Preparation of ammonium potassium dihydrogen phosphate

Abstract

The invention provides a method for preparing potassium dihydrogen phosphate. In the method, phosphate ores, sulphuric acid and potassium chloride are taken as base materials and subjected to phosphoric acid extraction, filtering, neutralization and separation, concentration and crystallization to obtain a full water-soluble potassium dihydrogen phosphate product, and the potassium dihydrogen phosphate solution prepared is high in concentration, the solid content reaches 40 percent, thereby reducing the load of the concentration process; in particular, the method adopts a process of neutralization first and concentration second, so that the corrosivity of concentration liquids is small, the boiling point is low, and the conventional multi-effect concentration by evaporation can be performed by the common equipment, and the equipment investment and the energy consumption are greatly lowered; because in the phosphoric acid extraction process, the potassium bisulfate is added, thereby effectively lowering the emission of fluorine-containing exhaust gases and facilitating the environmental protection; adding with the development and the utilization of potassium-containing phosphogypsum, the method of the invention can avoid the environmental pollution caused by the phosphogypsum, improve the material utilization ratio and make the material utilization ratio reach 100 percent.

Description

technical field [0001] The invention relates to a preparation method of ammonium potassium dihydrogen phosphate, which belongs to the technical field of chemical industry. Background technique [0002] Ammonium potassium dihydrogen phosphate is a composite crystal composed of potassium dihydrogen phosphate and ammonium dihydrogen phosphate in different proportions, and its molecular formula is KH 2 PO 4 ·NH 4 h 2 PO 4 . Like potassium dihydrogen phosphate, ammonium potassium dihydrogen phosphate also has the advantages of full water solubility and low salt index. In addition, because it also contains nitrogen, it is a fully water-soluble high-concentration ternary compound fertilizer, and its fertilizer effect is better than potassium dihydrogen phosphate. It is a very promising new compound fertilizer. [0003] American Pennzoil Company successfully developed ammonium potassium dihydrogen phosphate as early as the end of the 1970s. However, the company failed to sol...

AI Technical Summary

Problems solved by technology

At present, only Israel has produced potassium ammonium dihydrogen phosphate with better quality by using the solvent extraction purification method, but its production cost is high, the process is complicated, and the productivity is low.

There are also domestic enterprises trying to produce ammonium potassium dihydrogen phosphate with industrial phosphoric acid, but there is also the problem of high cost. Therefore, large-scale industrial production has not been realized so far, and the use of ammonium potassium dihydrogen phosphate cannot be promoted on a large scale.

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