Method for producing high-purity tungsten hexafluoride with fluidized bed and equipment thereof

Abstract

The invention discloses a method for preparing high-purity tungsten hexafluoride by a fluidized bed, and a device thereof. The method comprises the following steps: leading fluorine gas into a pre-heater and pre-heating to the temperature of 50 to 200 DEG C; allowing the pre-heated gas to enter a fluidized bed reactor, wherein, the temperature inside the fluidized bed is 200 to 400 DEG C, and the pressure is 0.1 to 0.5 MPa; continuously adding metered tungsten powder to the middle part of the reactor; allowing crude tungsten hexafluoride product obtained at the upper part of the reactor to enter a freezing collector, wherein, the freezing temperature is minus 35 to 0 DEG C; vacuumizing the top part of the collector so as to remove non-condensable gas impurity; and liquefying the obtained tungsten hexafluoride solid and allowing the tungsten hexafluoride solid to enter a rectifying tower so as to remove the heavy-component impurity, wherein, the purity of the prepared tungsten hexafluoride gas is as high as above 99.99%. The technique can realize automatic temperature control and automatic material feeding of the reactor; the operation is easy to control, safe and reliable; and filter pipes are internally arranged in the reactor which is equipped with a nitrogen backflow device, thereby preventing the product from carrying the tungsten powder.

Description

technical field [0001] The invention relates to a preparation process of high-purity tungsten hexafluoride, in particular to a method for synthesizing tungsten hexafluoride with a fluidized bed reactor. Background technique [0002] Tungsten hexafluoride (WF 6 ) is mainly used in the electronics industry and is the raw material for metal tungsten chemical vapor deposition (CVD) process, especially WSi made of it 2 Can be used as wiring material in large scale integration (LSI). The composite coating of tungsten and rhenium is prepared by the CVD process of mixed metals, which can be used for X-ray emitting electrodes. In addition, WF 6 In the electronics industry, it is also mainly used as a raw material for semiconductor electrodes and conductive pastes. WF 6 There are also many non-electronic applications. For example, tungsten can generate hard tungsten carbide on the surface of steel by CVD technology, which can be used to improve the surface properties of steel. I...

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Problems solved by technology

[0003] Fixed bed reactors are commonly used in industry to make metal tungsten and fluorine gas or NF 3 Direct reaction method to prepare WF 6 , in actual operation, the product is easy to entrain tungsten powder, it is difficult to carry out continuous production and the efficiency of the reactor is low

[0004] What JP 119024 discloses is exactly to make metal tungsten and high-purity NF with fixed bed reactor 3 Reaction to prepare WF 6 method, NF 3 The moisture content in the medium has a direct impact on the product purity, and the reactor efficiency is low

[0005] US 4960581 discloses a preparation method. First, tungsten powder and a certain high-melting point solid fluoride are pressurized and kneaded to form a mold with a certain strength. After deoxidation and dehydration, WF is synthesized by passing fluorine gas under heating conditions. 6 , this method can avoid the entrainment of tungsten powder in the product, but the reaction rate is slow and the reactor efficiency is low

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