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Method for defluorination, purification and separation of wet-process phosphoric acid

A wet-process phosphoric acid, purification and separation technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve problems such as high content of phosphorus pentoxide, low purity of sodium fluorosilicate, harsh working environment, etc., to achieve filtration The effect of low cake moisture, reduced labor intensity and low operating cost

Active Publication Date: 2012-10-17
GUIZHOU CHANHEN CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, domestic wet-process phosphoric acid defluorination purification and separation methods usually use primary filtration equipment, and the filtration equipment is mainly box-type filter press, which is backward in equipment, high in failure rate, poor in production stability, high in labor intensity, and harsh in working environment. , serious running, popping, dripping and leaking, high phosphorus content in the filtered solid, high liquid content in the slag, high phosphorus pentoxide content, high environmental protection pressure for stacking, large phosphorus loss, low phosphorus yield, and the production of fluorine The purity of sodium silicate is low (the purity of sodium fluorosilicate is about 60%). Based on the above factors, the rapid development of the entire phosphorus chemical industry is restricted.

Method used

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  • Method for defluorination, purification and separation of wet-process phosphoric acid
  • Method for defluorination, purification and separation of wet-process phosphoric acid
  • Method for defluorination, purification and separation of wet-process phosphoric acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] The quality indicators of wet-process phosphoric acid are shown in Table 1:

[0041] Table 1 Example 1 wet-process phosphoric acid index

[0042] P 2 o 5

density

Solid content

F

SO 3

％

g / ml

％

％

％

40.50

1.47

0.5

1.40

1.50

[0043] 1. Wet process phosphoric acid defluorination reaction

[0044] Wet-process phosphoric acid from phosphoric acid storage tanks, P 2 o 5 Concentration 40.50%, density 1.47g / ml, solid content 0.5%, F content 1.40%, SO 3 1.50%, temperature 45°C; at 31M 3 The flow rate per hour enters the defluorination reaction tank, and then a reaction amount of defluorination agent is added into the defluorination reaction tank to react to form a defluorination slurry.

[0045] 2. Solid-liquid separation of defluorinated slurry

[0046]The defluorinated slurry is pumped into the first-stage horizontal screw discharge sedimentation centrifuge for filtrati...

Embodiment 2

[0057] The quality indicators of wet-process phosphoric acid are shown in Table 4:

[0058] Table 4 Example two wet-process phosphoric acid indicators

[0059] P 2 o 5 %

density

Solid content

F

SO 3

％

g / ml

％

％

％

35.00

1.40

0.8

1.60

1.20

[0060] 1. Wet process phosphoric acid defluorination reaction

[0061] Wet-process phosphoric acid from phosphoric acid storage tanks, P 2 o 5 Concentration 35.00%, density 1.40g / ml, solid content 0.8%, F content 1.60%, temperature 43°C; at 33.5M 3 The flow rate per hour enters the defluorination reaction tank, and then a reaction amount of defluorination agent is added into the defluorination reaction tank to react to form a defluorination slurry.

[0062] 2. Solid-liquid separation of defluorinated slurry

[0063] The defluorinated slurry is pumped into the first-stage horizontal screw discharge sedimentation centrifuge for filtratio...

Embodiment 3

[0074] The quality indicators of wet-process phosphoric acid are shown in Table 7:

[0075] Table 7 Example three wet-process phosphoric acid indicators

[0076] P 2 o 5 %

density

Solid content

F

SO 3

％

g / ml

％

％

％

49.80

1.60

1.1

0.85

1.82

[0077] 1. Wet-process phosphoric acid defluorination reaction;

[0078] Wet-process phosphoric acid from phosphoric acid storage tanks, P 2 o 5 Concentration 49.80%, density 1.60g / ml, solid content 1.1%, F content 0.85%, SO3 1.82%, temperature 40°C; at 30.0M 3 The flow rate per hour enters the defluorination reaction tank, and then a reaction amount of defluorination agent is added into the defluorination reaction tank to react to form a defluorination slurry.

[0079] 2. Solid-liquid separation of defluorinated slurry;

[0080] The defluorinated slurry is pumped into the first-stage horizontal screw discharge sedimentation centrifug...

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Abstract

The present invention discloses a method for improving phosphorus yield by defluorination, purification and separation of wet-process phosphoric acid, and belongs to the field of wet-process phosphoric acid production. The method comprises the following steps: a, adding a reaction amount of a defluorination agent to wet-process phosphoric acid to carry out a compete reaction; b, adding the material slurry from the step a to a scroll discharge sedimentation centrifuge to carry out solid-liquid separation, and adding the separated liquid to a defluorinated phosphoric acid storage tank; c, adding hot water to the solid-liquid separated solid from the step b to carry out slurry conditioning, wherein density of the material slurry is 1.35-1.50 g / ml; and d, conveying the conditioned material slurry from the step c to a belt filter to carry out filtration and countercurrent washing, wherein the liquid after filtration and countercurrent washing enters the defluorinated phosphoric acid storage tank, and the solid after filtration and countercurrent washing is the by-product sodium fluorosilicate. With the method of the present invention, phosphorus yield in the defluorination purification process can be increased to more than 99% from 95%, and pure sodium fluorosilicate by-product can be obtained, such that comprehensive utilization of resources is achieved.

Description

technical field [0001] The invention belongs to the field of wet-process phosphoric acid production, and in particular relates to a method for defluorination, purification and separation of wet-process phosphoric acid. Background technique [0002] The wet-process phosphoric acid production process is the process of decomposing phosphate rock with inorganic acid (mainly sulfuric acid) to produce phosphoric acid, that is, reacting sulfuric acid with phosphate rock to generate calcium sulfate crystals and phosphoric acid solution, and then performing liquid-solid separation. The separated phosphoric acid solution is collectively referred to as For wet-process phosphoric acid. The sources of wet-process phosphoric acid mainly include dihydrate method, semi-hydrate method, and semi-hydrate-dihydrate method. [0003] Since there are some harmful substances containing fluorine in wet-process phosphoric acid (usually below 2%), wet-process phosphoric acid cannot be directly proces...

Claims

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Application Information

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IPC IPC(8): C01B25/237C01B33/10
Inventor 李子军赵小林李顺方马永强龙辉
Owner GUIZHOU CHANHEN CHEM CO LTD
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