Method of producing zinc phosphate using phosphorus fertilizer

Abstract

A process for preparing zinc phosphate from P fertilizer includes such steps as respectively dissolving fertilizer-class ammonium phosphate and soluble Zn salt in hot water, proportionally adding them to a container with stirrer, keeping the temp to 50-80 deg.C, regulating pH=6.5-8.5, ageing reaction, filtering, washing the filtered cake with hot water to obtain wet zinc phosphate, and drying.

Description

[0001] 1. Technical Field: Inorganic Salt Chemical Industry 2. Background technology: [0002] Zinc Phosphate Zn 3 (PO 4 ) 2 ·ΧH 2 O (χ is 0, 2, 4), mainly used for environmentally friendly anti-corrosion pigments, ferrous metal phosphating, and a small amount used for glass, enamel, ceramics, etc. There are currently two types of industrial production methods, as follows: [0003] 1. Neutralization method [0004] It is obtained by adding dilute phosphoric acid to the zinc oxide water slurry for neutralization, maturation, filtration and drying. [0005] 3ZnO+2H 3 PO 4 +H 2 O→Zn 3 (PO 4 ) 2 ·4H 2 O↓ [0006] The production process is more complicated. The ratio of the amount of zinc oxide and phosphoric acid used is 3:1, and zinc oxide cannot be completely converted. Zinc oxide and the product zinc phosphate tetrahydrate are almost insoluble in water, and this reaction is essentially a precipitation conversion reaction. The traditional external heating method must be time-consumin...

AI Technical Summary

Problems solved by technology

There are three disadvantages in this method: the one, because impurity exists in the solution after acid-dissolving zinc oxide, or this solution must be further purified, or product impurity content is higher, and purity is low; More energy; the third is that the wet product produced by the reaction contains organic solvents. If the organic solvent is recovered, it will consume a lot of energy, and because the boiling point of TBP is higher than the dehydration temperature of zinc phosphate dihydrate, it is difficult to control the amount of crystal water in the product

The essence of this process is to prepare zinc phosphate by double decomposition reaction. The purity requirements of the two raw materials are relatively high, and the production cost is also relatively high.

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