Method for producing industrial and agricultural monoammonium phosphate and magnesium ammonium phosphate with wet-process phosphoric acid

Abstract

The invention provides a method for producing industrial and agricultural grade monoammonium phosphate and magnesium ammonium phosphate with wet-process phosphoric acid. The wet-process phosphoric acid is taken as a raw material. Sodium fluosilicate, monoammonium phosphate solution, monoammonium phosphate filter cakes and magnesium ammonium phosphate are respectively obtained through defluorination and a three-section substep neutralization process, wherein the monoammonium phosphate solution is concentrated and crystallized to obtain high-quality water soluble industrial monoammonium phosphate, and the monoammonium phosphate filter cakes and the monoammonium phosphate mother solution subjected to repeated crystallization are subjected to size mixed and dried to obtain qualified agricultural monoammonium phosphate. The magnesium ammonium phosphate is a good slow release nitrogenous fertilizer per se. The process has the advantages of little investment of equipment, good adaptability of raw material, low production cost and good product quality. The water soluble industrial monoammonium phosphate with low cost can provide a cheap and good water soluble phosphatic fertilizer for modern facility agriculture.

Description

technical field [0001] The invention relates to a method for producing monoammonium phosphate and magnesium ammonium phosphate, in particular to a method for graded production of industrial grade monoammonium phosphate and agricultural grade monoammonium phosphate and magnesium ammonium phosphate by wet-process phosphoric acid, belonging to the technical field of chemical industry. Background technique [0002] With the popularization of modern facility agriculture, the market demand for fully water-soluble phosphate fertilizers is increasing. The traditional monoammonium phosphate production process such as "concentration method" is to concentrate phosphoric acid first, and then neutralize it with ammonia; while "dilute acid slurry method" is to neutralize phosphoric acid with ammonia first, then concentrate and dry it. Both methods belong to a one-stage neutralization process. Although the scale is large and the production cost is low, they can only produce agricultural-gr...

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Problems solved by technology

Both methods belong to a one-stage neutralization process. Although the scale is large and the production cost is low, they can only produce agricultural-grade monoammonium phosphate, and the product has poor water solubility, which cannot meet the requirements of modern facility agriculture for fully water-soluble phosphate fertilizers.

Although some manufacturers use the two-stage neutralization process to produce industrial-grade monoammonium phosphate, the filter cake of the two-stage neutralization method needs the support of the traditional one-stage neutralization method system to be converted into qualified agricultural grade monoammonium phosphate Ammonium, the ammonium phosphate solution after magnesium removal needs to adjust the pH value with thermal phosphoric acid to produce industrial grade monoammonium phosphate, so its cost is still high

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