CN112409110A

CN112409110A - Special coating agent for bulk blending fertilizer and preparation method and application thereof

Info

Publication number: CN112409110A
Application number: CN202011341535.7A
Authority: CN
Inventors: 张怡
Original assignee: Anhui Zhuoli Environmental Protection Technology Co ltd
Current assignee: Anhui Zhuoli Environmental Protection Technology Co ltd
Priority date: 2020-11-25
Filing date: 2020-11-25
Publication date: 2021-02-26

Abstract

The invention discloses a special coating agent for bulk blending fertilizer and a preparation method and application thereof, relating to the technical field of bulk blending fertilizer, wherein the special coating agent for bulk blending fertilizer comprises a component A and a component B; the component A comprises the following raw materials in parts by weight: 30-45 parts of a coating main agent, 15-22 parts of a film-forming assistant, 10-20 parts of a filler, 0.1-10 parts of a synergistic assistant and 20-40 parts of water, wherein the coating main agent is an oligomeric polymer; the component B comprises a curing agent. The coating agent is used for surface coating treatment of the bulk blending fertilizer raw materials, so that the difference of the angle of repose among the raw materials is reduced, and uniform blending is facilitated; the storage stability of the processed blended fertilizer is also greatly improved; in addition, the coating does not change the original nutrient release rule of the fertilizer, and other varieties of functional coated fertilizers can still be reprocessed by using the coating agent, and the performance of the original fertilizer is not influenced. The invention can realize the production of the blended fertilizer with lower energy consumption, simpler process and no dependence on fixed production environment.

Description

Special coating agent for bulk blending fertilizer and preparation method and application thereof

Technical Field

The invention relates to the technical field of bulk blending fertilizers, in particular to a special coating agent for bulk blending fertilizers as well as a preparation method and application thereof.

Background

China is a big agricultural country, and the reduction of the application and the efficiency improvement of fertilizers and the increase of the use amount of organic fertilizers are the development directions of great concern. According to the nutrient demand characteristics of different areas, different crops and different periods, special formula fertilizers with different nutrient proportions and different release periods are designed, and the utilization rate of the fertilizer is improved by accurate fertilization agronomic measures such as mechanical fertilization and the like and the improvement of the characteristics of the fertilizer, so that the fertilizer becomes a future fertilizer development trend.

The bulk blending fertilizer (also called BB fertilizer) is prepared by physically mixing unit fertilizers or compound fertilizers as raw materials, is one of high-flexibility formulated fertilizers, and is particularly suitable for areas with large land area, complex soil types and various crops in China. At present, the main stream blended fertilizer in the market has the following problems: 1. the storage stability is poor. The blended fertilizer generally needs to be packaged and stored for a certain time after being produced, however, the mixed fertilizers (such as urea and organic fertilizers) of different varieties have adverse reactions, moisture absorption, caking, dissolution and the like, and cause a plurality of inconveniences in storage and use. 2. Mechanical application is poor. The angle of repose of the fertilizer is an important factor influencing the nutrient distribution of the blended fertilizer, and the closer the angle of repose of the fertilizer is, the more uniform the machine application is. The common bulk blending fertilizer raw materials are mostly irregular in particle shape, and the different angles of repose among different fertilizers are large, so that the nutrient uniformity of the bulk blending fertilizer can be seriously influenced, and the application effect of the bulk blending fertilizer is further influenced. 3. The fertilizer effect is poor. Different crops have different nutrient requirements and utilization rates, so that different fertilizers can absorb and utilize more fertilizer nutrients applied to soil by the crops through physical, chemical or biological actions on the basis of substances capable of providing mineral nutrients of plants, thereby improving the fertilizer effect.

Aiming at the problems, in the prior art, the fertilizer is modified by a coating technology, and fertilizer particles are coated by a coating material, so that the surfaces of the fertilizer particles are passivated, the contact among the fertilizer particles is isolated, the occurrence of adverse reactions is reduced, meanwhile, a certain slow release function is given to the fertilizer, and the utilization rate of the fertilizer is improved; for part of irregular particles, the particles can be processed in a particle screening mode, a surface retreatment mode and the like before being blended so as to avoid uneven blending and nutrient separation during application; the effect and the utilization rate of the fertilizer can be improved by adding the synergistic auxiliary agent into the fertilizer. However, under the large background of fertilizer application reduction and efficiency improvement, the requirements on the blended fertilizer are higher and higher, and the prior art cannot meet the development requirements of the blended fertilizer on quality improvement and efficiency improvement. For example: firstly, the fertilizer coating technology is mainly used for soluble fertilizers such as urea and the like, and has narrow application range, complex process and high price; secondly, although the organic fertilizer chemical-resistant coating material can reduce the occurrence of adverse reaction in the blending process to a certain extent, the used materials are mostly resin, mineral oil and the like, and the environmental protection property is poor; most of coating materials, anti-caking agents and the like have great influence on probiotics in the bacteria-containing organic fertilizer, so that the activity of effective bacteria is reduced; fourthly, although the additive is added internally or the additive is coated externally, the adverse reaction of the blended fertilizer cannot be solved although the synergistic component is introduced; in addition, different fertilizers use different surface modification modes to easily cause great difference of the repose angles of the fertilizers, cause poor mixing performance of raw material fertilizers and cause separation of nutrients of mixed fertilizers, thereby influencing the use effect.

Due to the flexibility of the blended fertilizer and the complexity of raw materials, the prior art cannot provide a universal mode, and the problems of the blended fertilizer at present can be conveniently solved.

Disclosure of Invention

Based on the technical problems in the background art, the invention provides a special coating agent for a bulk blending fertilizer, a preparation method and application thereof, which can effectively overcome the defects existing in the storage and use processes of the bulk blending fertilizer.

The invention provides a special coating agent for a bulk blending fertilizer, which comprises a component A and a component B; the component A comprises the following raw materials in parts by weight: 30-45 parts of a coating main agent, 15-22 parts of a film-forming assistant, 10-20 parts of a filler, 0.1-10 parts of a synergistic assistant and 20-40 parts of water, wherein the coating main agent is an oligomeric polymer; the component B comprises a curing agent.

Preferably, in the coating main agent, the number of the polymeric monomers of the oligomeric macromolecule is 2-8; preferably, the coating main agent comprises one or more of oligomeric polyol, acetal, oligomeric polysaccharide and small molecular peptide.

According to the invention, the coating main agent can form a film layer with a certain thickness on the surface of fertilizer particles to passivate the surface of the fertilizer, so that the fertilizer is isolated from being contacted with the outside to a certain extent, the smoothness of the surface of the fertilizer is improved, and the fertilizer is convenient to store and mechanically fertilize. Compared with the prior art, the main coating agent adopts the oligomeric high molecular compound, can better improve the weather resistance of the coating agent, and has higher flowability and spreadability under severe environments such as high temperature, high humidity, low temperature and the like, thereby achieving better coating effect.

Preferably, the film forming aid comprises one or more of polyvinyl alcohol and polyvinylpyrrolidone.

In the invention, the film-forming additive improves the adhesive force and strength of the coating, and simultaneously does not influence the release of fertilizer nutrients.

Preferably, the filler is a porous powder material; preferably, the filler comprises one or more of biochar, zeolite, attapulgite, kaolin.

In the present invention, the filler acts in two ways: firstly, in the coating process, irregular depressions/cracks on the surfaces of fertilizer particles are filled, so that the surface forms of the particles are more regular; and secondly, after the fertilizer is used, the coating on the surface of the fertilizer quickly absorbs water and disintegrates under the action of soil and water, and the nutrient release of the fertilizer is not influenced.

Preferably, the synergist comprises one or more of a chemical synergist and a biological synergist.

In the invention, the addition of the synergistic additive can improve the utilization rate of the fertilizer and promote the growth of crops. The synergistic auxiliary agent can be phytostimulin, urease inhibitor, microorganism metabolite, microorganism extract, animal and plant protein, microelement, chelating agent, amino acid or polypeptide, etc.

Preferably, the curing agent is a polyisocyanate.

Preferably, the weight ratio of the component A to the component B is 1-5: 1.

the invention also provides a preparation method of the special coating agent for the bulk blending fertilizer, which comprises the following steps: mixing the coating main agent, the film-forming additive, the filler, the synergistic additive and water in proportion, and grinding to obtain a component A; respectively and independently storing the component A and the component B; before use, the component A and the component B are mixed according to the weight ratio to obtain the coating agent coating material special for the blended fertilizer.

The invention also provides the application of the special coating agent for the bulk blending fertilizer in the bulk blending fertilizer, and the special coating agent for the bulk blending fertilizer is used for preparing the coated bulk blending fertilizer; the preparation of the coating blended fertilizer is as follows: mixing the component A and the component B of the special coating agent for the blended fertilizer to prepare a coating agent, then respectively adding the coating agent into each component fertilizer of the blended fertilizer, stirring and drying to obtain each component coated fertilizer, and mixing each component coated fertilizer of the blended fertilizer to obtain the coated blended fertilizer.

Preferably, the dosage of the special coating agent for the bulk blending fertilizer is 0.5-2.5% of the weight of the bulk blending fertilizer.

Compared with the prior art, the invention has the beneficial effects that:

1. the blended fertilizer processed by the coating agent has greatly improved storage stability, and can be stored and used in a severe environment.

2. The coating agent is used for surface coating treatment of the raw materials of the blended fertilizer, so that the difference of the repose angles among the raw materials is reduced, uniform blending is facilitated, and nutrient separation during blending and use is avoided.

3. The coating does not change the original nutrient release rule of the fertilizer, can be used for coating most common bulk blending fertilizer granule raw materials, can be reprocessed by using the coating agent on the basis of other functional coated fertilizers, such as slow-release urea, bacterium-coated organic fertilizers and the like, and does not influence the original coating performance.

4. The coating agent of the invention is suitable for coating bacterial organic fertilizer, and has no adverse effect on the activity of commonly used bacterial fertilizer strains such as bacillus licheniformis, bacillus subtilis, bacillus natto and the like.

5. The processing of the coated fertilizer can be carried out under the condition of normal temperature, and meanwhile, better coating performance and stability can be realized under severe environments such as high temperature, high humidity, low temperature and the like, the processing difficulty of the blended fertilizer is reduced, the processing time is shortened, and the processing efficiency is improved.

6. The coating agent can be used as a universal carrier of most synergistic auxiliaries (powder or aqueous agent), and is added to the surface of the fertilizer in a simple and convenient manner, so that the problems of high production energy consumption, easiness in decomposition of auxiliary materials, non-uniform mixing of the auxiliary in the fertilizer and the like caused by mixing and granulating the synergistic auxiliaries and the fertilizer in a high-temperature molten state in the traditional auxiliary internal addition manner are obviously improved.

The coating agent is different from a common sulfur coating or a resin coating, cannot endow the fertilizer with a slow release effect, aims to realize the production of the blended fertilizer with lower energy consumption, simpler process and no dependence on a fixed production environment, can effectively prevent the surface of the fertilizer from contacting, and can finish the surface smoothness of fertilizer particles, and can also be used as a carrier of a synergistic additive. The sulfur coating in the prior art generally needs high temperature condition, the resin coating material has poor fluidity and long curing time even is not cured under low temperature condition, and is not beneficial to production.

Drawings

FIG. 1 is a 200-fold magnified electronic photograph of coated urea in example 7 of the present invention;

FIG. 2 is a scanning electron microscope image of the surface of diammonium phosphate in example 8 of the present invention, the left image is uncoated diammonium phosphate, and the right image is coated diammonium phosphate;

FIG. 3 is a drawing showing the culture of the coated bacterial manure leaching liquor in example 12 of the present invention, the left drawing being a control group and the right drawing being an experimental group;

FIG. 4 is a graph showing the moisture absorption rate of the coated bulk blended fertilizer of example 14 of the present invention.

Detailed Description

The technical solution of the present invention will be described in detail below with reference to specific examples.

EXAMPLE 1 preparation of component A in coating agent I for bulk blending fertilizer

Coating main agent: 40 parts of triethylene glycol and 5 parts of fructo-oligosaccharide;

film-forming auxiliary agent: 15 parts of polyvinyl alcohol;

filling agent: 20 parts of rice hull biochar (200 meshes);

and (3) synergistic auxiliary agent: 0.1 part of polyglutamic acid;

water: 40 parts of the components.

The component A is prepared by grinding the components in proportion by a grinder.

Example 2 preparation of component A in coating agent II for bulk blending fertilizer

Coating main agent: 30 parts of polypropylene glycol (PPG 200);

film-forming auxiliary agent: 20 parts of polyvinyl alcohol and 2 parts of polyvinylpyrrolidone;

filling agent: 5 parts of attapulgite (250 meshes), 5 parts of kaolin (325 meshes);

and (3) synergistic auxiliary agent: 2 parts of urease inhibitor.

Water: and 20 parts.

Example 3 preparation of component A in coating agent III for bulk blending fertilizer

Coating main agent: 10 parts of pig blood protein peptide (average molecular weight 1000Da) and 20 parts of enzymolysis starch;

film-forming auxiliary agent: 15 parts of polyvinyl alcohol;

filling agent: 10 parts of zeolite (100 meshes);

and (3) synergistic auxiliary agent: 10 parts of yeast extract.

Water: 40 parts of the components.

Example 4 preparation of component A of coating agent IV for bulk blending fertilizer

Coating main agent: 10 parts of polypropylene glycol (PPG200), 10 parts of polypropylene glycol (PPG400) and 20 parts of polyethylene glycol (PEG 200);

film-forming auxiliary agent: 15 parts of polyvinyl alcohol;

filling agent: 10 parts of attapulgite (250 meshes);

and (3) synergistic auxiliary agent: 5 parts of gamma-aminobutyric acid.

Water: and 20 parts.

Example 5A coated bacterial fertilizer for bulk blended fertilizers (effective viable count ≥ 0.2 hundred million/g)

The coating material is obtained by uniformly mixing 105 parts of the component A and 25 parts of the component B of the special coating agent III for the bulk blending fertilizer in the embodiment 3 by taking the polyisocyanate as the component B. Adding 0.8 part by weight of coating material into 100 parts by weight of molasses liquid-coated bacterial organic fertilizer (bacillus subtilis as a strain), stirring at normal temperature for 3-5 min, and naturally drying to obtain the coating bacterial fertilizer for the blended fertilizer.

Example 6 coating organic fertilizer for blend fertilizer (organic matter dry basis is more than or equal to 25%)

The coating material is obtained by uniformly mixing 120.1 parts of the component A and 30 parts of the component B of the special coating agent I for the bulk blending fertilizer in the example 1 by taking polyisocyanate as the component B. Adding 0.5 part by weight of coating material into 100 parts by weight of granular organic fertilizer, stirring for 3-5 min at normal temperature, and naturally drying to obtain the coating organic fertilizer for the blended fertilizer.

Example 7 coated Urea for bulk blending Fertilizer (N.gtoreq.45%)

And taking polyisocyanate as a component B, and uniformly mixing 84 parts of the component A and 40 parts of the component B of the special coating agent II for the bulk blending fertilizer in the example 2 to obtain the coating material. Adding 2.0 parts by mass of coating material into 100 parts by mass of urea, stirring for 3-5 min at normal temperature, and naturally drying to obtain the coating urea for the blended fertilizer.

FIG. 1 is a graph of the coated urea obtained at 200 times magnification, and it can be seen from FIG. 1 that the average coating thickness is about 17 μm, the coating is uniform and complete, and the coating has good adhesion effect.

Example 8A coating diammonium phosphate for a bulk blending fertilizer (total nutrient: 55%)

And (3) taking polyisocyanate as a component B, and uniformly mixing 90 parts of the component A and 30 parts of the component B of the special coating agent IV for the bulk blending fertilizer in the embodiment 4 to obtain the coating material. Adding 2.5 parts by mass of coating material into 100 parts by mass of granular diammonium phosphate, and stirring at normal temperature for 3-5 min to obtain diammonium phosphate for the bulk blending fertilizer.

FIG. 2 is a scanning electron microscope image of the surface of diammonium phosphate, and it can be seen from the image that the coating agent of the present invention obviously plays a role in filling irregular pits/gaps on the surface of fertilizer, and thus, the surface state of fertilizer is modified.

Example 9 coating Potassium sulfate (K) for bulk blending fertilizer₂O≥50％)

And (3) taking polyisocyanate as a component B, and uniformly mixing 90 parts of the component A and 30 parts of the component B of the special coating agent IV for the bulk blending fertilizer in the embodiment 4 to obtain the coating material. And adding 2.0 parts by mass of coating material into 100 parts by mass of granular potassium sulfate, stirring for 3-5 min at normal temperature, and naturally drying to obtain the granular potassium sulfate for the bulk blending fertilizer.

Example 10A coated bulk blended fertilizer

And mechanically and uniformly mixing the fertilizer in the embodiment 6-9 according to the weight percentage of 10% of the coating organic fertilizer, 56% of the coating urea, 10% of the coating diammonium phosphate and 24% of the coating potassium sulfate.

EXAMPLE 11 Properties of component A in coating agent for bulk Fertilizer

The properties of the A-component prepared in examples 1-4 were examined and the results are shown in Table 1.

TABLE 1 Performance parameters for the A Components prepared in examples 1-4

Example 12 coating bacterial manure Activity

The coated bacterial manure in example 5 was used as an experimental group; in the same manner, the coating material of example 5 was replaced with a molasses solution in the same amount, and the correspondingly coated bacterial manure was used as a control group. The bacterial manure of 6 groups in the experimental group and the control group are processed at the same time, and the bacterial activity detection is carried out after the bacterial manure is placed for 1d and 7d, and the results are shown in table 2.

TABLE 2 coated bacterial manure Activity data

FIG. 3 is a culture diagram of the bacterial manure leaching solution after being placed for 7 days, and as can be seen from FIG. 3 and Table 2, the coating material of the present invention does not negatively affect the activity of Bacillus subtilis compared with the conventional sugar-honey solution containing bacterial manure.

Example 13 dissolution rate of coating Urea nutrient

The urea nutrient dissolution rate was measured for uncoated normal urea (CK) and coated urea (T) in example 7, and the results are shown in table 3.

TABLE 3 coating Urea nutrient dissolution Rate data

Numbering	CK	T
				1	76.3％	77.1％
2	77.5％	74.5％
			3	79.3％	73.6％
Average	77.7％	75.1％

As can be seen from the data in Table 3, the coating of the present invention has little effect on the dissolution of urea nitrogen and does not affect the release of fertilizer nutrients.

EXAMPLE 14 anti-caking Rate of coated bulk blending fertilizers

1000g of the coated bulk blended fertilizer prepared in example 10 was used as an experimental group and an uncoated conventional bulk blended fertilizer prepared in the same manner was used as a control group. The control group (CK) and the experimental group (T) were placed in a constant temperature and humidity cabinet at 20 ℃, 30 ℃, 40 ℃ and 70% humidity, and the moisture absorption rate and the caking of the two groups of fertilizers within 15 hours were continuously recorded and counted, and the results are shown in Table 4.

TABLE 4 coating layer bulk fertilizer anti-caking rate data

Note: "-" indicates no caking, "I" indicates slight caking, "II" indicates slight caking, "III" indicates some caking, and "IV" indicates a large amount of caking. "dissolve" means that the blended fertilizer absorbs water to dissolve.

FIG. 4 is a moisture absorption rate curve, and it can be seen from Table 4 and FIG. 4 that the coating material of the present invention can effectively isolate the blended fertilizer from the external moisture, and significantly reduce the moisture absorption rate and caking of the blended fertilizer in different temperature environments.

Example 15 coated blended fertilizer angle of repose

The average leading grain diameter SGN value of the raw material fertilizer is generally 280-340, the difference is controlled to be less than 59, and the raw material fertilizer is suitable for mixing. Under the condition of not changing the uniformity index UI, the smaller the angle of repose among the raw material fertilizers is, the easier the mixing is.

The angle of repose data for the coated fertilizers and the corresponding uncoated fertilizers (normal fertilizers) of examples 5-9 are shown in Table 5, as measured by KS M ISO 8398-2007.

TABLE 5 Angle of repose data for coated and ordinary fertilizers

The data in Table 5 show that the difference of the repose angles of the coated fertilizers is reduced, so that the fertilizers are easy to mix and are not easy to cause nutrient separation.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims

1. A special coating agent for bulk blending fertilizer is characterized by comprising a component A and a component B; the component A comprises the following raw materials in parts by weight: 30-45 parts of a coating main agent, 15-22 parts of a film-forming assistant, 10-20 parts of a filler, 0.1-10 parts of a synergistic assistant and 20-40 parts of water, wherein the coating main agent is an oligomeric polymer; the component B comprises a curing agent.

2. The special coating agent for the bulk blended fertilizer as claimed in claim 1, wherein the number of the polymeric monomers of the oligomeric high polymer in the coating main agent is 2-8; preferably, the coating main agent comprises one or more of oligomeric polyol, acetal, oligomeric polysaccharide and small molecular peptide.

3. The special coating agent for bulk blended fertilizer as claimed in claim 1, wherein the film forming aid comprises one or more of polyvinyl alcohol and polyvinylpyrrolidone.

4. The special coating agent for bulk blended fertilizer as claimed in claim 1, wherein the filler is a porous powder material; preferably, the filler comprises one or more of biochar, zeolite, attapulgite, kaolin.

5. The special coating agent for bulk fertilizers according to claim 1, wherein the synergist comprises one or more of a chemical synergist and a biological synergist.

6. The special coating agent for bulk blended fertilizer as claimed in claim 1, wherein the curing agent is polyisocyanate.

7. The special coating agent for the bulk blended fertilizer as claimed in claim 1, wherein the weight ratio of the component A to the component B is 1-5: 1.

8. the preparation method of the special coating agent for the bulk blended fertilizer as claimed in any one of claims 1 to 7, characterized by comprising the following steps: mixing the coating main agent, the film-forming additive, the filler, the synergistic additive and water in proportion, and grinding to obtain a component A; respectively and independently storing the component A and the component B; before use, the component A and the component B are mixed according to the weight ratio to obtain the coating agent coating material special for the blended fertilizer.

9. The application of the special coating agent for bulk blended fertilizer as defined in claims 1-7 or prepared by the method as defined in claim 8 in bulk blended fertilizer, characterized in that the special coating agent for bulk blended fertilizer is used for preparing the coated bulk blended fertilizer; the preparation of the coating blended fertilizer is as follows: mixing the component A and the component B of the special coating agent for the blended fertilizer to prepare a coating agent, then respectively adding the coating agent into each component fertilizer of the blended fertilizer, stirring and drying to obtain each component coated fertilizer, and mixing each component coated fertilizer of the blended fertilizer to obtain the coated blended fertilizer.

10. The application of the special coating agent for the bulk blended fertilizer in the bulk blended fertilizer as claimed in claim 9, wherein the dosage of the special coating agent for the bulk blended fertilizer is 0.5-2.5% of the weight of the bulk blended fertilizer.