Process method for preparing soluble and deposition-free phosphorus and potassium powder

Abstract

The invention relates to the technical field of phosphorus-potassium powder, in particular to a process method for preparing soluble and deposition-free phosphorus-potassium powder, which comprises the following steps: taking a crystallized phosphorus-potassium solution, carrying out heat preservation and stirring until crystals are completely dissolved to obtain a material solution, adjusting the pH value, adding potassium sulfate, and stirring and dissolving (the potassium content can be increased and the material caking can be prevented at the same time); the method comprises the following steps of: adding a flocculating agent, settling and separating (impurity ions such as calcium, magnesium and the like can be effectively removed), adding a surfactant (preventing the material liquid from sticking to the wall) into the collected filtrate, stirring and uniformly mixing, and spray-drying to obtain an easily-soluble and non-deposited phosphorus and potassium powder product without sticking to the wall in the spray-drying process. By means of the process method, the phosphorus and potassium powder product which is easy to dissolve and free of deposition can be obtained, and wall sticking is avoided in the spray drying process.

Description

Technical Field

[0001] This invention relates to the field of phosphorus and potassium powder technology, and in particular to a process for preparing easily soluble and sediment-free phosphorus and potassium powder. Background Technology

[0002] When preparing potassium phosphate powder using potassium phytate, the raw material potassium phytate carries magnesium and calcium ions from the corn soaking water. When using a spray drying process, the saturated potassium phosphate solution, when sprayed through a high-speed rotating nozzle, can cause nozzle clogging, clumping, and sedimentation. Furthermore, the presence of magnesium and calcium ions reduces the quality of the resulting potassium phosphate powder, specifically manifesting as turbidity and flocculent formation after dissolving in water, failing to meet practical requirements. Currently, direct filtration or sedimentation is used to remove calcium and magnesium ions from the potassium phosphate powder. However, due to incomplete sedimentation of magnesium and calcium ions in water, the removal effect is not ideal. Moreover, this process requires further dissolving, crystallizing, and drying of the potassium phosphate powder, which not only reduces the yield of potassium phosphate powder but also makes the process of separating magnesium and calcium ions cumbersome. Therefore, a new process method is urgently needed to solve these problems. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a process for preparing easily soluble and non-depositing potassium phosphate powder, which addresses the shortcomings of the prior art. Using this preparation method, easily soluble and non-depositing potassium phosphate powder products can be obtained, and there are no problems of sticking to the wall or clogging the nozzle during drying.

[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0005] A process for preparing easily soluble and sediment-free phosphorus and potassium powder, the process comprising the following steps:

[0006] (1) Take the crystalline potassium phosphate solution, keep it warm and stir at a temperature not lower than 50°C until all the crystals are dissolved, and use the resulting solution for later use.

[0007] (2) Take the liquid from step (1), adjust the pH to not less than 4, add potassium sulfate and stir to dissolve, then add flocculant and continue stirring. After the temperature is controlled and the mixture settles for a period of time, filter the mixture and collect the filtrate for later use.

[0008] (3) Take the filtrate from step (2), add a surfactant and stir to mix well. After spray drying, you can obtain an easily soluble and sediment-free phosphorus and potassium powder product.

[0009] As an improved technical solution, in step (1), the temperature of the crystallized potassium phosphate solution is controlled at 50-60℃, and the solid content of the solution is 48-50wt%.

[0010] As an improved technical solution, in step (2), potassium hydroxide is used to adjust the pH of the feed solution to 4-8.

[0011] As an improved technical solution, the amount of potassium sulfate added in step (2) is 2-10 wt% of the solid content of the liquid in step (1).

[0012] As an improved technical solution, the amount of flocculant added in step (2) is 1-3 wt% of the solid content of the liquid in step (1); the flocculant includes aluminum sulfate and microbial flocculant, and the aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:0.3-1.

[0013] As an improved technical solution, in step (2), the temperature is controlled at 50-75℃ and the settling time is 1-3 hours.

[0014] As an improved technical solution, the surfactant in step (3) includes anionic surfactant or cationic surfactant, and the amount of anionic surfactant or cationic surfactant added is 1-3 wt% of the solid content of the liquid in step (1).

[0015] As an improved technical solution, in step (3), during spray drying, the inlet air temperature is controlled at 180-230℃ and the outlet air temperature is controlled at 80-120℃.

[0016] After adopting the above technical solution, the beneficial effects of the present invention are:

[0017] This invention involves taking a crystalline potassium phosphate solution, keeping it warm and stirring until all the crystals are dissolved, adjusting the pH first, then adding potassium sulfate and stirring to dissolve it (this increases the potassium content and prevents material agglomeration, improving material flowability), then adding a flocculant, and separating it by sedimentation (effectively removing impurity ions such as calcium and magnesium). A surfactant is added to the collected filtrate (to prevent the solution from sticking to the wall), and after stirring and mixing, it is spray-dried to obtain an easily soluble potassium phosphate powder product without sedimentation, and there is no wall sticking during the spray-drying process. Detailed Implementation

[0018] 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.

[0019] Example 1

[0020] A process for preparing easily soluble and sediment-free potassium phosphate powder includes the following steps:

[0021] (1) Take 5L of crystallized phosphorus and potassium solution, keep it warm and stir at 50℃ until all the crystals are dissolved, and obtain 4.9L of solution with a solid content of 48wt% (total phosphorus content of 38% and potassium content of 26%) for later use.

[0022] (2) Take 4.9L of the liquid with a solid content of 48wt% in step (1), adjust the pH to 4 with potassium hydroxide, add potassium sulfate with a solid content of 2wt% and stir to dissolve, then add flocculant with a solid content of 1wt% (aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:0.3) and continue stirring. After settling at 50℃ for 1 hour, filter and collect 4.3L of filtrate for later use.

[0023] (3) Take 4.3L of the filtrate from step (2), add 1wt% of the solid content of the liquid with a surfactant (cationic surfactant, specifically hexadecyltrimethylammonium bromide), stir and mix well, and then spray dry (control the inlet air temperature to 180℃ and the outlet air temperature to 80℃) to obtain an easily soluble and sediment-free phosphorus and potassium powder product.

[0024] Example 2

[0025] A process for preparing easily soluble and sediment-free potassium phosphate powder includes the following steps:

[0026] (1) Take 5L of crystalline phosphorus and potassium solution, keep it warm and stir at 52℃ until all the crystals are dissolved, and obtain 4.95L of solution with a solid content of 48.5wt% (total phosphorus content of 39% and potassium content of 27%) for later use.

[0027] (2) Take 4.95L of the liquid with a solid content of 48.5wt% in step (1), adjust the pH to 5 with potassium hydroxide, add potassium sulfate with a solid content of 4wt% and stir to dissolve, then add flocculant with a solid content of 1.5wt% (aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:0.5) and continue stirring. After settling at 55℃ for 1.5h, filter and collect 4.2L of filtrate for later use.

[0028] (3) Take 4.2L of the filtrate from step (2), add 1.5wt% of surfactant (anionic surfactant, specifically sodium lignosulfonate) with a solid content of 1.5wt%, stir and mix well, and then spray dry (control the inlet air temperature to 190℃ and the outlet air temperature to 90℃) to obtain an easily soluble and sediment-free phosphorus and potassium powder product.

[0029] Example 3

[0030] A process for preparing easily soluble and sediment-free potassium phosphate powder includes the following steps:

[0031] (1) Take 5L of crystallized phosphorus and potassium solution, keep it warm and stir at 55℃ until all the crystals are dissolved, and obtain 5.1L of solution with a solid content of 49wt% (total phosphorus content of 40% and potassium content of 29%) for later use.

[0032] (2) Take 5.1L of the liquid with a solid content of 49wt% in step (1), adjust the pH to 5.5 with potassium hydroxide, add potassium sulfate with a solid content of 6wt% and stir to dissolve, then add flocculant with a solid content of 2wt% (aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:0.7) and continue stirring. After settling at 63℃ for 2 hours, filter and collect 4.5L of filtrate for later use.

[0033] (3) Take 4.5L of the filtrate from step (2), add 2wt% of the solid content of the liquid with a surfactant (cationic surfactant, specifically hexadecyltrimethylammonium bromide), stir and mix well, and then spray dry (control the inlet air temperature to 200℃ and the outlet air temperature to 100℃) to obtain an easily soluble and sediment-free phosphorus and potassium powder product.

[0034] Example 4

[0035] A process for preparing easily soluble and sediment-free potassium phosphate powder includes the following steps:

[0036] (1) Take 5L of crystalline phosphorus and potassium solution, keep it warm and stir at 58℃ until all the crystals are dissolved, and obtain 5.2L of solution with a solid content of 49.5wt% (total phosphorus content of 39% and potassium content of 27%) for later use.

[0037] (2) Take 5.2L of the liquid with a solid content of 49.5wt% in step (1), adjust the pH to 7 with potassium hydroxide, add potassium sulfate with a solid content of 8wt% and stir to dissolve, then add flocculant with a solid content of 2.5wt% (aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:0.9) and continue stirring. After settling at 68℃ for 2.5h, filter and collect 4.4L of filtrate for later use.

[0038] (3) Take 4.4L of the filtrate from step (2), add 2.5wt% of surfactant (cationic surfactant, specifically dodecyltrimethylammonium bromide) with a solid content of 2.5wt%, stir and mix well, and then spray dry (control the inlet air temperature to 215℃ and the outlet air temperature to 110℃) to obtain an easily soluble and sediment-free potassium phosphate powder product.

[0039] Example 5

[0040] A process for preparing easily soluble and sediment-free potassium phosphate powder includes the following steps:

[0041] (1) Take 5L of crystallized phosphorus and potassium solution, keep it warm and stir at 50-60℃ until all the crystals are dissolved, and obtain 5L of material solution with a solid content of 50wt% (total phosphorus content of 39% and potassium content of 27%) for later use.

[0042] (2) Take 5L of the liquid with a solid content of 50wt% in step (1), adjust the pH to 8 with potassium hydroxide, add potassium sulfate with a solid content of 10wt% and stir to dissolve, then add flocculant with a solid content of 3wt% (aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:1) and continue stirring. After settling at 75℃ for 3 hours, filter and collect 4.2L of filtrate for later use.

[0043] (3) Take 4.2L of the filtrate from step (2), add 3wt% of surfactant (anionic surfactant, specifically sodium lignosulfonate) with a solid content of 3wt%, stir and mix well, and then spray dry (control the inlet air temperature to 230℃ and the outlet air temperature to 120℃) to obtain an easily soluble and sediment-free phosphorus and potassium powder product.

[0044] To better demonstrate that the process of the present invention can produce easily soluble, non-depositional phosphorus and potassium powder products, the following comparative examples are given with reference to Example 3. The specific evaluation indicators of phosphorus and potassium powder in Examples 1-5 and the comparative examples are detailed in Table 1.

[0045] Comparative Example 1

[0046] Unlike Example 3, the temperature of the potassium phosphate solution in step (1) is controlled at 45°C, while the rest of the operation is the same.

[0047] Comparative Example 2

[0048] Unlike Example 3, the temperature of the potassium phosphate solution in step (1) is controlled at 65°C, while the rest of the operation is the same.

[0049] Comparative Example 3

[0050] Unlike Example 3, in step (2), potassium hydroxide is used to adjust the pH of the feed solution to 3.

[0051] Comparative Example 4

[0052] Unlike Example 3, in step (2), potassium hydroxide was used to adjust the pH of the feed solution to 9.

[0053] Comparative Example 5

[0054] Unlike Example 3, the amount of potassium sulfate added in step (2) is 1 wt% of the solid content of the liquid in step (1).

[0055] Comparative Example 6

[0056] Unlike Example 3, the amount of potassium sulfate added in step (2) is 11 wt% of the solid content of the liquid in step (1).

[0057] Comparative Example 7

[0058] Unlike Example 3, potassium sulfate was not added in step (2), but the rest of the operation was the same.

[0059] Comparative Example 8

[0060] Unlike Example 3, no flocculant was added in step (2), but the rest of the operation was the same.

[0061] Comparative Example 9

[0062] Unlike Example 3, the flocculant added in step (2) is aluminum sulfate, while the rest of the operation is the same.

[0063] Comparative Example 10

[0064] Unlike Example 3, the flocculant added in step (2) is a microbial flocculant, while the rest of the operation is the same.

[0065] Comparative Example 11

[0066] Unlike Example 3, the temperature is controlled at 45°C in step (2), while the rest of the operation is the same.

[0067] Comparative Example 12

[0068] Unlike Example 3, the temperature is controlled at 80°C in step (2), while the rest of the operation is the same.

[0069] Comparative Example 13

[0070] Unlike Example 3, no surfactant was added in step (3), but the rest of the operation was the same.

[0071] Comparative Example 14

[0072] Unlike Example 3, in step (3), the amount of surfactant added is 0.5 wt% of the solid content of the liquid, and the rest of the operation is the same.

[0073] Comparative Example 15

[0074] Unlike Example 3, in step (3), the amount of surfactant added is 4 wt% of the solid content of the liquid, and the rest of the operation is the same.

[0075] Comparative Example 16

[0076] Unlike Example 3, in step (3), the inlet air temperature is controlled at 170°C and the outlet air temperature is controlled at 70°C during spray drying.

[0077] Comparative Example 17

[0078] Unlike Example 3, in step (3), the inlet air temperature is controlled at 40°C and the outlet air temperature is controlled at 130°C during spray drying.

[0079] Table 1

[0080]

[0081]

[0082]

[0083] The data in Table 1 shows that the phosphorus and potassium powder product obtained by using the process method of Example 3 of the present invention has better yield, phosphorus and potassium content, color, solubility and sedimentation than other examples and comparative examples, and there is no sticking to the wall during spray drying.

[0084] The above description is merely 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 easily soluble and sediment-free potassium phosphate powder, characterized in that, The process includes the following steps: (1) Take the crystalline potassium phosphate solution, keep it warm and stir at a temperature not lower than 50°C until all the crystals are dissolved, and use the resulting solution for later use. (2) Take the liquid from step (1), adjust the pH to not less than 4, add potassium sulfate and stir to dissolve, then add flocculant and continue stirring. After the temperature is controlled and the mixture settles for a period of time, filter the mixture and collect the filtrate for later use. (3) Take the filtrate from step (2), add a surfactant and stir to mix well. After spray drying, you can obtain an easily soluble and sediment-free phosphorus and potassium powder product.

2. The process for preparing easily soluble and sediment-free phosphorus and potassium powder according to claim 1, characterized in that, In step (1), the temperature of the crystallizing potassium phosphate solution is controlled at 50-60℃, and the solid content of the solution is 48-50wt%.

3. The process for preparing easily soluble and sediment-free phosphorus and potassium powder according to claim 1, characterized in that, In step (2), potassium hydroxide is used to adjust the pH of the feed solution to 4-8.

4. The process for preparing easily soluble and sediment-free potassium phosphate powder according to claim 1, characterized in that, The amount of potassium sulfate added in step (2) is 2-10 wt% of the solid content of the liquid in step (1).

5. The process for preparing easily soluble and sediment-free phosphorus and potassium powder according to claim 1, characterized in that, The amount of flocculant added in step (2) is 1-3 wt% of the solid content of the liquid in step (1); the flocculant includes aluminum sulfate and microbial flocculant, and the aluminum sulfate and microbial flocculant are mixed in a mass ratio of 1:0.3-1.

6. The process for preparing easily soluble and sediment-free potassium phosphate powder according to claim 1, characterized in that, In step (2), the temperature is controlled at 50-75℃, and the sedimentation time is 1-3 hours.

7. The process for preparing easily soluble and sediment-free potassium phosphate powder according to claim 1, characterized in that, The surfactant in step (3) includes anionic surfactant or cationic surfactant, and the amount of anionic surfactant or cationic surfactant added is 1-3 wt% of the solid content of the liquid in step (1).

8. The process for preparing easily soluble and sediment-free potassium phosphate powder according to claim 1, characterized in that, In step (3), during spray drying, the inlet air temperature is controlled at 180-230℃ and the outlet air temperature is controlled at 80-120℃.

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