Process method for recovering monopotassium phosphate, potassium chloride and inositol from monopotassium phosphate mother liquor

Abstract

The invention relates to the technical field of corn soaking water treatment, in particular to a process method for recovering monopotassium phosphate, potassium chloride and inositol from monopotassium phosphate mother liquor, which comprises the following steps: treating the collected monopotassium phosphate mother liquor through a simulated moving bed chromatographic separation system, concentrating, crystallizing and filtering the collected inositol phase, and obtaining the monopotassium phosphate, potassium chloride and inositol from the monopotassium phosphate mother liquor. Adding water into the collected first filter cake, heating, decoloring, filtering, cooling, crystallizing, filtering and leaching the collected second filtrate, and drying the collected filter cake; adjusting the pH value of the collected salt phase, concentrating, cooling, crystallizing and filtering, drying the collected third filter cake to obtain a monopotassium phosphate product, concentrating and filtering the collected third filtrate, and drying the collected fourth filter cake to obtain a potassium chloride product; according to the process method, the yield and the purity of the inositol product are greatly improved, and meanwhile, the monopotassium phosphate product and the potassium chloride product which are high in yield and yield are obtained.

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, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor. 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] The existing 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, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor. Summary of the invention

[0005] The technical problem to be solved by the present invention is: in view of the deficiencies of the prior art, a process method for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor is provided, and the process method can obtain a high-yield inositol product, and potassium dihydrogen phosphate and potassium chloride products can also be obtained at the same time.

[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, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor comprises the following steps:

[0008] (1) treating the collected potassium dihydrogen phosphate crystal mother liquor with a simulated moving bed chromatography separation system to collect the inositol phase and the salt phase respectively;

[0009] (2) taking the inositol phase described in step (1), concentrating, cooling and crystallizing, filtering, and eluting, respectively collecting a first filter cake and a first filtrate, and combining the first filtrate with a potassium dihydrogen phosphate mother liquor;

[0010] (3) taking the first filter cake in step (2), adding purified water, stirring, heating, and then adding a decolorant, continuing to stir and filter, cooling and crystallizing the collected second filtrate, filtering, and eluting, and drying and crushing the collected filter cake to obtain an inositol product, and combining the collected filtrate into a salt phase;

[0011] (4) taking the salt phase described in step (1), adding potassium salt or potassium hydroxide, adjusting the pH of the salt phase to acidic, and then concentrating, cooling, crystallizing, filtering, and collecting the third filter cake to obtain a potassium dihydrogen phosphate product, and collecting the third filtrate for standby use;

[0012] (5) taking the third filtrate described in step (4), concentrating and filtering, and collecting the fourth filter cake and drying to obtain a potassium chloride product; cooling the collected fourth filtrate and filtering, and the collected fifth filter cake is dried and combined with the potassium dihydrogen phosphate product in step (4), and the collected fifth filtrate is reserved for later use;

[0013] (6) taking the fifth filtrate in step (5), concentrating and filtering, collecting the filter cake and drying it, and combining it with the potassium chloride product in step (5), and collecting the sixth filtrate for later use;

[0014] (7) taking the sixth filtrate in step (6), cooling and filtering, and combining the collected filter cake with the potassium dihydrogen phosphate product in step (4) after drying, and the collected filtrate is used as a liquid fertilizer component.

[0015] As an improved technical solution, the filler of the chromatographic column in the simulated moving bed chromatographic separation system in step (1) is a calcium-type S1850 or potassium-type S1850 gel chromatography resin with a particle size of 300±40μm, the height-to-diameter ratio of the chromatographic column is 1-1.5:2.0, the feed amount is 10-15% v / v of the single column volume, the speed of controlling the feed, circulation, water top salt and water top inositol is 1-2BV / h, and the operation cycle is 15-30min.

[0016] As an improved technical solution, in step (2), the inositol phase is concentrated to a solid content of 45-60 wt%, and then cooled to 25-35° C. for crystallization.

[0017] As an improved technical solution, in step (3), purified water is added at a mass volume ratio of 1:1-1.5 and heated to 90-98°C; the second filtrate is cooled to 25-40°C and kept warm for crystallization.

[0018] As an improved technical solution, the potassium salt added in step (4) is potassium carbonate or potassium bicarbonate, and the pH is adjusted to 3.2-3.8 and then concentrated to obtain a concentrated solution with a solid content of 50-60wt%, which is then cooled to 20-30°C for crystallization.

[0019] As an improved technical solution, the third filtrate in step (5) is thermally concentrated to obtain a concentrated solution with a solid content of 65-75wt%.

[0020] As an improved technical solution, in step (5), the fourth filtrate is cooled to 25-35° C. within 3 hours.

[0021] As an improved technical solution, the fifth filtrate in step (6) is concentrated to obtain a concentrated solution with a solid content of 60-70wt%.

[0022] After adopting the above technical solution, the beneficial effects of the present invention are:

[0023] The invention firstly processes the collected potassium dihydrogen phosphate mother liquor through a simulated moving bed chromatography separation system, collects the salt phase and the inositol phase respectively, concentrates, crystallizes and filters the inositol phase, collects the first filtrate and the first filter cake respectively, adds purified water to the collected first filter cake for heating and stirring, adds a decolorizing agent for decolorization and filtering, cools down the collected second filtrate for crystallization, filtration and leaching, and dries the collected filter cake to obtain an inositol product; adds potassium salt or potassium hydroxide to the collected salt phase to adjust the pH to acidity, concentrates, cools down, crystallizes and filters, dries the collected third filter cake to obtain the potassium dihydrogen phosphate product, concentrates, filters and dries the collected third filtrate to obtain the potassium chloride product; cools down, crystallizes and filters the collected fourth filtrate, dries the collected filter cake and combines it with the potassium dihydrogen phosphate product, continues to concentrate and filter the collected fifth filtrate, dries the collected filter cake and combines it with the potassium chloride product, and cools down, filters the collected sixth filtrate, dries the collected filter cake and combines it with the potassium dihydrogen phosphate product. The above process method first uses a simulated moving bed to separate inositol from potassium dihydrogen phosphate, potassium chloride, small molecule amino acids, proteins, etc. in the inositol mother liquor, and the inositol phase is crystallized twice to obtain the inositol product. The salt phase utilizes the difference in the solubility of potassium dihydrogen phosphate and potassium chloride to separate the two by solubility under different temperature conditions, thereby greatly improving the yield and purity of the inositol product, and also obtaining high-yield and high-yield potassium dihydrogen phosphate products and potassium chloride products. DETAILED DESCRIPTION

[0024] 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.

[0025] Example 1

[0026] A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor comprises the following steps:

[0027] (1) 1000L of collected potassium dihydrogen phosphate crystallization mother liquor (mother liquor solid content 29.3wt%, inositol concentration 37.6g / L, potassium dihydrogen phosphate concentration 238.9g / L, potassium chloride concentration 48.2g / L) was treated by a simulated moving bed chromatography separation system (the filler of the chromatographic column was calcium-type S1850 gel chromatography resin with a particle size of 300±40μm), the height-to-diameter ratio of the chromatographic column was 1:2.0, the feed amount was 10% v / v of the single column volume, the feed, circulation, water top salt and water top inositol speeds were controlled to be 1BV / h, the operation cycle was 30min, (the volume of each chromatographic column was 50L, and the number of chromatographic columns was 6) to collect 1300L of inositol phase and 2700L of salt phase respectively;

[0028] (2) taking 1300 L of the inositol phase in step (1), first concentrating it through a reverse osmosis membrane, then concentrating it through heat to a solid content of 45 wt %, cooling it to 25° C., crystallizing it through heat preservation, filtering it, and rinsing it, and collecting 38.3 kg of the first filter cake and 55 L of the first filtrate (merged into the potassium dihydrogen phosphate mother liquor);

[0029] (3) Take 38.3 kg of the first filter cake in step (2), add 38.3 L of purified water at a mass volume ratio of 1:1, stir, heat to 90 ° C, add a decolorizer (add 689 g of activated carbon at a ratio of 1% of the material volume), continue stirring and filtering, cool the collected second filtrate to 25 ° C, keep warm for crystallization, filter, and rinse, dry and crush the collected filter cake to obtain an inositol product, and merge the collected filtrate 42.7 L into the inositol phase;

[0030] (4) taking 2700 L of the salt phase in step (1), adding potassium carbonate, adjusting the pH of the salt phase to 3.2, and then concentrating to obtain a concentrated solution with a solid content of 50 wt%, cooling to 20° C. for crystallization, filtering, and collecting the third filter cake and drying to obtain a potassium dihydrogen phosphate product. The collected third filtrate 355 L is set aside;

[0031] (5) 355 L of the third filtrate in step (4) was taken, and a concentrated solution with a solid content of 65 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected fourth filter cake was dried to obtain a potassium chloride product; the collected fourth filtrate was cooled to 25° C. within 3 h and then filtered. The collected fifth filter cake was dried and combined with the potassium dihydrogen phosphate product in step (4). 138.8 L of the collected fifth filtrate was reserved for later use;

[0032] (6) 138.8 L of the fifth filtrate in step (5) was taken, and a concentrated solution with a solid content of 60 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected filter cake was dried and combined with the potassium chloride product in step (5). 95.4 L of the collected sixth filtrate was set aside;

[0033] (7) Take 95.4 L of the sixth filtrate in step (6), cool it to 20° C. within 3 hours, and then filter it. The collected filter cake is dried and combined with the potassium dihydrogen phosphate product of step (4). The collected filtrate is used as a liquid fertilizer component.

[0034] Example 2

[0035] A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor comprises the following steps:

[0036] (1) 1000L of the collected potassium dihydrogen phosphate crystallization mother liquor (mother liquor solid content 29.3wt%, inositol concentration 37.6g / L, potassium dihydrogen phosphate concentration 238.9g / L, potassium chloride concentration 48.2g / L) was treated by a simulated moving bed chromatographic separation system (the filler of the chromatographic column was a potassium-type gel chromatographic resin with a particle size of 300±40μm, the height-to-diameter ratio of the chromatographic column was 1.3:2.0, the feed amount was 13% v / v of the single column volume, the speed of feeding, circulation, water top salt and water top inositol was controlled to be 1.2BV / h, the operation cycle was 25.6min, (the volume of the chromatographic column was 65L, and the number of chromatographic columns was 6) to collect 1300L of inositol phase and 2700L of salt phase respectively;

[0037] (2) taking 1300 L of the inositol phase in step (1), first concentrating it through a reverse osmosis membrane, then concentrating it through heat to a solid content of 50 wt %, cooling it to 28° C., crystallizing it through heat preservation, filtering it, and rinsing it, collecting 39.8 kg of the first filter cake and 43 L of the first filtrate (merged into the potassium dihydrogen phosphate mother liquor);

[0038] (3) taking 39.8 kg of the first filter cake in step (2), adding 47.8 L of purified water at a mass volume ratio of 1:1.2, stirring, heating to 92 ° C, adding a decolorizer (adding 955 g of activated carbon at a ratio of 1.2% of the material volume), continuing to stir and filter, the collected second filtrate is cooled to 30 ° C, incubated for crystallization, filtered, and rinsed, the collected filter cake is dried and crushed to obtain an inositol product, and the collected filtrate 51.2 L is combined into the inositol phase;

[0039] (4) taking 2700 L of the salt phase in step (1), adding potassium hydroxide, adjusting the pH of the salt phase to 3.4, and then concentrating to obtain a concentrated solution with a solid content of 52 wt%, cooling to 23° C. for crystallization, filtering, and collecting the third filter cake and drying to obtain a potassium dihydrogen phosphate product. The collected third filtrate 323.8 L is set aside;

[0040] (5) 323.8 L of the third filtrate in step (4) was taken, and a concentrated solution with a solid content of 68 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected fourth filter cake was dried to obtain a potassium chloride product; the collected fourth filtrate was cooled to 28° C. within 3 h and then filtered. The collected fifth filter cake was dried and combined with the potassium dihydrogen phosphate product in step (4). 128.9 L of the collected fifth filtrate was reserved for later use;

[0041] (6) 128.9 L of the fifth filtrate in step (5) was taken, and a concentrated solution with a solid content of 68 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected filter cake was dried and combined with the potassium chloride product in step (5). 89.9 L of the collected sixth filtrate was set aside;

[0042] (7) Take 89.9 L of the sixth filtrate in step (6), cool it to 27° C. within 3 hours, and then filter it. The collected filter cake is dried and combined with the potassium dihydrogen phosphate product of step (4). The collected filtrate is used as a liquid fertilizer component.

[0043] Example 3

[0044] A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor comprises the following steps:

[0045] (1) 1000L of the collected potassium dihydrogen phosphate crystallization mother liquor (mother liquor solid content 29.3wt%, inositol concentration 37.6g / L, potassium dihydrogen phosphate concentration 238.9g / L, potassium chloride concentration 48.2g / L) was treated by a simulated moving bed chromatographic separation system (the filler of the chromatographic column was potassium-type S1850 gel chromatography resin with a particle size of 300±40μm, the height-to-diameter ratio of the chromatographic column was 1.5:2.0, the feed amount was 12% v / v of the single column volume, the speed of feeding, circulation, water top salt and water top inositol was controlled to be 1.5BV / h, the operation cycle was 20.4min, (the volume of the chromatographic column was 75L, and the number of chromatographic columns was 6) to collect 1300L of inositol phase and 2700L of salt phase respectively;

[0046] (2) taking 1300 L of the inositol phase in step (1), first concentrating it through a reverse osmosis membrane, then concentrating it through heat to a solid content of 53 wt %, cooling it to 30° C., crystallizing it through heat preservation, filtering it, and rinsing it, and collecting 39.9 kg of the first filter cake and 40 L of the first filtrate (merged into the potassium dihydrogen phosphate mother liquor);

[0047] (3) taking 39.9 kg of the first filter cake in step (2), adding 59.9 L of purified water at a mass volume ratio of 1:1.5, stirring, heating to 95 ° C, adding a decolorizer (adding 1377 g of activated carbon at a ratio of 1.5% of the material volume), continuing to stir and filter, the collected second filtrate is cooled to 32 ° C, incubated for crystallization, filtered, and rinsed, the collected filter cake is dried and crushed to obtain an inositol product, and the collected filtrate 62.1 L is combined into the inositol phase;

[0048] (4) taking 2700 L of the salt phase in step (1), adding potassium hydroxide, adjusting the pH of the salt phase to 3.5, and then concentrating to obtain a concentrated solution with a solid content of 55 wt%, cooling to 25° C. for crystallization, filtering, and collecting a third filter cake and drying to obtain a potassium dihydrogen phosphate product. The collected third filtrate 293.9 L is set aside;

[0049] (5) taking 293.9 L of the third filtrate in step (4), performing heat concentration to obtain a concentrate having a solid content of 70 wt%, filtering, and drying the collected fourth filter cake to obtain a potassium chloride product; cooling the collected fourth filtrate to 30° C. within 3 h and filtering, and drying the collected fifth filter cake and combining it with the potassium dihydrogen phosphate product in step (4), and collecting 122.2 L of the fifth filtrate for later use;

[0050] (6) 122.2 L of the fifth filtrate in step (5) was taken, and a concentrated solution with a solid content of 65 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected filter cake was dried and combined with the potassium chloride product in step (5). 86.5 L of the collected sixth filtrate was reserved for later use;

[0051] (7) Take 86.5 L of the sixth filtrate in step (6), cool it to 30° C. within 3 hours, and then filter it. The collected filter cake is dried and combined with the potassium dihydrogen phosphate product of step (4). The collected filtrate is used as a liquid fertilizer component.

[0052] Example 4

[0053] A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor comprises the following steps:

[0054] (1) 1000L of the collected potassium dihydrogen phosphate crystallization mother liquor (mother liquor solid content 29.3wt%, inositol concentration 37.6g / L, potassium dihydrogen phosphate concentration 238.9g / L, potassium chloride concentration 48.2g / L) was treated by a simulated moving bed chromatography separation system (the filler of the chromatographic column was calcium-type S1850 gel chromatography resin with a particle size of 300±40μm, the height-to-diameter ratio of the chromatographic column was 1.2:2.0, the feed amount was 15% v / v of the single column volume, the speed of feeding, circulation, water top salt and water top inositol was controlled to be 1.8BV / h, the operation cycle was 17.7min, (the volume of the chromatographic column was 60L, and the number of chromatographic columns was 6) to collect 1300L of inositol phase and 2700L of salt phase respectively;

[0055] (2) taking 1300 L of the inositol phase in step (1), first concentrating it through a reverse osmosis membrane, then concentrating it through heat to a solid content of 56 wt %, cooling it to 32° C., crystallizing it through heat preservation, filtering it, and rinsing it, and collecting 40.3 kg of the first filter cake and 38 L of the first filtrate (merged into the potassium dihydrogen phosphate mother liquor);

[0056] (3) taking 40.3 kg of the first filter cake in step (2), adding 60.5 L of purified water at a mass volume ratio of 1:1.5, stirring, heating to 98 ° C, adding a decolorizer (adding 1669 g of activated carbon at a ratio of 1.8% of the material volume), continuing to stir and filter, the collected second filtrate is cooled to 38 ° C, incubated for crystallization, filtered, and rinsed, the collected filter cake is dried and crushed to obtain an inositol product, and the collected filtrate 65.2 L is merged into the inositol phase;

[0057] (4) taking 2700 L of the salt phase in step (1), adding potassium bicarbonate, adjusting the pH of the salt phase to 3.7, and then concentrating to obtain a concentrated solution with a solid content of 58 wt%, cooling to 28° C. for crystallization, filtering, and collecting a third filter cake and drying to obtain a potassium dihydrogen phosphate product. The collected third filtrate 267.3 L is set aside;

[0058] (5) taking 267.3 L of the third filtrate in step (4), performing heat concentration to obtain a concentrate having a solid content of 72 wt%, filtering, and drying the collected fourth filter cake to obtain a potassium chloride product; cooling the collected fourth filtrate to 33° C. within 3 h and filtering, and drying the collected fifth filter cake and combining it with the potassium dihydrogen phosphate product in step (4), and collecting 117.9 L of the fifth filtrate for later use;

[0059] (6) 117.9 L of the fifth filtrate in step (5) was taken, and a concentrated solution with a solid content of 67 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected filter cake was dried and combined with the potassium chloride product in step (5). 83.6 L of the collected sixth filtrate was reserved for later use;

[0060] (7) Take 83.6 L of the sixth filtrate in step (6), cool it to 33° C. within 3 hours, and then filter it. The collected filter cake is dried and combined with the potassium dihydrogen phosphate product of step (4). The collected filtrate is used as a liquid fertilizer component.

[0061] Example 5

[0062] A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor comprises the following steps:

[0063] (1) 1000L of the collected potassium dihydrogen phosphate crystallization mother liquor (mother liquor solid content 29.3wt%, inositol concentration 37.6g / L, potassium dihydrogen phosphate concentration 238.9g / L, potassium chloride concentration 48.2g / L) was treated by a simulated moving bed chromatographic separation system (the filler of the chromatographic column was a calcium-type S1850 gel chromatography resin with a particle size of 300±40μm), the height-to-diameter ratio of the chromatographic column was 1.5:2.0, the feed amount was 13% v / v of the single column volume, the feed, circulation, water top salt and water top inositol speeds were controlled to be 2BV / h, the operation cycle was 15.6min, (the volume of the chromatographic column was 75L, and the number of chromatographic columns was 6) to collect 1300L of inositol phase and 2700L of salt phase respectively;

[0064] (2) taking 1300 L of the inositol phase in step (1), first concentrating it through a reverse osmosis membrane, then concentrating it to a solid content of 60 wt % and then cooling it to 35° C., crystallizing it by heat preservation, filtering it, and rinsing it, and collecting 41.1 kg of the first filter cake and 39 L of the first filtrate (merged into the potassium dihydrogen phosphate mother liquor);

[0065] (3) Take 41.1 kg of the first filter cake in step (2), add 61.7 L of purified water at a mass volume ratio of 1:1.5, stir, heat to 98 ° C, add a decolorizer (add 1892 g of activated carbon at a ratio of 2% of the material volume), continue stirring and filtering, cool the collected second filtrate to 40 ° C, keep warm for crystallization, filter, and rinse, dry and crush the collected filter cake to obtain an inositol product, and merge the collected filtrate 64.8 L into the inositol phase;

[0066] (4) taking 2700 L of the salt phase in step (1), adding potassium hydroxide, adjusting the pH of the salt phase to 3.8, and then concentrating to obtain a concentrated solution with a solid content of 60 wt%, cooling to 30° C. for crystallization, filtering, and drying the collected third filter cake to obtain a potassium dihydrogen phosphate product. The collected third filtrate 249.9 L was set aside;

[0067] (5) taking 249.9 L of the third filtrate in step (4), performing heat concentration to obtain a concentrate having a solid content of 75 wt%, filtering, and drying the collected fourth filter cake to obtain a potassium chloride product; cooling the collected fourth filtrate to 35° C. within 3 h and filtering, and drying the collected fifth filter cake and combining it with the potassium dihydrogen phosphate product in step (4), and collecting 110.8 L of the fifth filtrate for later use;

[0068] (6) 110.8 L of the fifth filtrate in step (5) was taken, and a concentrated solution with a solid content of 70 wt% was obtained by thermal concentration, and the concentrated solution was filtered. The collected filter cake was dried and combined with the potassium chloride product in step (5). 79.4 L of the collected sixth filtrate was set aside;

[0069] (7) Take 79.4 L of the sixth filtrate in step (6), cool it to 30° C. within 3 hours, and then filter it. The collected filter cake is dried and combined with the potassium dihydrogen phosphate product of step (4). The collected filtrate is used as a liquid fertilizer component.

[0070] In order to better prove that the process of the present invention can obtain a high-yield inositol product, as well as a high-yield potassium dihydrogen phosphate product and a potassium chloride product, 11 comparative examples are given with reference to Example 3, and the specific details are shown below.

[0071] Comparative Example 1

[0072] The difference from Example 3 is that the filler of the chromatographic column in step (1) has a particle size of 500 μm, and the rest of the operations are the same.

[0073] Comparative Example 2

[0074] The difference from Example 3 is that the resin in the chromatographic column in step (1) is a uniform particle size (particle size 300±40 μm) styrene-based chromatographic resin S1160 resin, and the remaining operations are the same.

[0075] Comparative Example 3

[0076] The difference from Example 3 is that the temperature is lowered to 15° C. in step (2), and the remaining operations are the same.

[0077] Comparative Example 4

[0078] The difference from Example 3 is that the temperature is lowered to 40° C. in step (2), and the remaining operations are the same.

[0079] Comparative Example 5

[0080] The difference from Example 3 is that the temperature is lowered to 20° C. in step (3), and the remaining operations are the same.

[0081] Comparative Example 6

[0082] The difference from Example 3 is that the temperature is lowered to 45° C. in step (3), and the remaining operations are the same.

[0083] Comparative Example 7

[0084] The difference from Example 3 is that in step (4), the pH is adjusted to 2.8, and the remaining operations are the same.

[0085] Comparative Example 8

[0086] The difference from Example 3 is that in step (4), the pH is adjusted to 4.2, and the remaining operations are the same.

[0087] Comparative Example 9

[0088] The difference from Example 3 is that the temperature is lowered to 15° C. in step (4), and the remaining operations are the same.

[0089] Comparative Example 10

[0090] The difference from Example 3 is that the temperature is lowered to 35° C. in step (4), and the remaining operations are the same.

[0091] Comparative Example 11

[0092] The difference from Example 3 is that in step (5), the temperature is lowered to 25° C. within 4 h, and the remaining operations are the same.

[0093] Table 1

[0094]

[0095]

[0096] It can be found from Table 1 that, by using the process of the present invention, the inositol yield, yield and purity, the potassium dihydrogen phosphate yield and the potassium chloride yield, yield and purity obtained in Example 3 are significantly higher than those in other examples and comparative examples 1-11.

[0097] 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, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor, characterized in that: The following steps are involved: (1) treating the collected potassium dihydrogen phosphate crystal mother liquor with a simulated moving bed chromatography separation system to collect the inositol phase and the salt phase respectively; (2) taking the inositol phase described in step (1), concentrating, cooling and crystallizing, filtering, and eluting, respectively collecting a first filter cake and a first filtrate, and combining the first filtrate with a potassium dihydrogen phosphate mother liquor; (3) taking the first filter cake in step (2), adding purified water, stirring, heating, and then adding a decolorant, continuing to stir and filter, cooling and crystallizing the collected second filtrate, filtering, and eluting, and drying and crushing the collected filter cake to obtain an inositol product, and combining the collected filtrate into a salt phase; (4) taking the salt phase described in step (1), adding potassium salt or potassium hydroxide, adjusting the pH of the salt phase to acidic, and then concentrating, cooling, crystallizing, filtering, and collecting the third filter cake to obtain a potassium dihydrogen phosphate product, and collecting the third filtrate for standby use; (5) taking the third filtrate described in step (4), concentrating and filtering, and collecting the fourth filter cake and drying to obtain a potassium chloride product; cooling the collected fourth filtrate and filtering, and the collected fifth filter cake is dried and combined with the potassium dihydrogen phosphate product in step (4), and the collected fifth filtrate is reserved for later use; (6) taking the fifth filtrate in step (5), concentrating and filtering, collecting the filter cake and drying it, and combining it with the potassium chloride product in step (5), and collecting the sixth filtrate for later use; (7) taking the sixth filtrate in step (6), cooling and filtering, and combining the collected filter cake with the potassium dihydrogen phosphate product in step (4) after drying, and the collected filtrate is used as a liquid fertilizer component.

2. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that, The filler of the chromatographic column in the simulated moving bed chromatographic separation system in step (1) is calcium-type S1850 or potassium-type S1850 gel chromatography resin with a particle size of 300±40μm, the height-to-diameter ratio of the chromatographic column is 1-1.5:2.0, the feed amount is 10-15% v / v of the single column volume, the speed of controlling the feed, circulation, water top salt and water top inositol is 1-2BV / h, and the operation cycle is 15-30min.

3. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that, In step (2), the inositol phase is concentrated to a solid content of 45-60 wt%, and then cooled to 25-35° C. for crystallization.

4. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that, In step (3), purified water is added in a mass-volume ratio of 1:1-1.5 and heated to 90-98° C.; the second filtrate is cooled to 25-40° C. and kept warm for crystallization.

5. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that: The potassium salt added in step (4) is potassium carbonate or potassium bicarbonate. After adjusting the pH to 3.2-3.8, the concentrated solution is concentrated to obtain a solid content of 50-60wt%, and then cooled to 20-30°C for crystallization.

6. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that: In step (5), the third filtrate is thermally concentrated to obtain a concentrated solution with a solid content of 65-75wt%.

7. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that: In step (5), the fourth filtrate is cooled to 25-35° C. within 3 h.

8. A process for recovering potassium dihydrogen phosphate, potassium chloride and inositol from potassium dihydrogen phosphate mother liquor according to claim 1, characterized in that: The fifth filtrate in step (6) is concentrated to obtain a concentrated solution with a solid content of 60-70wt%.

Images