volume is 16v / v% of the volume of the single column chromatographic column, the water analysis volume is 20v / v% of the volume of the single column chromatographic column, and the feed volume of the organic phase concentrate is 10v / v% of the volume of the single column chromatographic column. The flow rates of Va step, Vb step and Vc step are all 1.2BV / h of the volume of the single column resin, and the flow rate of Vd step is 0.6BV / h of the volume of the single column resin, and then switch to the next cycle.

[0106] After the protein phase is concentrated to a solid content of 40 wt% by reverse osmosis membrane, the obtained protein phase concentrated liquid is dried to obtain a protein product; the operating temperature of the reverse osmosis membrane during concentration is 40° C. and the membrane pressure is 4.0 MPa.

[0107] S8. The third reverse osmosis membrane concentration: the lactic acid phase is concentrated to a solid content of 20 wt % by using a reverse osmosis membrane, and the lactic acid phase concentrate is collected. The reverse osmosis membrane is operated at a temperature of 45° C. and a membrane pressure of 4.5 MPa during the concentration.

[0108] The lactic acid phase concentrate was heat concentrated at 90° C. to a solid content of 60 wt %, and filtered while hot to collect the filtrate, with a filter pore size of 400 meshes.

[0109] S9, adjusting pH: adding calcium oxide to the above filtrate at 90°C to adjust the pH value of the filtrate to 6, stirring and reacting for 1 hour, cooling to 35°C for filtration, and drying the filter cake obtained by filtration to obtain a calcium lactate product with a filtration pore size of 400 mesh.

[0110] Example 3

[0111] This embodiment provides a method for preparing calcium lactate using corn soaking water, comprising the following steps:

[0112] S1. Sedimentation: Soak the corn in water and let it settle for 6 hours, then take the supernatant.

[0113] S2. Phytic acid adsorption: the supernatant is passed through Purolite A600MB anion exchange resin for phytic acid adsorption, and the effluent is collected; after the adsorption is completed, the resin is rinsed with pure water, the rinse liquid is collected and merged with the effluent, the resin is analyzed with a 15wt% potassium chloride solution, the analyzed liquid is collected, and concentrated to 1 / 4 of the original volume to obtain a potassium phytate product.

[0114] Among them, based on the volume of the anion exchange resin, the loading flow rate of the supernatant is 4BV / h, and the loading amount is 12BV of the resin volume; the loading flow rate of pure water is 4BV / h, and the loading amount is 3BV of the resin volume; the loading flow rate of potassium chloride solution is 2BV / h, and the loading amount is 3BV of the resin volume.

[0115] S3, ceramic membrane filtration: the combined effluent is filtered through a ceramic membrane, and the filtrate of the ceramic membrane is collected. The pressure during the ceramic membrane filtration is controlled to be 0.6 MPa, and the pore size of the ceramic membrane is 50 nm.

[0116] S4, first reverse osmosis membrane concentration: the ceramic membrane filtrate is concentrated to a solid content of 40 wt% by reverse osmosis membrane, and the concentrated liquid is collected. The first reverse osmosis membrane concentration is performed at an operating temperature of 60°C and a membrane pressure of 6.0 MPa.

[0117] S5. Separation of organic phase and salt phase by simulated moving bed chromatography: Take the above concentrate, separate the organic phase and salt phase of the concentrate by simulated moving bed chromatography, and collect the organic phase and salt phase respectively. The stationary phase in the simulated moving bed chromatography separation technology is S1850 K type resin of Lanxiao Technology with an average particle size of 320um, and the mobile phase is water.

[0118] Wherein, the simulated moving bed separation system is six chromatographic columns in series, and is connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step) process, wherein water analysis and feeding are carried out simultaneously, inorganic salts are enriched in water flushing and feeding process, and organic phase is recovered in water analysis process simultaneously. In one circulation process, the flushing amount of the circulating liquid is 30v / v% of the volume of the single column chromatographic column, the water flushing amount is 14v / v% of the volume of the single column chromatographic column, the water analysis amount is 27v / v% of the volume of the single column chromatographic column, and the feed amount of the first reverse osmosis membrane concentrate is 13v / v% of the volume of the single column chromatographic column. The flow rates of Va step, Vb step and Vc step are 2BV / h of the volume of the single column resin, and the flow rate of Vd step is 1BV / h of the volume of the single column resin, and then switch to the next circulation.

[0119] The salt phase is concentrated using a nanofiltration membrane with a pore size of 400 Da to 1 / 4 of the original volume, and the obtained permeate is used to prepare the potassium chloride solution in step S2.

[0120] S6, second reverse osmosis membrane concentration: the organic phase is concentrated to a solid content of 45 wt% by using a reverse osmosis membrane, and the organic phase concentrate is collected. The reverse osmosis membrane concentration is operated at a temperature of 60°C and a membrane pressure of 6.0 MPa.

[0121] S7, simulated moving bed chromatography separation of lactic acid phase and protein phase: take the above organic phase concentrate, use simulated moving bed chromatography separation technology to separate lactic acid phase and protein phase, and collect lactic acid phase and protein phase respectively. Among them, the stationary phase in the simulated moving bed chromatography separation technology is S4850 resin of Lanxiao Technology with an average particle size of 420um, and the mobile phase is water.

[0122] The simulated moving bed separation system is composed of eight chromatographic columns connected in series, and connected end to end. The separation process includes circulating flushing (Va step), water flushing (Vb step), water analysis (Vc step) and feeding (Vd step) processes. Water analysis and feeding are carried out simultaneously. Lactic acid is enriched in the water flushing process and the feeding process, and protein is recovered in the water analysis process. The circulating liquid flushing volume is 40v / v% of the volume of the single column chromatographic column, the water flushing volume is 16v / v% of the volume of the single column chromatographic column, the water analysis volume is 20v / v% of the volume of the single column chromatographic column, and the feeding volume of the organic phase concentrate is 10v / v% of the volume of the single column chromatographic column. The flow rates of Va step, Vb step and Vc step are all 1.2BV / h of the volume of the single column resin, and the flow rate of Vd step is 0.6BV / h of the volume of the single column resin, and then switch to the next cycle.

[0123] After the protein phase is concentrated to a solid content of 50 wt% by reverse osmosis membrane, the obtained protein phase concentrated liquid is dried to obtain a protein product; the operating temperature of the reverse osmosis membrane during concentration is 60° C. and the membrane pressure is 6.0 MPa.

[0124] S8. The third reverse osmosis membrane concentration: the lactic acid phase is concentrated to a solid content of 30 wt % by using a reverse osmosis membrane, and the lactic acid phase concentrate is collected. The reverse osmosis membrane is operated at a temperature of 55° C. and a membrane pressure of 6.0 MPa during the concentration.

[0125] The lactic acid phase concentrate was heat concentrated at 95° C. to a solid content of 75 wt %, and filtered while hot to collect the filtrate, with a filtration pore size of 400 meshes.

[0126] S9, adjusting pH: adding calcium hydroxide to the above filtrate at 100°C to adjust the pH value of the filtrate to 8, stirring the reaction for 1.5 hours, cooling to 50°C for filtration, and drying the filter cake obtained by filtration to obtain a calcium lactate product with a filtration pore size of 400 mesh.

[0127] Example 4

[0128] Calcium lactate was prepared using corn soaking water according to the method of Example 1, except that step S2 also included: after the resin was rinsed with pure water, the resin was analyzed using a 10wt% potassium chloride solution, the analyzed solution was collected and concentrated to 1 / 5 of the original volume to obtain a potassium phytate product; wherein, based on the volume of the anion exchange resin, the loading flow rate of the potassium chloride solution was 1.5BV / h, and the loading amount was 2.5BV of the resin volume.

[0129] Step S5 also includes: concentrating the salt phase obtained by simulated moving bed chromatography separation to 1 / 6 of the original volume using a nanofiltration membrane with a pore size of 300 Da, and the obtained permeate is used to prepare the potassium chloride solution in the above step S2.

[0130] Example 5

[0131] Calcium lactate was prepared using corn soaking water according to the method of Example 1, except that step S7 also included: concentrating the protein phase obtained by simulated moving bed chromatography to a solid content of 45wt% through a reverse osmosis membrane, and then drying the obtained protein phase concentrate to obtain a protein product; and the operating temperature of the reverse osmosis membrane during concentration was 50°C and the membrane pressure was 5.0Mpa.

[0132] Comparative Example 1

[0133] Calcium lactate was prepared using corn soaking water according to the method of Example 1, except that in step S5, simulated moving bed chromatography separation technology was not used, and ordinary D851 ion exchange resin was used instead of simulated moving bed chromatography to separate the organic phase and the salt phase.

[0134] Comparative Example 2

[0135] Calcium lactate was prepared using corn steep water according to the method of Example 1, except that in step S7, a nanofiltration membrane was used instead of simulated moving bed chromatography to separate the lactic acid phase and the protein phase, and the pore size of the nanofiltration membrane was 200 Da.

[0136] Comparative Example 3

[0137] Calcium lactate was prepared using corn soaking water according to the method of Example 1, except that in step S9, calcium oxide was added to the filtrate at room temperature to adjust the pH value of the filtrate to 7, and the mixture was stirred for 1.5 hours and then filtered. The filter cake obtained by filtration was dried to obtain a calcium lactate product with a filtration pore size of 400 mesh.

[0138] Comparative Example 4

[0139] Calcium lactate was prepared using corn soaking water according to the method of Example 1, except that in step S9, calcium oxide was added to adjust the pH value of the filtrate to 5.5.

[0140] Comparative Example 5

[0141] Calcium lactate was prepared using corn soaking water according to the method of Example 1, except that in step S9, calcium oxide was added to adjust the pH value of the filtrate to 8.5.

[0142] Test Case

[0143] The content of calcium lactate in the calcium lactate products prepared in the above Examples 1 to 5 and Comparative Examples 1 to 5 was detected, and the results are shown in Table 1.

[0144] Table 1

[0145]

[0146]

[0147] From the above results, it can be seen that in comparative example 1, after ordinary D851 ion exchange resin is used to replace simulated moving bed chromatography to separate the organic phase and the salt phase in step S5, the content of calcium lactate in the obtained calcium lactate product is significantly reduced, indicating that the simulated moving bed chromatography using a specific stationary phase and mobile phase can fully separate the organic phase and the salt phase. In comparative example 2, in step S7, a nanofiltration membrane with a pore size of 200Da is used to replace simulated moving bed chromatography to separate the lactic acid phase and the protein phase, and the content of calcium lactate in the obtained calcium lactate product is reduced, indicating that the simulated moving bed chromatography using a specific stationary phase and mobile phase can fully separate the lactic acid phase and the protein phase. In step S9 of Comparative Example 3, after calcium oxide is added to the filtrate at room temperature to adjust the pH value of the filtrate, the content of calcium lactate in the obtained calcium lactate product is reduced, indicating that the present invention adds calcium oxide or calcium hydroxide to adjust the pH value under the condition of 90°C to 100°C, wherein the high temperature of 90°C to 100°C helps to ensure the fluidity of the material, dissolve calcium oxide or calcium hydroxide, and promote the chemical reaction between lactic acid and calcium ions, thereby increasing the content of calcium lactate in the calcium lactate product. After the pH value of the filtrate is changed in Comparative Examples 4 and 5, the content of calcium lactate in the obtained calcium lactate product is reduced, indicating that the present invention controls the pH value of the filtrate to 6 to 8, and this specific range of pH values ​​can avoid unnecessary side reactions and ensure the effective formation of calcium lactate.

[0148] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing calcium lactate using corn soaking water, characterized in that: The following steps are involved: (1) Sedimentation: Soak the corn in water and let it settle for 3 to 6 hours, then take the supernatant; (2) Phytic acid adsorption: the supernatant is passed into an anion exchange resin for phytic acid adsorption, and the effluent is collected; after the adsorption is completed, the resin is rinsed with pure water, and the rinse is collected and merged into the effluent; (3) Ceramic membrane filtration: filtering the combined effluent through a ceramic membrane and collecting the ceramic membrane filtrate; (4) First reverse osmosis membrane concentration: the ceramic membrane filtrate is concentrated to a solid content of 20 to 40 wt % using a reverse osmosis membrane, and the concentrated liquid is collected; (5) separating the organic phase and the salt phase by simulated moving bed chromatography: taking the concentrated solution, separating the organic phase and the salt phase of the concentrated solution by simulated moving bed chromatography separation technology, and collecting the organic phase and the salt phase respectively; (6) Second reverse osmosis membrane concentration: the organic phase is concentrated to a solid content of 25 to 45 wt % using a reverse osmosis membrane, and the organic phase concentrate is collected; (7) separating the lactic acid phase and the protein phase by simulated moving bed chromatography: taking the organic phase concentrate, separating the lactic acid phase and the protein phase by simulated moving bed chromatography, and collecting the lactic acid phase and the protein phase separately; (8) Third reverse osmosis membrane concentration: the lactic acid phase is concentrated to a solid content of 20-30 wt % using a reverse osmosis membrane, and the lactic acid phase concentrate is collected; the lactic acid phase concentrate is thermally concentrated to a solid content of 60-75 wt % at 90° C. to 100° C., filtered, and the filtrate is collected; (9) Adjusting pH: adding calcium oxide or calcium hydroxide to the filtrate at 90° C. to 100° C. to adjust the pH value of the filtrate to 6 to 8, stirring the reaction for at least 1 hour, cooling the mixture to 35° C. to 50° C. and filtering the mixture, drying the filter cake obtained by filtration to obtain a calcium lactate product.

2. The method according to claim 1, characterized in that In step (2), based on the volume of the anion exchange resin, the sample loading flow rate of the supernatant is 1-4 BV / h, and the sample loading amount is 7-12 BV of the resin volume; the sample loading flow rate of pure water is 2-4 BV / h, and the sample loading amount is 1.5-3 BV of the resin volume.

3. The method according to claim 1, characterized in that Step (2) further comprises: after the rinsing is completed, using 8-15 wt % potassium chloride solution to parse the resin, collecting the parsed liquid, concentrating it, and obtaining a potassium phytate product; Based on the volume of the anion exchange resin, the loading flow rate of the potassium chloride solution is 1 to 2 BV / h, and the loading amount is 2 to 3 BV of the resin volume.

4. The method according to claim 1, characterized in that: In step (3), the pressure is controlled to be 0.3-0.6 MPa during ceramic membrane filtration, and the pore size of the ceramic membrane is 5-50 nm.

5. The method according to claim 1, characterized in that During the first reverse osmosis membrane concentration in step (4), the operating temperature is 40-60° C. and the membrane pressure is 3.0-6.0 MPa.

6. The method according to claim 1, characterized in that In step (5), the stationary phase of the simulated moving bed chromatography separation technology is a homogeneous gel cationic resin with an average particle size of 220 to 320 μm, and the mobile phase is water.

7. The method according to claim 3, characterized in that Also includes: The salt phase obtained in step (5) is concentrated using a nanofiltration membrane with a pore size of 200 to 400 Da to 1 / 8 to 1 / 4 of the original volume, and the obtained permeate is used to prepare a potassium chloride solution; or, The protein phase in step (7) is concentrated to a solid content of 40 to 50 wt% by reverse osmosis membrane, and then the obtained protein phase concentrate is dried to obtain a protein product; the operating temperature of the reverse osmosis membrane during concentration is 40 to 60° C., and the membrane pressure is 4.0 to 6.0 MPa.

8. The method according to claim 1, characterized in that During the second reverse osmosis membrane concentration in step (6), the operating temperature is 40-60° C. and the membrane pressure is 4.0-6.0 MPa.

9. The method according to claim 1, characterized in that: In step (7), the stationary phase of the simulated moving bed chromatography separation technology is a homogeneous gel-type styrene resin with an average particle size of 320 to 420 μm, and the mobile phase is water.

10. The method according to claim 1, characterized in that During the third reverse osmosis membrane concentration in step (8), the operating temperature is 45-55° C. and the membrane pressure is 4.5-6.0 MPa.

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