Phosphorus potassium nitrate fertilizer and preparation method thereof
阅读说明：本技术 硝酸磷钾肥及其制备方法 (Phosphorus potassium nitrate fertilizer and preparation method thereof ) 是由 任光耀 顾春光 方进 张凌云 黄德明 赵国军 于 2018-07-19 设计创作，主要内容包括：本发明涉及一种硝酸磷钾肥及其制备方法。一种硝酸磷钾肥的制备方法,包括以下步骤：将硝酸磷钾肥浓缩料浆熔融,得到熔融料浆；采用蒸汽雾化的方式将熔融料浆在加压的条件下进行喷浆造粒,得到硝酸磷钾肥。上述硝酸磷钾肥的制备方法通过采用蒸汽雾化的方式来制备硝酸磷钾肥,在蒸汽的作用下,能够避免硝酸磷钾肥料浆堵塞喷头,以提高硝酸磷钾肥的生产效率,同时,相比干燥空气雾化的方式,蒸汽雾化的方式省去了干燥空气的步骤,简化了生产流程,进一步提高生产效率；相比双轴造粒工艺,喷浆造粒工艺制备得到的硝酸磷钾肥的光圆度更好。因此,上述硝酸磷钾肥的制备方法具有生产效率较高的优点,且制备得到的硝酸磷钾肥的光圆度较好。(The invention relates to phosphorus potassium nitrate fertilizers and a preparation method thereof. phosphorus potassium nitrate fertilizers comprise the following steps of melting concentrated slurry of the phosphorus potassium nitrate fertilizers to obtain molten slurry, and performing spray granulation on the molten slurry in a steam atomization mode under a pressurized condition to obtain the phosphorus potassium nitrate fertilizers.)
The preparation method of the phosphorus potassium nitrate fertilizer of 1 and is characterized by comprising the following steps:
melting the concentrated slurry of the phosphorus potassium nitrate fertilizer to obtain molten slurry;
and carrying out spraying granulation on the molten slurry in a steam atomization mode under a pressurized condition to obtain the phosphorus potassium nitrate fertilizer.
2. The method for preparing the phosphorus potassium nitrate fertilizer as claimed in claim 1, wherein in the step of performing spray granulation on the molten slurry under a pressurized condition by adopting a steam atomization mode, the pressure of the steam is 0.3 Mpa-2.0 Mpa.
3. The method for preparing the phosphorus-potassium nitrate fertilizer as claimed in claim 1, wherein the step of melting the concentrated slurry of the phosphorus-potassium nitrate fertilizer comprises the following specific steps: and heating the concentrated slurry of the phosphorus potassium nitrate fertilizer to 125-170 ℃ for melting.
4. The method for preparing the phosphorus potassium nitrate fertilizer as claimed in claim 1, wherein the mass percentage concentration of the concentrated slurry of the phosphorus potassium nitrate fertilizer is 95-99%.
5. The method for preparing the phosphorus potassium nitrate fertilizer as claimed in claim 1, wherein in the step of performing spray granulation on the molten slurry in a steam atomization manner under a pressurized condition, the method further comprises a step of adding a return material, wherein the mass ratio of the return material to the molten slurry is 3: 1-5: 1.
6. The method for preparing the phosphorus potassium nitrate fertilizer as claimed in claim 1, wherein the concentrated slurry of the phosphorus potassium nitrate fertilizer comprises the following preparation steps:
mixing nitric acid and phosphorite to obtain acidolysis solution;
filtering the acidolysis solution to obtain filtrate;
crystallizing the filtrate to obtain calcium nitrate crystals;
removing the calcium nitrate crystal to obtain clear liquid;
introducing ammonia gas into the clear liquid to obtain a neutralized liquid;
concentrating the neutralized solution to obtain concentrated slurry of the nitrophosphate fertilizer;
and adding a potassium salt into the concentrated nitrophosphate fertilizer slurry to obtain the concentrated nitrophosphate potash fertilizer slurry, wherein the potassium salt is at least selected from potassium chloride, potassium nitrate and potassium sulfate.
7. The method for preparing a phosphorus-potassium nitrate fertilizer according to claim 6, wherein the step of adding a potassium salt to the concentrated slurry of a nitric phosphate fertilizer is preceded by a step of subjecting the concentrated slurry of a nitric phosphate fertilizer to a polymerization reaction to obtain a polymerization slurry.
8. The method for preparing the phosphorus potassium nitrate fertilizer according to claim 7, wherein in the step of polymerizing the concentrated slurry of the nitric phosphate fertilizer, the temperature of the polymerization reaction is 175-200 ℃, and the time of the polymerization reaction is 20-60 min.
9. The method for preparing the phosphorus potassium nitrate fertilizer as claimed in claim 7, wherein the polymerization rate of the polymerization slurry is 3-10%.
10. The phosphorus potassium nitrate fertilizer prepared by the method of any of claims 1-9.
Technical Field
The invention relates to the technical field of nitrophosphate fertilizers, in particular to phosphorus and potassium nitrate fertilizers and a preparation method thereof.
Background
In the technical field of preparation of the freezing method of the phosphorus potassium nitrate fertilizer, the traditional preparation process of the phosphorus potassium nitrate fertilizer is mainly a biaxial granulation process, but fertilizer particles of the biaxial granulation process are not round; the fertilizer light roundness of the spray granulation is good, and the spray granulation is suitable for the current fertilizer requirements, but a spray head in the spray granulation process is easy to block, so that the production efficiency is reduced.
Disclosure of Invention
Therefore, there is a need for methods for preparing phosphorus potassium nitrate fertilizers with high production efficiency and good optical roundness of the prepared phosphorus potassium nitrate fertilizer.
In addition, kinds of potassium phosphate nitrate fertilizer are also provided.
A preparation method of a phosphorus potassium nitrate fertilizer, comprising the following steps:
melting the concentrated slurry of the phosphorus potassium nitrate fertilizer to obtain molten slurry;
and carrying out spraying granulation on the molten slurry in a steam atomization mode under a pressurized condition to obtain the phosphorus potassium nitrate fertilizer.
According to the preparation method of the phosphorus potassium nitrate fertilizer, the phosphorus potassium nitrate fertilizer is prepared in a steam atomization mode, under the action of steam, the situation that slurry of the phosphorus potassium nitrate fertilizer blocks a spray head can be avoided, the production efficiency of the phosphorus potassium nitrate fertilizer is improved, meanwhile, compared with a dry air atomization mode, a step of drying air is omitted in the steam atomization mode, the production flow is simplified, is further improved, and compared with a double-shaft granulation process, the light roundness of the phosphorus potassium nitrate fertilizer prepared through the slurry spraying granulation process is better.
In examples, in the step of performing spray granulation on the molten slurry under a pressurized condition by adopting a steam atomization mode, the pressure of the steam is 0.3 Mpa-2.0 Mpa.
In embodiments, the step of melting the concentrated slurry of the phosphorus potassium nitrate fertilizer is specifically to heat the concentrated slurry of the phosphorus potassium nitrate fertilizer to 125-170 ℃ for melting.
In embodiments, the mass percentage concentration of the concentrated slurry of the phosphorus potassium nitrate fertilizer is 95-99%.
In examples, the step of performing spray granulation on the molten slurry by adopting a steam atomization mode under a pressurized condition further comprises a step of adding a return material, wherein the mass ratio of the return material to the molten slurry is 3: 1-5: 1.
In embodiments, the concentrated slurry of the phosphorus potassium nitrate fertilizer comprises the following preparation steps:
mixing nitric acid and phosphorite to obtain acidolysis solution;
filtering the acidolysis solution to obtain filtrate;
crystallizing the filtrate to obtain calcium nitrate crystals;
removing the calcium nitrate crystal to obtain clear liquid;
introducing ammonia gas into the clear liquid to obtain a neutralized liquid;
concentrating the neutralized solution to obtain concentrated slurry of the nitrophosphate fertilizer;
and adding a potassium salt into the concentrated nitrophosphate fertilizer slurry to obtain the concentrated nitrophosphate potash fertilizer slurry, wherein the potassium salt is at least selected from potassium chloride, potassium nitrate and potassium sulfate.
In examples, before the step of adding the potassium salt to the nitrophosphate fertilizer concentrated slurry, the method further comprises a step of subjecting the nitrophosphate fertilizer concentrated slurry to polymerization reaction to obtain polymerization slurry.
In examples, in the step of polymerizing the nitrophosphate fertilizer concentrated slurry, the temperature of the polymerization reaction is 175-200 ℃, and the time of the polymerization reaction is 20-60 min.
In of these examples, the polymerization rate of the polymer slurry was 3% to 10%.
The phosphorus potassium nitrate fertilizer prepared by the preparation method of the phosphorus potassium nitrate fertilizer.
Drawings
FIG. 1 is a flow chart of a method of preparing a phosphorus potassium nitrate fertilizer in an embodiment of ;
FIG. 2 is a schematic structural view of a drum according to the embodiment ;
FIG. 3 is a schematic view of an alternative angle of the advance zone of the drum shown in FIG. 2;
FIG. 4 is a schematic view of another angle of the lifting area of the drum shown in FIG. 2;
fig. 5 is a schematic view of another angle of the cooling zone of the drum shown in fig. 2.
Detailed Description
To facilitate an understanding of the invention, the invention will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Referring to fig. 1, a method for preparing a phosphorus potassium nitrate fertilizer in includes the following steps:
step S110: and melting the concentrated slurry of the phosphorus potassium nitrate fertilizer to obtain molten slurry.
Wherein the mass percentage concentration of the concentrated slurry of the potassium phosphate nitrate fertilizer is 95-99%.
The method comprises the following steps of melting concentrated slurry of the phosphorus potassium nitrate fertilizer: heating the concentrated slurry of the phosphorus potassium nitrate fertilizer to 125-170 ℃ for melting. The melting of the concentrated slurry of the potassium phosphate nitrate fertilizer can remove the water in the concentrated slurry of the potassium phosphate nitrate fertilizer, so that the prepared potassium phosphate nitrate fertilizer has low water content and high stability.
The concentrated slurry of the potassium phosphate nitrate fertilizer comprises the following preparation steps:
step S111: mixing nitric acid and phosphorite to obtain acidolysis solution.
Step S112: filtering the acidolysis solution to obtain filtrate.
Wherein in the step of filtering the acidolysis solution, the filtering equipment is at least selected from a vortex screw machine, a washing drum and a plate-and-frame filter press.
Step S113: crystallizing the filtrate to obtain calcium nitrate crystals.
Wherein, the method for crystallizing the filtrate is freezing crystallization. Generally, the calcium nitrate crystal is calcium nitrate tetrahydrate crystal.
Step S114: removing calcium nitrate crystal to obtain clear liquid.
Wherein the method for removing the calcium nitrate crystals is filtration. In particular, the filtration device is a CN type filter.
, removing the crystal, concentrating, adding urea to obtain urea calcium nitrate, and recycling the urea calcium nitrate, wherein the urea calcium nitrate is water urea calcium nitrate, dihydrate urea calcium nitrate or mixture of water urea calcium nitrate and dihydrate urea calcium nitrate.
Or removing slag from the removed calcium nitrate crystal, concentrating, and adding urea and potassium-containing salt to prepare urea potassium calcium nitrate and urea calcium nitrate, wherein the urea potassium calcium nitrate is aqueous urea potassium calcium nitrate, dihydrate urea potassium calcium nitrate or a mixture of aqueous urea potassium calcium nitrate and dihydrate urea potassium calcium nitrate, and the urea calcium nitrate is aqueous urea calcium nitrate, dihydrate urea calcium nitrate or a mixture of aqueous urea calcium nitrate and dihydrate urea calcium nitrate, and steps are carried out, and the potassium-containing salt is at least selected from potassium feldspar, potassium chloride, potassium nitrate, potassium sulfate and potassium dihydrogen phosphate.
Step S115: and introducing ammonia gas into the clear liquid to obtain a neutralized liquid.
Step S116: and concentrating the neutralized solution to obtain concentrated slurry of the nitrophosphate fertilizer.
Wherein, in the step of concentrating the neutralized liquid, the neutralized liquid is concentrated by an evaporator.
Step S117: and adding sylvite into the concentrated slurry of the nitric phosphate fertilizer to obtain the concentrated slurry of the nitric phosphate and potash fertilizer.
Wherein the mass percentage concentration of the concentrated slurry of the potassium phosphate nitrate fertilizer is 95-99 percent, and the potassium salt is at least selected from potassium chloride and potassium nitrate.
The method further comprises a step of obtaining a polymerization slurry by subjecting the nitrophosphate concentrated slurry to a polymerization reaction, prior to the step of adding the potassium salt to the nitrophosphate concentrated slurry. The potassium salt is then added to the polymerization slurry. Wherein, the concentrated slurry of the nitrophosphate fertilizer is polymerized to form polyphosphate, and the polyphosphate has the effect of activating soil, thereby improving the utilization rate of the fertilizer. That is, the polymerization slurry is a polyphosphate-containing slurry.
, in the step of polymerizing the nitrophosphate concentrated slurry to obtain the polymerization slurry, the temperature of the polymerization reaction is 175-200 ℃, and the time of the polymerization reaction is 20-60 min, specifically, the polymerization rate of the polymerization slurry is 3-10%.
Step S120: and (3) carrying out spraying granulation on the molten slurry in a steam atomization mode under a pressurized condition to obtain the phosphorus potassium nitrate fertilizer.
Wherein, in the step of carrying out spray granulation on the fused slurry under the pressurized condition by adopting a steam atomization mode, the pressure of steam is 0.3 Mpa-2.0 Mpa. Specifically, the molten slurry is pressurized and atomized by a spray gun of the pelletizer using steam to coat the molten slurry on a curtain of a raised blade of the pelletizer.
, the method comprises a drying step after the step of spraying and granulating the molten slurry under the condition of pressurization by adopting a steam atomization mode, wherein in the drying step, the drying temperature is 100-130 ℃, and the drying time is 14-16 min.
And , after the drying step, cooling the material, wherein the discharging temperature is 30-50 ℃ after cooling, and the cooling time is 5-30 min.
Specifically, after the step of cooling, a step of sieving is further included. Wherein the aperture of the screen is 2.0 mm-4.5 mm, so as to obtain the phosphorus potassium nitrate fertilizer with the particle size of 2.0 mm-4.5 mm.
referring to fig. 2 to 5, wherein, the step of spraying granulation of the molten slurry under pressure by steam atomization is carried out by using a
The method comprises a step of spraying and granulating the molten slurry under a pressurized condition by adopting a steam atomization mode, and a step of adding a return material, wherein the mass ratio of the return material to the molten slurry is 3: 1-5: 1. Wherein the returned material is the phosphorus potassium nitrate fertilizer which is sieved and crushed without meeting the upper and lower limits of the particle size distribution specified by the granulated fertilizer.
The preparation method of the phosphorus potassium nitrate fertilizer at least has the following advantages:
1) according to the preparation method of the phosphorus potassium nitrate fertilizer, the phosphorus potassium nitrate fertilizer is prepared in a steam atomization mode, under the action of steam, the situation that slurry of the phosphorus potassium nitrate fertilizer blocks a spray head can be avoided, the production efficiency of the phosphorus potassium nitrate fertilizer is improved, meanwhile, compared with a dry air atomization mode, a step of drying air is omitted in the steam atomization mode, the production flow is simplified, is further improved, and compared with a double-shaft granulation process, the light roundness of the phosphorus potassium nitrate fertilizer prepared through the slurry spraying granulation process is better.
2) Compared with the dry air atomization mode, the steam atomization mode omits the step of drying air, and saves energy; in addition, compared with a high tower granulation process, the slurry spraying granulation process does not need to convey viscous phosphorus potassium nitrate fertilizer slurry to a high tower, so that the energy consumption is low, and the energy is saved. Therefore, the preparation method of the phosphorus potassium nitrate fertilizer has the advantage of energy conservation.
3) Before the step of adding the sylvite into the nitrophosphate concentrated slurry, the method also comprises the step of carrying out polymerization reaction on the nitrophosphate concentrated slurry to obtain polymerization slurry. The concentrated slurry of the nitric phosphate fertilizer is polymerized to form polyphosphate, potassium salt is added, and spraying granulation is performed, so that the obtained nitric phosphate potash fertilizer has the effect of activating soil, and the fertilizer utilization rate of the nitric phosphate potash fertilizer is increased.
4) The concentrated slurry of the potassium phosphate nitrate fertilizer is heated to 125-170 ℃ for melting, and the water in the concentrated slurry of the potassium phosphate nitrate fertilizer can be removed, so that the prepared potassium phosphate nitrate fertilizer has low water content and high stability.
The phosphorus-potassium nitrate fertilizer prepared by the preparation method has the advantages of uniform particles, good light roundness, high strength, low moisture content and high fertilizer utilization rate. Wherein the strength of the phosphorus potassium nitrate fertilizer can reach 30N-80N.
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