A process for preparing magnesium ammonium phosphate and inositol using corn steep liquor

Abstract

This invention relates to the field of corn soaking water treatment technology, and particularly to a process for preparing magnesium ammonium phosphate and inositol using corn soaking water. The process includes: adjusting the pH of the corn soaking water to acidic, filtering, passing the collected filtrate through an anion exchange resin column, followed by hydrochloric acid analysis. Magnesium oxide is added to the collected eluent, and the pH, temperature, and time are controlled. After the neutralization reaction, the mixture is filtered again. Water is added to the collected magnesium phytate filter cake, and the mixture is heated and pressurized for hydrolysis. The resulting hydrolysate is then cooled, and ammonia is added to adjust the pH to alkaline, controlling the molar ratio of magnesium ions to phosphate ions. After the reaction, the mixture is filtered again. The collected filtrate is decolorized, concentrated, cooled to crystallize, filtered, and dried to obtain the inositol product. The collected filter cake is dried to obtain the magnesium ammonium phosphate product. This process avoids resource waste and yields high-yield, high-purity magnesium ammonium phosphate and inositol products.

Description

Technical Field

[0001] This invention relates to the field of corn soaking water treatment technology, and in particular to a process for preparing magnesium ammonium phosphate and inositol using corn soaking water. Background Technology

[0002] Magnesium ammonium phosphate is an important chemical product with wide applications in agriculture and environmental protection, such as as a slow-release compound fertilizer and for treating phosphorus-containing wastewater. Inositol is a vitamin-like substance with important uses in the pharmaceutical, food, and feed industries. Current traditional preparation methods for magnesium ammonium phosphate require the consumption of pure chemicals, resulting in high costs. Inositol production processes often use zein (calcium magnesium phytate) as a raw material, requiring strong acid hydrolysis, which poses problems of equipment corrosion and waste acid pollution.

[0003] Corn soaking water is a byproduct of corn starch processing, rich in phytic acid (inositol hexaphosphate). Traditional treatment methods often result in wastewater discharge, leading to resource waste and environmental pollution. Developing a process to prepare magnesium ammonium phosphate and inositol from corn soaking water can achieve the dual goals of efficient resource utilization and environmental protection. However, existing processes for extracting related substances from corn soaking water suffer from problems such as complex procedures, low product purity, and high costs. For example, patent CN110950344A uses a chemical precipitation method to treat corn soaking water, but requires the addition of phosphate to adjust the phosphorus-magnesium ratio (Mg:PO4 = 1.2:1), increasing costs by more than 30%. Patent CN104945344C uses an acid hydrolysis-ion exchange method to extract inositol from soaking water, but requires the use of strong acid (pH ≤ 2), causing equipment corrosion, and the yield is only 68%. Many technologies process phosphates or organic matter separately (such as patent CN111995092A which only recovers nitrogen and phosphorus), resulting in: (1) low resource utilization (total carbon recovery rate < 40%); (2) generation of secondary wastewater (COD > 5000 mg / L); (3) lengthy process routes (average 5-7 unit operations); therefore, in order to address the above problems, it is necessary to develop an efficient, environmentally friendly and low-cost preparation process. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a process for preparing magnesium ammonium phosphate and inositol using corn soaking water, which can obtain high-yield, high-purity inositol and magnesium ammonium phosphate products, avoiding resource waste and reducing costs.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0006] A process for preparing magnesium ammonium phosphate and inositol using corn soaking water, the process comprising the following steps:

[0007] (1) Adjust the pH of the collected corn soaking water to acidic, filter it and collect the filtrate for later use.

[0008] (2) Take the filtrate from step (1) and feed it into the anion exchange resin column. When the phytic acid concentration in the effluent is less than 0.1 g / L, the feeding is stopped. Then, hydrochloric acid is used to elute the anion exchange resin column, and the collected eluent is used for later use.

[0009] (3) Take the elution solution described in step (2), add magnesium oxide to control the pH, control the reaction temperature and reaction time, filter after the reaction is completed, and collect the magnesium phytate filter cake for later use.

[0010] (4) Take the magnesium phytate filter cake from step (3), add water and stir. After hydrolysis, the hydrolysate is prepared for use.

[0011] (5) Take the hydrolysate described in step (4), cool it down, add ammonia water to adjust the pH to alkaline, and control the molar ratio of magnesium ions and phosphate ions. After the reaction is completed, filter and collect the filter cake and filtrate respectively. The collected filter cake can be dried to obtain magnesium ammonium phosphate product. The collected filtrate can be decolorized, concentrated, cooled and crystallized, and filtered. The collected solid phase can be dried to obtain inositol product.

[0012] As an improved technical solution, in step (1), the pH of the corn soaking water is adjusted to 3.5-5, and a plate and frame filter with a filter cloth pore size of 80-300 mesh is used for filtration.

[0013] As an improved technical solution, the filtrate in step (2) enters the anion exchange resin column at a flow rate of 1-3 BV / h, and the packing material in the anion exchange resin column is gel resin--ZGA412, gel resin--D315 or gel resin--ADS-600.

[0014] As an improved technical solution, the concentration of hydrochloric acid in step (2) is 5-8 wt%, and the hydrochloric acid is used to desorb the anion exchange resin column at a flow rate of 1-2 BV / h.

[0015] As an improved technical solution, in step (3), the pH is controlled at 6.0-7.5, the reaction temperature is controlled at 45-60℃, and the reaction time is controlled at 1-3h.

[0016] As an improved technical solution, the phytic acid magnesium filter cake and the water in step (4) are mixed in a mass ratio of 1:2-4 and hydrolyzed for 10-12 hours under the conditions of 0.8-1.2 MPa and 160-180℃.

[0017] As an improved technical solution, in step (5), the hydrolysate is cooled to 45-55℃, ammonia is added to adjust the pH to 9-10, the molar ratio of magnesium ions to phosphate ions is controlled to be 1-1.5:1, and the reaction time is controlled to be 20-40 min.

[0018] As an improved technical solution, the filtrate in step (5) is decolorized with activated carbon and concentrated to a specific gravity of 1.28-1.30.

[0019] After adopting the above technical solution, the beneficial effects of the present invention are:

[0020] This invention involves first adjusting the pH of corn soaking water to acidic, then filtering the solution. The collected filtrate is then treated with an anion exchange resin column, followed by hydrochloric acid analysis. Magnesium oxide is added to the collected eluent, and the pH, reaction temperature, and reaction time are controlled. After neutralization, the solution is filtered again. Water is added to the collected magnesium phytate filter cake, and the mixture is heated and pressurized for hydrolysis. The resulting hydrolysate is then cooled, and ammonia is added to adjust the pH to alkaline, controlling the molar ratio of magnesium ions to phosphate ions. After the reaction, the solution is filtered, and the collected filtrate is decolorized, concentrated, cooled to crystallize, filtered, and dried to obtain the inositol product. The collected filter cake is dried to obtain the magnesium ammonium phosphate product. This process avoids resource waste and yields high-yield, high-purity magnesium ammonium phosphate and inositol products, increasing economic benefits for enterprises. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1

[0023] A process for preparing magnesium ammonium phosphate and inositol using corn soaking water includes the following steps:

[0024] (1) Adjust the pH of the collected 15L corn soaking water (phytic acid content is 1.5%) to 3.5, filter it with a plate and frame filter press with a filter cloth pore size of 80-300 mesh, and collect 15L of filtrate for later use.

[0025] (2) Take 15L of the filtrate from step (1) and feed it into a 2L anion exchange resin column (the packing material is gel resin ZGA412) at a flow rate of 1BV / h. When the phytic acid concentration in the effluent is less than 0.1g / L, the feeding is stopped. Then, 4L of hydrochloric acid with a concentration of 5wt% is used to elute the anion exchange resin column at a flow rate of 1BV / h. The collected 4L eluent is used for later use.

[0026] (3) Take 4L of the elution solution from step (2), add magnesium oxide to control the pH at 6.0, control the reaction temperature at 45℃, filter after 1h of reaction, and collect 280g of magnesium phytate filter cake for later use.

[0027] (4) Take 280g of magnesium phytate filter cake from step (3), add water at a mass ratio of 1:2 and stir. Hydrolyze the mixture at 0.8MPa and 160℃ for 10h and obtain 0.5L of hydrolysate for later use.

[0028] (5) Take 0.5L of the hydrolysate from step (4), cool it to 45℃, add ammonia to adjust the pH to 9, and control the molar ratio of magnesium ions and phosphate ions to 1:1. After reacting for 20 minutes, filter and collect the filter cake and filtrate respectively. The 210g filter cake collected can be dried to obtain magnesium ammonium phosphate product. The 0.8L filtrate collected is decolorized by activated carbon, and the 0.8L decolorized liquid collected is concentrated to a specific gravity of 1.28, cooled to 30℃ for crystallization, filtered, and the 40g solid phase collected is dried to obtain inositol product.

[0029] Example 2

[0030] A process for preparing magnesium ammonium phosphate and inositol using corn soaking water includes the following steps:

[0031] (1) Adjust the pH of the collected 15L corn soaking water (phytic acid content is 1.5%) to 4, and filter it with a plate and frame filter press with a filter cloth pore size of 80-300 mesh. Collect 14L of filtrate for later use.

[0032] (2) Take 14L of the filtrate from step (1) and feed it into a 2L anion exchange resin column (the packing material is gel resin ADS-600) at a flow rate of 1.5BV / h. When the phytic acid concentration in the effluent is less than 0.1g / L, the feeding is stopped. Then, 4L of hydrochloric acid with a concentration of 6wt% is used to elute the anion exchange resin column at a flow rate of 1.2BV / h. The collected 4L eluent is used for later use.

[0033] (3) Take 4L of the elution solution from step (2), add magnesium oxide to control the pH at 6.5, control the reaction temperature at 48℃, filter after 1.5h, and collect 285g of magnesium phytate filter cake for later use.

[0034] (4) Take 285g of magnesium phytate filter cake from step (3), add water at a mass ratio of 1:2.5 and stir. Hydrolyze it for 10.5h at 0.9MPa and 165℃ to obtain 0.8L of hydrolysate for later use.

[0035] (5) Take 0.8L of the hydrolysate from step (4), cool it to 48℃, add ammonia to adjust the pH to 9.2, and control the molar ratio of magnesium ions to phosphate ions to 1.15:1. After reacting for 25 minutes, filter and collect the filter cake and filtrate respectively. The 230g filter cake collected can be dried to obtain magnesium ammonium phosphate product. The 1L filtrate collected is decolorized by activated carbon, and the 1L decolorized liquid collected is concentrated to a specific gravity of 1.29, cooled to 35℃ for crystallization, filtered, and the 40g solid phase collected is dried to obtain inositol product.

[0036] Example 3

[0037] A process for preparing magnesium ammonium phosphate and inositol using corn soaking water includes the following steps:

[0038] (1) Adjust the pH of the collected 15L corn soaking water (phytic acid content is 1.5%) to 4.3, filter it with a plate and frame filter press with a filter cloth pore size of 80-300 mesh, and collect 14.5L of filtrate for later use.

[0039] (2) Take 14.5L of the filtrate from step (1) and feed it into a 2L anion exchange resin column (the packing material is gel resin ZGA412) at a flow rate of 2BV / h. When the phytic acid concentration in the effluent is less than 0.1g / L, the feeding is stopped. Then, 4L of hydrochloric acid with a concentration of 7wt% is used to elute the anion exchange resin column at a flow rate of 1.5BV / h. The collected 4L eluent is used for later use.

[0040] (3) Take 4L of the elution solution from step (2), add magnesium oxide to control the pH at 7.0, control the reaction temperature at 53℃, filter after 2h of reaction, and collect 300g of magnesium phytate filter cake for later use.

[0041] (4) Take 300g of magnesium phytate filter cake from step (3), add water at a mass ratio of 1:3 and stir. Hydrolyze the mixture at 1MPa and 170℃ for 11h and obtain 1L of hydrolysate for later use.

[0042] (5) Take 1L of hydrolysate from step (4), cool it to 50℃, add ammonia to adjust the pH to 9.5, and control the molar ratio of magnesium ions to phosphate ions to 1.25:1. After reacting for 30 minutes, filter and collect the filter cake and filtrate respectively. The 280g filter cake collected can be dried to obtain magnesium ammonium phosphate product. The 1.5L filtrate collected is decolorized by activated carbon, and the 1.5L decolorized liquid collected is concentrated to a specific gravity of 1.30, cooled to 25℃ for crystallization, filtered, and the 50g solid phase collected is dried to obtain inositol product.

[0043] Example 4

[0044] A process for preparing magnesium ammonium phosphate and inositol using corn soaking water includes the following steps:

[0045] (1) Adjust the pH of the collected 15L corn soaking water (phytic acid content is 1.5%) to 4.6, filter it with a plate and frame filter press with a filter cloth pore size of 80-300 mesh, and collect 14L of filtrate for later use.

[0046] (2) Take 14L of the filtrate from step (1) and feed it into a 2L anion exchange resin column (the packing material is gel resin ZGA412) at a flow rate of 2.5BV / h. When the phytic acid concentration in the effluent is less than 0.1g / L, the feeding is stopped. Then, 4L of hydrochloric acid with a concentration of 7.5wt% is used to elute the anion exchange resin column at a flow rate of 1.8BV / h. The collected 4L eluent is used for later use.

[0047] (3) Take 4L of the eluent from step (2), add magnesium oxide to control the pH at 7.2, control the reaction temperature at 56℃, filter after 2.5h, and collect 280g of magnesium phytate filter cake for later use.

[0048] (4) Take 280g of magnesium phytate filter cake from step (3), add water at a mass ratio of 1:3.5 and stir. Hydrolyze it for 11.5h at 1.1MPa and 175℃ to obtain 1.1L of hydrolysate for later use.

[0049] (5) Take 1.1L of the hydrolysate from step (4), cool it to 52℃, add ammonia to adjust the pH to 9.8, and control the molar ratio of magnesium ions to phosphate ions to 1.35:1. After reacting for 35 minutes, filter and collect the filter cake and filtrate respectively. The 260g filter cake collected can be dried to obtain magnesium ammonium phosphate product. The 1.5L filtrate collected is decolorized by activated carbon, and the 1.45L decolorized liquid collected is concentrated to a specific gravity of 1.30, cooled to 35℃ for crystallization, filtered, and the 38g solid phase collected is dried to obtain inositol product.

[0050] Example 5

[0051] A process for preparing magnesium ammonium phosphate and inositol using corn soaking water includes the following steps:

[0052] (1) Adjust the pH of the collected 15L corn soaking water (phytic acid content is 1.5%) to 5, and filter it with a plate and frame filter press with a filter cloth pore size of 80-300 mesh to collect 14.5L of filtrate for later use.

[0053] (2) Take 14.5L of the filtrate from step (1) and feed it into a 2L anion exchange resin column (the packing material is gel resin D315) at a flow rate of 3BV / h. When the phytic acid concentration in the effluent is less than 0.1g / L, the feeding is stopped. Then, 4L of hydrochloric acid with a concentration of 8wt% is used to elute the anion exchange resin column at a flow rate of 2BV / h. The collected 4L eluent is used for later use.

[0054] (3) Take 4L of the elution solution from step (2), add magnesium oxide to control the pH at 7.5, control the reaction temperature at 60℃, filter after 3h of reaction, and collect 230g of magnesium phytate filter cake for later use.

[0055] (4) Take 230g of magnesium phytate filter cake from step (3), add water at a mass ratio of 1:4 and stir. Hydrolyze the mixture at 1.2MPa and 180℃ for 12h and obtain 1L of hydrolysate for later use.

[0056] (5) Take 1L of hydrolysate from step (4), cool it to 55℃, add ammonia to adjust the pH to 10, and control the molar ratio of magnesium ions to phosphate ions to 1.5:1. After reacting for 40 minutes, filter and collect the filter cake and filtrate respectively. The 180g filter cake collected can be dried to obtain magnesium ammonium phosphate product. The 1L filtrate collected is decolorized by activated carbon, and the 0.95L decolorized liquid collected is concentrated to a specific gravity of 1.30, cooled to 35℃ for crystallization, filtered, and the 32g solid phase collected is dried to obtain inositol product.

[0057] To better demonstrate that the process of the present invention can yield high-volume, high-yield, and high-purity magnesium ammonium phosphate and inositol products, the following comparative examples are provided with reference to Example 3. The yield, yield, and purity of magnesium ammonium phosphate and inositol in Examples 1-5 and the comparative examples are detailed in Table 1.

[0058] Comparative Example 1

[0059] Unlike Example 3, in step (1), the pH of the corn soaking water was adjusted to 3, while the rest of the operation was the same.

[0060] Comparative Example 2

[0061] Unlike Example 3, in step (1), the pH of the corn soaking water was adjusted to 5.5, while the rest of the operation was the same.

[0062] Comparative Example 3

[0063] Unlike Example 3, in step (2), the packing material in the anion exchange resin column is macroporous anion exchange resin D301, and the rest of the operation is the same.

[0064] Comparative Example 4

[0065] Unlike Example 3, in step (2), the flow rate of the filtrate into the anion exchange resin column is 3.5 BV / h, and the rest of the operation is the same.

[0066] Comparative Example 5

[0067] Unlike Example 3, the concentration of hydrochloric acid in step (2) is 4 wt%, while the rest of the operation is the same.

[0068] Comparative Example 6

[0069] Unlike Example 3, the concentration of hydrochloric acid in step (2) is 9 wt%, while the rest of the operation is the same.

[0070] Comparative Example 7

[0071] Unlike Example 3, in step (2), hydrochloric acid was introduced into the anion exchange resin column at a flow rate of 2.5 BV / h, and the rest of the operation was the same.

[0072] Comparative Example 8

[0073] Unlike Example 3, magnesium oxide was added in step (3) to control the pH at 5.5, while the rest of the operation was the same.

[0074] Comparative Example 9

[0075] Unlike Example 3, magnesium oxide was added in step (3) to control the pH at 8, while the rest of the operation was the same.

[0076] Comparative Example 10

[0077] Unlike Example 3, the reaction temperature in step (3) is controlled at 40°C, while the rest of the operation is the same.

[0078] Comparative Example 11

[0079] Unlike Example 3, the reaction temperature in step (3) is controlled at 65°C, while the rest of the operation is the same.

[0080] Comparative Example 12

[0081] Unlike Example 3, the hydrolysis time in step (4) is controlled to be 9 hours, while the rest of the operation is the same.

[0082] Comparative Example 13

[0083] Unlike Example 3, the hydrolysis time in step (4) is controlled to be 13 hours, while the rest of the operation is the same.

[0084] Comparative Example 14

[0085] Unlike Example 3, the pH is controlled at 8.5 in step (5), while the rest of the operation is the same.

[0086] Comparative Example 15

[0087] Unlike Example 3, the pH is controlled at 10.5 in step (5), while the rest of the operation is the same.

[0088] Comparative Example 16

[0089] Unlike Example 3, in step (5), the hydrolysate is cooled to 40°C, while the rest of the operation is the same.

[0090] Comparative Example 17

[0091] Unlike Example 3, in step (5), the hydrolysate is cooled to 60°C, while the rest of the operation is the same.

[0092] Comparative Example 18

[0093] Unlike Example 3, the molar ratio of magnesium ions to phosphate ions in step (5) is 0.8:1, while the rest of the operation is the same.

[0094] Comparative Example 19

[0095] Unlike Example 3, in step (5), the decolorizing solution is concentrated to a specific gravity of 1.25, while the rest of the operation is the same.

[0096] Comparative Example 20

[0097] Unlike Example 3, in step (5), the decolorizing solution is concentrated to a specific gravity of 1.32, while the rest of the operation is the same.

[0098] Table 1

[0099]

[0100]

[0101] The data in Table 1 shows that the magnesium ammonium phosphate product and the inositol product obtained by using the process method of Example 3 of the present invention have better yield, purity and color than other examples and comparative examples.

[0102] 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 within the protection scope of the present invention.

Claims

1. A process for preparing magnesium ammonium phosphate and inositol using corn soaking water, characterized in that, The process includes the following steps: (1) Adjust the pH of the collected corn soaking water to 3.5-5, filter it and collect the filtrate for later use; (2) Take the filtrate from step (1) and feed it into the anion exchange resin column at a flow rate of 1-3 BV / h. When the phytic acid concentration in the effluent is less than 0.1 g / L, the feeding is stopped. Then, the anion exchange resin column is eluted with 5-8 wt% hydrochloric acid at a flow rate of 1-2 BV / h. The collected eluent is used for later use. The packing material in the anion exchange resin column is gel resin--ZGA412, gel resin--D315 or gel resin--ADS-600. (3) Take the elution solution described in step (2), add magnesium oxide to control the pH to 6.0-7.5, control the reaction temperature to 45-60℃ and the reaction time, filter after the reaction is completed, and collect the magnesium phytate filter cake for later use. (4) Take the magnesium phytate filter cake from step (3), add water and stir. After hydrolysis for 10-12 hours, the hydrolysate is ready for use. (5) Take the hydrolysate described in step (4), cool it to 45-55℃, add ammonia water to adjust the pH to 9-10, and control the molar ratio of magnesium ions and phosphate ions to 1-1.5:

1. After the reaction is completed, filter and collect the filter cake and filtrate respectively. The collected filter cake can be dried to obtain magnesium ammonium phosphate product. The collected filtrate is decolorized, concentrated to a specific gravity of 1.28-1.30, cooled to crystallize, and filtered. The collected solid phase can be dried to obtain inositol product.

2. The process for preparing magnesium ammonium phosphate and inositol using corn soaking water according to claim 1, characterized in that, In step (1), a plate and frame filter with a filter cloth pore size of 80-300 mesh is used for filtration.

3. The process for preparing magnesium ammonium phosphate and inositol using corn soaking water according to claim 1, characterized in that, In step (3), the reaction time is controlled to be 1-3 hours.

4. The process for preparing magnesium ammonium phosphate and inositol using corn soaking water according to claim 1, characterized in that, The phytic acid magnesium filter cake and the water in step (4) are mixed in a mass ratio of 1:2-4 and hydrolyzed under conditions of 0.8-1.2 MPa and 160-180℃.

5. The process for preparing magnesium ammonium phosphate and inositol using corn soaking water according to claim 1, characterized in that, In step (5), the reaction time is controlled to be 20-40 min.

6. The process for preparing magnesium ammonium phosphate and inositol using corn soaking water according to claim 1, characterized in that, The filtrate in step (5) is decolorized with activated carbon.

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