Anti-caking agent for potassium chloride granules, its preparation method and application

Abstract

This invention relates to an anti-caking agent for potassium chloride granules, its preparation method, and its application. The anti-caking agent comprises organically modified montmorillonite and hydrophobic silica. The organically modified montmorillonite is prepared by modifying montmorillonite with a composite coupling agent composed of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane. This modification significantly improves the hydrophobicity of montmorillonite and optimizes its interlayer spacing, thereby enhancing the hydrophobic properties of the anti-caking agent and strengthening its anti-caking effect. When the organically modified montmorillonite and hydrophobic silica are used simultaneously in the anti-caking agent, a hydrophobic film can be formed on the surface of the potassium chloride granules, synergistically reducing the hygroscopicity of the potassium chloride granules, improving their chemical stability, ensuring good dispersibility during storage and transportation, and preventing caking.

Description

Technical Field

[0001] This invention relates to the technical field of anti-caking agents, specifically to an anti-caking agent for potassium chloride granules, its preparation method, and its application. Background Technology

[0002] The clumping problem of water-soluble potassium chloride granular fertilizer is mainly affected by the hygroscopicity of raw materials, moisture content, stacking pressure, humidity of the production environment, and water absorption of packaging materials. When fertilizer granules absorb moisture, their surface will dissolve and evaporate, and crystal bridges will form during recrystallization, causing the fertilizer granules to stick together and gradually agglomerate into large clumps.

[0003] In practical applications, fertilizer caking disrupts its normal flowability, requiring crushing before use. This not only wastes resources and pollutes the environment but also increases usage costs. To address this issue, various anti-caking technologies have been adopted, including optimizing product packaging, improving production equipment and processes, adjusting fertilizer formulations, modifying fertilizer composition, improving storage conditions, and adding anti-caking agents. Among these, adding anti-caking agents is considered a simple and effective method.

[0004] Currently, commonly used anti-caking agents in powdered water-soluble fertilizers mainly include inorganic inert materials, surfactants, and polymers. Inorganic inert materials, such as talc, silica, and anhydrous magnesium sulfate, primarily prevent caking through mechanical isolation, but this may affect the fertilizer's water solubility and its effectiveness is limited in high-humidity environments. Surfactants, such as sodium dodecylbenzene sulfonate, mainly utilize their water solubility to reduce the adsorption force between particles, thereby achieving the purpose of preventing caking; however, their effectiveness is limited when used alone, and they are ineffective in some high-humidity environments. Polymers, such as polyacrylamide, while highly effective, are costly, and their environmental performance needs improvement. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an anti-caking agent for potassium chloride granules, its preparation method and application, which can effectively solve the problem of potassium chloride granules caking during long-term storage.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides an anti-caking agent for potassium chloride granules, comprising the following components in parts by weight: 50-60 parts of organically modified montmorillonite and 20-30 parts of hydrophobic silica; wherein the organically modified montmorillonite comprises the following raw materials: montmorillonite, a composite coupling agent, and an initiator, wherein the mass ratio of montmorillonite, the composite coupling agent, and the initiator is (1-1.5):1:(0.02-0.06), and the composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of (1-1.5):1:(0.5-0.6); and the particle size of the hydrophobic silica is less than the particle size of the organically modified montmorillonite.

[0008] The anti-caking agent of the present invention comprises organically modified montmorillonite and hydrophobic silica. The organically modified montmorillonite is prepared by modifying montmorillonite with a composite coupling agent composed of bis-(3-(triethoxysilane)propyl)-tetrasulfide, triisostearoyl titanate isopropyl ester, and heptadecafluorodecyltrimethoxysilane. The bis-(3-(triethoxysilane)propyl)-tetrasulfide contains triethoxysilyl groups (-Si(OEt)3) and tetrasulfide bonds (-S4-). The triethoxysilyl groups can undergo a condensation reaction with the hydroxyl groups on the surface of montmorillonite, thereby grafting hydrophobic tetrasulfide bonds onto the surface of montmorillonite, thus improving the hydrophobic properties of montmorillonite. The triisostearoyl titanate isopropyl ester contains hydrophobic... The stearoyl group significantly enhances the hydrophobic properties of montmorillonite; the heptadecafluorodecyltrimethoxysilane molecule contains a long-chain perfluoroalkyl group (-CF3(CF2)7CH2CH2-), which has extremely low surface energy and can significantly reduce the hydrophilicity of the montmorillonite surface. These three coupling agents work synergistically to enter the interlayer of montmorillonite through chemical bonding, effectively improving the hydrophobicity of montmorillonite and optimizing the interlayer spacing, so that a stable hydrophobic film is attached to the surface of montmorillonite. When the anti-caking agent is combined with potassium chloride particles, this hydrophobic film not only reduces the hygroscopicity of potassium chloride particles, but also improves the chemical stability of potassium chloride particles, so that they maintain good stability during storage and transportation and avoid caking.

[0009] In addition, since the particle size of the hydrophobic silica in this invention is smaller than that of the organically modified montmorillonite, the small-particle-size silica can be embedded in the layered structure of montmorillonite, thereby further increasing the interlayer spacing of montmorillonite, reducing the adsorption of water molecules, and synergistically improving the hydrophobic properties of the anti-caking agent.

[0010] Preferably, the initiator is dicumyl peroxide.

[0011] Preferably, the montmorillonite has a mesh size of 200-300.

[0012] Preferably, the hydrophobic silica has a mesh size of 400-600 mesh.

[0013] Preferably, the composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1.3:1:0.5.

[0014] In a second aspect, the present invention provides a method for preparing the anti-caking agent for potassium chloride granules in the first aspect, comprising the following steps:

[0015] S1. Disperse montmorillonite in anhydrous ethanol and stir evenly. Add composite coupling agent and initiator to react. After the reaction is complete, filter, wash until neutral, and dry to obtain organic modified montmorillonite.

[0016] S2. Organically modified montmorillonite and hydrophobic silica are ball-milled to obtain the anti-caking agent for the potassium chloride granules.

[0017] Preferably, the amount of anhydrous ethanol added is 1-2 times the total mass of montmorillonite, composite coupling agent and initiator.

[0018] Preferably, in step S1, the reaction temperature is 70-90℃ and the reaction time is 2-3 hours.

[0019] Preferably, in step S1, the organically modified montmorillonite and hydrophobic silica are ball-milled to 600-700 mesh.

[0020] Thirdly, the present invention provides the application of the anti-caking agent for potassium chloride granules in the first aspect in the preparation of potassium chloride granular fertilizer.

[0021] Preferably, the amount of the anti-caking agent for the potassium chloride granules added to the potassium chloride granule fertilizer is 0.1-0.5 wt%.

[0022] Specifically, the method of combining anti-caking agent with potassium chloride granular fertilizer includes the following steps: adding the anti-caking agent into the mixing equipment through a feeder, mixing it evenly with potassium chloride granules, and then conveying and packaging it through a conveyor belt and a finished product scraper.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] The anti-caking agent of this invention comprises organically modified montmorillonite and hydrophobic silica. The organically modified montmorillonite is prepared by modifying montmorillonite with a composite coupling agent composed of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane. This modification introduces hydrophobic groups through chemical bonding, significantly improving the hydrophobicity of montmorillonite and optimizing its interlayer spacing, thereby enhancing the hydrophobic properties of the anti-caking agent and strengthening its anti-caking effect. When the organically modified montmorillonite and hydrophobic silica are used simultaneously in the anti-caking agent, a hydrophobic film can be formed on the surface of potassium chloride particles, synergistically reducing the hygroscopicity of the potassium chloride particles and improving their chemical stability. When this anti-caking agent is compounded with potassium chloride particles, the hydrophobic film adhering to the surface of the potassium chloride particles reduces their hygroscopicity, improves their chemical stability, ensures good dispersibility during storage and transportation, and prevents agglomeration. Detailed Implementation

[0025] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0026] The sources of the raw materials used in the following examples and comparative examples are as follows:

[0027] Montmorillonite: Manufacturer is Lingshou County Kaihaoming Mineral Products Processing Plant, model number is K0005, mesh size is 200 mesh;

[0028] Bis-(3-(triethoxysilane)propyl)-tetrasulfide: Manufacturer: Evonik, Germany; Model: Si-69;

[0029] Isopropyl triisostearoyl titanate: Manufacturer: Guangdong Wengjiang Chemical Technology Co., Ltd., Model: PC96666;

[0030] Heptadecafluorodecyltrimethoxysilane: Manufacturer: Nanjing Quanxi New Material Technology Co., Ltd., Model No. 1713;

[0031] Dicumyl peroxide: Manufacturer: Jiangsu Daoming Chemical Co., Ltd.; Model: DCP.

[0032] Hydrophobic silica: Manufacturer: Tonghua Shuanglong Chemical Co., Ltd., Model: 1-3-5, Mesh: 600 mesh, Purity: 91%;

[0033] Potassium chloride: The manufacturer is Shandong Xinheng Chemical Co., Ltd.

[0034] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.

[0035] It should be noted that montmorillonite and hydrophobic silica need to be sieved to a specific mesh size before use.

[0036] Example 1

[0037] An anti-caking agent for potassium chloride granules comprises the following components in parts by weight: 52 parts of organically modified montmorillonite and 25 parts of hydrophobic silica; wherein the organically modified montmorillonite comprises the following raw materials: montmorillonite, a composite coupling agent, and an initiator, wherein the mass ratio of montmorillonite, the composite coupling agent, and the initiator is 1.2:1:0.05, the composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1.3:1:0.5; and the initiator is dicumyl peroxide.

[0038] The preparation method of the anti-caking agent for potassium chloride granules includes the following steps:

[0039] S1. Disperse montmorillonite in anhydrous ethanol and stir evenly. Add composite coupling agent and initiator, and react at 80℃ for 2.5h. After the reaction is complete, filter, wash until neutral, and dry to obtain organic modified montmorillonite. The amount of anhydrous ethanol added is twice the total mass of montmorillonite, composite coupling agent and initiator.

[0040] S2. Organically modified montmorillonite and hydrophobic silica are ball-milled to 650 mesh to obtain the anti-caking agent for potassium chloride granules.

[0041] Example 2

[0042] An anti-caking agent for potassium chloride granules comprises the following components in parts by weight: 50 parts of organically modified montmorillonite and 20 parts of hydrophobic silica; wherein the organically modified montmorillonite comprises the following raw materials: montmorillonite, a composite coupling agent, and an initiator, wherein the mass ratio of montmorillonite, the composite coupling agent, and the initiator is 1:1:0.02, the composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1:1:0.5; the montmorillonite has a mesh size of 200 mesh, and the hydrophobic silica has a mesh size of 400 mesh; the initiator is dicumyl peroxide.

[0043] The preparation method of the anti-caking agent for potassium chloride granules includes the following steps:

[0044] S1. Disperse montmorillonite in anhydrous ethanol and stir evenly. Add composite coupling agent and initiator, and react at 70°C for 3 hours. After the reaction is complete, filter, wash until neutral, and dry to obtain organic modified montmorillonite. The amount of anhydrous ethanol added is twice the total mass of montmorillonite, composite coupling agent and initiator.

[0045] S2. Organically modified montmorillonite and hydrophobic silica are ball-milled to 600 mesh to obtain the anti-caking agent for the potassium chloride granules.

[0046] Example 3

[0047] An anti-caking agent for potassium chloride granules comprises the following components in parts by weight: 60 parts of organically modified montmorillonite and 30 parts of hydrophobic silica; wherein the organically modified montmorillonite comprises the following raw materials: montmorillonite, a composite coupling agent, and an initiator, wherein the mass ratio of montmorillonite, the composite coupling agent, and the initiator is 1.5:1:0.06, the composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1.5:1:0.6; and the initiator is dicumyl peroxide.

[0048] The preparation method of the anti-caking agent for potassium chloride granules includes the following steps:

[0049] S1. Disperse montmorillonite in anhydrous ethanol and stir evenly. Add composite coupling agent and initiator, and react at 90℃ for 2 hours. After the reaction is complete, filter, wash until neutral, and dry to obtain organic modified montmorillonite. The amount of anhydrous ethanol added is 3 times the total mass of montmorillonite, composite coupling agent and initiator.

[0050] S2. Organically modified montmorillonite and hydrophobic silica are ball-milled to 700 mesh to obtain the anti-caking agent for the potassium chloride granules.

[0051] Comparative Example 1

[0052] The difference between Comparative Example 1 and Example 1 is that the montmorillonite was not modified by the composite coupling agent, and an equal amount of montmorillonite was used to replace the organically modified montmorillonite.

[0053] Comparative Example 2

[0054] The difference between Comparative Example 2 and Example 1 is that the total mass of the composite coupling agent remains unchanged, bis-(3-(triethoxysilane)propyl)-tetrasulfide is not added, and triisostearoyl titanate isopropyl ester and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1:0.5 are used to make up for the missing amount.

[0055] Comparative Example 3

[0056] The difference between Comparative Example 3 and Example 1 is that the total mass of the composite coupling agent remains unchanged, triisostearoyl titanate isopropyl ester is not added, and bis-(3-(triethoxysilane)propyl)-tetrasulfide and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1.3:0.5 are used to make up for the missing amount.

[0057] Comparative Example 4

[0058] The difference between Comparative Example 4 and Example 1 is that the total mass of the composite coupling agent remains unchanged, heptadecafluorodecyltrimethoxysilane is not added, and the missing amount is made up by bis-(3-(triethoxysilane)propyl)-tetrasulfide and triisostearoyl titanate isopropyl ester in a mass ratio of 1.3:1.

[0059] Comparative Example 5

[0060] The difference between Comparative Example 5 and Example 1 is that the total mass of the composite coupling agent remains unchanged, and the mass ratio of the composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate and heptadecafluorodecyltrimethoxysilane is 1:1.3:0.5.

[0061] Comparative Example 6

[0062] The difference between Comparative Example 6 and Example 1 is that the total mass of the composite coupling agent remains unchanged, and the mass ratio of the composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate and heptadecafluorodecyltrimethoxysilane is 1.3:0.5:1.

[0063] Comparative Example 7

[0064] The difference between Comparative Example 7 and Example 1 is that the total mass of the composite coupling agent remains unchanged, and the mass ratio of the composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate and heptadecafluorodecyltrimethoxysilane is 0.5:1:1.3.

[0065] Comparative Example 8

[0066] The difference between Comparative Example 8 and Example 1 is that no hydrophobic silica was added, and an equal amount of organically modified montmorillonite was used to make up for the missing amount.

[0067] Comparative Example 9

[0068] The difference between Comparative Example 9 and Example 1 is that no organically modified montmorillonite was added, and an equal amount of hydrophobic silica was used to make up for the missing amount.

[0069] Performance testing

[0070] The method for compounding anti-caking agents with potassium chloride granular fertilizer includes the following steps: The anti-caking agents of Examples 1-3 and Comparative Examples 1-9 are added to a mixing device via a feeder, mixed evenly with potassium chloride granules, and then conveyed and packaged via a conveyor belt and a finished product scraper. The amount of anti-caking agent added to the potassium chloride granular fertilizer is 0.1 wt%, resulting in anti-caking potassium chloride granular fertilizer.

[0071] Each group of anti-caking potassium chloride granular fertilizers was placed at 60℃ and 95% humidity for 2 hours, followed by drying in a vacuum drying oven for 2 hours. The dried compound fertilizer was then sieved for 15 minutes using a vibrating sieve (all testing conditions, including sieve frequency, were the same across all test groups). The residue was then calculated. The caking rate J1 (%) = m1 / m0 × 100%; where m1 is the weight of the residue, and m0 is the original weight of each group of anti-caking potassium chloride granular fertilizers before the test. Specific test results are shown in Table 1.

[0072] Meanwhile, each group of anti-caking potassium chloride granular fertilizers was sealed and stored at 55℃ (humidity the same as the natural environment, without special treatment) for 60 days. The clumps were weighed, and the clumping rate was calculated and recorded as J2. The clumping rate J2 (%) = m2 / m0 × 100%; where m2 is the weight of the sieve residue, and m0 is the original weight of each group of anti-caking potassium chloride granular fertilizers before the test. The specific test results are shown in Table 1.

[0073] Table 1. Agglomeration rate of anti-caking potassium chloride granular fertilizer in each group under different conditions.

[0074] Group / Performance <![CDATA[J1 / %]]> <![CDATA[J2 / %]]> Example 1 4.0 2.1 Example 2 4.7 2.5 Example 3 4.3 2.3 Comparative Example 1 25.2 23.4 Comparative Example 2 19.1 17.2 Comparative Example 3 19.2 17.5 Comparative Example 4 19.5 17.6 Comparative Example 5 8.7 7.9 Comparative Example 6 8.1 7.2 Comparative Example 7 8.2 7.4 Comparative Example 8 11.5 9.3 Comparative Example 9 27.4 25.1

[0075] As shown in Table 1, and in conjunction with the data from Example 1 and Comparative Examples 1-4, the type of coupling agent has a significant impact on the high-temperature and room-temperature stability of the anti-caking agent. When bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane are used in combination, the anti-caking performance of the product is better. When any one of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane is missing, the performance of the anti-caking agent decreases.

[0076] Based on the data obtained from Example 1 and Comparative Examples 5-7, it can be seen that when the mass ratio of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane is (1-1.5):1:(0.5-0.6), the high-temperature stability and room-temperature stability of the anti-caking agent reach a relatively good level.

[0077] Based on the data from Example 1 and Comparative Examples 8-9, it can be seen that the anti-caking agent of the present invention is a composite of hydrophobic silica and organically modified montmorillonite. The small-particle-size silica is embedded in the layered structure of montmorillonite, increasing the interlayer spacing of montmorillonite and further reducing the adsorption of water molecules, thereby improving the hydrophobic properties of the anti-caking agent and thus improving the performance of the anti-caking agent.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An anti-caking agent for potassium chloride granules, characterized in that, The product is composed of the following components in parts by weight: 50-60 parts of organically modified montmorillonite and 20-30 parts of hydrophobic silica; wherein the organically modified montmorillonite is composed of the following raw materials: montmorillonite, a composite coupling agent, and an initiator, wherein the mass ratio of montmorillonite, the composite coupling agent, and the initiator is (1-1.5):1:(0.02-0.06), and the composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of (1-1.5):1:(0.5-0.6); the particle size of the hydrophobic silica is smaller than the particle size of the organically modified montmorillonite. The preparation method of the anti-caking agent for potassium chloride granules includes the following steps: S1. Disperse montmorillonite in anhydrous ethanol and stir evenly. Add composite coupling agent and initiator to react. After the reaction is complete, filter, wash until neutral, and dry to obtain organic modified montmorillonite. S2. Organically modified montmorillonite and hydrophobic silica are ball-milled to obtain the anti-caking agent for the potassium chloride granules.

2. The anti-caking agent for potassium chloride granules as described in claim 1, characterized in that, The initiator is dicumyl peroxide.

3. The anti-caking agent for potassium chloride granules as described in claim 1, characterized in that, The montmorillonite has a mesh size of 200-300; and / or the hydrophobic silica has a mesh size of 400-600.

4. The anti-caking agent for potassium chloride granules as described in claim 1, characterized in that, The composite coupling agent is a composition of bis-(3-(triethoxysilane)propyl)-tetrasulfide, isopropyl triisostearoyl titanate, and heptadecafluorodecyltrimethoxysilane in a mass ratio of 1.3:1:0.

5.

5. The anti-caking agent for potassium chloride granules as described in claim 1, characterized in that, In step S1 of the preparation of the anti-caking agent for potassium chloride granules, the amount of anhydrous ethanol added is 1-2 times the total mass of montmorillonite, composite coupling agent and initiator.

6. The anti-caking agent for potassium chloride granules as described in claim 1, characterized in that, In step S1 of the preparation of the anti-caking agent for potassium chloride granules, the reaction temperature is 70-90℃ and the time is 2-3h.

7. The anti-caking agent for potassium chloride granules as described in claim 1, characterized in that, In step S1 of preparing the anti-caking agent for potassium chloride granules, organic modified montmorillonite and hydrophobic silica are ball-milled to 600-700 mesh.

8. The use of the anti-caking agent for potassium chloride granules according to any one of claims 1-7 in the preparation of potassium chloride granular fertilizer.

9. The application as described in claim 8, characterized in that, The amount of anti-caking agent used in the potassium chloride granules added to the potassium chloride granule fertilizer is 0.1-0.5 wt%.