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Method for producing SiF4 from Na2SiF6 through pyrolysis

A technology of pyrolysis and feeder, applied in the direction of silicon halide compound, halosilane, etc., can solve the problems of low conversion rate of silicon tetrafluoride, difficult removal of impurities, high production cost, etc., to solve the problem of waste of fluorine resources and production cost Low, high value-added effect

Active Publication Date: 2012-04-04
河南省氟基新材料科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These two production methods have the following disadvantages: high production cost, low conversion rate from raw materials to silicon tetrafluoride, many by-products, difficult to remove impurities, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] In this example SiF 4 The production method, the steps are as follows:

[0012] (1) Take Na, a by-product of the phosphate fertilizer industry 2 SiF 6 About 3kg, sent to the vacuum tray dryer through the feeder, Na 2 SiF 6 Vacuum dry in a vacuum tray dryer at 200°C for 3 hours, and the vacuum pressure in the vacuum tray dryer is controlled at -0.095MPa;

[0013] (2) Na 2 SiF 6 After being vacuum-dried, it enters the quantitative feeder from the material guide tank, and in the quantitative feeder, Na 2 SiF 6 NaF by weight ratio is Na 2 SiF 6 :NaF=10:1 mixed, then sent to high temperature circulating fluidized bed, pyrolyzed at 750°C for 1 hour, the pressure inside the high temperature circulating fluidized bed is controlled to 10mmH 2 O, pyrolysis produces NaF and SiF 4 gas;

[0014] (3) The NaF produced by pyrolysis is cooled and returned to the quantitative feeder for reuse, and the SiF produced by pyrolysis 4 The gas is exported by the dry vacuum pump, en...

Embodiment 2

[0016] In this example SiF 4 The production method, the steps are as follows:

[0017] (1) Take Na, a by-product of the phosphate fertilizer industry 2 SiF 6 About 3.5kg, sent to the vacuum target dryer through the feeder, Na 2 SiF 6 Vacuum dry in a vacuum target dryer at 300°C for 2.5 hours, and the vacuum pressure in the vacuum target dryer is controlled at -0.095MPa;

[0018] (2) Na 2 SiF 6 After being vacuum-dried, it enters the quantitative feeder from the material guide tank, and in the quantitative feeder, Na 2 SiF 6 NaF by weight ratio is Na 2 SiF 6 :NaF=10:3 mixed, then sent to the high temperature circulating fluidized bed, pyrolyzed at 700°C for 2 hours, the pressure in the high temperature circulating fluidized bed is controlled to 30mmH 2 O, pyrolysis produces NaF and SiF 4 gas;

[0019] (3) The NaF produced by pyrolysis is cooled and returned to the quantitative feeder for reuse, and the SiF produced by pyrolysis 4 The gas is exported by the dry vacu...

Embodiment 3

[0021] In this example SiF 4 The production method, the steps are as follows:

[0022] (1) Take Na, a by-product of the phosphate fertilizer industry 2 SiF 6 About 3kg, sent to the vacuum target dryer through the feeder, Na 2 SiF 6 Vacuum dry in a vacuum target dryer at 350°C for 1 hour, and the vacuum pressure in the vacuum target dryer is controlled at -0.095MPa;

[0023] (2) Na 2 SiF 6 After being vacuum-dried, it enters the quantitative feeder from the material guide tank, and in the quantitative feeder, Na 2 SiF 6 NaF by weight ratio is Na 2 SiF 6 :NaF=10:5 mixed, then sent into high temperature reactor, pyrolyzed at 600°C for 3 hours, the pressure inside the high temperature reactor was controlled to 50mmH 2 O, pyrolysis produces NaF and SiF 4 gas;

[0024] (3) The NaF produced by pyrolysis is cooled and returned to the quantitative feeder for reuse, and the SiF produced by pyrolysis 4 The gas is exported by the dry vacuum pump, enters the condenser to conde...

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Abstract

The invention discloses a method for producing SiF4 from a phosphorus fertilizer industry by-product Na2SiF6 through pyrolysis. The method comprises steps that: Na2SiF6 is dried in a vacuum dryer, and is delivered into a fixed-quantity feeder through a material guiding groove; Na2SiF6 is mixed with NaF in the fixed-quantity feeder, and the mixture is delivered into a high-temperature reaction vessel or a high-temperature circulating fluidized bed; the mixture is subject to pyrolysis for 1-3 hours under a temperature of 600-750 DEG C, wherein the pressure in the high-temperature reaction vessel or the high-temperature circulating fluidized bed is controlled at 10-50mmH2O, such that NaF and SiF4 gases are produced through pyrolysis; NaF is delivered back into the fixed-quantity feeder and is reused; the SiF4 gas is condensed in a condenser, processed though a dust-removing treatment, and purified by using two stages of activated carbon adsorbing columns; the SiF4 gas is then processed through refrigeration compression; the SiF4 gas is delivered into a cylinder, and is stored in the cylinder. The production method provided by the invention is advantaged in low production cost. No waste is generated during the production process, such that clean production is realized. The quality of the produced silicon tetrafluoride gas is stable, and the purity of the silicon tetrafluoride gas reaches 99.9%.

Description

technical field [0001] The invention relates to the technical field of fluorine chemical industry, in particular to a Na 2 SiF 6 Pyrolysis to produce SiF 4 Methods. Background technique [0002] SiF 4 It is an important raw material in the electronic processing industry and is widely used in the fields of semiconductors and optical fibers. In the semiconductor industry, SiF 4 It is mainly used as etchant for silicon nitride, tantalum silicide, etc., P-type dopant, epitaxial deposition diffusion silicon source, etc. It can also be used for the preparation of electronic grade silane and polysilicon. In addition, SiF 4 It is also used as a raw material for the production of high-purity quartz glass for optical fibers and as a production material for construction. With SiF 4 Development and maturity of polysilicon production process as an intermediate product, SiF 4 It will show broad application prospects in the semiconductor industry. Current SiF 4 There are two mai...

Claims

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Application Information

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IPC IPC(8): C01B33/107
Inventor 李世江侯红军杨华春于贺华薛旭金陈宏伟刘海霞王建萍郑艳萍尚钟声
Owner 河南省氟基新材料科技有限公司
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