阅读说明：本技术 一种高纯砷工艺尾气回收循环利用的工艺及尾气回收系统 (Process for recycling high-purity arsenic process tail gas and tail gas recycling system ) 是由 曲胜利 张俊峰 邹琳 李辉 于守贵 周君祺 修振东 于丕永 曲振强 曲兴启 孙净 于 2021-01-27 设计创作，主要内容包括：本发明提供了一种回收再利用高纯砷工艺尾气的工艺,将高纯砷生产中所产生的尾气经过滤、水洗、喷淋、干燥、增压,将氯化氢和氢气回收并用于生产高纯砷。本发明还提供了一种尾气回收系统,前述的回收再利用高纯砷工艺尾气的工艺,通过尾气回收系统实现,这样能回收利用废气、节省成本、降低排放。(The invention provides a process for recycling high-purity arsenic process tail gas, which is characterized in that tail gas generated in the production of high-purity arsenic is filtered, washed, sprayed, dried and pressurized, and hydrogen chloride and hydrogen are recycled and used for producing the high-purity arsenic. The invention also provides a tail gas recovery system, and the process for recovering and recycling the high-purity arsenic process tail gas is realized through the tail gas recovery system, so that the waste gas can be recovered and utilized, the cost is saved, and the emission is reduced.)

1. A process for recycling high-purity arsenic process tail gas is characterized by comprising the following steps:

a. filtering process tail gas generated by preparing high-purity arsenic to remove dust to obtain dust-free gas;

b. introducing dust-free gas into pure water for washing, wherein the temperature of the pure water for washing is 30-50 ℃, and hydrogen which is insoluble in water and hydrogen chloride which cannot be dissolved in water due to saturation are discharged from the pure water to obtain washing gas;

c. spraying the water scrubbing gas by pure water, wherein the temperature of the pure water for spraying is 0-20 ℃, fully dissolving hydrogen chloride in the gas into concentrated hydrochloric acid, and simultaneously generating water-containing hydrogen;

d. drying the water-containing hydrogen to absorb moisture in the gas to obtain dry hydrogen;

e. pressurizing the dry hydrogen with the pressure of 0.3-0.5 Mpa to obtain pressurized hydrogen;

f. the obtained concentrated hydrochloric acid and pressurized hydrogen are used for preparing high-purity arsenic.

2. The process for recycling and reusing the tail gas of the high-purity arsenic process according to claim 1, which is characterized in that: the temperature of pure water for water washing is 35-45 ℃.

3. The process for recycling and reusing the tail gas of the high-purity arsenic process according to claim 1, which is characterized in that: the temperature of pure water for spraying is 5-10 ℃.

4. The process for recycling and reusing the tail gas of the high-purity arsenic process according to claim 1, which is characterized in that: the pressure of hydrogen is 0.35-0.4 MPa.

5. A tail gas recovery system for implementing a process for the recovery and recycle of a high purity arsenic process tail gas according to any one of claims 1 to 4, wherein the tail gas recovery system comprises:

a. the tail gas filtering device (100), the tail gas filtering device (100) receives tail gas generated by hydrogen reduction, and solid particles in the tail gas are filtered to obtain dust-free tail gas;

b. the washing device (200) is connected with the tail gas filtering device (100), and the washing device (200) receives the dust-free tail gas output by the tail gas filtering device (100) and washes the dust-free tail gas to further purify the tail gas to obtain washing gas;

c. the spraying device (300) is connected with the water washing device (200), and the spraying device (300) receives the water washing gas output by the water washing device (200), performs multi-stage circulating spraying on the water washing gas, absorbs hydrogen chloride to prepare concentrated hydrochloric acid with the maximum concentration and obtains hydrogen containing water;

d. the drying device (400) is connected with the spraying device (300), and the drying device (400) receives the hydrous hydrogen output by the spraying device (300), dries the hydrogen and absorbs moisture to obtain dry hydrogen;

e. and the pressurizing device (500) is connected with the drying device (400), and the pressurizing device (500) receives the dry hydrogen output by the drying device (400) and compresses and pressurizes the dry hydrogen to obtain pressurized hydrogen.

Technical Field

The invention relates to the field of high-purity arsenic preparation, in particular to a process for recycling tail gas in a high-purity arsenic process and a tail gas recycling system.

Background

High-purity arsenic is high-purity arsenic having a purity of not less than 99.9999% (6N), and is used in the advanced fields of semiconductors, national defense and military industry, aerospace, and the like because of its excellent electrical properties.

The liquid phase-chlorination reduction method is a method for preparing high-purity arsenic, and the method comprises the following steps: sublimating the crude white arsenic (namely arsenic trioxide with the purity of about 99 percent) to prepare refined white arsenic; and dissolving the refined white arsenic in concentrated hydrochloric acid to generate arsenic trichloride, wherein the chemical equation (1) of the reaction is as follows: as₂O₃+6HCl=2AsCl₃+3H₂O; the purity of the generated arsenic trichloride can reach 6N and 7N after dechlorination and rectification, the arsenic trichloride is reduced into 6N and 7N simple substance arsenic by using hydrogen as a reducing agent, and a chemical equation (2) is as follows: 2AsCl₃+3H₂ 2As +6H ≈ ≈ 2As +6H ≈ 6H. The tail gas mainly comprises two parts: the first is the hydrogen chloride produced by formula (2) and the second is excess hydrogen. Usually, the tail gas is introduced into alkali liquor for neutralization to treat hydrogen chloride, and then the waste liquid is discharged, so that a large amount of cost is spent on treating the tail gas, and a larger amount of cost is broughtAnd (5) environmental protection pressure. After the hydrogen chloride is neutralized, the residual hydrogen is usually directly discharged to the atmosphere, and the discharged hydrogen amount is quite large due to the fact that the hydrogen is excessive by 0.8-1 time in the high-purity arsenic production process, and the potential safety hazard is caused. At present, no relevant patent or paper report of tail gas recycling is seen in the field of high-purity arsenic preparation. Furthermore, as can be seen from the formulas (1) and (2), hydrogen chloride (which is dissolved in water to form concentrated hydrochloric acid) and hydrogen are used as raw materials for producing high-purity arsenic, and if the raw materials cannot be recycled, the raw materials are wasted, and the manufacturing cost of the high-purity arsenic is increased. Therefore, it is necessary to invent a process for recycling hydrogen chloride in the tail gas at a low cost, which can not only reduce the manufacturing cost and the tail gas treatment cost of high-purity arsenic, but also greatly reduce the emission, and is environment-friendly.

Disclosure of Invention

The invention provides a process for recycling high-purity arsenic process tail gas, which aims to solve the problems, and the process is based on the preparation of high-purity arsenic by a liquid-phase chlorination-reduction method, and the process tail gas is recycled and purified through a series of steps to generate hydrochloric acid and hydrogen meeting the requirements for preparing the high-purity arsenic.

The technical scheme of the invention is realized as follows:

a process for recycling high-purity arsenic process tail gas comprises the following steps:

a. filtering process tail gas generated by preparing high-purity arsenic to remove dust to obtain dust-free gas;

b. introducing dust-free gas into pure water for washing, wherein the temperature of the pure water for washing is 30-50 ℃, and hydrogen which is insoluble in water and hydrogen chloride which cannot be dissolved in water due to saturation are discharged from the pure water to obtain washing gas;

c. spraying the water scrubbing gas by pure water, wherein the temperature of the pure water for spraying is 0-20 ℃, fully dissolving hydrogen chloride in the gas into concentrated hydrochloric acid, and simultaneously generating water-containing hydrogen;

d. drying the water-containing hydrogen to absorb moisture in the gas to obtain dry hydrogen;

e. pressurizing the dry hydrogen with the pressure of 0.3-0.5 Mpa to obtain pressurized hydrogen;

f. the obtained concentrated hydrochloric acid and pressurized hydrogen are used for preparing high-purity arsenic.

Preferably, the temperature of pure water for washing is 35-45 ℃;

preferably, the temperature of pure water used for spraying is between 5 ℃ and 10 ℃.

Preferably, the hydrogen pressurization pressure is 0.35MPa to 0.4 MPa.

A tail gas recovery system is used for implementing a process for recovering and recycling tail gas of a high-purity arsenic process, and comprises:

a. the tail gas filtering device receives tail gas generated by hydrogen reduction and filters solid particles in the tail gas to obtain dust-free tail gas;

b. the washing device is connected with the tail gas filtering device and is used for receiving the dust-free tail gas output by the tail gas filtering device and washing the dust-free tail gas to further purify the tail gas to obtain washing gas;

c. the spraying device is connected with the water washing device, receives the water washing gas output by the water washing device, performs multi-stage circulating spraying on the water washing gas, absorbs hydrogen chloride to prepare concentrated hydrochloric acid with the maximum concentration, and obtains hydrogen containing water;

d. the drying device is connected with the spraying device, receives the hydrous hydrogen output by the spraying device, and dries and absorbs the hydrogen to obtain dry hydrogen;

e. and the supercharging device is connected with the drying device, receives the dry hydrogen output by the drying device, and performs volume compression and supercharging on the dry hydrogen to obtain the supercharged hydrogen.

The invention has the beneficial effects that: the invention saves the cost while completely reducing the gas emission and greatly reducing the liquid emission, and the recycling rate of the hydrogen chloride can reach 90 percent and the recycling rate of the hydrogen can reach 99 percent. The whole process is simple and clear, the cost is saved, and the emission is greatly reduced.

Drawings

FIG. 1 is a process flow diagram of the recycling of the tail gas of the high-purity arsenic process;

FIG. 2 is a schematic flow diagram of a seed tail gas recovery system.

In the figure: 100-dust filtration means; 200-a water washing device; 300-a spraying device; 400-a drying device; 500-a supercharging device.

Detailed Description

The technical solutions of the present invention will be described below with reference to examples, and it should be noted that the examples are only intended to illustrate the present invention, and not to limit the scope of the present invention. The examples are not provided with specific conditions, and should be regarded as conventional technical advances. The reagents or instruments used are not specified by the manufacturer, and are all conventional products which are easily bought on the market.

The following is a specific description of the present invention:

the invention aims to enable the recovered concentrated hydrochloric acid and hydrogen to be used for producing high-purity arsenic by the process for recovering and recycling the high-purity arsenic process tail gas.

The process for recycling the tail gas of the high-purity arsenic process can obtain concentrated hydrochloric acid and hydrogen with higher purity.

The process for recycling the tail gas of the high-purity arsenic process comprises the following steps;

a. filtering dust in the process tail gas to obtain dust-free gas;

b. introducing dust-free gas into pure water for washing, wherein the temperature of the pure water for washing is 35 ℃, and the dust-free gas is washed to obtain washing gas;

c. spraying the water scrubbing gas with pure water, wherein the temperature of the pure water for spraying is 10 ℃, the hydrogen chloride in the gas is fully dissolved into concentrated hydrochloric acid, and the water-containing hydrogen is generated;

d. drying the water-containing hydrogen to absorb moisture in the gas to obtain dry hydrogen;

e. pressurizing the dry gas with the pressure of 0.4Mpa to obtain pressurized hydrogen;

f. the obtained concentrated hydrochloric acid and hydrogen are reused for preparing high-purity arsenic.

In the above steps, the process tail gas refers to tail gas generated in a hydrogen reduction process in the process of preparing high-purity arsenic. The main components of the process tail gas are hydrogen and hydrogen chloride, and because the hydrogen is excessive in the high-purity arsenic production process, 1 part of hydrogen is introduced according to the formula (2) to generate two parts of hydrogen chloride, and the ratio of the hydrogen to the hydrogen chloride in the process tail gas is usually between 1.5:1 and 4: 1; in addition, the process tail gas also contains part of arsenic ash and a very small amount of elemental particles such as sulfur, silicon and the like.

As the diameter of the solid particles is far larger than that of the gas particles, the dust filter can be used for filtering simple substance particles such as arsenic ash, sulfur, silicon and the like in the process tail gas.

The tail gas is introduced into pure water, hydrogen floats out of the water because the hydrogen is hardly dissolved in the water, hydrogen chloride remains in the water because the hydrogen chloride is very soluble in the water to become hydrochloric acid, and the hydrogen chloride does not dissolve in the water any more and floats out of the water along with the saturation of the hydrochloric acid. The solid particles are insoluble in water and float or sink in water, and cannot float out of the water surface along with the gas, so that the dust-free gas is washed by water, and the content of impurities in the gas can be reduced to ppm level.

In order to fully dissolve the hydrogen chloride in the gas by water, the gas is introduced into a spray tower, the hydrogen chloride is dissolved in water to form hydrochloric acid, and the hydrogen is not dissolved in water to form hydrous hydrogen. The hydrochloric acid concentration reaches the maximum value as far as possible by adopting a multi-stage circulating spraying mode.

The water-containing hydrogen is dried and purified by using the technologies such as molecular sieve and the like to obtain high-purity hydrogen, and the high-purity hydrogen is pressurized to obtain pressurized hydrogen meeting the production requirement of high-purity arsenic.

Based on the process for recycling the high-purity arsenic process tail gas, the invention also provides a tail gas recycling system, and the process for recycling the high-purity arsenic process tail gas is realized through the tail gas recycling system.

Referring to fig. 2, the tail gas recycling system includes a dust filtering device 100, a water washing device 200, a spraying device 300, a drying device 400, and a pressurizing device 500. The connection relationship and functions of the respective devices can be defined by the following description.

a. A tail gas filtering device 100 configured to receive a process tail gas from hydrogen reduction and filter solid particles in the process tail gas to obtain a dust-free tail gas;

b. the water washing device 200 is connected to the tail gas filtering device 100, and the water washing device 200 receives the dust-free tail gas output from the tail gas filtering device 100 and washes the dust-free tail gas to further purify the tail gas to obtain a water washing gas.

c. The spraying device 300 is connected with the water washing device 200, and the spraying device 300 receives the water washing gas output by the water washing device 200, performs multi-stage circulating spraying on the water washing gas, absorbs the hydrogen chloride to prepare concentrated hydrochloric acid with the maximum concentration, and simultaneously forms the hydrogen containing water.

d. The drying device 400 is connected with the spraying device 300, and the drying device 400 receives the hydrogen containing water output by the spraying device 300, and dries and absorbs the hydrogen to obtain dry hydrogen.

e. The pressurizing device 500 is connected to the drying device 400, and receives the dry hydrogen output from the drying device, and compresses and pressurizes the dry hydrogen to obtain pressurized hydrogen.

The tail gas recovery system of the invention is operated under the above conditions, and the obtained concentrated hydrochloric acid and pressurized hydrogen are both used for preparing high-purity arsenic.

As described above, according to the present invention, when concentrated hydrochloric acid and hydrogen gas are produced from the recovery process off-gas and recycled, it is possible to minimize the energy to be supplied to the off-gas recovery system and the hydrogen chloride discharged to the outside of the system.

Although the present invention has been described with reference to specific embodiments, those skilled in the art will appreciate that any additions, subtractions or modifications are within the scope of the present invention without departing from the spirit thereof.