WO2018032844A1

WO2018032844A1 - Method for preparing zinc-containing sustained-release pellet potash fertilizer

Info

Publication number: WO2018032844A1
Application number: PCT/CN2017/085273
Authority: WO
Inventors: 胡育化; 王仁宗; 田凯; 刘春梅; 孙阳; 刘裕; 詹水华
Original assignee: 湖北富邦科技股份有限公司
Priority date: 2016-08-15
Filing date: 2017-05-22
Publication date: 2018-02-22
Also published as: CN106278607A

Abstract

A method for preparing a zinc-containing sustained-release pellet potash fertilizer, comprising the following steps: adding, at a temperature of 65-115ºC to a phosphoric acid or sludge phosphoric acid solution with a mass concentration of 5-50%, a reactant accounting for 0.1-2.5% of the mass of the phosphoric acid or sludge phosphoric acid solution, and reacting for 10-60 min to obtain a mixed solution; spraying the mixed solution to the surfaces of potassium chloride or potassium sulfate crystals in a pelletizer, and then adding zinc oxide powder, so that the reactant and zinc oxide undergo an in-situ reaction on the surfaces of the potassium chloride or potassium sulfate crystals, to form a cured product having binding power; repeating the process, so that the mixed solution and the zinc oxide powder are alternately added to the surfaces of the potassium chloride or potassium sulfate crystals, and small fertilizer particles are continuously rolled and gradually wrapped and gradually grow larger till the pellet size of the fertilizer is 2-5 mm; and drying and screening to obtain the zinc-containing sustained-release pellet potash fertilizer with the pellet size of 2-5 mm. The pellet potash fertilizer has good sustained-release performance, and contains nutrient elements such as N, P, and Zn.

Description

Preparation method of zinc-containing slow-release round granule potassium fertilizer

Technical field

The invention relates to a preparation method of a zinc-containing slow-release round granule potassium fertilizer, in particular to a method for preparing an in-situ reaction using a powdery zinc oxide and a liquid acid on the surface of a basic nutrient crystal of potassium nutrients, and adopting physical and chemical methods for preparing zinc-containing material. Preparation method of slow release round granule potassium fertilizer.

Background technique

At present, the national soil testing and fertilization project has been carried out for more than ten years. Rural formula fertilization has been popularized. The main raw materials for formula fertilization are granular fertilizers containing nitrogen, phosphorus and potassium. Farmers can choose nitrogen according to crop varieties and soil fertility. The ratio of phosphorus to potassium is mixed before sowing. The existing nitrogen fertilizer for formula fertilizer is mainly large granular urea. The large granular urea is a very regular spherical particle. The phosphate fertilizer used for formula fertilizer is granular diammonium phosphate/ Monoammonium phosphate, diammonium phosphate/monoammonium phosphate particles are also regular spherical particles. Potassium fertilizer used in formula fertilizers, mainly potassium chloride/potassium sulfate, generally irregular polyhedral particles produced by extrusion and phosphorus breaking. After the three kinds of fertilizers are mixed together, because the shape and particle size of the granular potash fertilizer are different from those of nitrogen fertilizer and phosphate fertilizer, stratification is easy to occur during transportation or fertilization, and irregular potassium-containing particles will precipitate to the lower layer, causing upper and lower layers of fertilizer. Uneven nutrients will eventually affect fertilizer efficiency and affect crop yields. With the development of blended fertilizers, the demand for round granular potash is also growing. At present, the potassium fertilizer on the market is mainly irregular in the form of powder and extrusion granulation, and the round granule potassium fertilizer becomes a scarce product. Compared with traditional compound fertilizer granulation, the granulation difficulty of potassium fertilizer mainly has the following reasons: 1. Potassium chloride/potassium sulphate belongs to sand type material, and has no viscosity and plasticity. It is difficult to granulate by conventional methods; 2. Potassium chloride / Potassium sulphate has a large solubility in water, and the amount of liquid phase required for granulation by agglomeration is too large, so that the granule potassium fertilizer formed during granulation is extremely low in strength and cannot be mass-produced; 3. too low wet strength makes the granules Potassium fertilizer is severely damaged during drying and the yield is extremely low.

Summary of the invention

The object of the present invention is to solve the above problems, and to provide a preparation method of a zinc-containing slow-release round granule potassium fertilizer. The method has simple operation and simple process, and is easy to realize industrial production. The obtained product has uniform appearance and roundness, high particle strength and balanced nutrients, and meets the requirements. The process of blending fertilizer is also convenient for farmers to apply. At the same time, it can provide the necessary elements such as nitrogen, phosphorus, potassium and zinc needed for crop growth, which can meet the demand for potassium in the whole growth period of the crop. The prepared round granular potassium fertilizer also has good sustained release properties, zinc and potassium. Synergistic effects of elements, improve the utilization of potassium fertilizer, improve the comprehensive benefits of fertilizers, and have good market prospects and social and economic benefits.

The technical proposal for producing zinc-containing slow release round granule potassium fertilizer proposed by the invention is:

The invention relates to a preparation method of zinc-containing slow-release round-particle potassium fertilizer, which comprises the following steps: a phosphoric acid or a phosphoric acid slag acid solution having a mass concentration of 5-50%, and adding phosphoric acid or phosphoric acid slag at a temperature of 65-115 ° C The reaction solution is 0.1-2.5% of the reactant, and the mixture is reacted for 10-60 minutes to prepare a mixed solution; the mixed solution is sprayed onto the surface of the potassium chloride or potassium sulfate crystal in the granulation equipment, and then the powder zinc oxide is added to allow the reactant and oxidation. Zinc reacts in situ on the surface of potassium chloride or potassium sulfate crystals to form a solidified material with a certain binding force. Thus, the mixture and the powdered zinc oxide are alternately added on the surface of potassium chloride or potassium sulfate crystals. The small granular fertilizer is gradually wrapped and gradually grown until the fertilizer particle size grows to 2-5 mm. After drying and sieving, the zinc-containing slow-release round-grain potassium fertilizer with a particle size of 2-5 mm is obtained.

The powdered zinc oxide and the mixed liquid were sprayed onto the surface of the potassium chloride or potassium sulfate crystal in the granulation apparatus at a mass ratio of 1:2.5.

The fineness of the potassium chloride or potassium sulfate is 20-100 mesh.

The fineness of the powdered zinc oxide is 300-1000 mesh.

Phosphoric acid or phosphoric acid slag acid solutions are industrial products.

The reactant is one of ammonium chloride, ammonium sulfate or a mixture of the two.

The granulation apparatus is a disc granulator.

The finished round pellets have a nutrient release period of up to 25-80 days.

The invention utilizes the reaction agent and the zinc oxide to react in situ on the surface of the potassium chloride or potassium sulfate crystal to form a cured product having a certain binding force, and forms a round granular potassium fertilizer under the action of physical movement. The formed round-particle potassium fertilizer has the characteristics of slow dissolution and release of nutrients, solves the problem that potassium fertilizer is quickly dissolved in water and is lost through runoff, leaching, etc., and provides trace element zinc, zinc nutrition and potassium nutrition synergy necessary for crop growth. To promote crop growth, increase production and income, and increase the utilization rate of potassium fertilizer.

The present invention has the following outstanding advantages:

1. The process is simple to operate. The traditional compound fertilizer manufacturing process can be used without additional equipment.

2. Low production costs. Phosphoric acid, reactants, etc. can be used in industrial products, and the reacted acid mixture is reacted with zinc oxide to obtain a cured product which is used as both a granulation binder and a nitrogen, phosphorus and zinc nutrient for plant growth. The combined cost of fertilizer.

3. High particle strength. The production, storage, transportation and use of fertilizers require that the fertilizer has a certain particle strength. The average particle strength of the round-particle potassium fertilizer prepared by the invention is above 45N, which can fully meet the requirements.

4. The rate of becoming a ball is high. The preparation rate of the potassium fertilizer containing round particles of the invention is more than 90%, and the returning material is small, and has a broad market prospect.

5, good release performance. The round granular potassium fertilizer prepared by the invention has good sustained release performance and improves the utilization rate of potassium fertilizer.

detailed description

Hereinafter, the present invention will be further described in conjunction with specific embodiments:

Embodiment 1

Add 12g ammonium sulfate reactant to 1000g of 25% phosphoric acid solution, and keep reacting at 105°C for 15min under constant stirring (90°/min) to prepare a mixture with potassium chloride with 60% nutrient content. (50 mesh) The raw materials are added to a disc granulator for granulation, and the powdered zinc oxide (600 mesh) and the mixed solution are alternately added at a mass ratio of 1:2.5 on the surface of the granulated potassium chloride fertilizer until chlorination. When the potassium fertilizer grows to a particle size of about 4 mm, it can be discharged. The yield of the sieve was 91%, the potassium chloride nutrient content of the finished product was 57%, and the nutrient release period was 36 days.

Embodiment 2

25 g of ammonium sulfate was added to 1000 g of a 45% by mass phosphoric acid solution, and maintained at 105 ° C for 25 min under constant stirring (90 rpm) to prepare a mixed solution. The nutrient content of 50% potassium sulfate raw material is added to a disc granulator for granulation, and powdered zinc oxide (600 mesh) and the mixed liquid are alternately added on the surface of the granulated potassium fertilizer according to a mass ratio of 1:2.5. Until the potassium fertilizer grows to a size of about 4 mm, it can be discharged. The yield of the sieve was 94.5%, the potassium sulfate content of the finished product was 47%, and the nutrient release period was 65 days.

Embodiment 3

18 g of ammonium chloride was added to 1000 g of a 35% by mass phosphoric acid slag acid solution, and maintained at 105 ° C for 45 min under uniform stirring (90 rpm) to prepare a mixed solution. The potassium chloride (50 mesh) raw material having a nutrient content of 60% is added to a disc granulator for granulation, and the powdered zinc oxide (600 mesh) and the mixed solution are alternately added in a mass ratio of 1:2.5 in rolling. The surface of the potassium chloride fertilizer can be discharged until the diameter of the potassium chloride fertilizer grows to about 4 mm. The yield of the sieve was 93%, the potassium chloride nutrient content of the finished product was 53%, and the nutrient release period was 45 days.

Embodiment 4

1 g of ammonium chloride was added to 1000 g of a 50% by mass phosphoric acid solution, and maintained at 65 ° C for 60 min under uniform stirring (90 rpm) to prepare a mixed solution. The potassium sulfate (100 mesh) raw material having a nutrient content of 50% is added to a disc granulator for granulation, and the powdered zinc oxide (1000 mesh) and the mixed liquid are alternately added in a mass ratio of 1:2.5. It can be added to the surface of the granulated potassium chloride fertilizer until the particle size of the potassium chloride fertilizer grows to about 4 mm. The yield of the sieve was 93%, the potassium sulfate content of the finished product was 46%, and the nutrient release period was 60 days.

Embodiment 5

14 g of ammonium sulfate was added to 1000 g of a 5% phosphoric acid slag acid solution, and the mixture was activated at 115 ° C for 10 min under uniform stirring (90 rpm) to prepare a mixed solution. The potassium chloride (20 mesh) raw material having a nutrient content of 60% is added to a disc granulator for granulation, and the powdered zinc oxide (300 mesh) and the mixed liquid are alternately added in a mass ratio of 1:2.5 in rolling. The surface of the potassium chloride fertilizer can be discharged until the diameter of the potassium chloride fertilizer grows to about 4 mm. The yield of the sieve was 93%, the potassium chloride nutrient content of the finished product was 52%, and the nutrient release period was 40 days.

Claims

The invention discloses a preparation method of zinc-containing slow-release round-particle potassium fertilizer, which comprises the following steps: a phosphoric acid or a phosphoric acid slag acid solution having a mass concentration of 5-50%, and adding phosphoric acid or phosphoric acid slag at a temperature of 65-115 ° C; The reaction solution is 0.1-2.5% by mass of the acid solution, and the mixture is reacted for 10-60 minutes to prepare a mixed solution; the mixed solution is sprayed onto the surface of the potassium chloride or potassium sulfate crystal in the granulation equipment, and then the powder zinc oxide is added to allow the reactant to react with Zinc oxide reacts in situ on the surface of potassium chloride or potassium sulfate crystals to form a solidified material with a certain binding force. Thus, the mixture and the powdered zinc oxide are alternately added on the surface of the potassium chloride or potassium sulfate crystal. The small granular fertilizer is gradually wrapped and gradually grown, and gradually grows to a size of 2-5 mm. After drying and sieving, a zinc-containing slow-release round-grained potassium fertilizer having a particle size of 2-5 mm is obtained.
The method for preparing a zinc-containing slow-release round-particle potassium fertilizer according to claim 1, wherein the powdered zinc oxide and the mixed liquid are sprayed into the potassium chloride in the granulating device at a mass ratio of 1:2.5. Or potassium sulfate crystal surface.
The method for preparing a zinc-containing slow-release round granule potassium fertilizer according to claim 1, wherein the potassium chloride or potassium sulfate has a fineness of 20-100 mesh.
The method for preparing a zinc-containing sustained-release round granule potassium fertilizer according to claim 1, wherein the powder zinc oxide has a fineness of 300-1000 mesh.
The method for preparing a zinc-containing sustained-release round granule potassium fertilizer according to claim 1, wherein the phosphoric acid or phosphoric acid slag acid solution is an industrial product.
The method for preparing a zinc-containing sustained-release round-particle potassium fertilizer according to claim 1, wherein the reactant is one of ammonium chloride, ammonium sulfate or a mixture of the two.
The method for preparing a zinc-containing slow release round granule potassium fertilizer according to claim 1, wherein the granulation device is a disc granulator.