Method for producing 55% powdery monoammonium phosphate by using filter-press white fertilizer and phosphoric acid sludge acid

Abstract

The invention discloses a method for producing 55% powdery monoammonium phosphate by using filter-press white fertilizer and phosphoric acid sludge acid, and belongs to the technical field of production of powdery monoammonium phosphate. According to the method for producing novel 55% powdery monoammonium phosphate in a tubular reactor by using waste white fertilizer and phosphoric acid sludge acid which cannot be treated in the filter-press production process, the production process flow is greatly shortened, the production cost is reduced, and the production efficiency is improved. The number of process pipelines and production equipment is reduced, the length of the process pipelines is shortened, the energy consumption and the equipment maintenance cost are greatly reduced, and the effects of saving energy, reducing consumption and improving quality and efficiency are achieved; meanwhile, the waste white fertilizer which cannot be treated in the filter pressing production process and the waste phosphoric acid slag slurry generated in phosphoric acid production are treated, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of powdered monoammonium phosphate production technology, specifically a method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphate residue. Background Technology

[0002] Powdered MAP is mainly used as a phosphorus feedstock in compound or blended fertilizers. It can also be applied directly. After dissolving in the soil, MAP has a pH of around 4.4, which is beneficial for phosphorus absorption by crops. Powdered MAP is primarily used as a raw material in compound and blended fertilizers.

[0003] On the one hand, most of my country's phosphate rock resources are low- to medium-grade collophane, containing high levels of impurities and difficult to beneficiate. With the rapid development of high-concentration phosphate compound fertilizers, the supply of phosphate rock resources falls short of demand, and many enterprises are unable to operate normally due to insufficient resources. On the other hand, to meet the needs of national economic development, industrial production has consistently prioritized energy conservation and emission reduction through technological upgrades, and the phosphate compound fertilizer industry is one of the largest energy consumers. Traditional powdered MAP products, mainly 66% MAP, 60% MAP, and 58% MAP, require phosphate rock resources with low impurity content and involve high energy consumption. Therefore, developing and promoting low-nutrient MAP products is of positive significance for further reducing product costs and improving economic efficiency. Summary of the Invention

[0004] The purpose of this invention is to provide a method for producing 55% powdered monoammonium phosphate (MAP) using filter press white fertilizer and phosphate residue acid. This method solves the problem that traditional methods for producing 66% MAP, 60% MAP, and 58% MAP cannot produce MAP due to the use of medium- and low-grade phosphate rock with high impurity content. Furthermore, it utilizes waste white fertilizer and phosphate residue acid with high solids content that cannot be processed during the filter press process. Simultaneously, it fully leverages the advantages of a tubular reactor, shortening the process flow, reducing the number of production equipment, and lowering energy consumption, thus achieving energy conservation and emission reduction.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphoric acid residue involves directly neutralizing gaseous ammonia and a mixed acid (phosphoric acid residue with high solid content and waste white fertilizer that cannot be processed during the filter press production) in a tubular reactor. The reaction slurry is atomized and sprayed through a specially designed spray pipe and dried and dehydrated in a drying tower. The process includes the following steps:

[0007] A. Phosphate residue with a P2O5 content of 37%~42% and a solid content of 5%~7% and waste white fertilizer with a P2O5 content of 20~22% and a N content of 4%~5% are buffered in a buffer tank. The waste white fertilizer is specifically waste white fertilizer that cannot be processed during the filter press production process. The mixed acid has a solid content of 9%~10%. After buffering, the mixed acid is mixed evenly under the stirring action of the mixed acid tank in a tubular reactor and then reacted with gaseous ammonia in the tubular reactor to generate a monoammonium phosphate slurry with a neutralization degree of 0.95~1.02. After the monoammonium phosphate slurry has fully reacted in the tubular reactor, the effective phosphorus P2O5 content reaches 41~42%, the N content reaches 11~12%, and the moisture content is 23~27%, which can be directly used as a qualified slurry.

[0008] B. The slurry product from step A is atomized and sprayed into a drying tower through a specially designed spray pipe;

[0009] C. Qualified monoammonium phosphate slurry is metered and packaged after being dried in a fluidized bed.

[0010] Preferably, in step A, the phosphoric acid residue with a P2O5 content of 37%~42% and a solid content of 5%~7% and the waste white fertilizer that cannot be treated in the filter press production process with a P2O5 content of 20~22% and an N content of 4%~5% are first buffered, then mixed evenly, and finally reacted with gaseous ammonia to generate monoammonium phosphate slurry.

[0011] Preferably, in step A, the gaseous ammonia is at a pressure of 0.4~0.8 MPa (absolute pressure); the operating temperature in the reactor is 145~165℃, and the operating pressure is ~0.5MPa (absolute pressure); the phosphoric acid pressure entering the reactor is >0.6MPa (absolute pressure), and the degree of neutralization of the ammonium phosphate neutralization slurry is 0.95~1.02.

[0012] Preferably, in step A, the phosphoric acid residue, waste white fertilizer and gaseous ammonia that cannot be processed during the filter press production process are mixed under pressure in a special mixer and then neutralized in a special reactor.

[0013] Preferably, in step C, the hot air temperature of the material undergoing fluidized bed drying needs to be controlled within the range of 120~140℃; the pressure of the drying tower air chamber is 3~4.5kPa; and the temperature of the dry fluidized bed is within the range of 50~60℃.

[0014] In summary, due to the adoption of the above technical solutions, the beneficial effects of this invention are as follows: This invention can utilize waste white fertilizer and phosphoric acid residue that cannot be processed during the filter press production process to produce a novel 55% powdered MAP in a tubular reactor. This significantly shortens the production process, reduces the number of process pipelines and production equipment, shortens the length of process pipelines, and greatly reduces energy consumption and equipment maintenance costs, achieving the effects of energy saving, consumption reduction, quality improvement, and efficiency enhancement. At the same time, it treats the waste white fertilizer that cannot be processed during the filter press production process and the waste phosphoric acid residue slurry generated in phosphoric acid production, reducing production costs. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a production process according to the present invention. Detailed Implementation

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention, but are not intended to limit the present invention.

[0017] Example 1:

[0018] like Figure 1 This paper presents a method for producing a novel 55% powdered MAP using urea phosphate mother liquor and phosphate residue acid in a tubular reactor.

[0019] a. Phosphate residue acid (P2O5 content of 37%~42%, solid content of 5%~7%)1 and waste white fertilizer (P2O5 content of 20~22%, N% of 4%~5%)2 that cannot be processed in the filter press production process are buffered in buffer tank 3, and after buffering, they are stirred evenly in a special mixed acid tank 4 to generate mixed acid;

[0020] b. The mixed acid and gaseous ammonia 5 (pressure 0.4~0.8MPa (absolute pressure)) undergo a neutralization reaction in a specially designed reactor 6 to produce a monoammonium phosphate slurry with a degree of neutralization of 0.95~1.02. The slurry has an effective phosphorus (P2O5) content of 41~42%, an nitrogen content of 11~12%, and a moisture content of 23~27%.

[0021] c. Qualified monoammonium phosphate slurry is atomized through a special spray pipe 7 and sprayed into the top of the drying tower 8;

[0022] d. After being atomized and sprayed into the top of the drying tower 8, the monoammonium phosphate slurry is initially dried and dehydrated by the upward hot air 9 blown into the drying tower during its descent. Then, it falls into the fluidized bed 10 for further thorough drying and dehydration, producing qualified powdered monoammonium phosphate with an effective phosphorus content of 41-42%, an N content of 11-12%, and a moisture content of <3%.

[0023] e. The dehydrated powdered monoammonium phosphate material is metered and packaged by the packaging and metering device 11.

[0024] In step b, the heat and gasification pressure generated by the neutralization reaction of gaseous ammonia 5 and mixed acid (1, 2) in the special reactor 6 play a role in fully atomizing and promoting the slurry; in step c, the special spray pipe plays an important role in further atomizing the slurry after the neutralization reaction and adjusting the spray volume.

[0025] The above description is merely a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, based on the technical teachings provided by the present invention and as common knowledge in the field, other equivalent variations and improvements can be made, which should also be considered within the scope of protection of the present invention.

Claims

1. A method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphate residue, comprising the following steps: A. Phosphate residue with a P2O5 content of 37%~42% and a solid content of 5%~7% and waste white fertilizer with a P2O5 content of 20~22% and a N content of 4%~5% are buffered in a buffer tank. The waste white fertilizer is specifically waste white fertilizer that cannot be processed during the filter press production process. The mixed acid has a solid content of 9%~10%. After buffering, the mixed acid is mixed evenly under the stirring action of the mixed acid tank in a tubular reactor and then reacted with gaseous ammonia in the tubular reactor to generate a monoammonium phosphate slurry with a neutralization degree of 0.95~1.

02. After the monoammonium phosphate slurry has been fully reacted in the tubular reactor, the effective phosphorus P2O5 content reaches 41~42%, the N content reaches 11~12%, and the moisture content is 23~27%, which can be directly used as a qualified slurry. B. The slurry product from step A is atomized and sprayed into a drying tower through a specially designed spray pipe; C. Qualified monoammonium phosphate slurry is metered and packaged after being dried in a fluidized bed.

2. The method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphoric acid residue according to claim 1, characterized in that: In step A, the phosphoric acid residue with a P2O5 content of 37%~42% and a solid content of 5%~7% and the waste white fertilizer that cannot be treated in the filter press production process with a P2O5 content of 20~22% and an N content of 4%~5% are first buffered, then mixed evenly, and finally reacted with gaseous ammonia to generate monoammonium phosphate slurry.

3. The method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphoric acid residue according to claim 1, characterized in that: In step A, the gaseous ammonia is at a pressure of 0.4~0.8 MPa (absolute pressure); the operating temperature in the reactor is 145~165℃, and the operating pressure is ~0.5MPa (absolute pressure); the phosphoric acid entering the reactor is at a pressure >0.6MPa (absolute pressure), and the degree of neutralization of the ammonium phosphate neutralization slurry is 0.95~1.

02.

4. The method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphoric acid residue according to claim 1, characterized in that: In step A, the phosphate residue acid, waste white fertilizer and gaseous ammonia that cannot be processed during the filter press production process are mixed under pressure in a special mixer and then neutralized in a special reactor.

5. The method for producing 55% powdered monoammonium phosphate using filter press white fertilizer and phosphoric acid residue according to claim 1, characterized in that: In step c, the material needs to be dried in a fluidized bed with the hot air temperature controlled within the range of 120~140℃; the pressure in the drying tower air chamber should be 3~4.5kPa and the temperature of the dry fluidized bed should be within the range of 50~60℃.

Images