CN-121974766-A - Method for producing solid fertilizer granules and fertilizer composition

Abstract

The present invention relates to a method for producing solid fertilizer granules and a fertilizer composition. The present invention provides a method of producing solid fertilizer granules comprising the steps of spraying coated seed granules with a sprayable suspension comprising micronized elemental sulphur particles dispersed in a solution of a primary macronutrient fertilizer to form a coating layer on the seed granules, and drying the coating layer to form a dried shell of the primary macronutrient fertilizer having the micronized sulphur particles dispersed therein. The invention also provides a fertilizer composition comprising seed particles and an encapsulation layer.

Inventors

• Satish Iye
• PEDERSEN ERIC
• Richard Noll
• Bassola Agiboe
• Mitchell Frieger

Assignees

• 苏尔瓦瑞斯公司

Dates

Publication Date

20260505

Application Date

20170228

Priority Date

20160229

Claims (10)

1. 1. A method of producing solid fertilizer granules comprising the steps of spraying coated seed granules with a sprayable suspension comprising micronized elemental sulphur particles dispersed in a solution of a primary macronutrient fertilizer to form a coating layer on the seed granules, and drying the coating layer to form a dried shell of the primary macronutrient fertilizer having micronized sulphur particles dispersed therein.
2. 2. The method of claim 1, wherein the seed particles comprise a primarily macronutrient fertilizer.
3. 3. The method of claim 1 or 2, wherein the seed particles comprise micronized sulphur particles mixed with a primary macronutrient fertilizer.
4. 4. A method according to claim 1, 2 or 3, wherein the seed particles comprise urea, MAP, DAP, micronized sulphur or potassium salts or mixtures thereof.
5. 5. The method of claim 1, 2, 3 or 4, wherein the spray coating step occurs in a rotating drum or fluid bed granulator.
6. 6. A fertilizer composition comprising seed particles and an encapsulation layer comprising micronized elemental sulphur particles dispersed and embedded in the outer shell of a water soluble primary macronutrient fertilizer, wherein the seed particles comprise a primary macronutrient fertilizer, the primary macronutrients of the encapsulation layer comprise urea, MAP, DAP, micronized sulphur or potassium salt or mixtures thereof, and the primary macronutrient composition of the encapsulation layer is different from the primary macronutrient composition of the seed particles.
7. 7. The fertilizer composition of claim 6, wherein the seed particles comprise a primary macronutrient composition.
8. 8. The composition of claim 6 or 7, wherein the seed particles comprise micronized sulphur particles.
9. 9. The composition of claim 7 or 8, wherein the primary macronutrient composition of the seed particles comprises urea, MAP, DAP, micronized sulphur or potassium salt or mixtures thereof.
10. 10. The composition of any one of claims 6 to 9, further comprising a dispersant in the seed particles or the coating layer or both.

Description

Method for producing solid fertilizer granules and fertilizer composition The application is a divisional application of an application patent application with the application number 2017800198372, of which the application name is 'spray coated fertilizer composition' with the application number 2017, 2 and 28. Technical Field The present invention relates to fertilizer compositions and more particularly to fertilizers formed from spray coated granules. Background Vigorous growth of plants requires major macronutrients and minor macronutrients and micronutrients. The main macronutrients include carbon, hydrogen, oxygen, nitrogen, phosphorus and potassium. The secondary macronutrients include calcium, sulfur and magnesium and are generally required in smaller amounts than the primary macronutrients. The required amount of micronutrients is very small and includes zinc, calcium, magnesium, manganese, iron, copper, molybdenum, selenium, boron, chlorine, cobalt and sodium. Any fertilizer comprising elemental sulphur is desirable if most of the sulphur is oxidised to the plant available sulphate form during the application season. However, sulfur oxidizes slowly in the soil because it depends on the colonization and activity of microorganisms. If the sulfur particles become smaller, the oxidation rate increases due to the increased surface area available for microbial colonization. Therefore, micronized sulphur particles are suitably used. Solid fertilizer granules formed by granulation, pelleting or compaction are commonly used to supplement soil with macro-and micronutrients. Granulation is typically accomplished using a granulator well known in the art, including a spray dryer granulator, a roller granulator, a paddle mixer (blender), a fluid bed, a granulator, or a pan granulator. For example, the fertilizer mixture may be fed and distributed over a rolling bed of material within a roller granulator. Water and/or steam may be fed to the granulator to control the temperature and humidity of the granulation process. The granules are then dried and screened, and the on-screen granules and undersize material (so-called off-spec fines) are recycled back to the granulator. The on-screen material may first be crushed or ground before being returned to the granulator. The undersize and crushed oversize material provides seed particles to promote particle formation within the granulator and to form a recycle stream to the granulator. There is a need in the art for alternative methods of producing fertilizer compositions comprising a primary fertilizer and micronized sulphur. Disclosure of Invention In one aspect, the invention includes a fertilizer composition that includes seed particles and an encapsulation layer that includes a soluble primarily macronutrient fertilizer and micronized sulfur particles. The seed particles may include a primary macronutrient fertilizer and may also include micronized sulphur particles. The seed particles may be solids of any desired shape or size and may be formed by any suitable method such as pelleting or compaction. In one embodiment, the seed particles may include urea, MAP, DAP, micronized sulphur, potassium salts, or mixtures thereof. The coating layer may include urea, MAP, DAP, micronized sulphur, potassium salts or mixtures thereof. The coating layer major macronutrient composition may be the same as or different from the seed particle major macronutrient composition. In one embodiment, the composition may include a dispersant in the seed particles or the coating layer or both. The dispersant may include anionic, cationic, amphoteric or nonionic surfactants or mixtures thereof. In one embodiment, the micronized sulphur particles may have an average diameter of less than about 30 microns, and preferably less than about 10 microns. In another aspect, the invention may include a method of producing a fertilizer composition, the method comprising the steps of: (a) Producing seed particles; (b) Preparing a sprayable suspension comprising a solution of a fertilizer material dissolved in water, a suspended insoluble fertilizer material, and a dispersant; (c) A mixture layer of coated soluble and insoluble fertilizer materials is sprayed onto the seed particles using a suspension. In one embodiment, the seed particles themselves comprise a fertiliser material. Preferably, the seed particles are used to form a bed in an encapsulation apparatus such as a rotating drum, pan granulator, or fluid bed granulator, and the bed is continuously agitated by mechanical or fluid means. Preferably, the seed particles are heated to the desired temperature by heating the bed material using hot air. Preferably, the sprayable suspension may be heated to obtain a higher concentration of soluble material in the solution prior to spraying the coating. In one embodiment, the sprayable suspension may be sprayed through a nozzle configured in a coating apparatus to effectively coat seed particles in a mov