Method for producing disodium hydrogen phosphate with wet-process phosphoric acid

Abstract

Provided is a process for producing disodium hydrogen phosphate with wet-process phosphoric acid, which comprises the following steps, a, wet-process phosphoric acid, sodium sulfate and rock phosphate are mixed according to the weight parts of 10: 1.2: 2, and reacted for five hours at the temperature of 80 DEG C to 85 DEG C, and filtered and washed to obtain material liquid which contains disodium hydrogen phosphate, and the leached residue is used for producing phosphate fertilizer, b, the disodium hydrogen phosphate solution obtained in step a is added with soda to be neutralized to have the pH value of 5-6, the mixture is filtered to obtain one time neutralization material liquid, and the leached residue is used for phosphate fertilizer production, c, the one time neutralization material liquid obtained in step b is added with soda to be neutralized to have the pH value of 8-9, the mixture is filtered to obtain secondary neutralization material liquid, and the leached residue is returned to step b to be reacted, d, the secondary neutralization material liquid obtained in step c is cooled to the temperature of 18 DEG C to 20 DEG C, and is crystallized and separated to obtain disodium hydrogen phosphate products and mother solution, and the mother solution is returned to step a to be reacted. The invention employs sodium sulfate to substitute for part of the soda, which reduces the amount of the soda when producing the disodium hydrogen phosphate and greatly lowers the manufacturing cost of the disodium hydrogen phosphate.

Description

technical field [0001] The invention relates to a method for producing disodium hydrogen phosphate, in particular to a method for producing disodium hydrogen phosphate with wet-process phosphoric acid. Background technique [0002] The existing method of using wet-process phosphoric acid to produce disodium hydrogen phosphate generally directly uses soda ash and wet-process phosphoric acid to carry out neutralization reaction, and filter to remove impurity elements, and the production cost is relatively high. Contents of the invention [0003] The purpose of the present invention is exactly to provide a kind of method with wet-process phosphoric acid to produce disodium hydrogen phosphate, and it uses wet-process phosphoric acid to decompose phosphate ore, and the calcium ion that precipitates with sodium sulfate produces, and sodium sulfate both does the precipitating agent of calcium ion, It can also provide some so...

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Problems solved by technology

[0002] The existing method of using wet-process phosphoric acid to produce disodium hydrogen phosphate generally directly uses soda ash and wet-process phosphoric acid for neutralization reaction, and filters out impurity elements, and the production cost is relatively high