A method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water

Abstract

The invention discloses a method for removing calcium and magnesium in a potassium phytate hydrolyzate prepared by using corn soaking water, and relates to the technical field of corn soaking water recycling. The method has a high calcium and magnesium removal rate, and the calcium and magnesium contents in the potassium phytate hydrolyzate are reduced from initial calcium 20-30 ppm and magnesium 300-600 ppm to calcium less than 5 ppm and magnesium less than 60 ppm. A resin column after adsorbing calcium and magnesium can be regenerated through subsequent analysis and the like, and can be reused without stopping for cleaning.

Description

Technical Field

[0001] The invention relates to the technical field of corn soaking water recycling, and in particular to a method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water. Background Art

[0002] The corn soaking water in the starch factory contains a large amount of effective ingredients, including phytic acid 1.0-1.5wt%, potassium 0.3-0.9wt%, calcium 40ppm, magnesium 1700ppm. The factory usually uses anion resin column to adsorb phytic acid, and then uses potassium chloride solution to analyze. The analytical solution contains potassium phytate and potassium chloride. The membrane separation technology is used to separate the potassium phytate solution and potassium chloride solution. The content of potassium phytate in the potassium phytate solution is about 25wt%, which contains some calcium brought in from the corn pulp. Magnesium impurities, including 100-200ppm calcium and 2000-3000ppm magnesium, are hydrolyzed at high temperature with alkali added to adjust the pH to 4.7-5.0. Some calcium and magnesium are precipitated, but 20-30ppm calcium and 300-600ppm magnesium are still present in the potassium phytate hydrolyzate. The potassium phytate hydrolyzate is concentrated and crystallized to produce potassium dihydrogen phosphate. Some calcium and magnesium will be attached to the potassium dihydrogen phosphate crystals along with the crystals. Calcium and magnesium impurities will cause turbidity when the potassium dihydrogen phosphate is dissolved in water at a ratio of 1:10 (w / w), affecting product quality. Summary of the invention

[0003] The technical problem to be solved by the present invention is: in view of the deficiencies in the prior art, a method for removing calcium and magnesium in a potassium phytate hydrolyzate prepared by using corn soaking water is provided, the calcium and magnesium contents in the potassium phytate hydrolyzate are reduced, and the prepared potassium dihydrogen phosphate product has higher quality.

[0004] In order to solve the above technical problems, the technical solution of the present invention is:

[0005] A method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water comprises the following steps:

[0006] A: Take the clarified corn soaking water and flow it into the anion resin column in reverse flow to adsorb phytic acid. The effluent is collected and returned to the starch plant.

[0007] B: Take potassium chloride solution to parse the anion resin column in step A, and collect the parse solution for later use;

[0008] C: The analytical solution in step B is concentrated by nanofiltration membrane, washed with purified water, the retentate is collected, potassium hydroxide is added to adjust the pH to 4.7-5.0, hydrolyzed at 160°C for 10h, cooled to 50-60°C by flash evaporation, and filtered by plate and frame to obtain potassium phytate hydrolyzate;

[0009] D: The potassium phytate hydrolyzate is passed into a continuous ion exchange device, and the outflowing tail liquid is the calcium- and magnesium-free hydrolyzate.

[0010] Preferably, the concentration of the potassium chloride solution in step B is 8 to 15 wt %.

[0011] Preferably, the continuous ion exchange equipment in step D comprises an adsorption zone, an air-pressure top acid water zone, a water-pressure top acid zone, a decomposition zone, a filling zone, an air-pressure top salt water zone and a water-pressure top salt zone which are arranged in sequence.

[0012] Preferably, the adsorption zone comprises two adsorption column groups arranged in series, and each adsorption column group comprises 5 resin columns connected in series through pipelines.

[0013] The analytical zone includes two analytical column groups arranged in series, and each analytical column group includes three resin columns connected in series through pipelines.

[0014] The resin column drain liquid from the air-pressure top acid water area and the air-pressure top salt water area is collected and returned to the pure water tank. The drain liquid from the water-pressure top salt area can be returned to the hydrolyzed liquid in step C.

[0015] The analytical agent used in the analytical zone is a hydrochloric acid solution with a concentration of 6 to 12 wt%.

[0016] In step D, the introduction rate of potassium phytate hydrolyzate is 8 to 12 L / h.

[0017] The resin columns in the continuous ion exchange device have the same structure and are all filled with LSC-500 cationic resin.

[0018] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0019] 1. The calcium and magnesium removal rate is high. The calcium and magnesium content in the potassium phytate hydrolyzate is reduced from the initial calcium 20-30ppm and magnesium 300-600ppm to calcium <5ppm and magnesium <60ppm.

[0020] 2. The potassium dihydrogen phosphate obtained by concentrated crystallization of potassium phytate hydrolyzate after removing calcium and magnesium will not produce turbidity when dissolved in water at a ratio of 1:10, and the product quality is high.

[0021] 3. The resin column after adsorbing calcium and magnesium can be regenerated through subsequent analysis and reused without stopping for cleaning.

[0022] 4. Collect the resin column drain liquid from the air pressure top acid water area and the air pressure top salt water area, return it to the pure water tank, and use it in the water top acid area and the water top salt area. The water top acid area can be used to return to the acid preparation and to prepare the analytical agent hydrochloric acid solution. The water top salt area can be returned to the potassium phytate hydrolyzate in step C. The mother liquor after the analytical liquid is evaporated and concentrated to extract potassium chloride can be discharged back to the corn pulp, and evaporated into corn pulp by the starch factory, without the trouble of waste liquid treatment, and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1It is a process flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the embodiments.

[0025] Example 1

[0026] The continuous ion exchange equipment includes 24 resin columns, each of which is filled with 0.45L of LSC-500 cationic resin. In this embodiment, resin columns No. 1 to 5 are connected in series to form a first adsorption column group, and resin columns No. 6 to 10 are connected in series to form a second adsorption column group. The two adsorption column groups are connected in series through a transfer tank and a pump to adsorb calcium and magnesium in potassium phytate hydrolyzate to avoid excessive column pressure caused by direct series connection. Potassium phytate hydrolyzate is introduced from the bottom of resin column No. 1, and the tail liquid flowing out from the top of resin column No. 10 is calcium-magnesium-free hydrolyzate. The No. 11 resin column is emptied in the forward direction by compressed air, and the bottom discharge of the No. 11 resin column is collected into a purified water tank, and the No. 12-14 resin columns are connected in series, and the No. 12 resin column is flushed with purified water, and the bottom discharge of the No. 14 resin column is collected into an acid preparation tank, which can be used to prepare an analytical agent, and the No. 15 resin column is flushed with hydrochloric acid solution, and the No. 15, 16, and 17 resin columns are connected in series to form a primary analysis, and the No. 18, 19, and 20 resin columns are connected in series to form a secondary analysis, and the bottom discharge of the No. 17 resin column enters from the top of the No. 18 resin column as an analytical agent for the secondary analysis, and the No. 21 resin column is filled with analytical liquid (220 ml is filled), and the No. 22 resin column is emptied into a purified water tank, and the No. 23-24 resin columns are topped with purified water to a hydrolysis liquid tank;

[0027] In the continuous separation equipment of this embodiment, 24 resin columns are arranged in a circle, and each resin column is connected by a pipeline and an electric valve. The control system switches the corresponding electric valve in a clockwise direction according to the set time to execute the program action of the next position. The resin column after adsorbing calcium and magnesium can be regenerated through subsequent analysis and reused without stopping for cleaning. The set time in this embodiment is 15 minutes.

[0028] Example 2

[0029] (1) taking clarified corn soaking water, countercurrently entering an anion resin column for phytic acid adsorption, and collecting the effluent and returning it to the starch factory;

[0030] (2) taking a 12 wt % potassium chloride solution to parse the anion resin column in step A, and collecting the parse solution for later use;

[0031] (3) The analytical solution in step B is concentrated by nanofiltration membrane, washed with purified water, and the retentate is collected. The pH value is adjusted to 4.7 by adding potassium hydroxide, and the solution is hydrolyzed at 160° C. for 10 h. The solution is cooled to 50-60° C. by flash evaporation, and filtered by plate and frame to obtain a potassium phytate hydrolyzate solution having a potassium phytate concentration of 25 wt %, a calcium content of 30 ppm, and a magnesium content of 600 ppm;

[0032] (4) Potassium phytate hydrolyzate was passed into the No. 1 resin column of the continuous ion exchange device in Example 1 at a rate of 10 L / h, a hydrochloric acid solution with a concentration of 10 wt% was passed into the No. 15 resin column at a rate of 1.8 L / h, the No. 21 resin column was filled with a calcium and magnesium analysis solution at a rate of 0.88 L / h, the No. 22 resin column actually produced a calcium and magnesium analysis solution at a rate of 0.92 L / h, the No. 14 resin column produced a water top acid at a rate of 0.88 L / h, the No. 11 resin column produced an air pressure top acid water at a rate of 0.84 L / h, and the No. 10 resin column obtained a calcium-free and magnesium-free hydrolyzate with a calcium content of 3 ppm and a magnesium content of 45 ppm. The specific data are shown in Table 1 below.

[0033] Table 1

[0034]

[0035] Example 3

[0036] (1) taking clarified corn soaking water, countercurrently entering an anion resin column for phytic acid adsorption, and collecting the effluent and returning it to the starch factory;

[0037] (2) taking a 12 wt % potassium chloride solution to parse the anion resin column in step A, and collecting the parse solution for later use;

[0038] (3) The analytical solution in step B was concentrated by nanofiltration membrane, washed with purified water, and the retentate was collected. Potassium hydroxide was added to adjust the pH to 4.8, and hydrolyzed at 160° C. for 10 h. The temperature was cooled to 50-60° C. by flash evaporation, and plate and frame filtration was performed to obtain potassium phytate hydrolyzate with a potassium phytate concentration of 25 wt %, a calcium content of 28 ppm, and a magnesium content of 590 ppm;

[0039] (4) Potassium phytate hydrolyzate was passed into the No. 1 resin column of the continuous ion exchange device in Example 1 at a rate of 8 L / h, a hydrochloric acid solution with a concentration of 10 wt% was passed into the No. 15 resin column at a rate of 1.8 L / h, the No. 21 resin column was filled with a calcium and magnesium analysis solution at a rate of 1.8 L / h, the No. 22 resin column actually produced a calcium and magnesium analysis solution of 0.92 L / h, the No. 14 resin column produced a water top acid of 0.88 L / h, the No. 11 resin column produced an air pressure top acid water of 0.88 L / h, and the No. 10 resin column obtained a calcium-free and magnesium-free hydrolyzate with a calcium content of 1 ppm and a magnesium content of 25 ppm. The specific data are shown in Table 2 below.

[0040] Table 2

[0041]

[0042] Example 4

[0043] (1) taking clarified corn soaking water, countercurrently entering an anion resin column for phytic acid adsorption, and collecting the effluent and returning it to the starch factory;

[0044] (2) taking a 12 wt % potassium chloride solution to parse the anion resin column in step A, and collecting the parse solution for later use;

[0045] (3) The analytical solution in step B was concentrated by nanofiltration membrane, washed with purified water, and the retentate was collected. The pH was adjusted to 4.9 by adding potassium hydroxide, and the solution was hydrolyzed at 160° C. for 10 h. The solution was cooled to 50-60° C. by flash evaporation, and filtered on a plate and frame to obtain a potassium phytate hydrolyzate solution having a potassium phytate concentration of 25 wt %, a calcium content of 25 ppm, and a magnesium content of 550 ppm.

[0046] (4) Potassium phytate hydrolyzate was passed into the No. 1 resin column of the continuous ion exchange device in Example 1 at a rate of 12 L / h, a hydrochloric acid solution with a concentration of 10 wt% was passed into the No. 15 resin column at a rate of 1.8 L / h, the No. 21 resin column was filled with a calcium and magnesium analysis solution at a rate of 0.88 L / h, the No. 22 resin column actually produced a calcium and magnesium analysis solution at a rate of 0.92 L / h, the No. 14 resin column produced a water top acid at a rate of 0.88 L / h, the No. 11 resin column produced an air pressure top acid water at a rate of 0.84 L / h, and the No. 10 resin column obtained a calcium-free and magnesium-free hydrolyzate with a calcium content of 4 ppm and a magnesium content of 60 ppm. The specific data are shown in Table 3 below.

[0047] Table 3

[0048]

[0049] Example 5

[0050] (1) taking clarified corn soaking water, countercurrently entering an anion resin column for phytic acid adsorption, and collecting the effluent and returning it to the starch factory;

[0051] (2) using a potassium chloride solution with a concentration of 8 wt % to parse the anion resin column in step A, and collecting the parse solution for later use;

[0052] (3) The analytical solution in step B is concentrated by nanofiltration membrane, washed with purified water, and the retentate is collected. The pH value is adjusted to 4.7 by adding potassium hydroxide, and the solution is hydrolyzed at 160° C. for 10 h. The solution is cooled to 50-60° C. by flash evaporation, and filtered by plate and frame to obtain a potassium phytate hydrolyzate solution having a potassium phytate concentration of 25 wt %, a calcium content of 30 ppm, and a magnesium content of 600 ppm;

[0053] (4) The potassium phytate hydrolyzate was passed into the resin column No. 1 of the continuous ion exchange device in Example 1 at a rate of 10 L / h, the hydrochloric acid solution with a concentration of 6 wt% was passed into the resin column No. 15 at a rate of 1.8 L / h, the filling liquid of the resin column No. 21 was the calcium and magnesium analysis liquid at 0.88 L / h, the top salt solution of the resin column No. 22 was 0.92 L / h, the water top acid produced by the resin column No. 14 was 0.88 L / h, and the air pressure top acid water produced by the resin column No. 11 was 0.88 L / h. The calcium-depleted and magnesium-depleted hydrolyzate obtained by the resin column No. 10 had a calcium content of 4.5 ppm and a magnesium content of 55 ppm. The specific data are shown in Table 4 below.

[0054] Table 4

[0055]

[0056] Example 6

[0057] (1) taking clarified corn soaking water, countercurrently entering an anion resin column for phytic acid adsorption, and collecting the effluent and returning it to the starch factory;

[0058] (2) using a 15 wt% potassium chloride solution to parse the anion resin column in step A, and collecting the parse solution for later use;

[0059] (3) The analytical solution in step B is concentrated by nanofiltration membrane, washed with purified water, and the retentate is collected. The pH value is adjusted to 4.7 by adding potassium hydroxide, and the solution is hydrolyzed at 160° C. for 10 h. The solution is cooled to 50-60° C. by flash evaporation, and filtered by plate and frame to obtain a potassium phytate hydrolyzate solution having a potassium phytate concentration of 25 wt %, a calcium content of 30 ppm, and a magnesium content of 600 ppm;

[0060] (4) The potassium phytate hydrolyzate was passed into the resin column No. 1 of the continuous ion exchange device in Example 1 at a rate of 10 L / h, a hydrochloric acid solution with a concentration of 12 wt% was passed into the resin column No. 15 at a rate of 1.8 L / h, the filling liquid of the resin column No. 21 was the calcium and magnesium analysis liquid at a rate of 0.88 L / h, the top salt solution of the resin column No. 22 was 0.92 L / h, the water top acid produced by the resin column No. 14 was 0.88 L / h, and the air pressure top acid water produced by the resin column No. 11 was 0.84 L / h. The calcium and magnesium-free hydrolyzate obtained by the resin column No. 10 had a calcium content of 2 ppm and a magnesium content of 40 ppm. The specific data are shown in Table 5 below.

[0061] Table 5

[0062]

[0063] Example 7

[0064] (1) taking clarified corn soaking water, countercurrently entering an anion resin column for phytic acid adsorption, and collecting the effluent and returning it to the starch factory;

[0065] (2) using a 15 wt% potassium chloride solution to parse the anion resin column in step A, and collecting the parse solution for later use;

[0066] (3) The analytical solution in step B was concentrated by nanofiltration membrane, washed with purified water, and the retentate was collected. The pH was adjusted to 4.8 by adding potassium hydroxide, and the solution was hydrolyzed at 160° C. for 10 h. The solution was cooled to 50-60° C. by flash evaporation, and filtered by plate and frame to obtain a potassium phytate hydrolyzate solution with a potassium phytate concentration of 25 wt %, a calcium content of 25 ppm, and a magnesium content of 500 ppm.

[0067] (4) Potassium phytate hydrolyzate was passed into the No. 1 resin column of the continuous ion exchange device in Example 1 at a rate of 9 L / h, a hydrochloric acid solution with a concentration of 12 wt% was passed into the No. 15 resin column at a rate of 1.6 L / h, the No. 21 resin column was filled with calcium and magnesium analysis solution at a rate of 0.88 L / h, the No. 22 resin column top salt solution was 0.92 L / h, the No. 14 resin column produced water top acid at a rate of 0.88 L / h, the No. 11 resin column produced air pressure top acid water at a rate of 0.84 L / h, and the No. 10 resin column obtained a calcium-free and magnesium-free hydrolyzate with a calcium content of 1 ppm and a magnesium content of 30 ppm. The specific data are shown in Table 6 below.

[0068] Table 6

[0069]

[0070] Example 8

[0071] The calcium- and magnesium-free hydrolyzate in step (4) of Examples 2 to 7 was taken respectively, filtered through medium-speed filter paper, and the filtrate was collected.

[0072] The filtrate is concentrated and crystallized under vacuum at -0.09 to -0.095 MPa and in a water bath at 80 to 90° C., filtered, rinsed with purified water, and dried to obtain potassium dihydrogen phosphate.

[0073] In addition, the potassium phytate hydrolyzate in step (3) of Examples 2 to 7 was taken respectively, filtered with medium-speed filter paper, and the filtrate was collected.

[0074] The filtrate is concentrated and crystallized under vacuum at -0.09 to -0.095 MPa and in a water bath at 80 to 90° C., filtered, rinsed with purified water, and dried to obtain potassium dihydrogen phosphate.

[0075] The above potassium dihydrogen phosphate was added with water at a ratio of 1:10 (V / V), stirred for 10 minutes, and the dissolution was observed to obtain the following results: Table 7:

[0076] Table 7

[0077]

[0078]

[0079] It can be seen from the above examples that after the potassium phytate hydrolyzate is treated by the continuous ion exchange device, the removal rate of calcium and magnesium reaches more than 80%, and the prepared potassium dihydrogen phosphate will not produce turbidity after being mixed with water at a ratio of 1:10 (V / V), thereby improving the product quality.

[0080] It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water, characterized in that The following steps are involved: A: Take the clarified corn soaking water and flow it into the anion resin column in reverse flow to adsorb phytic acid. The effluent is collected and returned to the starch plant. B: Take potassium chloride solution to parse the anion resin column in step A, and collect the parse solution for later use; C: The analytical solution in step B is concentrated by nanofiltration membrane, washed with purified water, the retentate is collected, potassium hydroxide is added to adjust the pH to 4.7-5.0, hydrolyzed at 160°C for 10h, cooled to 50-60°C by flash evaporation, and filtered by plate and frame to obtain potassium phytate hydrolyzate; D: The potassium phytate hydrolyzate is passed into a continuous ion exchange device, and the outflowing tail liquid is a calcium-magnesium-removed hydrolyzate, wherein the continuous ion exchange device comprises an adsorption zone, an air-pressure top acid water zone, a water-pressure top acid zone, a decomposition zone, a filling zone, an air-pressure top salt water zone and a water-pressure top salt zone arranged in sequence; The adsorption zone includes two adsorption column groups arranged in series, each of which includes five resin columns connected in series through pipelines; the desorption zone includes two desorption column groups arranged in series, each of which includes three resin columns connected in series through pipelines; The resin columns in the continuous ion exchange device have the same structure and are all filled with LSC-500 cationic resin.

2. The method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water as claimed in claim 1, characterized in that: The concentration of the potassium chloride solution in step B is 8-15wt%.

3. The method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water as claimed in claim 1, characterized in that: The analytical agent used in the analytical zone is a hydrochloric acid solution with a concentration of 6 to 12 wt%.

4. The method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water as claimed in claim 1, characterized in that: The resin column drain liquid from the air-pressure top acid water area and the air-pressure top salt water area is collected and returned to the pure water tank. The drain liquid from the water-pressure top salt area can be returned to the hydrolyzed liquid in step C.

5. The method for removing calcium and magnesium from potassium phytate hydrolyzate prepared by using corn soaking water as claimed in claim 1, characterized in that: In step D, the introduction rate of potassium phytate hydrolyzate is 8 to 12 L / h.

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