阅读说明：本技术 一种圆颗粒钾肥及其制备方法 (Round particle potash fertilizer and preparation method thereof ) 是由 王永红 张洪江 吴玉龙 刘光海 杨静 徐文冰 余赟 于 2021-10-12 设计创作，主要内容包括：本发明提供了一种圆颗粒钾肥,一种圆颗粒钾肥,按重量份数计,包括20～40份的核芯和60～80份包覆核芯的核壳；核芯包括基础钾原料及粘结剂；核壳包括基础钾原料、粘结剂、润湿剂、改性环糊精和改性膨润土；改性环糊精为磷酸盐玻璃粉末改性的β-环糊精,改性膨润土为以磷酸二氢钾及碳酸钾的共混物进行插层柱撑改性的膨润土。本发明还提供了上述圆颗粒钾肥的制备方法,本发明的圆颗粒钾肥及其制备方法,其可提高钾肥的成球率；并提高颗粒钾肥的K-(2)O含量；同时提高钾肥强度,使得钾肥颗粒不易粉化。(The invention provides a round particle potash fertilizer, which comprises 20-40 parts of a core and 60-80 parts of a core shell covering the core in parts by weight; the core comprises a basic potassium raw material and a binder; the core shell comprises a basic potassium raw material, a binder, a wetting agent, modified cyclodextrin and modified bentonite; the modified cyclodextrin is beta-cyclodextrin modified by phosphate glass powder, and the modified bentonite is bentonite modified by intercalation pillared support of a blend of potassium dihydrogen phosphate and potassium carbonate. The invention also provides a preparation method of the round granular potash fertilizer, and the round granular potash fertilizer and the preparation method thereof can improve the balling rate of the potash fertilizer; and improve K of the granular potash fertilizer 2 The content of O; simultaneously improve the strength of the potash fertilizer so thatThe potassium fertilizer particles are not easy to pulverize.)

1. The round particle potash fertilizer is characterized in that: the core comprises 20-40 parts of a core and 60-80 parts of a core shell covering the core in parts by weight;

the core comprises a basic potassium raw material and a binder; the core shell comprises a basic potassium raw material, a binder, a wetting agent, modified cyclodextrin and modified bentonite;

the modified cyclodextrin is beta-cyclodextrin modified by phosphate glass powder, and the modified bentonite is bentonite modified by intercalation pillared with a blend of potassium dihydrogen phosphate and potassium carbonate.

2. The round particle potash fertilizer of claim 1, wherein the modified cyclodextrin is prepared by dissolving chitosan powder and beta-cyclodextrin powder in water, then adding phosphate glass powder in proportion, stirring, mixing and drying, and the mass ratio of the chitosan powder to the beta-cyclodextrin powder to the phosphate glass powder is 1:1: 1.

3. The round particle potash fertilizer of claim 1, wherein the preparation method of the modified bentonite comprises the following steps: mixing the blend of potassium dihydrogen phosphate and potassium carbonate with bentonite, dissolving in distilled water for pulping, heating and stirring, adding sulfuric acid, stirring, adding trace surfactant, and filtering to obtain modified bentonite.

4. The round granule potash fertilizer of claim 1, wherein the basic potassium raw material comprises one or both of potassium chloride and potassium sulfate powder.

5. The round particle potash fertilizer of claim 1, wherein the binder is one or both of calcium sulfate hemihydrate and magnesium oxide.

6. The round particle potash fertilizer of claim 1, wherein the wetting agent is one or more of phosphoric acid, ferrous sulfate, polyethylene glycol 200 or polyethylene glycol 400.

7. The round particle potash fertilizer of claim 1, wherein the mass ratio of the basic potassium raw material to the binder in the core is 20-40: 1; the mass ratio of the basic potassium raw material, the binder, the modified cyclodextrin, the modified bentonite and the wetting agent in the core shell is as follows: 60-80: 1:1-1.5: 1-1.5: 1-1.5.

8. A method for preparing round particle potash fertilizer as claimed in any one of claims 1-7, comprising the steps of:

(1) weighing basic potassium raw materials and a binder according to the proportion in the core, and granulating to form the core;

(2) weighing the raw materials according to the core-shell proportion, and uniformly mixing 2/5-3/5 parts by weight of basic potassium raw material and modified cyclodextrin to form a core-shell material A; evenly mixing 2/5-3/5 parts by weight of basic potassium raw material and modified bentonite to form a core-shell material B;

(3) adding the core in the step (1), the core-shell material A in the step (2), the core-shell material B and a binder into a granulator; spraying a wetting agent and a liquid conditioner into the granulator in an atomizing and spraying manner; granulating each material in a granulator;

(4) aging the granules granulated in the step (3) in an aging machine;

(5) and (4) drying, cooling and screening the aged material in sequence, and packaging the qualified particles into a product.

9. The preparation method of the round particle potash fertilizer as claimed in claim 8, wherein the liquid conditioner is prepared by mixing carboxymethylcellulose, mineral oil and chitosan according to a weight ratio of 1:1:1 and dissolving in water, and the concentration of the liquid conditioner is 3-5%.

10. The method for preparing round particle potash fertilizer in accordance with claim 8, wherein the aging treatment is aging at 20-35 ℃ for 15-20 min.

Technical Field

The invention relates to the technical field of fertilizers, and particularly relates to a round granular potash fertilizer and a preparation method thereof.

Background

Potassium chloride/potassium sulfate are two most common and important potash fertilizers in agricultural use, the potash fertilizers in the market at present are mainly in a powder shape and irregular shapes obtained by extrusion granulation, and round particle potash fertilizers become rare products.

Compared with the traditional compound fertilizer granulation, the difficult granulation of the potassium fertilizer is mainly caused by 1. the potassium chloride/potassium sulfate belongs to sand mould materials, has poor self-adhesion and is difficult to form balls during granulation; even if spherical particles are barely produced, a large amount of substances such as a binder and the like are added to produce the K of the granular potash fertilizer₂The O content is far lower than 60 percent (potassium chloride) and 50 percent (potassium sulfate), and the BB fertilizer, especially the BB fertilizer with high content, is difficult to meet the use requirement; 2. the solubility of potassium chloride/potassium sulfate in water is high, and the amount of liquid phase required by granulation by a granulation method is too large, so that the strength of the granular potassium fertilizer formed during granulation is extremely low, and large-scale production cannot be realized; 3. too low wet strength causes serious damage of the granular potash fertilizer during drying and extremely low yield.

In the prior art, a preparation method of more round granular potash fertilizers is disclosed, such as patents with publication numbers of CN102718601A and CN103819271A, however, the round granular potash fertilizer prepared by the method disclosed by the above documents by the technicians in the field has low nutrient content, low interest rate and low strength, and is difficult to meet the actual requirements.

Disclosure of Invention

The invention aims to provide a round particle potash fertilizer and a preparation method thereof, which can improve the balling rate of the potash fertilizer; and improve K of the granular potash fertilizer₂The content of O; meanwhile, the strength of the potash fertilizer is improved, so that the potash fertilizer particles are not easy to pulverize.

The embodiment of the invention is realized by the following technical scheme:

a round particle potash fertilizer comprises, by weight, 20-40 parts of a core and 60-80 parts of a core shell covering the core; the core comprises a basic potassium raw material and a binder; the core shell comprises a basic potassium raw material, a binder, a wetting agent, modified cyclodextrin and modified bentonite; the modified cyclodextrin is beta-cyclodextrin modified by phosphate glass powder, and the modified bentonite is bentonite modified by intercalation pillared support of a blend of potassium dihydrogen phosphate and potassium carbonate.

A preparation method of round particle potash fertilizer comprises the following steps:

(1) weighing basic potassium raw materials and a binder according to the proportion in the core, and granulating to form the core;

(2) weighing the raw materials according to the core-shell proportion, and uniformly mixing 2/5-3/5 parts by weight of basic potassium raw material and modified cyclodextrin to form a core-shell material A; evenly mixing 2/5-3/5 parts by weight of basic potassium raw material and modified bentonite to form a core-shell material B;

(3) adding the core in the step (1), the core-shell material A in the step (2), the core-shell material B and a binder into a granulator; spraying a wetting agent and a liquid conditioner into the granulator in an atomizing and spraying manner; granulating each material in a granulator;

(4) aging the granules granulated in the step (3) in an aging machine;

(5) and (4) drying, cooling and screening the aged material in sequence, and packaging the qualified particles into a product.

The technical scheme of the embodiment of the invention at least has the following advantages and beneficial effects:

1. the beta-cyclodextrin is modified, so that the specific surface area and the adsorption performance of the beta-cyclodextrin are improved, more basic potassium fertilizer can be stably adsorbed, the modified beta-cyclodextrin and the basic potassium fertilizer are uniformly mixed and uniformly dispersed among the basic potassium fertilizer in the fertilizer granulation process, and more basic potassium fertilizer can be stably coated on the surface of a core in the granulation process, so that more powdery potassium fertilizer can be subjected to high-density binding granulation by adding a small amount of binder, the use amount of the binder is reduced, and the K of the granular potassium fertilizer is improved₂The content of O; meanwhile, the stability of powder bonding can be ensured,thereby ensuring the strength of the round granular potash fertilizer.

2. According to the invention, the blend of potassium dihydrogen phosphate and potassium carbonate is used for intercalation pillared modification of bentonite, so that the adsorption capacity and the binding capacity of the bentonite on powder are improved; before granulation, the modified bentonite is mixed with the basic potash fertilizer powder, so that the bentonite is uniformly and stably combined with the basic potash fertilizer, a larger amount of basic potash fertilizer can be more stably coated on the surface of a core in the granulation process, the forming amount and forming stability of the granular potash fertilizer are improved, and the granulation rate and the granule strength are improved.

3. The preparation method of the invention mixes the powder material and the caking agent with higher proportion to granulate into the core, and then coats other powder materials on the core, thereby effectively ensuring the granulation rate; when the core shell is coated, the basic powder is respectively mixed with the modified cyclodextrin and the modified bentonite, so that the basic powder is more and more stably adsorbed on the viscous substance, and the uniform dispersion of the viscous substance among the sand mould potash fertilizers is ensured; in the coating and granulating process, a wetting agent and a liquid conditioner are sprayed into a granulator, so that the modified cyclodextrin, the modified bentonite and the binder can fully exert the viscosity, the material is granulated uniformly, and the granule strength is high.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The following is a detailed description of the round particle potash fertilizer and the preparation method thereof provided by the embodiment of the present invention.

A round particle potash fertilizer comprises, by weight, 20-40 parts of a core and 60-80 parts of a core shell covering the core; the core comprises a basic potassium raw material and a binder; the core shell comprises a basic potassium raw material, a wetting agent, modified cyclodextrin and modified bentonite; the modified cyclodextrin is beta-cyclodextrin modified by phosphate glass powder, and the modified bentonite is bentonite modified by intercalation pillared support of a blend of potassium dihydrogen phosphate and potassium carbonate.

Specifically, the modified cyclodextrin is prepared by dissolving chitosan powder and beta-cyclodextrin powder in water, then adding phosphate glass powder in proportion, stirring, mixing and drying, wherein the mass ratio of the chitosan powder to the beta-cyclodextrin powder to the phosphate glass powder is 1:1: 1.

Further concretely: the preparation method of the modified bentonite comprises the following steps: the blend of potassium dihydrogen phosphate and potassium carbonate is mixed with bentonite, dissolved in distilled water for pulping, heated and stirred, sulfuric acid is added for continuous stirring, and a large amount of micropores are formed by flushing out the formed carbon dioxide gas to change the layered structure so as to provide more interlayer space for the forming of spherical particles of the potassium sulfate fertilizer, thereby improving the forming amount and forming stability of the granular potassium fertilizer, and improving the granulation effect and the particle strength; simultaneously adding a trace amount of surfactant, such as surfactant M-60, to prevent large crystal particles which are not beneficial to intercalation and are formed due to crystal nucleus agglomeration or a wrapping phenomenon, and performing suction filtration on the mixed solution to obtain the modified bentonite. The mass ratio of the potassium dihydrogen phosphate to the potassium hydrochloride to the bentonite meets the following requirements: 1:1:5.

Specifically, the basic potassium raw material comprises one or two of potassium chloride and potassium sulfate powder. The binder is one or two of calcium sulfate hemihydrate and magnesium oxide. The wetting agent is one or more of phosphoric acid, ferrous sulfate, polyethylene glycol 200 or polyethylene glycol 400.

More specifically, the mass ratio of the basic potassium raw material to the binder in the core is 20-40: 1; the mass ratio of the basic potassium raw material, the binder, the modified cyclodextrin, the modified bentonite and the wetting agent in the core shell is as follows: 60-80: 1:1-1.5: 1-1.5: 1-1.5.

The total additive amount of the additive is only about 5%, so that the condition of low nutrient content of the granular potash fertilizer caused by excessive additives can be avoided.

The preparation method of the round particle potash fertilizer comprises the following steps:

(1) weighing basic potassium raw materials and a binder according to the proportion in the core, and granulating to form the core;

(2) weighing the raw materials according to the core-shell proportion, and uniformly mixing 2/5-3/5 parts by weight of basic potassium raw material and modified cyclodextrin to form a core-shell material A; evenly mixing 2/5-3/5 parts by weight of basic potassium raw material and modified bentonite to form a core-shell material B;

(3) adding the core in the step (1), the core-shell material A in the step (2), the core-shell material B and a binder into a granulator; spraying a wetting agent and a liquid conditioner into the granulator in an atomizing and spraying manner; granulating each material in a granulator;

(4) aging the granules granulated in the step (3) in an aging machine;

(5) and (4) drying, cooling and screening the aged material in sequence, and packaging the qualified particles into a product.

Specifically, the liquid conditioner is prepared by mixing carboxymethylcellulose, mineral oil and chitosan according to the weight ratio of 1:1:1 and dissolving the mixture in water, and the concentration of the liquid conditioner is 3-5%.

Further specifically, the aging treatment is aging for 15-20 min at 20-35 ℃. The particles have certain strength and cold hardness through aging treatment, and the generation of particle pulverization phenomenon in the subsequent drying and cooling processes is avoided; if the aging treatment is not carried out or the aging treatment effect is not good, the materials can be pulverized in a large area in the drying process, so that the yield is reduced, the powder in the system is increased, and the production process system is deteriorated.

Because the difficulty of forming the core is higher in the granulating process, in the invention, part of powdered potassium chloride or potassium sulfate is bonded by using a bonding agent with slightly higher content to form the core, so that the adhesiveness between the powdered potassium chloride or potassium sulfate is improved, and a tiny spherical core is formed in advance; and then the surface of the core is continuously coated with the basic potassium raw material and the binder for deep coating treatment, thereby being beneficial to balling, greatly reducing the difficulty of pelletizing and balling and leading the balling to be more stable and firmer.

The invention utilizes the modified cyclodextrin to mix with the basic potash fertilizer to coat the core, thereby improving the coating efficiency and the balling stabilityQualitative determination; specifically, the method comprises the following steps: according to the invention, chitosan modified cyclodextrin is utilized to improve the specific surface area and the adsorption performance of the cyclodextrin, and more basic potash fertilizer can be adsorbed more stably, so that more powdery potassium chloride and potassium sulfate can be bonded and granulated at high density by adding a small amount of binder; meanwhile, the characteristics of porosity and large specific surface area of the phosphate glass powder also provide more attachment sites for the basic potash fertilizer, which is beneficial to carrying out adhesive granulation on powdery potassium chloride and potassium sulfate and reducing the using amount of an adhesive, thereby improving the K of the granular potash fertilizer₂And (4) the content of O.

According to the invention, the liquid conditioner is prepared by mixing carboxymethylcellulose, mineral oil and chitosan according to the weight ratio of 1:1:1 and dissolving the mixture in water, and the concentration of the liquid conditioner is 3-5%.

In the invention, the aging treatment is aging for 15-20 min at 20-35 ℃.

Example 1

The embodiment provides a round particle potash fertilizer which comprises, by weight,

comprises a core consisting of 300g of potassium chloride powder, 5g of magnesium oxide and 5g of calcium sulfate hemihydrate; the composite material also comprises a nuclear shell consisting of 700g of potassium chloride powder, 5g of magnesium oxide, 5g of calcium sulfate hemihydrate, 10g of phosphoric acid, 10g of modified cyclodextrin and 10g of modified bentonite.

The preparation method of the round particle potash fertilizer comprises the following steps:

(1) weighing potassium chloride (with particle size less than 60 meshes), magnesium oxide and calcium sulfate according to the proportion in the core, placing in a rotary drum granulator, heating, adding water for granulation, and controlling granulation time to form the core;

(2) weighing each component in the core-shell according to the core-shell proportion, and uniformly mixing 2/5 parts by weight of potassium chloride and modified cyclodextrin to form a core-shell material A; evenly mixing 3/5 parts by weight of potassium chloride raw material and modified bentonite to form a core-shell material B;

(3) adding the core in the step (1), the core-shell material A and the core-shell material B in the step (2), magnesium oxide and calcium sulfate into a granulator; spraying phosphoric acid and a liquid conditioner into the granulator in an atomizing and spraying manner; granulating each material in a granulator; the liquid conditioner is prepared by mixing carboxymethylcellulose, mineral oil and chitosan according to the weight ratio of 1:1:1 and dissolving in water, wherein the concentration of the liquid conditioner is 3%;

(4) aging the granules granulated in the step (3) in an aging machine at 25 ℃ for 20 min;

(5) and (4) drying, cooling and screening the aged material in sequence, and packaging the qualified particles into a product.

Example 2

This example differs from example 1 in that: comprises a core consisting of 300g of potassium chloride powder and 10g of magnesium oxide; the composite material also comprises a core shell consisting of 700g of potassium chloride powder, 10g of calcium sulfate hemihydrate, 10g of phosphoric acid, 10g of modified cyclodextrin and 10g of modified bentonite.

The preparation method is the same as that of example 1.

Example 3

This example differs from example 1 in that:

the magnesium-calcium-magnesium-calcium composite material comprises a core consisting of 200g of potassium chloride powder, 5g of magnesium oxide and 5g of calcium sulfate hemihydrate in parts by weight; the composite material also comprises a nuclear shell consisting of 800g of potassium chloride powder, 5g of magnesium oxide, 5g of calcium sulfate hemihydrate, 10g of phosphoric acid, 15g of modified cyclodextrin and 15g of modified bentonite.

The preparation method is the same as that of example 1.

Comparative example 1

This comparative example provides a round granular potash fertilizer, the difference from example 1 is: the core shell is composed of 700g of potassium chloride powder, 10g of calcium sulfate hemihydrate and 10g of phosphoric acid.

The preparation method of the round particle potash fertilizer comprises the following steps:

(1) weighing potassium chloride (with particle size less than 60 meshes) and magnesium oxide according to the proportion in the core, placing the potassium chloride and the magnesium oxide in a rotary drum granulator, heating, adding water for granulation, and controlling granulation time to form the core;

(2) weighing each component in the core-shell according to the core-shell proportion, and adding the core in the step (1), the potassium chloride in the core-shell and the binder into a granulator; spraying phosphoric acid and a liquid conditioner into the granulator in an atomizing and spraying manner; granulating each material in a granulator; the liquid conditioner is prepared by mixing carboxymethylcellulose, mineral oil and chitosan according to the weight ratio of 1:1:1 and dissolving in water, wherein the concentration of the liquid conditioner is 3%;

(3) aging the granules granulated in the step (2) in an aging machine at 25 ℃ for 20 min;

(4) and (4) drying, cooling and screening the aged material in sequence, and packaging the qualified particles into a product.

Comparative example 2

This comparative example differs from example 1 in that: replacing the modified cyclodextrin with equivalent beta-cyclodextrin; the modified bentonite is replaced by equivalent bentonite.

The preparation method was the same as that of example 1.

Comparative example 3

This comparative example differs from example 1 in that:

in the preparation method of the round particle potash fertilizer, all cores, potassium chloride powder in the core shell, the binder, the modified cyclodextrin and the modified bentonite are directly added into a granulator at the same time, the wetting agent and the liquid conditioner are sprayed for granulation, and then the step (4) and the step (5) are carried out.

Comparative example 4

This comparative example differs from example 1 in that: the preparation method of the round particle potash fertilizer does not contain the aging treatment in the step (4).

The potassium chloride powders used in the examples and comparative examples of the present application were all K₂Potassium chloride powder with an O content of 61.8%.

The granulation temperature of each example and each comparative example in the application is 60-70 ℃.

Comparative example 5

Prepared by the preparation method of example 1 in a patent with publication number CN 102718601A.

Experimental example 1

The potassium fertilizer granule samples prepared in examples 1 to 3 and comparative examples 1 to 5 were subjected to index analysis and detection, and the results are shown in table 1:

	K2o content (%)	Granulation Rate (2-4mm) (%)	Degree of regularity of round grains	Average intensity (N)
					Example 1	58.9	78	Rules	45
Example 2	58.9	71	Rules	46
					Example 3	58.3	85	Rules	48
Comparative example 1	48.2	40	Irregularity	34
					Comparative example 2	51.1	45	Irregularity	36
Comparative example 3	54.8	38	Irregularity	30
					Comparative example 4	56.2	53	Irregularity	24
Comparative example 5	57.4	52	Rules	23

As can be seen from Table 1, compared with comparative examples 1-3 and the prior art, the preparation method disclosed by the invention can be used for preparing the round particle potash fertilizer with high nutrient content, high particle strength and high yield, and has a good popularization and application prospect.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.