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Precipitation pre-defluorination and steam stripping defluorination coupled wet process phosphoric acid defluorination method

A wet-process phosphoric acid and defluorination technology, which is applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of defluorinated phosphoric acid with many impurities, large loss of phosphorus, and limited production capacity, and achieve good quality and low impurity content low effect

Active Publication Date: 2019-11-19
YUNNAN PHOSPHATE CHEM GROUP CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a wet phosphoric acid defluorination method coupled with precipitation pre-defluorination and stripping defluorination, so as to solve the problems in the prior art of defluorinated phosphoric acid with many impurities, large loss of phosphorus and limited production capacity

Method used

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  • Precipitation pre-defluorination and steam stripping defluorination coupled wet process phosphoric acid defluorination method
  • Precipitation pre-defluorination and steam stripping defluorination coupled wet process phosphoric acid defluorination method
  • Precipitation pre-defluorination and steam stripping defluorination coupled wet process phosphoric acid defluorination method

Examples

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Effect test

Embodiment 1

[0036] A 250,000-ton / year feed-grade phosphoric acid plant in a phosphoric acid plant adopts the coupling process of chemical precipitation pre-defluorination and tower air blowing deep defluorination to purify phosphoric acid.

[0037] Firstly, the raw phosphoric acid is subjected to arsenic and lead heavy metal removal treatment, and the raw phosphoric acid is stirred in the mixing reaction tank with sodium sulfide solution twice the theoretical amount, and after mixing and reacting for 20 minutes, it is transported to the pretreatment clarification tank and added flocculant for clarification to obtain clarification Concentrated phosphoric acid a, P in concentrated phosphoric acid a 2 o 5 The content is 47.28%, the F content is 0.82%, and the solid content is 1.71%. The hydrogen sulfide gas produced in the mixing reaction tank and the pretreatment clarification tank is washed and absorbed by the washing tower with sodium hydroxide solution circulation. The theoretical dosa...

Embodiment 2

[0046] A 260,000-ton / year feed-grade phosphoric acid plant in a phosphoric acid plant uses chemical precipitation pre-defluorination and tower air blowing deep defluorination coupling process to purify phosphoric acid.

[0047] Firstly, the raw phosphoric acid is subjected to arsenic and lead heavy metal removal treatment. The raw phosphoric acid is stirred with sodium sulfide solution 3 times the theoretical amount in the mixing reaction tank. After mixing and reacting for 21 minutes, it is transported to the pretreatment clarification tank and added flocculant for clarification to obtain clarification. Concentrated phosphoric acid a, P in concentrated phosphoric acid a 2 o 5 The content is 47.45%, the F content is 0.77%, and the solid content is 1.62%. The hydrogen sulfide gas produced in the mixing reaction tank and the pretreatment clarification tank is washed and absorbed by the washing tower with sodium hydroxide solution circulation. The theoretical dosage is calculat...

Embodiment 3

[0056] A 270,000-ton / year feed-grade phosphoric acid plant in a phosphoric acid plant adopts the coupling process of chemical precipitation pre-defluorination and tower air blowing deep defluorination to purify phosphoric acid.

[0057] Firstly, the raw material phosphoric acid is subjected to arsenic and lead heavy metal removal treatment. The raw material phosphoric acid is stirred with sodium sulfide solution 4 times the theoretical amount in the mixing reaction tank. After mixing and reacting for 22 minutes, it is transported to the pretreatment clarification tank and added flocculant for clarification to obtain clarification. Concentrated phosphoric acid a, P in concentrated phosphoric acid a 2 o 5 The content is 47.28%, the F content is 0.72%, and the solid content is 1.66%. The hydrogen sulfide gas produced in the mixing reaction tank and the pretreatment clarification tank is washed and absorbed by the washing tower with sodium hydroxide solution circulation. The the...

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Abstract

The invention discloses a precipitation pre-defluorination and steam stripping defluorination coupled wet process phosphoric acid defluorination method, and relates to the field of wet process phosphoric acid defluorination processes. The method comprises: 1) heavy metal removal treatment: removing heavy metals such as arsenic and lead from a raw material phosphoric acid, and clarifying to removethe solid impurities in the phosphoric acid so as to obtain clarified concentrated phosphoric acid a; 2) precipitation pre-defluorination: carrying out defluorination on the concentrated phosphoric acid a by using a precipitation method, and removing the solid impurities from the phosphoric acid through clarification and pressure filtration to obtain concentrated phosphoric acid b; and 3) multi-stage steam stripping defluorination: mixing the concentrated phosphoric acid b and a defluorinating agent in the communication groove of a first-stage defluorination tower, heating by an acid heater, conveying into the first-stage defluorination tower, carrying out countercurrent contact with air from the lower portion of the first-stage defluorination tower, mixing one part of the phosphoric aciddefluorinated to a certain degree, a newly added raw material phosphoric acid and a defluorination agent, continuously carrying out defluorination, exporting the other part of the phosphoric acid defluorinated to a certain degree out of the first-stage defluorination tower, entering a next-stage defluorination tower, continuously carrying out heating defluorination, and introducing the phosphoricacid with the standard fluorine content into a finished acid groove after multi-stage defluorination.

Description

technical field [0001] The invention relates to the field of wet-process phosphoric acid defluorination technology, in particular to a wet-process phosphoric acid defluorination method coupled with precipitation pre-defluorination and stripping defluorination. Background technique [0002] Since the 1950s, countries around the world have used wet-process phosphoric acid as a raw material to produce calcium phosphate as a feed additive, of which calcium hydrogen phosphate is the main one. The key technology of using wet-process phosphoric acid to produce feed phosphate is the purification of wet-process phosphoric acid, that is, the content of fluorine and other impurities in wet-process phosphoric acid can be purified to meet the requirements of producing feed-grade phosphate. The pros and cons of defluorination technology directly affect the yield and quality of the final product. [0003] There are two main techniques for wet-process phosphoric acid defluorination: chemic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/237C01B25/238
CPCC01B25/2375C01B25/238
Inventor 周琼波牛司江方竹堃刘正东朱剑锋周云刚李杰李键李建闻谭顺仓杨雄俊
Owner YUNNAN PHOSPHATE CHEM GROUP CORP