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Preparation and purification methods of silicon tetrafluoride

A technology of silicon tetrafluoride and purification method, which is applied in the fields of halide silicon compounds, chemical instruments and methods, inorganic chemistry, etc., can solve the problems of many impurities in raw materials, high corrosion risk of HF, difficult disposal of waste acid, etc., so as to reduce impurities The effect of content

Inactive Publication Date: 2016-04-20
718TH RES INST OF CHINA SHIPBUILDING INDAL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The patent is prepared by the torch of the plasma reactor, and special equipment limits its application
[0020] In the above several preparation methods of silicon tetrafluoride, there are many disadvantages, for example: the use of raw materials has more impurities, and the use of acidic substances HF, H 2 SO 4 、H 2 SiF 6 It has a greater risk, especially HF has a greater risk of corrosion. After the production process, water is produced or HF waste acid, H 2 SO 4 Spent acid, H 2 SiF 6 It is difficult to treat waste acid, and the thermal decomposition production equipment NaF and KF are attached to the furnace wall, or use special equipment for plasma reactors
To sum up, there are defects in the preparation method of silicon tetrafluoride in the prior art that it is easy to introduce various impurities to reduce the purity of the product silicon tetrafluoride. Method for preparing silicon tetrafluoride with high yield and more economically

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  • Preparation and purification methods of silicon tetrafluoride
  • Preparation and purification methods of silicon tetrafluoride
  • Preparation and purification methods of silicon tetrafluoride

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preparation example Construction

[0063] A kind of preparation device of silicon tetrafluoride, described preparation device is made of monel alloy, the reaction chamber of described preparation device has 10L volume, is equipped with heating tile outside described preparation device, the reaction of described preparation device The diameter of the chamber is 100mm. Before the reaction, silicon-containing substances are added to the reaction chamber, and the fluorine-containing substances and silicon-containing substances are mixed through the inlet pipe. When the dilution medium needs to be added, it is added through the dilution medium pipe. When the fluorine substance is mixed, it is added for dilution. Under heating conditions, the silicon-containing substance reacts with the fluorine-containing substance, and the crude silicon tetrafluoride gas obtained by the reaction passes through the gas outlet pipe and enters a subsequent cold trap to collect and prepare silicon tetrafluoride.

[0064] A kind of purif...

Embodiment 1

[0071] (1) 200g of dried AgF 2 As a catalyst, put it into the reaction chamber of the dry silicon tetrafluoride preparation device, add 200g of dry silicon-containing substance Si, and supply the dry fluorine-containing substance F to the reaction chamber through the air inlet pipe of the preparation device 2 Start the reaction, the fluorine-silicon ratio is 40:1, the reaction temperature in the reaction chamber is 51°C, and the reaction pressure is -0.05MPa; the reaction product is derived from the gas outlet of the preparation device, passed into a low-temperature cold trap at -110°C, and collected prepared gas;

[0072] Detecting the prepared gas shows that the prepared gas is crude silicon tetrafluoride to be purified, with a purity of 60% and a yield of 21%.

[0073] (2) Pass the crude silicon tetrafluoride to be purified into the silicon tetrafluoride purification device, and react with the purification reaction substance fluoride NH 4 F reaction preparation obtains cr...

Embodiment 2

[0076] (1) No catalyst is used, and the fluorine-containing substance is COF 2 , the ratio of fluorine to silicon is 0.025:1, and the dilution medium is N 2 , temperature of reaction is 499 ℃, reaction pressure is 0.5MPa, all the other are with embodiment 1 step (1);

[0077] Detecting the prepared gas shows that the prepared gas is crude silicon tetrafluoride to be purified, with a purity of 98% and a yield of 97%.

[0078] (2) Pass the crude silicon tetrafluoride to be purified into the silicon tetrafluoride purification device, and react with the reaction substance hydrofluoride NaHF for purification 2 The reaction prepares crude product hydrofluorosilicate as crude product NaHSiF 6 , the crude NaHSiF 6 Filter through filter paper to remove dust and other impurities, recrystallize in water, then vacuumize to -0.09MPa and heat to 50°C to dry, and the purified hydrofluorosilicate is NaHSiF 6 , and then carry out heating pretreatment in the purification device, the heating...

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Abstract

The invention relates to preparation and purification methods of silicon tetrafluoride and belongs to the field of fluorine chemical engineering and electronic industry gas. The preparation method comprises the step as follows: a silicon-containing substance and a fluorine-containing substance are mixed to react to produce silicon tetrafluoride. The purification method comprises steps as follows: the to-be-purified coarse product, namely, silicon tetrafluoride, and a reactive material for purification react to produce coarse product Mm(SiF6)p or Mn(HSiF6)q, then thermal decomposition is performed, and purified silicon tetrafluoride is obtained. With the adoption of the preparation method, no acid or corrosive liquid substances are used, the silicon-containing substance and the fluorine-containing substance, particularly a gaseous fluorine-containing substance, react to produce silicon tetrafluoride, fewer impurities are introduced, the purity of the product silicon tetrafluoride is higher, the preparation method has the advantages of high safety, simplicity in operation, high yield, economy and the like, fewer waste acid and residues can be produced, and environmental pollution is lower; with the adoption of the purification method, high-purity silicon tetrafluoride gas can be obtained, and the content of impurity (SiF3)2O and HF is extremely low.

Description

technical field [0001] The invention relates to a method for preparing and purifying silicon tetrafluoride, belonging to the fields of fluorine chemical industry and electronic industry gas. Background technique [0002] Silicon tetrafluoride (SiF 4 ) is mainly used in the electronics and semiconductor industries as etchant for silicon nitride, tantalum silicide, etc., P-type dopant, epitaxial deposition diffusion silicon source, etc., and can also be used to prepare electronic grade silane or silicon. Silicon tetrafluoride can also be used as a raw material for high-purity quartz glass for optical fibers. It can be hydrolyzed in a high-temperature flame to produce a heat sink SiO with a high specific surface area. 2 . In addition, silicon tetrafluoride is also widely used in the preparation of solar cells, fluorosilicic acid and aluminum fluoride, chemical analysis, fluorinating agents, oil well drilling, magnesium alloy casting, catalysts, fumigants, hardeners for cement...

Claims

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Application Information

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IPC IPC(8): C01B33/107
CPCC01B33/10705C01B33/10778
Inventor 蒋玉贵李翔宇孟祥军张净普胡帅朱文冬张长金
Owner 718TH RES INST OF CHINA SHIPBUILDING INDAL CORP
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