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Preparation method of high-purity ammonium hydrogen fluoride

An ammonium bifluoride, high-purity technology, applied in ammonium halide and other directions, can solve problems such as environmental pollution and dehydration

Inactive Publication Date: 2011-01-12
DALIAN LIFANG CHEM TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The mother liquor must be concentrated, and the crystallization must be dehydrated, causing environmental pollution

Method used

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Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0006] The reaction system of the method for purifying ammonium bifluoride of the present invention is composed of "fluidized reactor 7 - cyclone separator 8 - centrifugal fan 9 - condensing cooler 10" to form a closed circuit. The working pressure of the system is controlled by the inert gas regulating port 1, the pressure is indicated by the pressure gauge 2, and the phase change liquid CP is charged into the port 3, NH 3 Inlet 4 and HF inlet 5 are respectively located in different parts of reactor 7, and the synthesized product NH 4 HF 2 It is collected at the outlet 6 of the cyclone separator 8 . The first recrystallization steps are as follows:

[0007] [Step 1] In an ultra-clean quartz beaker, heat 500ml of water to 80°C, pour the water into an ultra-clean wide-mouth polypropylene container, and put the NH to be purified 4 HF 2 Put 360g into a plastic container and stir to dissolve it all.

[0008] [Step 2], the [Step 1] solution is ultrafinely filtered in a polypro...

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Abstract

The invention discloses a synthesized method of NH4HF2 with reacting NH3 and HF, which comprises the following steps: choosing 18. 25 M omega . cm electronic grade water as solvent; adopting fluidized method in the producing course; entering into reactor with 1molNH3 and 2molHF stoichiometric relation; diluting NH3 and HF completely; charging into inert gas into reacting system as diluting agent and carrier to transport reactant, reaction product and reaction heat; separating materials in cyclone separator; pushing carrier gas flow with centrifugal blower; cooling the carrier gas with exchanger; coming back to the reactor to proceed next time cycle.

Description

Technical field: [0001] The invention relates to the use of fluorine-based etchant in the manufacture and treatment of silicon wafers in the semiconductor industry, wherein the buffered oxide etchant (Buffered Oxid Etchent, BOE) uses ammonium hydrogen fluoride NH 4 HF 2 , A process for preparing ammonium bifluoride. Background technique: [0002] Industrial ammonium bifluoride NH 4 HF 2 98% purity, while electronic grade NH 4 HF 2 The purity needs to be above 99.99%, and the industrial NH 4 HF 2 To be purified, the usual method of purification is to purify the raw materials and then synthesize NH 4 HF 2 , Industrial NH 4 HF 2 Sublimation, Industrial NH 4 HF 2 Recrystallization, the purity achieved by recrystallization is higher than the other two methods. Usually, ammonium bifluoride is produced by reacting ammonia water and hydrofluoric acid to form crystals in a saturated state, and the heat of reaction is taken away by the heat exchange jacket. The mother li...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01C1/16
Inventor 王同文
Owner DALIAN LIFANG CHEM TECH