Method for increasing and stabilizing neutralization defluorination concentration in phosphoric acid by wet process

Abstract

A method for increasing and stabilizing neutralization defluorination concentration in phosphoric acid by wet process. The invention adopts the following process: 1) sending phosphoric acid by wet process with the concentration, calculated by P2O5, of 100-140 g / L, into a first stage of re-dissolution slot for conducting re-dissolution with a second stage of thick paste; 2), sending the slurry after re-dissolution into a dilution tank and adding white phosphorus fertilizer washing water with concentration, calculated by P2O5, of 40-60 g / L; and 3), sending the diluted phosphoric acid into a reaction tank, adding heavy calcium slurry for a first stage of neutralization and defluorination. The technology has the following beneficial effects: the process flow of an original production process does not change, and only one white phosphorus fertilizer washing water transfer pool needs to be added, so as to effectively wash white phosphorus fertilizer; all the dilution water is white phosphorus fertilizer washing water to reduce water consumption of the system; the defluorination effect is more stable and in favor of neutralization defluorination operation control, so as to provide stability for the subsequent process; the P2O5 concentration of a supernatant in a second stage of neutralization defluorination is increased to 10-20 g / L, system capacity is improved by 15-30%, and the economic benefits of enterprises are increased.

Description

technical field [0001] The invention relates to a method for stabilizing the concentration of dilute acid method feed grade calcium hydrogen phosphate wet-process phosphoric acid in the neutralization and defluorination process. More specifically, it is a method for effectively recovering and digesting white phosphorus fertilizer washing water and stabilizing the neutralization and defluorination concentration of wet-process phosphoric acid. Background technique [0002] Currently, in the production of feed-grade calcium hydrogen phosphate, wet-process phosphoric acid is produced first, and then wet-process phosphoric acid is neutralized and defluorinated in the first and second stages, and then neutralized in the third stage. [0003] In the production of wet-process phosphoric acid, the concentration of wet-process phosphoric acid is generally P 2 o 5 The concentration is 100-140 (g / L). If the concentration is too high, it will cause: (1) the washing rate will decrease; ...

AI Technical Summary

Problems solved by technology

[0003] In the production of wet-process phosphoric acid, the concentration of wet-process phosphoric acid is generally P 2 o 5 The concentration is 100-140 (g / L). If the concentration is too high, it will cause: (1) the washing rate will decrease; (2) the system will be blocked too quickly; (3) the corrosion degree of the production system will be aggravated

[0004] If the concentration is too low, it will lead to (1) the poor remelting effect of the first-stage neutralization and defluorination second-stage thick pulp; (2) the first-stage and second-stage neutralization and defluorination production capacity will decrease; (3) the fertilizer-grade hydrogen phosphate produced by the first-stage neutralization and defluorination Calcium (commonly known as white phosphorus fertilizer) is difficult to digest in washing water; (4) The concentration of the first and second neutralization defluorination clear liquid is low, which affects the first and second neutralization and defluorination effects

[0005] At present, the washing water of white phosphorus fertilizer directly enters the defluorination reaction tank in the second stage, which will cause: (1) the white phosphorus fertilizer cannot be effectively washed, and the washing water is difficult to digest; (2) the first and second stages of neutralization and defluorination clear liquid Low concentration affects the effect of neutralization and defluorination in the first and second stages; (3) The production capacity of neutralization and defluorination in the first and second stages decreases; (4) The concentration of neutralization and defluorination in the first and second stages fluctuates greatly, which is not conducive to the stable operation of the subsequent process

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