Purification method of impurity iodine in silicon tetrafluoride gas

A technology of silicon tetrafluoride and fluorine-containing gas, which is applied in the direction of silicon halide compounds, halosilanes, etc., and can solve the problems that there is no technical solution for the purification of silicon tetrafluoride impurity iodine

Active Publication Date: 2013-04-03
贵州瓮福蓝天氟化工股份有限公司 +1
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  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

[0004] So far, there is no report on the purification technology scheme of impurity iodine in silicon tetrafluoride gas

Method used

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  • Purification method of impurity iodine in silicon tetrafluoride gas

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Embodiment 1

[0021] A factory is a chemical enterprise that handles phosphate rock by wet method, and a large amount of fluorine-containing gas is produced in the process of treating phosphate rock with sulfuric acid. The collected gas is treated with the method of the present invention to produce high purity silicon tetrafluoride. First, collect the gas containing hydrogen fluoride and silicon tetrafluoride produced in the process of wet treatment of phosphate rock, and introduce the gas containing fluorine into a concentrated sulfuric acid with a mass fraction of 85% to 98% and a silicon dioxide content of ≥95%, fine In the reactor with quartz sand whose density is less than 0.3mm, the mass ratio of quartz sand and concentrated sulfuric acid added is 2:10; hydrogen fluoride in fluorine-containing gas is converted into silicon tetrafluoride gas at a temperature of 45°C to 130°C; Then introduce silicon tetrafluoride gas into the purification tank, and use 98% concentrated sulfuric acid or ...

Embodiment 2

[0023] A factory mixes fluosilicic acid and concentrated sulfuric acid and heats it to produce gaseous compounds, then introduces the gaseous compounds into a container filled with concentrated sulfuric acid, removes impurities such as HF and moisture, and obtains silicon tetrafluoride gas; use the same method as in Example 1 A method for processing the collected gas to produce high-purity silicon tetrafluoride gas SiF 4 Mass fraction ≥ 99.9%, of which iodine content is less than 10 -6 (1ppm).

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Abstract

The invention discloses a purification method of impurity iodine in a silicon tetrafluoride gas. The purification method comprises the following steps of: (1) collecting a fluorine-containing gas generated in the process of treating rock phosphate by using wet processing, introducing the fluorine-containing gas into a reactor to which sulfuric acid and silicon dioxide are added so that HF (Hydrogen Fluoride) in the fluorine-containing gas is converted into a SiF4 gas; or mixing and heating fluosilicic acid and concentrated sulfuric acid, introducing a generated gaseous compound into a container filled with the concentrated sulfuric acid, removing impurities and obtaining the SiF4 gas; (2) introducing the obtained SiF4 gas into a purification tank, removing moisture and oxygen containing siliconfluoride in the SiF4 gas by using the concentric sulfuric acid or the mixture of the concentrated sulfuric acid and hydrofluoric acid; (3) enabling the SiF4 gas to sequentially enter filters which are filled with pre-dried activated carbon and diatomaceous earth so that the impurities in the SiF4 gas are filtered out; and (4) introducing the purified the SiF4 gas into a freezing plant, and removing HI and I2 by freezing. The purification method is used for producing high-purity silicon tetrafluoride by resolving the industrial byproduct fluosilicic acid in a phosphatic fertilizer industry, and therefore, high-purity raw materials for producing silicon series products are supplied for electronics, photovoltaic, and optical fiber industries.

Description

technical field [0001] The present invention relates to silicon halides, especially silicon tetrafluoride, and iodine, specifically, the purification of impurity iodine in silicon tetrafluoride. Background technique [0002] In recent years, research on silicon tetrafluoride as a raw material for the production of silane, crystalline silicon, amorphous silicon, and silicon oxide has attracted more and more attention. increasingly attracting people's attention. The source of silicon tetrafluoride in my country is mainly a by-product of the phosphate fertilizer industry. Chinese patent ZL201010529976.X "Method for producing high-purity silicon tetrafluoride in the process of wet treatment of phosphate rock" discloses that the collected wet phosphoric acid production When the fluorine-containing gas is introduced into a reactor with sulfuric acid and silicon dioxide, hydrogen fluoride is converted into silicon tetrafluoride gas, and then the resulting gas is passed through conc...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/107
Inventor 唐安江刘松林张妙鹤汤正河张瑞韦德举龚孝祥
Owner 贵州瓮福蓝天氟化工股份有限公司
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