Method and device for preparing hydrogen fluoride by taking silicon tetrafluoride as raw material through electric field polarization hydrolysis

Abstract

The invention relates to the technical field of preparation of hydrogen fluoride from silicon tetrafluoride, in particular to a method and a device for preparing hydrogen fluoride from silicon tetrafluoride through electric field polarization hydrolyzing.According to the characteristics that SiF4 makes contact with H2O to form H2SiF6, and H2SiF6 is unstable in property and extremely easy to form HF and SiF4, electric field polarization treatment is adopted during hydrolysis, so that particles such as SiF6 < 2-> and OH <-> migrate in the direction close to a positive electrode; particles such as H < + > migrate close to the negative electrode; siO2 solid particles sink to greatly prevent decomposition reaction in the hydrolysis process and promote SiF4 gas to be converted into H2SiF6, after solid-liquid separation, H2SiF6 liquid is decomposed to enable HF and SiF4 to escape, after condensation, HF forms liquid by utilizing boiling point difference of HF and SiF4, concentrated H2SO4 is utilized for absorption to form HF-H2SO4 mixed liquid, and HF is volatilized from the HF-H2SO4 mixed liquid through thermal desorption, so that the HF-H2SO4 is separated from the H2F6. And anhydrous HF is obtained, so that the energy consumption is reduced, the cost is reduced, and the conversion rate of converting fluorine in SiF4 into hydrogen fluoride is improved.

Description

technical field [0001] The invention relates to the technical field of preparing hydrogen fluoride from silicon tetrafluoride, in particular to a method and a device for preparing hydrogen fluoride by using silicon tetrafluoride as a raw material by electric field polarization hydrolysis. Background technique [0002] At present, the recycling and efficient utilization of fluorine resources in phosphate rock has become the key direction of the development of the fluoride salt industry, which makes the development and utilization of fluorine resources realized in the development process of the phosphorus chemical industry. For example: Patent No. 201110192918.7 discloses Based on the current development status of fluorine resources in phosphate rock, the industrial production and research results at home and abroad are all using fluorosilicic acid or fluorosilicate by-product of phosphate rock as raw material to produce hydrogen fluoride, but this process has the following sho...

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Problems solved by technology

[0002] At present, the recycling and efficient utilization of fluorine resources in phosphate rock has become the key direction of the development of the fluoride salt industry, enabling the development and utilization of fluorine resources in the development process of the phosphorus chemical industry. For example: Patent No. 201110192918.7 disclosed In view of the current development status of phosphate rock fluorine resources, industrial production and research results at home and abroad all use fluosilicic acid or fluorosilicate by-product of phosphorite rock as a raw material to produce hydrogen fluoride, but this process has the following disadvantages in general: ① Transformation Incomplete, low main content; ②Equipment corrosion problem has not been fundamentally resolved; ③High energy consumption, uneconomical industrialization; ④By-product white carbon black is difficult to collect or filter; ⑤The production process is prone to secondary pollution

[0004] It can be seen that the production of hydrogen fluoride by silicon tetrafluoride as a raw material in the prior art has been extensively studied, and all of them can make the purity of anhydrous hydrogen fluoride reach more than 99.9%, greatly improving the quality of hydrogen fluoride products, but, In the prior art, in the hydrolysis process, silicon tetrafluoride needs to be hydrolyzed by contacting with water vapor, so that the temperature during the hydrolysis treatment reaches above 100°C, resulting in high energy consumption, and the separation of fluorine and silicon in silicon tetrafluoride to prepare hydrogen fluoride The cost is still high; otherwise, the conversion rate of fluorine into hydrogen fluoride in silicon tetrafluoride will be lower than 94%

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