Anti-caking potassium chloride particles and preparation method thereof

Abstract

The invention relates to an anti-caking potassium chloride particle and a preparation method thereof, the potassium chloride particle comprises potassium chloride and an anti-caking agent, the anti-caking agent comprises the following components by weight: 30-50 parts of a surfactant, 15-20 parts of a water-soluble polymer, 10-20 parts of inorganic powder and 6-10 parts of a film-forming agent; wherein the surfactant is a composition of sodium polyethylene glycol disulfonate, propylene glycol monostearate and 2-hydroxypropyl-beta-cyclodextrin, and the surfactant is a composition of sodium polyethylene glycol disulfonate, propylene glycol monostearate and 2-hydroxypropyl-beta-cyclodextrin. The potassium chloride particles provided by the invention can still keep good flowability even under harsh conditions of high humidity, long-term storage or transportation vibration and the like, and high-efficiency long-acting anti-caking is realized.

Description

Technical Field

[0001] This invention relates to the technical field of potassium chloride fertilizer, specifically to an anti-caking potassium chloride granule and its preparation method. Background Technology

[0002] The clumping of water-soluble potassium chloride granular fertilizer is mainly affected by a variety of factors, including the hygroscopic properties of the raw materials, their own moisture content, the compressibility of the material, the humidity conditions of the production environment, and the water absorption properties of the packaging materials. When fertilizer granules absorb moisture from the air, their surface dissolves first, followed by water evaporation. During recrystallization, crystal bridges are formed, causing the fertilizer granules to stick together and eventually aggregate into large clumps.

[0003] In practical use, potassium chloride caking disrupts the product's normal flowability, necessitating crushing before use. This process not only wastes fertilizer but also potentially causes environmental pollution and increases usage costs. Currently, various technical methods exist to prevent fertilizer caking, such as improving product packaging, optimizing production equipment processes, adjusting fertilizer formulations, altering fertilizer composition, improving storage conditions, and adding anti-caking agents. Among these, adding anti-caking agents is widely considered a simple and effective method. Currently, anhydrous magnesium sulfate is often added to powdered water-soluble fertilizers to absorb excess moisture and prevent caking. However, if the amount of magnesium sulfate added is small, its moisture absorption capacity is limited; moreover, magnesium sulfate may react chemically with certain raw materials to form substances insoluble in water. Therefore, researching anti-caking agents suitable for powdered water-soluble fertilizers has become an urgent task. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an anti-caking potassium chloride granule and its preparation method.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides potassium chloride granules for preventing caking, comprising potassium chloride and an anti-caking agent, wherein the anti-caking agent comprises the following components in parts by weight: 30-50 parts of surfactant, 15-21 parts of water-soluble polymer, 10-20 parts of inorganic powder and 6-10 parts of film-forming agent; wherein the surfactant is a composition of sodium polyethylene glycol disulfonate, propylene glycol monostearate and 2-hydroxypropyl-β-cyclodextrin.

[0006] The functions of each component in the anti-caking agent of this invention are as follows: Sodium polyethylene glycol disulfonate contains a hydrophilic group (-SO3Na) of sodium disulfonate. + The product contains a hydrophobic backbone of polyethylene glycol, exhibiting both ionic and water-soluble properties, while the surface of potassium chloride particles carries a positive charge due to electrolyte dissociation (K).+ The anionic group (-SO3) of sodium polyethylene glycol disulfonate - It is adsorbed onto the surface of potassium chloride by electrostatic attraction.

[0007] Propylene glycol monostearate contains long-chain fatty acid hydrophobic groups (stearic acid chains) and propylene glycol hydrophilic groups (-OH). Its hydrophilic groups interact with the hydrophilic groups (-SO3Na) of sodium polyethylene glycol disulfonate. + The -OH groups on the polyethylene glycol chain interact through hydrogen bonds, and the hydrophobic stearic acid chains are oriented on the outer surface of the particles to form a dense hydrophobic film. This physically prevents water from penetrating the potassium chloride interior and also isolates direct contact between adjacent potassium chloride particles.

[0008] 2-Hydroxypropyl-β-cyclodextrin is a cyclic oligosaccharide with a unique structure of hydrophobic cavities and hydrophilic outer walls, thus exhibiting good amphiphilic surface properties. This allows 2-hydroxypropyl-β-cyclodextrin to intercalate in the membrane structure formed by polyethylene glycol disulfonate and propylene glycol monostearate, further improving the membrane's density through hydrogen bonding crosslinking.

[0009] Potassium chloride is a strong electrolyte. When anionic surfactants are used alone, the electrolyte compresses the electric double layer of the surfactant, reducing its surface activity. However, the nonionic properties of propylene glycol monostearate allow it to form a stable film even in an electrolyte environment, and the cyclic structure of 2-hydroxypropyl-β-cyclodextrin can encapsulate part of the potassium chloride. + This reduces its damage to the double layer of polyethylene glycol disulfonate, ensuring that all three components can perform optimally in the potassium chloride system and preventing any single component from failing due to electrolyte interference.

[0010] Water-soluble polymers act as binders, firmly bonding surfactants, inorganic powders, and potassium chloride together to form a continuous, flexible composite coating on the particle surface. This polymer film itself can also reversibly bind environmental moisture through hydrogen bonds, reducing the presence of liquid water, and its elasticity can buffer static pressure during storage and transportation, preventing the coating from cracking.

[0011] Preferably, the mass ratio of the polyethylene glycol disulfonate sodium, propylene glycol monostearate and 2-hydroxypropyl-β-cyclodextrin is (0.1-0.5):1:(1-3).

[0012] Preferably, the amount of the anti-caking agent added is 0.1-0.5 wt% of the potassium chloride.

[0013] Preferably, the water-soluble polymer is at least one selected from carrageenan, gum arabic, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, and sodium polyacrylate.

[0014] Preferably, the inorganic powder is fumed hydrophilic silicon dioxide.

[0015] Preferably, the film-forming agent is modified hydroxyethyl cellulose, manufactured by Ashland, USA, and model number Natrosol Plus 330.

[0016] In a second aspect, the present invention provides a method for preparing the anti-caking potassium chloride granules of the first aspect, comprising the following steps: (1) First, the inorganic powder is ball-milled, and then the surfactant, water-soluble polymer and film-forming agent are added and ball-milled to obtain the anti-caking agent; (2) The anti-caking agent is added to the mixing equipment by the feeder and mixed evenly with the granular potassium chloride. Then, it is conveyed and packaged by the conveyor belt and the finished product scraper to obtain the anti-caking potassium chloride granules.

[0017] Preferably, the ball milling parameters are: ball-to-material ratio of (2-4):1, rotation speed of 200-300 r / min, and ball milling time of 0.5-2h.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The anti-caking effect of the potassium chloride granules in this invention is achieved through the functional division and hierarchical synergy of surfactant complex, water-soluble polymer, inorganic powder, and film-forming agent: sodium polyethylene glycol disulfonate, propylene glycol monostearate, and 2-hydroxypropyl-β-cyclodextrin synergistically improve the density and stability of the anti-caking composite film. The water-soluble polymer crosslinks with the surfactant through hydrogen bonds, filling film voids and binding the components to form a flexible network structure that enhances film toughness, while also assisting in particle dispersion through steric hindrance. The inorganic powder acts as a micro-spacer, dispersed on the particle surface and in the gaps, increasing particle spacing and reducing contact adhesion; its rigid particles are embedded in the composite film, improving wear resistance. The film-forming agent helps form a continuous and dense physical barrier film, blocking moisture intrusion and direct particle contact, and its crosslinking with the water-soluble polymer and surfactant further strengthens the film structure. Therefore, the potassium chloride granules of this invention can maintain good particle flowability even under harsh conditions such as high humidity, long-term storage, or transportation vibration, achieving efficient and long-lasting anti-caking. Detailed Implementation

[0019] 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.

[0020] The sources of the raw materials used in the following examples and comparative examples are as follows: Polyvinyl alcohol: Manufacturer is THIAI (Shanghai) Chemical Trading Co., Ltd., model number is 013-P0804, molecular weight is 2000; Carrageenan: Manufacturer: Haiyang Luxin Marine Biotechnology Co., Ltd., Model: CKC101 Polyethylene glycol: Manufacturer: Dow, Model: CARBOWAX™ PEG 400, Molecular weight: 400; Polyvinylpyrrolidone: Manufacturer is Gongbike New Material Technology (Shanghai) Co., Ltd., model number is PVPK30; Sodium polyethylene glycol disulfonate: Obtained by reacting polyethylene glycol disulfonic acid with sodium bicarbonate. The manufacturer of polyethylene glycol disulfonic acid is Xi'an Qiyue Biotechnology Co., Ltd., and the model number is Q-0156156. Propylene glycol monostearate: Manufacturer: Shandong Yousuo Chemical Technology Co., Ltd., Product No.: S12773115; 2-Hydroxypropyl-β-cyclodextrin: Manufacturer: Anhui Jingke Biotechnology Co., Ltd., Product No.: JK-766; Fumed hydrophilic silica: Manufacturer: Evonik Degussa, Model: AEROSIL ® 200; Modified hydroxyethyl cellulose: manufactured by Ashland, USA, model number Natrosol Plus 330.

[0021] Unless otherwise specified, all other materials, reagents, etc. used in the examples and comparative examples are commercially available.

[0022] Example 1 An anti-caking potassium chloride granule comprises potassium chloride and an anti-caking agent, wherein the amount of the anti-caking agent added is 0.2 wt% of the potassium chloride; the anti-caking agent comprises the following components in parts by weight: 43 parts of surfactant, 18 parts of water-soluble polymer, 15 parts of inorganic powder, and 8 parts of film-forming agent; wherein the surfactant is a composition of polyethylene glycol disulfonate, propylene glycol monostearate, and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 0.3:1:2.5, the water-soluble polymer is polyvinyl alcohol and carrageenan in a mass ratio of 1:0.5, the inorganic powder is fumed hydrophilic silica, and the film-forming agent is modified hydroxyethyl cellulose; A method for preparing anti-caking potassium chloride granules includes the following steps: (1) First, the inorganic powder is ball-milled, and then the surfactant, water-soluble polymer and film-forming agent are added and ball-milled to obtain the anti-caking agent; wherein, the parameters for the two ball millings are: ball-to-material ratio of 3:1, rotation speed of 250 r / min, and ball milling time of 1 h; (2) The anti-caking agent is added to the mixing equipment by the feeder and mixed evenly with the granular potassium chloride. Then, it is conveyed and packaged by the conveyor belt and the finished product scraper to obtain the anti-caking potassium chloride granules.

[0023] Example 2 An anti-caking potassium chloride granule comprises potassium chloride and an anti-caking agent, wherein the amount of the anti-caking agent added is 0.1 wt% of the potassium chloride; the anti-caking agent comprises the following components in parts by weight: 30 parts of surfactant, 15 parts of water-soluble polymer, 10 parts of inorganic powder, and 6 parts of film-forming agent; wherein the surfactant is a composition of polyethylene glycol disulfonate, propylene glycol monostearate, and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 0.1:1:1, the water-soluble polymer is polyethylene glycol and polyvinylpyrrolidone in a mass ratio of 1:1, the inorganic powder is fumed hydrophilic silica, and the film-forming agent is modified hydroxyethyl cellulose; A method for preparing anti-caking potassium chloride granules includes the following steps: (1) First, the inorganic powder is ball-milled, and then the surfactant, water-soluble polymer and film-forming agent are added and ball-milled to obtain the anti-caking agent; wherein, the parameters for the two ball millings are: ball-to-material ratio of 2:1, rotation speed of 200 r / min, and ball milling time of 2 h; (2) The anti-caking agent is added to the mixing equipment by the feeder and mixed evenly with the granular potassium chloride. Then, it is conveyed and packaged by the conveyor belt and the finished product scraper to obtain the anti-caking potassium chloride granules.

[0024] Example 3 An anti-caking potassium chloride granule comprises potassium chloride and an anti-caking agent, wherein the anti-caking agent is added at an amount of 0.5 wt% of the potassium chloride; the anti-caking agent comprises the following components in parts by weight: 50 parts of surfactant, 21 parts of water-soluble polymer, 20 parts of inorganic powder, and 10 parts of film-forming agent; wherein the surfactant is a composition of polyethylene glycol disulfonate, propylene glycol monostearate, and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 0.5:1:3, the water-soluble polymer is polyvinyl alcohol and polyethylene glycol in a mass ratio of 1:1, the inorganic powder is fumed hydrophilic silica, and the film-forming agent is modified hydroxyethyl cellulose; A method for preparing anti-caking potassium chloride granules includes the following steps: (1) First, the inorganic powder is ball-milled, and then the surfactant, water-soluble polymer and film-forming agent are added and ball-milled to obtain the anti-caking agent; wherein, the parameters of the two ball millings are: ball-to-material ratio of 4:1, rotation speed of 300 r / min, and ball milling time of 0.5h; (2) The anti-caking agent is added to the mixing equipment by the feeder and mixed evenly with the granular potassium chloride. Then, it is conveyed and packaged by the conveyor belt and the finished product scraper to obtain the anti-caking potassium chloride granules.

[0025] Example 4 The only difference between Example 4 and Example 1 is that the surfactant is a mixture of polyethylene glycol disulfonate sodium, propylene glycol monostearate and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 1:0.3:2.5.

[0026] Example 5 The only difference between Example 5 and Example 1 is that the surfactant is a mixture of polyethylene glycol disulfonate sodium, propylene glycol monostearate and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 0.3:2.5:1.

[0027] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the anti-caking agent does not contain surfactants, and the missing amount is made up by water-soluble polymer, inorganic powder and film-forming agent in a mass ratio of 18:15:8.

[0028] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the amount of anti-caking agent added remains the same, sodium polyethylene glycol disulfonate is not added, and propylene glycol monostearate and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 1:2.5 are used to make up for the missing amount.

[0029] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the amount of anti-caking agent added remains the same, propylene glycol monostearate is not added, and the missing amount is made up by using polyethylene glycol disulfonate sodium and 2-hydroxypropyl-β-cyclodextrin in a mass ratio of 0.3:2.5.

[0030] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that the amount of anti-caking agent added remains the same, 2-hydroxypropyl-β-cyclodextrin is not added, and the missing amount is made up by using polyethylene glycol disulfonate and propylene glycol monostearate in a mass ratio of 0.3:1.

[0031] Performance testing The anti-caking potassium chloride granules from Examples 1-5 and Comparative Examples 1-4 were placed at 60°C 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 test conditions, including sieve frequency, were the same across all test groups). The residue was calculated as follows: Caking rate J1 (%) = m1 / m0 × 100%; where m1 is the weight of the residue, and m0 is the original weight of the anti-caking potassium chloride granule fertilizer in each group before the test. Specific test results are shown in Table 1.

[0032] Meanwhile, each group of anti-caking potassium chloride granular fertilizers was sealed and stored at 35℃ (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.

[0033] Table 1. Agglomeration rate of potassium chloride particles in each group Group / Performance <![CDATA[J1 / %]]> <![CDATA[J2 / %]]> Example 1 5.3 2.5 Example 2 5.8 3.0 Example 3 4.6 2.1 Example 4 6.9 3.4 Example 5 7.5 3.9 Comparative Example 1 17.3 8.6 Comparative Example 2 11.5 6.1 Comparative Example 3 13.1 6.6 Comparative Example 4 15.6 7.9 The lower the J1 agglomeration rate, the better the high temperature and high humidity stability of potassium chloride particles; the lower the J2 agglomeration rate, the better the room temperature stability of potassium chloride particles and the better the anti-agglomeration effect.

[0034] Table 1 shows that, combining the data from Examples 1 and 4-5, the high-temperature and high-humidity stability and room-temperature stability of the potassium chloride particles in Examples 4-5 are lower than those in Example 1. This may be because the propylene glycol monostearate in Example 4 is insufficient, failing to effectively stabilize the electrolyte environment and reducing the density of the hydrophobic membrane. The insufficient 2-hydroxypropyl-β-cyclodextrin in Example 5 leads to a decrease in membrane cross-linking density and K... + The reduced encapsulation ability affects the stability of the anti-caking agent. When the mass ratio of the sodium polyethylene glycol disulfonate, propylene glycol monostearate, and 2-hydroxypropyl-β-cyclodextrin in the surfactant is in the range of (0.1-0.5):1:(1-3), the potassium chloride particles have a better anti-caking effect.

[0035] Based on the data from Example 1 and Comparative Examples 1-4, it can be seen that Comparative Example 1, without the addition of surfactant, had the worst agglomeration rate among all groups, indicating that the addition of surfactant is an important factor affecting the agglomeration effect. The high-temperature and high-humidity stability and room-temperature stability of potassium chloride particles in Comparative Examples 2-4 were significantly lower than those in Example 1, indicating that polyethylene glycol disulfonate, propylene glycol monostearate, and 2-hydroxypropyl-β-cyclodextrin can synergistically improve the density and stability of the film formed by the anti-agglomeration agent.

[0036] In summary, the potassium chloride granules of the present invention can maintain good granule flowability even under harsh conditions such as high humidity, long-term storage or transportation vibration, thus achieving efficient and long-lasting anti-caking.

[0037] 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. Anti-caking potassium chloride particles, characterized in that, The anti-caking agent comprises potassium chloride and an anti-caking agent, and the anti-caking agent comprises the following components by weight: 30-50 parts of a surfactant, 15-21 parts of a water-soluble polymer, 10-20 parts of an inorganic powder, and 6-10 parts of a film-forming agent; wherein the surfactant is a combination of polyethylene glycol disulfate sodium, propylene glycol monostearate, and 2-hydroxypropyl-beta-cyclodextrin.

2. The anti-caking potassium chloride granules according to claim 1, wherein, The mass ratio of the polyethylene glycol disulfate sodium, propylene glycol monostearate, and 2-hydroxypropyl-beta-cyclodextrin is (0.1-0.5):1:(1-3).

3. The anti-caking potassium chloride particulate of claim 1, wherein, The anti-caking agent is added in an amount of 0.1-0.5 wt% of the potassium chloride.

4. The anti-caking potassium chloride particulate of claim 1, wherein, The water-soluble polymer is at least one of carrageenan, gum arabic, polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, and sodium polyacrylate.

5. The anti-caking potassium chloride particulate of claim 1, wherein, The inorganic powder is fumed hydrophilic silica.

6. The anti-caking potassium chloride particulate of claim 1, wherein, The film-forming agent is modified hydroxyethyl cellulose, and the modified hydroxyethyl cellulose is Natrosol Plus 330 from Ashland, USA.

7. The process for the preparation of the anti-caking potassium chloride particles according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: (1) first ball-milling the inorganic powder, and then adding the surfactant, water-soluble polymer, and film-forming agent for ball-milling to obtain the anti-caking agent; (2) adding the anti-caking agent into a stirring device through a feeder, mixing the anti-caking agent with the granular potassium chloride uniformly, and then conveying and packaging through a conveying belt and a finished product scraper to obtain the anti-caking potassium chloride granules.

8. The method of preparing anti-caking potassium chloride particles according to claim 7, wherein The ball-milling parameters are as follows: the ball-to-material ratio is (2-4):1, the rotation speed is 200-300 r / min, and the ball-milling time is 0.5-2 h.