Method for producing silicon dioxide hydrate from silicon recovered from wet-process phosphoric acid reaction flue gas

A technology of hydrated silica and wet-process phosphoric acid, which is applied in the direction of silica, silica, chemical instruments and methods, etc., to reduce labor intensity, prolong production cycle, and reduce blockage of equipment pipelines

Inactive Publication Date: 2013-04-03
WENGFU (GRP) CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Industrially, it is usually produced by reducing silicon dioxide with carbon in an electric furnace, and recovering silicon resources from phosphate rock. At present, there is no special production process, but people are still developing technology for recovering silicon resources from phosphate rock according to local conditions.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Example 1: First, 1.2 tons of solid ammonium fluoride is prepared into 10 tons of absorbent; it is prepared into an ammonium fluoride absorption solution with a mass fraction of 12% and a pH value of 6.0; then pump the absorption solution into the wet-process phosphoric acid tail washing device for Circularly absorb the fluorine-containing silicon gas in the wet-process phosphoric acid reaction flue gas, and control the absorption temperature at 55°C; when the mass percentage ratio of nitrogen and fluorine in the absorption liquid is controlled at 3.5, feed ammonia gas, and when the pH reaches 8.7, Hydrated silica was obtained after filtration.

Embodiment 2

[0018] Example 2: First, 2.5 tons of solid ammonium fluoride is prepared into 10 tons of absorbent; it is prepared into an ammonium fluoride absorption solution with a mass fraction of 26% and a pH value of 6.5; then pump the absorption solution into the wet-process phosphoric acid tail washing device for Circularly absorb the fluorine-containing silicon gas in the wet-process phosphoric acid reaction flue gas, and control the absorption temperature at 45°C; control the ratio of nitrogen and fluorine mass percentages in the absorption liquid to 4.0, and feed ammonia gas until the pH reaches 9.0. Hydrated silica was obtained after filtration.

Embodiment 3

[0019] Example 3: First, 2.5 tons of solid ammonium fluoride is prepared into 10 tons of absorbent; it is prepared into an ammonium fluoride absorption solution with a mass fraction of 26% and a pH value of 7.0; then pump the absorption solution into the wet phosphoric acid tail washing device for Circularly absorb the fluorine-containing silicon gas in the wet-process phosphoric acid reaction flue gas, and control the absorption temperature at 40°C; control the ratio of nitrogen and fluorine mass percentages in the absorption liquid to 3.5, feed ammonia gas, and carry out the process when the pH reaches 9.2. Hydrated silica was obtained after filtration.

[0020] Adopt the method of above-mentioned 3 embodiments, the fluorine yield in wet process phosphoric acid reaction flue gas reaches 99.52%, silicon yield reaches 99.50%; Recover the fluorine 2194 tons / year in wet process reaction flue gas, reclaim wet process reaction flue gas The silicon in the gas is 850 tons / year; th...

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PUM

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Abstract

The invention discloses a method for producing silicon dioxide hydrate from silicon recovered from wet-process phosphoric acid reaction flue gas, which comprises the following steps: preparing crystal ammonium fluoride into a 10-25% ammonium fluoride solution to be used as an SiFe gas absorbent for flue gas in wet-process phosphoric acid reaction; washing the wet-process phosphoric acid F-containing exhaust with the absorption liquid in a pump circulation mode; and finally, introducing gas ammonia into the ammonium fluosilicate solution generated by absorbing SiF4 gas by ammonium fluoride, thereby producing the silicon dioxide hydrate and ammonium fluoride. The method recovers fluorine and silicon resources in wet-process phosphoric acid reaction flue gas, so that the fluorine content in the phosphoric acid reaction flue gas is reduced from 10.5g / m<3> to 0.05g / m<3>, and the silicon content is reduced from 4.08g / m<3> to 0.02g / m<3>; and meanwhile, the method reduces the possibility of equipment pipeline blockage by silica gel, prolongs the production cycle of wet-process phosphoric acid from 7 days to 25 days, lowers the labor intensity for cleaning scales in the equipment pipeline, and enhances the operating ratio of the device.

Description

technical field [0001] The present invention relates to silicon dioxide, and furthermore, relates to a method for preparing hydrated silicon dioxide from wet-process phosphoric acid reaction flue gas. Background technique [0002] As we all know, the silicon in the wet process phosphoric acid reaction flue gas is SiF 4 The traditional wet-process phosphoric acid reaction flue gas absorption process of silicon-containing gas is through water absorption, in the process of water absorption, to generate SiO 2 , resulting in SiO 2 Due to the high content of impurities, it can only be piled up as waste. And absorb SiF in flue gas of wet-process phosphoric acid reaction with water 4 Form SiO 2 , Phosphoric acid equipment pipes are seriously fouled and blocked, which not only affects the absorption effect of fluorine in the wet phosphoric acid reaction flue gas, but also requires a lot of manpower and material resources to clean due to the serious fouling of equipment pipes, whi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/12B01D53/78B01D53/68C01C1/16
Inventor 姚石林刘海赵建勇饶轶晟
Owner WENGFU (GRP) CO LTD
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