CN107188719B

CN107188719B - Internal addition anti-caking agent capable of reducing biuret content in high-tower compound fertilizer and preparation method thereof

Info

Publication number: CN107188719B
Application number: CN201710560625.7A
Authority: CN
Inventors: 江世文
Original assignee: Hubei Doxn Agricultural Technology Co ltd
Current assignee: Hubei Doxn Agricultural Technology Co ltd
Priority date: 2017-07-11
Filing date: 2017-07-11
Publication date: 2021-06-18
Anticipated expiration: 2037-07-11
Also published as: CN107188719A

Abstract

The invention relates to an internal addition anti-caking agent capable of reducing biuret content in a high-tower compound fertilizer and a preparation method thereof, wherein the internal addition anti-caking agent comprises the following raw materials in percentage by mass: 0.01-20% of polyaspartic acid chelate; sodium dodecyl sulfate and/or sodium dodecyl sulfate 0.01-20%; 0.01 to 20 percent of modified bentonite; 0.01-30% of superfine sepiolite and/or magnesium aluminum silicate; 0.01-20% of trace element compound; 0.01-30% of high molecular surfactant; the balance being water. The preparation method comprises heating water, adding the above materials according to their mass percentage, and stirring. The beneficial effects are that the eutectic point system of the compound fertilizer can be constructed after the eutectic point system is mixed with the raw materials such as urea and the like, the raw materials such as urea and the like can be melted at the temperature of 100-120 ℃, and the content of biuret in the compound fertilizer product can be effectively reduced.

Description

Internal addition anti-caking agent capable of reducing biuret content in high-tower compound fertilizer and preparation method thereof

Technical Field

The invention belongs to the field of compound fertilizer production, and particularly relates to an internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer and a preparation method thereof.

Background

In recent years, high-tower compound fertilizer processes are continuously developed in China, factors such as overhigh cost of ammonium nitrate reaction and the like are comprehensively considered, most enterprises select urea as a nitrogen source carrier, and produce various high-nitrogen compound fertilizers through high-temperature granulation, but biuret is easily generated at the temperature higher than 120 ℃.

Biuret is a substance produced by urea molecules in a high-temperature chemical reaction, is also called biuret and is harmful to the germination of seeds and the growth of crops. It is understood that when the content of biuret in the fertilizer is higher than 0.5%, the biuret cannot be applied as an extra-root top dressing, otherwise the seedling is easy to burn. The biuret can inhibit and damage the capillary root system of seedlings, even the capillary root system of crops in the growing period can be damaged, and the absorption of the crops to fertilizers can be reduced. In recent years, fertilizer damage caused by a higher biuret content in fertilizers has occurred. Most of the prior fertilizers taking urea as a nitrogen source contain biuret, and a plurality of fertilizer damage events are probably caused by excessive biuret.

The existing national standard of composite (mixed) fertilizers does not need to detect the content of biuret or specify the upper limit of the content, and only needs to mark whether the biuret is contained on a package, so that the biuret forms an invisible bomb. Many persons in the industry indicate that in recent years, some fertilizer damage events occur everywhere, although sampling detection results show that the contents of nitrogen, phosphorus and potassium are all qualified, the actual result is caused by the excessive biuret content of the fertilizer.

In the production of high tower compound fertilizer, a large amount of urea is used as a raw material, the biuret content in the urea product in China is generally below 1%, but sometimes the production process of manufacturers is not tightly controlled, so that the biuret raw material can seriously exceed the standard. In addition, experts believe that: the temperature of the urine is below 120 ℃, and the biuret content is basically unchanged; the temperature of the urine is above 120 ℃, and the biuret content is increased by 0.02-0.05% every time the temperature is increased by 1 ℃. If the temperature of the urea melting tank on the high tower is kept for 1 hour, the biuret content can be close to 1 percent or even higher, as shown in figure 1.

Experts recommend that the biuret content of the urea-based compound fertilizer should be controlled within 0.5%, otherwise the fertilizer damage to crops is easy to generate. The standard CNS3076-70 of Taiwan compound fertilizer in China requires that the content of biuret is less than 0.4%. The overproof biuret has become the bottleneck problem to be solved urgently in the current high-tower compound fertilizer.

Disclosure of Invention

The invention provides an internally added anti-caking agent capable of reducing the content of biuret in a high-tower compound fertilizer and a preparation method thereof, aiming at solving the problem of overproof biuret in the current high-tower compound fertilizer production to a certain extent.

The technical scheme for solving the technical problems is as follows: an internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer comprises the following raw materials in percentage by mass: 0.01-20% of polyaspartic acid chelate; sodium dodecyl sulfate and/or sodium dodecyl sulfate 0.01-20%; 0.01 to 20 percent of modified bentonite; 0.01-30% of superfine sepiolite and/or magnesium aluminum silicate; 0.01-20% of trace element compound; 0.01-30% of high molecular surfactant; the balance being water. The above "and/or" means a mixture of either or both in any ratio.

Preferably, the internally added anti-caking agent consists of the following raw materials in percentage by mass: 8% of polyaspartic acid chelate; 3 percent of sodium dodecyl sulfate; 2% of modified bentonite; 2% of ultrafine sepiolite; 2% of trace element compound; 8% of a high molecular surfactant; and (5) 75% of water. More specifically, in the preferred embodiment, the modified bentonite is sodium bentonite, and the polymeric surfactant is polyvinyl acetal.

Specifically, the polyaspartic acid chelate is one or a mixture of a plurality of polyaspartic acid chelated calcium, polyaspartic acid chelated magnesium, polyaspartic acid chelated zinc, polyaspartic acid chelated manganese, polyaspartic acid chelated iron and polyaspartic acid chelated selenium.

Specifically, the modified bentonite is any one or a mixture of more of lithium bentonite, sodium bentonite and calcium bentonite.

Specifically, the trace element compound is one or a mixture of more of a calcium compound, a magnesium compound, a sulfur compound, a zinc compound, an iron compound, a manganese compound, a molybdenum compound, a selenium compound, a copper compound and a boron compound.

Specifically, the polymer surfactant is any one or a mixture of polyvinyl alcohol, polyvinyl formal and polyvinyl acetal.

The invention also provides a preparation method of the internally added anti-caking agent capable of reducing the biuret content in the high-tower compound fertilizer, which comprises the following steps:

firstly, adding water into a reaction kettle, and heating to 40-80 ℃;

then, the following components are added according to the corresponding mass percentage: polyaspartic acid chelate; sodium lauryl sulfate and/or sodium dodecyl sulfate; modified bentonite; ultra-fine sepiolite and/or magnesium aluminum silicate; a compound of a trace element; a polymeric surfactant;

and finally, uniformly stirring, and discharging to obtain the internally added anti-caking agent.

Compared with the prior art, the invention has the beneficial effects that: the internally added anti-caking agent and the urea and other raw materials can be mixed to construct a eutectic point system of the compound fertilizer, the urea and other raw materials can be melted at the temperature of 100-120 ℃, the whole production process is carried out at the temperature of not higher than 120 ℃ from the source, the production energy consumption is greatly reduced, and the generation of biuret is effectively reduced at the same time, wherein the mass percentage content of the biuret in the compound fertilizer produced by using the internally added anti-caking agent is lower than 0.4%; in actual production of factories, the temperature of high-tower slurry can be obviously reduced by adding 1-3 kg of anti-caking agent into each ton of urea; after the polyaspartic acid chelate (PASP) and urea are mixed, molecular groups of the polyaspartic acid chelate (PASP) continuously permeate into urea particles, an anti-caking agent is added into the urea particles to promote the urea to melt, the melting temperature of the urea is obviously reduced, the generation of biuret can be controlled by reducing the temperature of slurry, the flowability of the slurry is improved, and the appearance of the particles is improved.

Drawings

FIG. 1 is a graph showing the relationship between biuret content in the production process of a compound fertilizer and the temperature and reaction time in the production process, which has been pointed out by prior research results in the prior art.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific embodiments, which are given by way of illustration only and are not intended to limit the scope of the invention.

The methods used in the following examples are conventional methods unless otherwise specified, and the starting materials used are commercially available products unless otherwise specified.

Example 1

An internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer comprises the following raw materials in percentage by mass: polyaspartic acid chelate 10%; 10 percent of sodium dodecyl sulfate; 10% of sodium bentonite; 10% of ultra-fine sepiolite; 10% of trace element compound; 15% of a high molecular surfactant; 35% of water.

The internally added anti-caking agent is prepared by the following method: adding water into a reaction kettle, heating to 40 ℃, adding polyaspartic acid chelate (comprising calcium polyaspartic acid chelate, magnesium polyaspartic acid chelate and zinc polyaspartic acid chelate with equal mass), sodium dodecyl sulfate, lithium bentonite, superfine sepiolite, trace element compound (zinc sulfate) and high molecular surfactant (polyvinyl acetal) according to corresponding mass percentage, uniformly stirring, and discharging to obtain the internally added anti-blocking agent.

Example 2

An internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer comprises the following raw materials in percentage by mass: 8% of polyaspartic acid chelate; 3 percent of sodium dodecyl sulfate; 2% of modified bentonite; 2% of ultrafine sepiolite; 2% of trace element compound; 8% of a high molecular surfactant; and (5) 75% of water.

The internally added anti-caking agent is prepared by the following method: adding water into a reaction kettle, heating to 40 ℃, adding polyaspartic acid chelate (polyaspartic acid chelated zinc), sodium dodecyl sulfate, sodium bentonite, superfine sepiolite, trace element compound (zinc sulfate) and high molecular surfactant (polyvinyl acetal) according to corresponding mass percentage, uniformly stirring, and discharging to obtain the internally added anti-blocking agent.

Example 3

An internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer comprises the following raw materials in percentage by mass: polyaspartic acid chelate 20%; 6 percent of sodium dodecyl sulfate; 5% of sodium bentonite; 8% of magnesium aluminum silicate; 4% of trace element compound; 15% of a high molecular surfactant; and (5) 75% of water.

The internally added anti-caking agent is prepared by the following method: adding water into a reaction kettle, heating to 40 ℃, adding polyaspartic acid chelate (polyaspartic acid chelated zinc), lauryl sodium sulfate, sodium bentonite, magnesium aluminum silicate, trace element compounds (zinc sulfate, magnesium chloride and copper sulfate which are equal in mass) and high molecular surfactants (polyvinyl alcohol and polyvinyl formal) according to corresponding mass percentage, uniformly stirring, and discharging to obtain the anti-caking agent added in the reaction kettle.

The compound fertilizer production was carried out using the internally added anti-caking agents obtained in examples 1 to 3, respectively, to examine their ability to reduce the biuret content in the compound fertilizer, the specific process was as follows:

a) conveying 495kg of urea and return materials (or no return materials at the beginning) of a system at that time to a melting tank through conveying equipment, adding 1.2 kg of anti-caking agent to form a eutectic system, and forming a urine melt liquid by the materials within the temperature range of 100 plus 118 ℃; an automatic overflow device is arranged in the melting tank for continuously producing and feeding materials, and when the liquid level exceeds a certain liquid level, the urine melt begins to automatically overflow to the mixer;

b) overflowing the urine melt to a mixer, and adding 65kg of ammonium chloride, 340kg of potash fertilizer, 235kg of monoammonium phosphate and 1kg of zinc sulfate to mix at 105 ℃; an automatic overflow device is arranged in the mixer for continuous production, when the liquid level exceeds a certain liquid level, the slurry starts to automatically overflow to the emulsion grinder, and the slurry flowing out of the emulsion grinder is granulation slurry;

c) introducing the granulation slurry into a high tower granulator for granulation; and (4) collecting, cooling, screening and coating the compound fertilizer granules obtained by granulation to obtain the compound fertilizer.

The obtained compound fertilizer is 25-10-16% of 51% high-tower compound fertilizer. The detection method refers to GB15063-2009 compound fertilizer (compound fertilizer) detection standard. Through detection, the biuret content in the urea used in the production of the compound fertilizer is 0.52 wt%, and the biuret content of the final product is 0.28 wt% (corresponding to the internally added anti-caking agent used in example 1), 0.24 wt% (corresponding to the internally added anti-caking agent used in example 2) and 0.35 wt% (corresponding to the internally added anti-caking agent used in example 3).

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. An internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer is characterized by comprising the following raw materials in percentage by mass: 8-10% of polyaspartic acid chelate; 3-6% of sodium dodecyl sulfate and/or sodium dodecyl sulfate; 2-10% of modified bentonite; 2-10% of ultra-fine sepiolite and/or magnesium aluminum silicate; 2-10% of trace element compound; 8-15% of a high molecular surfactant; the balance of water;

the internal addition caking agent and the raw material containing urea can form a eutectic system after being mixed, so that the compound fertilizer is melted at the temperature of 100-120 ℃.

2. The internally added anti-caking agent capable of reducing the biuret content in the high-tower compound fertilizer according to claim 1, is characterized by comprising the following raw materials in percentage by mass: 8% of polyaspartic acid chelate; 3 percent of sodium dodecyl sulfate; 2% of modified bentonite; 2% of ultrafine sepiolite; 2% of trace element compound; 8% of a high molecular surfactant; and (5) 75% of water.

3. The internally added anti-caking agent capable of reducing the content of biuret in a high-tower compound fertilizer according to claim 1 or 2, wherein the polyaspartic acid chelate is a mixture of any one or more of polyaspartic acid chelated calcium, polyaspartic acid chelated magnesium, polyaspartic acid chelated zinc, polyaspartic acid chelated manganese, polyaspartic acid chelated iron and polyaspartic acid chelated selenium.

4. The internally added anti-caking agent capable of reducing the biuret content in the high-tower compound fertilizer according to claim 1 or 2, characterized in that the modified bentonite is a mixture of one or more of lithium bentonite, sodium bentonite and calcium bentonite.

5. The internally added anti-caking agent capable of reducing the biuret content in a high-tower compound fertilizer according to claim 1 or 2, characterized in that the trace element compound is a mixture of one or more of calcium compounds, magnesium compounds, sulfur compounds, zinc compounds, iron compounds, manganese compounds, molybdenum compounds, selenium compounds, copper compounds and boron compounds.

6. The internally added anti-caking agent capable of reducing the biuret content in the high tower compound fertilizer according to claim 1 or 2, characterized in that the polymeric surfactant is a mixture of one or more of polyvinyl alcohol, polyvinyl formal and polyvinyl acetal.

7. The preparation method of the internally added anti-caking agent capable of reducing the biuret content in the high-tower compound fertilizer as claimed in any one of claims 1 to 6, characterized by comprising the following steps:

firstly, adding water into a reaction kettle, and heating to 40-80 ℃; then, the following components are added according to the corresponding mass percentage: polyaspartic acid chelate; sodium lauryl sulfate and/or sodium dodecyl sulfate; modified bentonite; ultra-fine sepiolite and/or magnesium aluminum silicate; a compound of a trace element; a polymeric surfactant; and finally, uniformly stirring, and discharging to obtain the internally added anti-caking agent.