Process method for recovering monopotassium phosphate and inositol from monopotassium phosphate mother liquor and byproduct phytic acid desorption agent

Abstract

The invention relates to the technical field of corn soaking water treatment, in particular to a process method for recovering monopotassium phosphate and inositol from monopotassium phosphate mother liquor and producing a phytic acid resolving agent as a byproduct, which comprises the following steps: adjusting the pH value of the collected monopotassium phosphate mother liquor to be acidic, stirring, filtering, treating the collected filtrate by a hollow fiber membrane, and collecting the treated filtrate to obtain the phytic acid resolving agent. Treating the collected first permeate by a nanofiltration membrane, treating the collected second trapped fluid in a simulated moving bed chromatographic separation system, concentrating the collected inositol phase, decolorizing, filtering, cooling and crystallizing, filtering, leaching, drying and crushing to obtain an inositol product; and concentrating, cooling, filtering and drying the collected salt phase to obtain a monopotassium phosphate product. And treating the second permeate through a reverse osmosis membrane to obtain a concentrated solution containing potassium chloride. According to the process method, an inositol product with high yield and high purity can be obtained, and a monopotassium phosphate product can also be obtained; in addition, a phytic acid desorption agent can be produced as a byproduct, and the use of raw materials of the phytic acid desorption agent is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of corn soaking water treatment, in particular to a process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analyzing agent as a by-product. Background Art

[0002] Corn soaking water is a waste product produced during the wet production of corn starch, in which the phytic acid content is 1-2%. At present, a process for recovering phytic acid from corn soaking water, preparing potassium phytate, and then producing inositol and potassium dihydrogen phosphate through hydrolysis, separation, concentration, and crystallization has been reported. Compared with traditional potassium dihydrogen phosphate production processes such as neutralization method and double decomposition method, the production of potassium dihydrogen phosphate using corn soaking water as raw material not only avoids the environmental damage caused by the phosphate rock mining process, but also realizes the recycling of phosphorus resources in plants, which has obvious economic and social benefits.

[0003] In the existing process, potassium dihydrogen phosphate and inositol obtained after corn soaking water is treated are usually separated by simulated moving bed chromatography to obtain potassium dihydrogen phosphate solution and inositol solution. However, inositol and potassium dihydrogen phosphate are both soluble in water. In actual production, the obtained potassium dihydrogen phosphate solution is usually limited by the separation degree of chromatographic resins, process parameters and other conditions. A certain concentration of inositol is contained in the obtained potassium dihydrogen phosphate solution. In the process of potassium dihydrogen phosphate crystallization, inositol, pigments, proteins, calcium, magnesium, chloride ions and other substances are gradually enriched in the potassium dihydrogen phosphate mother liquor, and the final inositol concentration in the mother liquor can reach 25-45g / L. At present, the potassium dihydrogen phosphate crystallization mother liquor is mostly sold directly as liquid fertilizer, and the value of inositol therein is not fully utilized, resulting in a large loss.

[0004] At present, a patent discloses a process for recovering inositol from potassium dihydrogen phosphate mother liquor. Although the process can recover inositol from potassium dihydrogen phosphate mother liquor, the small molecule salt is not separated from inositol during the crystallization of the crude product, resulting in a low inositol yield and failure to fully recover the phosphate radical and potassium ion in the mother liquor. Therefore, in view of the above problems, it is necessary to develop a process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a byproduct. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the deficiencies in the prior art, a process method is provided for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid decomposing agent as a byproduct. The process method can obtain an inositol product with a high yield, and potassium dihydrogen phosphate can also be recovered, and a phytic acid decomposing agent byproduct can also be obtained, thereby increasing the economic benefits for the enterprise.

[0006] In order to solve the above technical problems, the technical solution of the present invention is:

[0007] A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a by-product, comprising the following steps:

[0008] (1) adding alkali or carbonate to the collected potassium dihydrogen phosphate mother liquor, stirring, adjusting the pH of the liquid to acidity, controlling the reaction temperature, and the liquid obtained after the reaction is completed is used for later use;

[0009] (2) taking the feed solution in step (1), filtering and collecting the filtrate for later use;

[0010] (3) taking the filtrate described in step (2), treating it through a hollow fiber membrane, and collecting a first retentate and a first permeate respectively;

[0011] (4) taking the first permeate in step (3), treating it with a nanofiltration membrane, and collecting a second retentate and a second permeate respectively;

[0012] (5) taking the second retentate in step (4), subjecting it to a simulated moving bed chromatography separation system, and collecting the inositol phase and the salt phase respectively;

[0013] (6) taking the inositol phase described in step (5), concentrating it, decolorizing it, filtering it, cooling and crystallizing the collected decolorized liquid, filtering it, eluting it, and drying and crushing the collected filter cake to obtain an inositol product; combining the collected filtrate with a potassium dihydrogen phosphate mother liquor;

[0014] (7) taking the salt phase described in step (5), concentrating, cooling, filtering, and collecting the filter cake to obtain a potassium dihydrogen phosphate product through drying, and collecting the filtrate as a liquid organic fertilizer component;

[0015] (8) The second permeate in step (4) is concentrated to obtain a concentrated solution containing potassium chloride as a phytic acid decomposing agent.

[0016] As an improved technical solution, the base in step (1) is potassium hydroxide, the carbonate is potassium carbonate or potassium bicarbonate, the reaction temperature is controlled at 35-55°C, and the pH of the feed solution is adjusted to 4.0-5.5.

[0017] As an improved technical solution, when hollow fiber membrane is used for treatment in step (3), the operating pressure is controlled at 0.4-0.6MPa, the operating temperature is 35-55°C, and the permeate is backflushed for 30-60s every 20-40min of operation, and the filtration is stopped when the filtration volume reaches 4-8% of the original volume; the material of the hollow fiber membrane is polyvinylidene fluoride, and the membrane model of the hollow fiber membrane is NF-40~50.

[0018] As an improved technical solution, in step (4), the first permeate is treated with a nanofiltration membrane with a molecular weight cutoff of 100-200 Da, and the solid content of the second retentate is 20-30 wt%.

[0019] As an improved technical solution, when the moving bed chromatography separation system is simulated in step (5), the operation cycle is 28-40min, the filler of the chromatography column is a potassium-type cationic resin with a particle size of 300±50μm, the height-to-diameter ratio of the chromatography column is 1-1.5:2.0, the feed amount is 15-17% of the volume of the single column chromatography column, the feed flow rate is 0.6-0.8BV / h, and the flow rates of circulation, water inlet top salt and water inlet top inositol are all 1.1-1.5BV / h.

[0020] As an improved technical solution, the salt phase in step (7) is subjected to heat concentration treatment to obtain a concentrated solution with a solid content of 50-60 wt %, which is then cooled to 20-30° C. and filtered.

[0021] After adopting the above technical solution, the beneficial effects of the present invention are:

[0022] The present invention adds alkali or carbonate to the collected potassium dihydrogen phosphate mother liquor to adjust the pH to acidity, and the feed liquid after stirring the reaction is filtered again, and the collected filtrate is processed by hollow fiber membrane, and the first retentate and the first permeate are collected respectively, and the first permeate is processed by nanofiltration membrane again, and the collected second retentate enters the simulated moving bed chromatographic separation system for processing, and the salt phase and inositol phase are collected respectively, wherein the collected inositol phase is concentrated and then decolorized and filtered, and the collected decolorized liquid is cooled and crystallized, filtered, rinsed, and the collected filter cake is dried and crushed to obtain an inositol product; the collected salt phase is concentrated, cooled, filtered, and the collected filter cake is dried to obtain a potassium dihydrogen phosphate product. The second permeate is processed by reverse osmosis membrane to obtain a concentrated solution containing potassium chloride as a phytic acid analytical agent. The above-mentioned process method can obtain a high-yield, high-purity inositol product, and a potassium dihydrogen phosphate product can also be obtained, which increases economic benefits for enterprises; in addition, a phytic acid analytical agent can be produced as a by-product, reducing the use of phytic acid analytical agent raw materials. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the 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.

[0024] Example 1

[0025] A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a by-product, comprising the following steps:

[0026] (1) adding alkali (1 wt % potassium hydroxide solution) to 500 L of collected potassium dihydrogen phosphate mother liquor (inositol concentration 38.1 g / L, potassium dihydrogen phosphate concentration 256.5 g / L, potassium chloride concentration 36.8 g / L), stirring, adjusting the pH of the liquid to 4.0, controlling the reaction temperature to 35° C., and after the reaction, obtaining 1788 L of the liquid for standby use;

[0027] (2) taking 1788 L of the feed liquid in step (1), filtering it through a plate and frame filter with a filter cloth pore size of 400 mesh, and collecting 1788 L of the filtrate for later use;

[0028] (3) 1788 L of the filtrate in step (2) was taken and treated with a hollow fiber membrane (the operating pressure was controlled at 0.4 MPa, the operating temperature was 35° C., and the permeate was backflushed for 30 s every 20 min of operation, and the filtration was stopped when the volume was 4% of the original volume; the material of the hollow fiber membrane was polyvinylidene fluoride, and the membrane model of the hollow fiber membrane was NF-40), and 72 L of the first retentate (combined with the potassium dihydrogen phosphate mother liquor) and 1716 L of the first permeate were collected respectively;

[0029] (4) taking 1716 L of the first permeate in step (3), and treating it with a nanofiltration membrane with a molecular weight cutoff of 100 Da, and collecting 538 L of the second retentate (solid content of 30 wt%) and 1180 L of the second permeate respectively;

[0030] (5) taking 538 L of the second retentate in step (4), and subjecting it to a simulated moving bed chromatography separation system (operating cycle 28.9 min, the filler of the chromatographic column is a potassium-type cationic resin with a particle size of 300 ± 50 μm, the height-to-diameter ratio of the chromatographic column is 1:2.0, the feed amount is 15% of the volume of the single column chromatographic column, the feed flow rate is 0.8 BV / h, the flow rates of the circulation, the influent top salt, and the influent top inositol are all 1.5 BV / h, the volume of each chromatographic column is 50 L, and the number of chromatographic columns is 6), and collecting 646 L of the inositol phase and 1345 L of the salt phase respectively;

[0031] (6) taking 646 L of the inositol phase in step (5), concentrating to obtain 35.3 L of a concentrated solution having a solid content of 45 wt%, adding 353 g of activated carbon (added at a dosage of 1% of the volume of the concentrated solution) for decolorization for 0.5 h, filtering, cooling the collected decolorized solution to 25 ° C. within 4 h, keeping the temperature for crystallization for 1 h, filtering and rinsing, and drying and crushing the collected filter cake to obtain an inositol product; the collected filtrate is combined with a potassium dihydrogen phosphate mother liquor;

[0032] (7) taking the salt phase in step (5), subjecting it to thermal concentration treatment to obtain a concentrated solution having a solid content of 50 wt%, cooling it to 20° C. and filtering it, collecting the filter cake and drying it to obtain a potassium dihydrogen phosphate product, and collecting the filtrate as a liquid organic fertilizer component;

[0033] (8) The second permeate 1180 L in step (4) was taken and treated with a reverse osmosis membrane (temperature 30° C., pressure 4.5 MPa) to obtain a concentrated solution containing potassium chloride (solid content 15 wt%) as a phytic acid decomposing agent.

[0034] Example 2

[0035] A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a by-product, comprising the following steps:

[0036] (1) adding carbonate (1 wt % potassium bicarbonate solution) to 500 L of collected potassium dihydrogen phosphate mother liquor (inositol concentration 38.1 g / L, potassium dihydrogen phosphate concentration 256.5 g / L, potassium chloride concentration 36.8 g / L), stirring, adjusting the pH of the liquid to 4.5, controlling the reaction temperature to 40° C., and after the reaction, obtaining 1854 L of the liquid for use;

[0037] (2) taking 1854 L of the feed liquid in step (1), filtering it through a plate and frame filter with a filter cloth pore size of 400 mesh, and collecting 1856 L of the filtrate for later use;

[0038] (3) 1856 L of the filtrate in step (2) was treated with a hollow fiber membrane (the operating pressure was controlled at 0.45 MPa, the operating temperature was 40° C., and the permeate was backflushed for 40 s every 25 min, and the filtration was stopped when the volume was 5% of the original volume; the hollow fiber membrane was made of polyvinylidene fluoride and the membrane model of the hollow fiber membrane was NF-50), and 93 L of the first retentate (combined with the potassium dihydrogen phosphate mother liquor) and 1763 L of the first permeate were collected respectively;

[0039] (4) taking 1763 L of the first permeate in step (3), and treating it with a nanofiltration membrane with a molecular weight cutoff of 200 Da, and collecting 760 L of the second retentate (solid content of 22 wt%) and 1007 L of the second permeate respectively;

[0040] (5) taking 760 L of the second retentate in step (4), and processing it through a simulated moving bed chromatography separation system (operating cycle 31.0 min, the filler of the chromatographic column is a potassium-type cationic resin with a particle size of 300±50 μm, the height-to-diameter ratio of the chromatographic column is 1.5:2.0, the feed amount is 17% of the volume of the single column chromatographic column, the feed flow rate is 0.75 BV / h, the flow rates of circulation, water top salt and water top inositol are all 1.4 BV / h, the volume of each chromatographic column is 75 L, and the number of chromatographic columns is 6), and collecting 912 L of inositol phase and 1900 L of salt phase respectively;

[0041] (6) taking 912 L of the inositol phase in step (5), concentrating to obtain 33.9 L of a concentrated solution having a solid content of 50 wt%, adding 509 g of activated carbon (added in an amount of 1.5% of the volume of the concentrated solution) for decolorization for 0.6 h, filtering, cooling the collected decolorized solution to 30 ° C within 5 h, keeping the temperature for crystallization for 1 h, filtering and rinsing, and drying and crushing the collected filter cake to obtain an inositol product; the collected filtrate is combined with a potassium dihydrogen phosphate mother liquor;

[0042] (7) taking the salt phase in step (5), subjecting it to thermal concentration treatment to obtain a concentrated solution having a solid content of 52 wt%, cooling it to 22 ° C and filtering it, collecting the filter cake and drying it to obtain a potassium dihydrogen phosphate product, and collecting the filtrate as a liquid organic fertilizer component;

[0043] (8) The second permeate 1007L in step (4) was taken and treated with a reverse osmosis membrane (temperature 40°C, pressure 5 MPa) to obtain a concentrated solution containing potassium chloride (solid content 8 wt%) as a phytic acid decomposing agent.

[0044] Example 3

[0045] A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a by-product, comprising the following steps:

[0046] (1) adding alkali (1 wt % potassium hydroxide solution) to 500 L of collected potassium dihydrogen phosphate mother liquor (inositol concentration 38.1 g / L, potassium dihydrogen phosphate concentration 256.5 g / L, potassium chloride concentration 36.8 g / L), stirring, adjusting the pH of the liquid to 5, controlling the reaction temperature to 45° C., and after the reaction, obtaining 1896 L of the liquid for use;

[0047] (2) 1896 L of the feed liquid in step (1) was filtered through a plate and frame filter with a filter cloth pore size of 400 mesh, and 1899 L of the filtrate was collected for later use;

[0048] (3) 1899 L of the filtrate in step (2) was taken and treated with a hollow fiber membrane (the operating pressure was controlled at 0.5 MPa, the operating temperature was 45° C., and the permeate was backflushed for 47 seconds every 30 min of operation, and the filtration was stopped when the filtration volume was 6% of the original volume; the material of the hollow fiber membrane was polyvinylidene fluoride, and the membrane model of the hollow fiber membrane was NF-45), and 114 L of the first retentate (combined with the potassium dihydrogen phosphate mother liquor) and 1786 L of the first permeate were collected respectively;

[0049] (4) taking 1786 L of the first permeate in step (3), and treating it with a nanofiltration membrane with a molecular weight cutoff of 150 Da, respectively collecting 608 L of the second retentate (solid content of 27 wt%) and 1178 L of the second permeate;

[0050] (5) taking 608 L of the second retentate in step (4), and processing it through a simulated moving bed chromatography separation system (operating cycle 33.3 min, the filler of the chromatographic column is a potassium-type cationic resin with a particle size of 300±50 μm, the height-to-diameter ratio of the chromatographic column is 1.2:2, the feed amount is 16% of the volume of the single column chromatographic column, the feed flow rate is 0.7 BV / h, the flow rates of circulation, water top salt and water top inositol are all 1.3 BV / h, the volume of each chromatographic column is 60 L, and the number of chromatographic columns is 6 columns), and collecting 730 L of inositol phase and 1520 L of salt phase respectively;

[0051] (6) taking 730 L of the inositol phase in step (5), concentrating to obtain 29.2 L of a concentrated solution having a solid content of 53 wt%, adding 438 g of activated carbon (added in an amount of 1.5% of the volume of the concentrated solution) for decolorization for 0.8 h, filtering, cooling the collected decolorized solution to 32 ° C. within 6 h, keeping the temperature for crystallization for 1 h, filtering and rinsing, and drying and crushing the collected filter cake to obtain an inositol product; the collected filtrate is combined with a potassium dihydrogen phosphate mother liquor;

[0052] (7) taking the salt phase in step (5), subjecting it to thermal concentration treatment to obtain a concentrated solution having a solid content of 55 wt%, cooling it to 25 ° C and filtering it, collecting the filter cake and drying it to obtain a potassium dihydrogen phosphate product, and collecting the filtrate as a liquid organic fertilizer component;

[0053] (8) The second permeate 1178 L in step (4) was treated with a reverse osmosis membrane (temperature 50° C., pressure 5.5 MPa) to obtain a concentrated solution containing potassium chloride (solid content 11 wt %) as a phytic acid decomposing agent.

[0054] Example 4

[0055] A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a by-product, comprising the following steps:

[0056] (1) adding carbonate (1 wt % potassium carbonate solution) to 500 L of collected potassium dihydrogen phosphate mother liquor (inositol concentration 38.1 g / L, potassium dihydrogen phosphate concentration 256.5 g / L, potassium chloride concentration 36.8 g / L), stirring, adjusting the pH of the liquid to 5.2, controlling the reaction temperature to 50° C., and after the reaction, obtaining 1925 L of the liquid for use;

[0057] (2) 1925 L of the feed liquid in step (1) was filtered through a plate and frame filter with a filter cloth pore size of 400 mesh, and 1936 L of the filtrate was collected for later use;

[0058] (3) 1936 L of the filtrate in step (2) was taken and treated with a hollow fiber membrane (the operating pressure was controlled at 0.55 MPa, the operating temperature was 50° C., and the permeate was backflushed for 55 s every 35 min of operation, and the filtration was stopped when the filtration volume was 7% of the original volume; the material of the hollow fiber membrane was polyvinylidene fluoride, and the membrane model of the hollow fiber membrane was NF-40), and 136 L of the first retentate (combined with the potassium dihydrogen phosphate mother liquor) and 1807 L of the first permeate were collected respectively;

[0059] (4) taking 1807 L of the first permeate in step (3), and treating it with a nanofiltration membrane with a molecular weight cutoff of 200 Da, and collecting 579 L of the second retentate (solid content of 28 wt%) and 1228 L of the second permeate respectively;

[0060] (5) taking 579 L of the second retentate in step (4), and processing it through a simulated moving bed chromatography separation system (operating cycle 35.1 min, the filler of the chromatographic column is a potassium-type cationic resin with a particle size of 300±50 μm, the height-to-diameter ratio of the chromatographic column is 1.3:2.0, the feed amount is 15% of the volume of the single column chromatographic column, the feed flow rate is 0.7 BV / h, the flow rates of circulation, water top salt and water top inositol are all 1.2 BV / h, the volume of each chromatographic column is 65 L, and the number of chromatographic columns is 6), and collecting 695 L of inositol phase and 1448 L of salt phase respectively;

[0061] (6) taking 695 L of the inositol phase in step (5), concentrating to obtain 27 L of a concentrated solution having a solid content of 60 wt%, adding 540 g of activated carbon (added in an amount of 2% of the volume of the concentrated solution) for decolorization for 0.8 h, filtering, cooling the collected decolorized solution to 35 ° C. within 7 h, keeping the temperature for crystallization for 1 h, filtering and rinsing, and drying and crushing the collected filter cake to obtain an inositol product; the collected filtrate is combined with a potassium dihydrogen phosphate mother liquor;

[0062] (7) taking the salt phase in step (5), subjecting it to thermal concentration treatment to obtain a concentrated solution having a solid content of 58 wt %, cooling it to 28 ° C and filtering it, collecting the filter cake and drying it to obtain a potassium dihydrogen phosphate product, and collecting the filtrate as a liquid organic fertilizer component;

[0063] (8) The second permeate 1228 L in step (4) was treated with a reverse osmosis membrane (temperature 55° C., pressure 6 MPa) to obtain a concentrated solution containing potassium chloride (solid content 13 wt%) as a phytic acid decomposing agent.

[0064] Example 5

[0065] A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a by-product, comprising the following steps:

[0066] (1) adding alkali (1 wt % potassium hydroxide solution) to 500 L of collected potassium dihydrogen phosphate mother liquor (inositol concentration 38.1 g / L, potassium dihydrogen phosphate concentration 256.5 g / L, potassium chloride concentration 36.8 g / L), stirring, adjusting the pH of the liquid to 5.5, controlling the reaction temperature to 55° C., and after the reaction, obtaining 1974 L of the liquid for standby use;

[0067] (2) taking 1974 L of the feed liquid in step (1), filtering it through a plate and frame filter with a filter cloth pore size of 400 mesh, and collecting 1977 L of the filtrate for later use;

[0068] (3) 1977 L of the filtrate in step (2) was treated with a hollow fiber membrane (the operating pressure was controlled at 0.6 MPa, the operating temperature was 55° C., and the permeate was backflushed for 60 s every 39.2 min of operation, and the filtration was stopped when the filtration volume was 8% of the original volume; the hollow fiber membrane was made of polyvinylidene fluoride and the membrane model of the hollow fiber membrane was NF-50), and 158 L of the first retentate (combined with the potassium dihydrogen phosphate mother liquor) and 1821 L of the first permeate were collected respectively;

[0069] (4) taking 1821 L of the first permeate in step (3), and treating it with a nanofiltration membrane with a molecular weight cutoff of 150 Da, respectively collecting 534 L of the second retentate (solid content of 30 wt%) and 1287 L of the second permeate;

[0070] (5) taking 534 L of the second retentate in step (4), and subjecting it to a simulated moving bed chromatography separation system (operating cycle 40 min, the filler of the chromatographic column is a potassium-type cationic resin with a particle size of 300 ± 50 μm, the height-to-diameter ratio of the chromatographic column is 1.1:2, the feed amount is 17% of the volume of the single column chromatographic column, the feed flow rate is 0.6 BV / h, the flow rates of the circulation, the influent top salt, and the influent top inositol are all 1.1 BV / h, the volume of each chromatographic column is 55 L, and the number of chromatographic columns is 6), and collecting 641 L of the inositol phase and 1335 L of the salt phase respectively;

[0071] (6) taking 641 L of the inositol phase in step (5), concentrating to obtain 27.7 L of a concentrated solution having a solid content of 60 wt%, adding 277 g of activated carbon (added at a dosage of 1% of the volume of the concentrated solution) for decolorization for 1 h, filtering, cooling the collected decolorized solution to 40° C. within 8 h, keeping the temperature for crystallization for 1 h, filtering, eluting, and drying and crushing the collected filter cake to obtain an inositol product; the collected filtrate is combined with a potassium dihydrogen phosphate mother liquor;

[0072] (7) taking the salt phase in step (5), subjecting it to thermal concentration treatment to obtain a concentrated solution having a solid content of 60 wt %, cooling it to 30° C. and filtering it, collecting the filter cake and drying it to obtain a potassium dihydrogen phosphate product, and collecting the filtrate as a liquid organic fertilizer component;

[0073] (8) The second permeate 1287 L in step (4) was treated with a reverse osmosis membrane (temperature 60° C., pressure 6.5 MPa) to obtain a concentrated solution containing potassium chloride (solid content 9 wt%) as a phytic acid decomposing agent.

[0074] In order to better prove that the process method of the present invention can obtain high-purity, high-yield, high-yield inositol products, and can also obtain high-yield potassium dihydrogen phosphate, and can also produce a phytic acid analytical agent as a by-product, 15 comparative examples are given with reference to Example 3, and the details are shown below.

[0075] Comparative Example 1

[0076] The difference from Example 3 is that the pH of the feed solution is adjusted to 3.5 in step (1), and the remaining operations are the same.

[0077] Comparative Example 2

[0078] The difference from Example 3 is that the temperature in step (1) is controlled to 60° C., and the rest of the operations are the same.

[0079] Comparative Example 3

[0080] The difference from Example 3 is that the operating pressure of the membrane in step (3) is 0.3 MPa, and the rest of the operations are the same.

[0081] Comparative Example 4

[0082] The difference from Example 3 is that the operating temperature of the membrane in step (3) is 25°C, and the rest of the operations are the same.

[0083] Comparative Example 5

[0084] The difference from Example 3 is that the operating temperature of the membrane in step (3) is 65°C, and the rest of the operations are the same.

[0085] Comparative Example 6

[0086] The difference from Example 3 is that the model of the membrane in step (3) is NF-35, and the rest of the operations are the same.

[0087] Comparative Example 7

[0088] The difference from Example 3 is that the model of the membrane in step (3) is NF-55, and the rest of the operations are the same.

[0089] Comparative Example 8

[0090] The difference from Example 3 is that step (4) is missing, and the remaining operations are the same.

[0091] Comparative Example 9

[0092] The difference from Example 3 is that step (5) is missing, and the remaining operations are the same.

[0093] Comparative Example 10

[0094] The difference from Example 3 is that the particle size of the chromatographic column filler in step (5) is 600 μm, and the rest of the operations are the same.

[0095] Comparative Example 11

[0096] The difference from Example 3 is that in step (5), the feed flow rate is 1.0 BV / h, the flow rates of circulation, water inlet top salt and water inlet top inositol are all 2.0 BV / h, and the rest of the operations are the same.

[0097] Comparative Example 12

[0098] The difference from Example 3 is that in step (7), the salt phase is concentrated to a solid content of 45 wt %, and the remaining operations are the same.

[0099] Comparative Example 13

[0100] The difference from Example 3 is that in step (7), the salt phase is concentrated to a solid content of 65 wt %, and the remaining operations are the same.

[0101] Comparative Example 14

[0102] The difference from Example 3 is that the temperature is lowered to 15° C. in step (7), and the remaining operations are the same.

[0103] Comparative Example 15

[0104] The difference from Example 3 is that the temperature is lowered to 35° C. in step (7), and the remaining operations are the same.

[0105] Table 1

[0106]

[0107] It can be found from Table 1 that, by using the process of the present invention, the inositol yield, yield and purity, the yield of potassium dihydrogen phosphate and the yield of phytic acid desorbent obtained in Example 3 are significantly higher than those in other examples and comparative examples 1-15.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a phytic acid analytical agent as a byproduct, characterized in that: The following steps are involved: (1) adding alkali or carbonate to the collected potassium dihydrogen phosphate mother liquor, stirring, adjusting the pH of the liquid to acidity, controlling the reaction temperature, and the liquid obtained after the reaction is completed is used for later use; (2) taking the feed solution in step (1), filtering and collecting the filtrate for later use; (3) taking the filtrate described in step (2), treating it through a hollow fiber membrane, and collecting a first retentate and a first permeate respectively; (4) taking the first permeate in step (3), treating it with a nanofiltration membrane, and collecting a second retentate and a second permeate respectively; (5) taking the second retentate in step (4), subjecting it to a simulated moving bed chromatography separation system, and collecting the inositol phase and the salt phase respectively; (6) taking the inositol phase described in step (5), concentrating it, decolorizing it, filtering it, cooling and crystallizing the collected decolorized liquid, filtering it, eluting it, and drying and crushing the collected filter cake to obtain an inositol product; combining the collected filtrate with a potassium dihydrogen phosphate mother liquor; (7) taking the salt phase described in step (5), concentrating, cooling, filtering, and collecting the filter cake to obtain a potassium dihydrogen phosphate product through drying, and collecting the filtrate as a liquid organic fertilizer component; (8) The second permeate in step (4) is concentrated to obtain a concentrated solution containing potassium chloride as a phytic acid decomposing agent.

2. A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a by-product phytic acid analytical agent according to claim 1, characterized in that, The base in step (1) is potassium hydroxide, the carbonate is potassium carbonate or potassium bicarbonate, the reaction temperature is controlled to be 35-55° C., and the pH of the feed solution is adjusted to be 4.0-5.

5.

3. A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a by-product phytic acid analytical agent according to claim 1, characterized in that, When hollow fiber membrane treatment is used in step (3), the operating pressure is controlled at 0.4-0.6MPa, the operating temperature is 35-55°C, and the permeate is backflushed for 30-60s every 20-40min of operation, and the filtration is stopped when the filtration volume reaches 4-8% of the original volume; the material of the hollow fiber membrane is polyvinylidene fluoride, and the membrane model of the hollow fiber membrane is NF-40~50.

4. A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a by-product phytic acid analytical agent according to claim 1, characterized in that, In step (4), the first permeate is treated with a nanofiltration membrane with a molecular weight cutoff of 100-200 Da, and the solid content of the second retentate is 20-30 wt%.

5. A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a by-product phytic acid analytical agent according to claim 1, characterized in that, When the moving bed chromatography separation system is simulated in step (5), the operation cycle is 28-40min, the filler of the chromatographic column is a potassium-type cationic resin with a particle size of 300±50μm, the height-to-diameter ratio of the chromatographic column is 1-1.5:2.0, the feed amount is 15-17% of the volume of the single column chromatographic column, the feed flow rate is 0.6-0.8BV / h, and the flow rates of circulation, water inlet top salt and water inlet top inositol are all 1.1-1.5BV / h.

6. A process for recovering potassium dihydrogen phosphate and inositol from potassium dihydrogen phosphate mother liquor and producing a by-product phytic acid analytical agent according to claim 1, characterized in that, In step (7), the salt phase is subjected to heat concentration treatment to obtain a concentrated solution with a solid content of 50-60 wt %, which is then cooled to 20-30° C. and filtered.

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