阅读说明：本技术 一种氯化钾腐殖酸复合缓释肥颗粒及其制备方法 (Potassium chloride and humic acid composite slow-release fertilizer granules and preparation method thereof ) 是由 郭延乐 高洪宇 王磊 梁演扬 乔涵驰 于 2019-10-29 设计创作，主要内容包括：本发明公开了一种氯化钾腐殖酸复合缓释肥颗粒及其制备方法,将氯化钾粉末、腐殖酸粉末混合均匀,得到混合粉料,加入到造粒设备中,通过雾化器向混合粉料中均匀喷洒一定量的水分润湿,然后继续喷加一定量的粘结剂,通过造粒设备得到3～5mm的颗粒,并烘干,最后通过包膜工艺,在颗粒表面包覆一层缓释膜即得。本发明制备产品的兼具有机无机肥料及缓释肥料各自优点,可为土壤补充全面及短长效养分同时具有一定改良土壤作用,缓解无机肥料对土壤物理结构的损害；同时,腐植酸和钾肥互作可以提高土壤肥力,调节土壤C/N平衡,增强土壤的生物活性,协调土壤养分释放。(The invention discloses potassium chloride and humic acid composite slow-release fertilizer granules and a preparation method thereof, wherein potassium chloride powder and humic acid powder are uniformly mixed to obtain mixed powder, the mixed powder is added into granulation equipment, a certain amount of moisture is uniformly sprayed into the mixed powder through an atomizer for wetting, then a certain amount of binder is continuously sprayed, granules with the diameter of 3-5 mm are obtained through the granulation equipment, the granules are dried, and finally a layer of slow-release film is coated on the surfaces of the granules through a film coating process to obtain the potassium chloride and humic acid composite slow-release fertilizer granules. The product prepared by the invention has the advantages of both organic and inorganic fertilizers and slow release fertilizers, can supplement comprehensive and short-acting nutrients for soil, has a certain effect of improving soil and relieves the damage of the inorganic fertilizers to the physical structure of the soil; meanwhile, the interaction of the humic acid and the potash fertilizer can improve the soil fertility, adjust the C/N balance of the soil, enhance the biological activity of the soil and coordinate the release of soil nutrients.)

1. A preparation method of potassium chloride humic acid composite slow release fertilizer particles is characterized by comprising the following steps:

(1) uniformly mixing potassium chloride powder and humic acid powder to obtain mixed powder;

(2) adding the mixed powder obtained in the step (1) into granulation equipment, uniformly spraying a certain amount of moisture into the mixed powder through an atomizer for wetting, continuously spraying a certain amount of binder, obtaining particles with the particle size of 3-5 mm through the granulation equipment, and drying;

(3) and (3) coating a layer of slow release film on the surface of the granules obtained in the step (2) through a coating process.

2. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 1, wherein in the step (1), the fineness of the potassium chloride powder is 10-60 meshes; the fineness of the humic acid powder is 10-60 meshes.

3. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 1, wherein in the step (1), the mixing mass ratio of the potassium chloride powder to the humic acid powder is 5-8: 1.

4. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 1, wherein in the step (2), the spraying amount of the moisture is 3-5% of the mass of the mixed powder.

5. The method for preparing potassium chloride-humic acid composite slow-release fertilizer granules according to claim 1, wherein in the step (2), the binder is urea formaldehyde aqueous solution or urea formaldehyde powder.

6. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 5, wherein in the step (2), the spraying amount of the binder is 15-25% of the mass of the mixed powder.

7. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 1, wherein in the step (2), the granulation equipment is a disc granulator, wherein the atomization time is 10-75 min, the water addition amount is 8-13%, the rotating speed of a rotating disc is 30-60 r/min, and the inclination angle is 30-60 °.

8. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 1, wherein in the step (3), the slow-release film is thermosetting urea-formaldehyde resin.

9. The preparation method of the potassium chloride-humic acid composite slow-release fertilizer granules according to claim 8, wherein in the step (3), the coating amount of the slow-release film is 5-10% of the total mass of the granules.

10. The potassium chloride and humic acid composite slow-release fertilizer particles prepared by any one preparation method of claims 1-9.

Technical Field

The invention belongs to the field of fertilizer manufacturing, and particularly relates to potassium chloride humic acid composite slow-release fertilizer granules and a preparation method thereof.

Background

Potassium (K) is a necessary nutrient element for influencing the growth and development of plants, but only a small part of potassium can be absorbed and utilized by the plants after fertilization, the problem of low utilization rate of the potassium fertilizer is common, and the current utilization rate of the potassium fertilizer in China is reported to be 35-50%. The fertilizer is a material basis of modern agriculture, and according to the report of grain and agriculture organizations, the global potassium fertilizer demand is increased by 2.6% from 2014 to 2018. Meanwhile, the potassium ore reserves in China are insufficient, and soil potassium is relatively deficient. Therefore, how to improve the utilization rate of the potash fertilizer becomes one of hot researches in the field of plant nutrition and fertilization. Meanwhile, for some crops with longer growth period, after the common potash fertilizer is applied as a base fertilizer, the supply of potassium and the nutrient demand of the crops are often asynchronous, particularly, the growth of the crops is inhibited due to potassium deficiency in the later growth period of the crops, and the labor cost is increased by adopting a later-period topdressing mode, which is not beneficial to the improvement of economic benefit.

The main potassium fertilizer product types currently on the market are potassium chloride (KCl) and potassium sulphate (K)₂SO₄). The most common potassium fertilizer product worldwide is potassium chloride, which accounts for almost 70% of the potassium fertilizer requirement and in some countries, such as the united states, brazil or india, it accounts for over 90% of the total potassium fertilizer. The potassium chloride has high potassium content and the price thereof is generally far lower than that of potassium sulfate, and is now the main potash fertilizer in modern agricultural production. However, the salinity coefficient of potassium chloride is higher than that of potassium sulfate, and the potassium chloride is applied to saline-alkali soil or arid soil with poor drainage, so that the seed germination and seedling growth are not facilitated. In addition, some crops that are sensitive to chloride ions are known as "chlorine-sparing crops" and are not suitable for application of potassium chloride but only the more expensive potassium sulfate.

In recent years, the controlled release fertilizer is developed rapidly as a new technology, and the product mainly takes the controlled release nitrogen fertilizer as a main material and can improve the crop yield and the nutrient utilization efficiency. If the potassium chloride is prepared into the controlled-release potassium chloride, the chloride ions and the potassium ions can be slowly released to improve the utilization rate of the potassium fertilizer, and the requirement of the crops on nutrients in the later growth period can be met; meanwhile, the potassium chloride is relatively low in price and high in effective potassium content, so that the idea has high feasibility.

However, there are few reports on the research on the production and application of controlled-release potassium chloride, and the main reasons are as follows. Firstly, the potassium chloride products in the existing market are mainly powdery Qinghai salt lake potassium and irregular granular Hongniu potassium chloride produced by extrusion granulation. Powdery potassium chloride cannot be coated; the surface of the potassium chloride of the red bull is uneven and has a plurality of irregular edges, so that the coated potassium chloride with good controlled release effect is difficult to prepare. However, the preparation of coated potassium chloride with good sustained and controlled release effects must be guaranteed by a rounded core with good particle properties. Therefore, the adhesive can be added to granulate the potassium chloride powder, the potassium chloride powder is prepared into spherical particles with the particle size of 2-5 mm, and then the spherical products are coated to obtain the coated potash fertilizer with good controlled release performance. Meanwhile, the spherical granulated fertilizer has great advantages in the aspects of storage, transportation, application and the like, and is suitable for mechanized seed manure simultaneous sowing.

Granulation is the process of making a powder into small particles and gradually accumulating and enlarging under certain conditions. Granulation is widely used in various industrial production fields, such as pesticide, food processing, agricultural products, medicine, etc. Among them, the composition of the material and its properties have very important influence on granulation production, granule quality and the like. The fertilizer granulation can reduce the loss of powder fertilizer and prevent dust pollution, and the granulation mechanism comprises three stages: wetting nucleation, increased consolidation, wear damage. Essentially, granulation is a series of natural mechanical processes that occur in the formation of small particles, and consists of raw material substances and properties that exhibit different production effects; the disc granulator is used as a common production device, and the rotation speed and the inclination angle of a disc of the disc granulator affect the granulation effect.

Because of the poor cohesiveness and plasticity of potassium chloride, a binder needs to be added to obtain high-strength spherical particles with smooth surfaces. The cost of the binder and the granulation effect thereof become important problems influencing the granulation production of the powdery potassium chloride. Urea-formaldehyde (UF) resin is a high-molecular polymer formed by reacting urea and formaldehyde, has strong bonding performance and low price, is widely applied to the fields of wood processing and the like, and the molar ratio of urea to formaldehyde is generally 0.50-0.67 or less. However, when the molar ratio of urea to formaldehyde is 1-2, the urea-formaldehyde resin prepared by the method can be used as a fertilizer granulation binder and a slow-release nitrogen fertilizer (urea formaldehyde). Urea formaldehyde is one of the commonly used slow-release fertilizers in the world, can promote the formation of a soil granular structure, improve the soil permeability, improve the utilization rate of a nitrogen fertilizer, can be completely degraded in soil and has unique advantages.

Good core guarantee is needed to prepare the coated potassium chloride with good sustained and controlled release performance; the urea-formaldehyde is used as a slow release binder and is organically combined with auxiliary substances, so that the technical idea and means for producing the excellent core are provided, and the scientific basis of the technical innovation of the fertilizer is provided for the efficient and sustainable application of the potash fertilizer.

In the process of fertilizer granulation, it is a common practice to add auxiliary substances (clay, bentonite and the like) as binders, so that the fertilizer granulation efficiency can be improved.

Humic acid as a resource widely exists in nature, has wide source and low price, has the functions of improving soil, enhancing fertilizer efficiency, stimulating crop growth, improving crop yield and stress resistance, improving the quality of agricultural products and the like, and is widely applied in the fields of industry and agriculture, medicine and environmental protection; the side chain of the gel has active groups such as aromatic ring, condensed ring, alicyclic ring or heterocyclic ring, the active groups have stronger exchange, complexation, flocculation and adsorption effects, the molecular weight is different from hundreds to tens of thousands, and the gel is a hydrophilic reversible colloid. Meanwhile, humic acid is a binder selected in the prior art for manufacturing the briquette, and has high viscosity, so that the humic acid has feasibility as an auxiliary substance for binding and granulating fertilizers. In addition, the interaction of humic acid and potash fertilizer can improve soil fertility, adjust soil C/N balance, enhance soil biological activity and coordinate soil nutrient release; taking tobacco as an example, the two have obvious positive effects on reducing sugar, total nitrogen, nitrogen-base ratio, potassium and organic potassium salt index of tobacco leaves.

Disclosure of Invention

The invention aims to solve the technical problem of the prior art, and provides a slow release fertilizer prepared by mixing and granulating potassium chloride and humic acid, so as to improve the utilization efficiency of a potash fertilizer, reduce the fertilization times, and solve the problems of low utilization rate of the potash fertilizer, inconvenient later-stage topdressing, high potassium sulfate price, low potassium content and the like.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

a preparation method of potassium chloride humic acid composite slow release fertilizer granules comprises the following steps:

(1) uniformly mixing potassium chloride powder and humic acid powder to obtain mixed powder;

(2) adding the mixed powder obtained in the step (1) into granulation equipment, uniformly spraying a certain amount of moisture into the mixed powder through an atomizer for wetting, continuously spraying a certain amount of binder, obtaining particles with the particle size of 3-5 mm through the granulation equipment, and drying;

(3) and (3) coating a layer of slow release film on the surface of the granules obtained in the step (2) through a coating process.

Specifically, in the step (1), the fineness of the potassium chloride powder is 10-60 meshes; the fineness of the humic acid powder is 10-60 meshes.

Preferably, in the step (1), the mixing mass ratio of the potassium chloride powder to the humic acid powder is 5-8: 1.

Preferably, in the step (2), the spraying amount of the moisture for wetting the powder is 3-5% of the mass of the mixed powder.

Preferably, in step (2), the binder is an aqueous urea-formaldehyde solution or a urea-formaldehyde powder, preferably an aqueous urea-formaldehyde solution.

Preferably, in the step (2), the spraying amount of the binder is 15-25% of the mass of the mixed powder.

Specifically, in the step (2), the granulating equipment is a disc granulator, wherein the atomizing time is 10-75 min, the water addition amount is 8-13%, the rotating speed of the turntable is 30-60 r/min, and the inclination angle is 30-60 °.

Specifically, in the step (3), the slow release film is thermosetting urea-formaldehyde resin.

Preferably, in the step (3), the coating amount of the slow release film is 5-10% of the total mass of the particles.

The potassium chloride humic acid composite slow-release fertilizer particles prepared by the method are also in the protection scope of the invention.

Has the advantages that:

the material used by the composite slow-release fertilizer particles is high in popularization degree, and the preparation method is simple and easy to implement; the preparation efficiency is high, and the preparation reproducibility is good; the prepared product has the advantages of both organic and inorganic fertilizers and slow release fertilizers, can supplement comprehensive and short-acting nutrients for soil, has a certain effect of improving the soil and relieves the damage of the inorganic fertilizers to the physical structure of the soil; meanwhile, the interaction of the humic acid and the potash fertilizer can improve the soil fertility, adjust the soil C/N balance, enhance the soil bioactivity and coordinate the soil nutrient release, which has important practical significance for improving the fertilizer utilization rate, further reducing the fertilizer use, promoting the high-quality crop yield increase and the income increase of farmers, and has wide application prospect.

Drawings

The foregoing and/or other advantages of the invention will become further apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

FIG. 1 is a flow chart of a preparation process of the potassium chloride humic acid composite slow-release fertilizer granules.

Fig. 2 is a graph showing the release effect of the composite slow release fertilizer particles prepared in example 2.

Detailed Description

The invention will be better understood from the following examples.