阅读说明：本技术 一种六氟化钨废液的综合利用方法 (Comprehensive utilization method of tungsten hexafluoride waste liquid ) 是由 朱姜涛 范娜 彭立培 张雷 苏子杰 吕随强 于 2021-08-17 设计创作，主要内容包括：本发明提供了一种六氟化钨废液的综合利用方法,包括以下步骤：S1、向电解槽中加入废液和导电剂,形成电解液；S2、在温度为-15℃～25℃,电压为6V～8.5V的条件下,阳极得到氟气,阴极得到金属钨；S3、电解得到的氟气与金属钨反应可以得到六氟化钨产品。本发明提供的电化学方法,能安全有效的将六氟化钨废液进行无害化处理,操作简便、成本低、适宜进行规模化应用。(The invention provides a comprehensive utilization method of tungsten hexafluoride waste liquid, which comprises the following steps: s1, adding waste liquid and a conductive agent into the electrolytic cell to form electrolyte; s2, obtaining fluorine gas at the anode and metal tungsten at the cathode under the conditions that the temperature is-15-25 ℃ and the voltage is 6-8.5V; s3, reacting the fluorine gas obtained by electrolysis with metallic tungsten to obtain a tungsten hexafluoride product. The electrochemical method provided by the invention can safely and effectively carry out harmless treatment on the tungsten hexafluoride waste liquid, is simple and convenient to operate, has low cost and is suitable for large-scale application.)

1. A comprehensive utilization method of tungsten hexafluoride waste liquid is characterized by comprising the following steps:

s1, adding tungsten hexafluoride waste liquid and a conductive agent into an electrolytic cell to form electrolyte, wherein the tungsten hexafluoride waste liquid contains tungsten hexafluoride and hydrogen fluoride;

s2, carrying out an electrolytic reaction on the electrolyte in the electrolytic cell at the temperature of-15-25 ℃ and the voltage of 6-8.5V, carrying out an anodic electrolytic reaction in the electrolytic cell to obtain fluorine gas, and carrying out a cathodic electrolytic reaction to obtain metal tungsten;

s3, reacting the fluorine gas generated in the S2 with metal tungsten to prepare a tungsten hexafluoride product.

2. The method for comprehensively utilizing tungsten hexafluoride waste liquid according to claim 1, wherein the anode is made of nickel, nickel alloy or carbon, and the cathode is made of nickel, nickel alloy, tungsten or carbon steel.

3. The method for comprehensively utilizing tungsten hexafluoride waste liquid according to claim 1, wherein the tungsten hexafluoride waste liquid contains tungsten hexafluoride and hydrogen fluoride, and the mass ratio of tungsten hexafluoride in the tungsten hexafluoride waste liquid is 30-45%, and the balance is hydrogen fluoride.

4. The method for comprehensively utilizing tungsten hexafluoride waste liquid according to claim 1, wherein the mass ratio of the tungsten hexafluoride waste liquid in the electrolyte is 90-97%, and the mass ratio of the conductive agent is 3-10%.

5. The method for comprehensively utilizing tungsten hexafluoride waste liquid according to claim 1, wherein the conductive agent is one or more of lithium fluoride, potassium fluoride and potassium bifluoride.

6. The comprehensive utilization method of tungsten hexafluoride waste liquid according to claim 1, wherein the electrolysis temperature in S2 is-5 ℃ to 10 ℃, and the voltage is 6.5V to 8V.

7. The method of comprehensively utilizing tungsten hexafluoride waste liquid according to claim 1, wherein the reaction temperature of the fluorine gas and the metallic tungsten in S3 is 250 to 450 ℃.

Technical Field

The invention belongs to the field of harmless treatment of tungsten-containing substance hazardous waste, and particularly relates to a comprehensive utilization method of tungsten hexafluoride waste liquid.

Background

The tungsten hexafluoride gas is mainly applied to integrated circuits, chip manufacturing and preparation of high-purity tungsten products. The preparation of ultra-high purity tungsten products (with purity as high as 99.99999%) mainly adopts chemical vapor deposition process, uses tungsten hexafluoride as raw material, and makes it react with hydrogen gas at high temperature to produce hydrogen fluoride and tungsten products. The hydrogen fluoride after the reaction contains a large amount of unreacted tungsten hexafluoride with the content of 30-45 percent, and the tungsten hexafluoride cannot be treated as waste liquid.

The components in the waste liquid are hydrogen fluoride and tungsten hexafluoride, and the hydrogen fluoride and the tungsten hexafluoride are close in boiling point and cannot be separated by adopting a rectification mode; the content of hydrogen fluoride in the waste liquid is high and reaches more than 50 percent, and the adsorption method cannot be separated; the generated waste liquid can not be recycled for the second time, and the equipment can be seriously corroded at high temperature. There is currently no relevant technology for treating such waste streams.

Disclosure of Invention

The invention aims to solve the technical problem of providing a comprehensive utilization method of tungsten hexafluoride waste liquid aiming at the defects of the prior art, the method is scientific and reasonable, the recovery and the cyclic utilization of tungsten metal resources are realized, and the production cost of high-purity tungsten products is obviously reduced.

In order to solve the technical problems, the invention adopts the technical scheme that: a comprehensive utilization method of tungsten hexafluoride waste liquid is characterized by comprising the following steps:

s1, adding waste liquid containing tungsten hexafluoride and a conductive agent into an electrolytic cell to form electrolyte, wherein the waste liquid containing tungsten hexafluoride contains tungsten hexafluoride and hydrogen fluoride;

s2, obtaining fluorine gas at the anode and metal tungsten at the cathode under the conditions that the temperature is-15-25 ℃ and the voltage is 6-8.5V;

s3, reacting the fluorine gas generated in the S2 with metal tungsten to prepare a tungsten hexafluoride product.

Preferably, the material of the anode is nickel or nickel alloy or carbon, and the material of the cathode is nickel or nickel alloy or tungsten or carbon steel.

Preferably, the tungsten hexafluoride waste liquid contains tungsten hexafluoride and hydrogen fluoride, the mass ratio of tungsten hexafluoride in the tungsten hexafluoride waste liquid is 30-45%, and the rest is hydrogen fluoride. The mass percentage of the tungsten hexafluoride waste liquid in the electrolyte is 90-97%, and the mass percentage of the conductive agent is 3-10%.

Preferably, the conductive agent is one or more of lithium fluoride, potassium fluoride and potassium bifluoride.

Preferably, the electrolysis temperature in S2 is preferably-5 ℃ to 10 ℃, and the voltage is preferably 6.5V to 8V.

Preferably, the reaction temperature of the fluorine gas and the metallic tungsten in S3 is 250 to 450 ℃.

Compared with the prior art, the invention has the following advantages:

1. the main principle of the invention is as follows: the tungsten hexafluoride waste liquid mainly contains hydrogen fluoride and tungsten hexafluoride; firstly, adding a conductive agent into the waste liquid to form a conductive electrolyte; then carrying out electrochemical reaction at constant pressure at a set temperature, generating fluorine gas at an anode and generating metal tungsten at a cathode; if the temperature is too high, the hydrogen fluoride is seriously volatilized, and the anode is corroded due to too high voltage; lower temperatures and voltages result in lower reaction rates. The generated fluorine gas and metal tungsten react at a certain temperature to generate tungsten hexafluoride gas. The method can reuse resources, does not generate new three wastes, is simple to operate, has high safety and is easy for industrial application.

2. The invention realizes the recovery of tungsten metal resources and fluorine element, only needs to add the conductive agent, and carries out the recovery and utilization under the action of electric energy, so that no new impurity is introduced in the process of tungsten hexafluoride waste liquid, the generation of new three wastes is avoided, and the invention has higher environmental protection benefit.

3. In the electrolytic reaction, the conductive agent is added, and the suitable conductive agent can reduce the voltage value required by electrolysis and the electrolytic reaction temperature, thereby reducing the energy consumption cost of the electrolytic reaction; and the volatilization of the hydrogen fluoride is less at a lower electrolysis reaction temperature, so that the loss of materials is reduced.

4. The fluorine gas and the tungsten prepared in the electrochemical mode can continuously react to generate the tungsten hexafluoride, and the tungsten hexafluoride can be used as a raw material of a high-purity tungsten product, so that the cyclic utilization of the tungsten and the fluorine is realized, and the production cost is obviously reduced.

The present invention will be described in further detail with reference to examples.

Detailed Description

Example 1

The embodiment comprises the following steps:

s1, adding 0.9kg of tungsten hexafluoride waste liquid and 0.10kg of potassium fluoride into an electrolytic cell to form a conductive electrolyte, wherein the anode material adopted by electrolysis is nickel, the cathode material is carbon steel, and the tungsten hexafluoride waste liquid mainly comprises 0.3g of tungsten hexafluoride and 0.6g of hydrogen fluoride;

s2, carrying out electrolysis under the conditions that the temperature is-5 ℃ and the voltage is 6.5V to carry out electrochemical fluorination reaction, obtaining fluorine gas at the anode and 0.15g of metal tungsten at the cathode;

s3, reacting the generated fluorine gas with metal tungsten at 350 ℃ to obtain tungsten hexafluoride gas, wherein the conversion rate can reach 95%.

Example 2

The embodiment comprises the following steps:

s1, adding 0.97kg of tungsten hexafluoride waste liquid and 0.03kg of potassium bifluoride into an electrolytic cell to form a conductive electrolyte, wherein the anode material adopted by electrolysis is carbon, the cathode material is nickel, and the tungsten hexafluoride waste liquid mainly comprises 0.43g of tungsten hexafluoride and 0.5g of hydrogen fluoride;

s2, carrying out electrolysis under the conditions that the temperature is 25 ℃ and the voltage is 7.5V to carry out electrochemical fluorination reaction, obtaining fluorine gas at the anode and 0.22g of metal tungsten at the cathode;

s3, reacting the generated fluorine gas with metal tungsten at 450 ℃ to obtain tungsten hexafluoride gas, wherein the conversion rate can reach 97%.

Example 3

The embodiment comprises the following steps:

s1, adding 0.95kg of tungsten hexafluoride waste liquid and 0.05kg of lithium fluoride into an electrolytic cell to form a conductive electrolyte, wherein the anode material adopted by electrolysis is nickel alloy, the cathode material is nickel alloy, and the tungsten hexafluoride waste liquid mainly comprises 0.4g of tungsten hexafluoride and 0.55g of hydrogen fluoride;

s2, carrying out electrolysis under the conditions that the temperature is-15 ℃ and the voltage is 8.5V to carry out electrochemical fluorination reaction, obtaining fluorine gas at the anode and 0.19g of metal tungsten at the cathode;

s3, reacting the generated fluorine gas with metal tungsten at 250 ℃ to obtain tungsten hexafluoride gas, wherein the conversion rate can reach 93%.

The effects of the three examples are compared as follows:

	tungsten product/g	Tungsten hexafluoride conversion/%)
			Example 1	0.15	95
Example 2	0.22	97
			Example 3	0.19	93

In conclusion, the method for utilizing the tungsten hexafluoride waste liquid can convert and utilize the tungsten hexafluoride in the waste liquid for the second time with extremely high conversion rate, obviously improves the recovery rate of the tungsten hexafluoride waste liquid, reduces the production cost of high-purity tungsten products, and has obvious environmental protection value and economic value.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention in any way. Any simple modification, change and equivalent changes of the above embodiments according to the technical essence of the invention are still within the protection scope of the technical solution of the invention.