Production method for diammonium hydrogen phosphate

Abstract

The invention relates to the technical field of chemical engineering, and particularly relates to a production method for diammonium hydrogen phosphate. A diammonium hydrogen phosphate product is prepared by subjecting a high pure urea phosphate solution and ammonia to a double decomposition reaction, reacting for 20-60 min under stirring and at a temperature of 50-80 DEG C by controlling a pH value at 7.8-8.2. Physical and chemical indexes of the diammonium hydrogen phosphate product are as follows: the total nutrient content of diammonium hydrogen phosphate is higher than 74%; the content of total nitrogen is 21.02-21.20%; the content of phosphorus pentoxide is 53.0-53.52%; moisture content is 0.25-0.32%; the content of water insoluble substances is 0.087-0.096%; and the content of fluoride is 0.1-0.14%. The diammonium hydrogen phosphate product fully meets an industrial first level product standard.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a production method of diammonium hydrogen phosphate. Background technique [0002] With the progress of human society, industry and agriculture have developed by leaps and bounds, and the awareness of safety and environmental protection has been further improved. Industrial grade diammonium hydrogen phosphate is widely used in fire protection, drip irrigation fertilizer, medicine and food. At present, the production of industrial-grade diammonium phosphate generally adopts thermal phosphoric acid or purified phosphoric acid process; the production of thermal phosphoric acid consumes a lot of energy, high cost, and heavy pollution; The impurity content is high, so it cannot be used as an industrial product, and the purification process route of wet-process phosphoric acid is long, the investment in equipment construction is large, and the cost is high; high question. ...

AI Technical Summary

Problems solved by technology

At present, the production of industrial-grade diammonium phosphate generally adopts thermal phosphoric acid or purified phosphoric acid process; the production of thermal phosphoric acid consumes a lot of energy, high cost, and heavy pollution; The impurity content is high, so it cannot be used as an industrial product, and the purification process route of wet-process phosphoric acid is long, the investment in equipment construction is large, and the cost is high; high problem

[0003] For example, the patent No. 201210402974.3 "Preparation Method for Co-production of Diammonium Phosphate from Acidic Slurry" discloses feeding ammonia gas into dilute phosphoric acid with a concentration of 22.0-24.0%, and then sending the dilute phosphoric acid once into the outer circulation evaporator, the second effect A heat exchanger and a one-effect heat exchanger are used to obtain acidic slurry; ammonia gas is passed into concentrated phosphoric acid with a concentration of 35-40% to obtain concentrated phosphoric acid with a neutralization degree of 0.4-0.7; the acidic slurry is mixed with concentrated Phosphoric acid is mixed according to the volume ratio of 1:3-5 and then sent to the acid pump to prepare a mixed solution of phosphoric acid slurry and then sent to the neutralization tank, and ammonia gas is sent into the neutralization tank at the same time to carry out ammoniation granulation reaction. The neutralized slurry is prepared, and then the neutralized slurry is sent to the granulator for ammonium granulation process to obtain diammonium phosphate granules, and finally the diammonium phosphate granules are dried and dehydrated, graded and screened to obtain diammonium phosphate Particles; it can be seen that this method uses concentrated phosphoric acid, which has high requirements for equipment materials, long process routes, and high production costs.

[0004] Another example is that the patent No. is 200910244335.7 " a ​​kind of preparation method of diammonium phosphate " discloses that reaction raw material phosphoric acid (40-60%H 3 PO 4 ) and reaction raw material ammonia (70-90% NH 3 ) into the tubular reactor for neutralization reaction to generate ammonium phosphate slurry; then spray the ammonium phosphate slurry into the granulator, then feed ammonia into it, and adjust the neutralization degree of the ammonium phosphate slurry to be 1.7-1.9 , and granulate at the same time of ammonification to generate solid wet material and granulation tail gas; then dry to obtain diammonium phosphate product; it can be seen that the raw material ammonia used in this method is relatively large, the production process is long, and the phosphoric acid The higher the concentration, the higher the requirements for the material of the equipment, the larger the generation of citrate-soluble phosphate, the lower the utilization rate of phosphorus, and the waste discharge, which is not conducive to environmental protection and the production cost is high.

[0005] It can be seen that in the prior art, the production process for diammonium hydrogen phosphate products is long, the energy consumption is large, the utilization rate of raw materials is low, and the requirements for equipment materials are high, which will produce a large amount of waste gas and waste; the demand for raw material ammonia Larger, not conducive to environmental protection, and higher production costs

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