阅读说明：本技术 超纯硫酸中二氧化硫的去除方法 (Method for removing sulfur dioxide in ultrapure sulfuric acid ) 是由 曹传兴 阮汝明 于 2020-12-18 设计创作，主要内容包括：本发明公开了一种超纯硫酸中二氧化硫的去除方法,以过氧化氢的硫酸溶液作为氧化剂,在密闭容器中氧化超纯硫酸中的二氧化硫,使超纯硫酸中二氧化硫的含量低于5ppm。本发明一种超纯硫酸中二氧化硫的去除方法,以双氧水或过氧化氢的硫酸溶液作为氧化剂,直接把超纯硫酸中的二氧化硫氧化成三氧化硫或硫酸,不产生工业废水,清洁环保,操作过程简单、可靠,大大节约生产成本,适合工业化生产。(The invention discloses a method for removing sulfur dioxide in ultrapure sulfuric acid, which takes a sulfuric acid solution of hydrogen peroxide as an oxidizing agent to oxidize the sulfur dioxide in the ultrapure sulfuric acid in a closed container, so that the content of the sulfur dioxide in the ultrapure sulfuric acid is lower than 5 ppm. The method for removing sulfur dioxide in the ultrapure sulfuric acid takes the sulfuric acid solution of hydrogen peroxide or hydrogen peroxide as an oxidant, directly oxidizes the sulfur dioxide in the ultrapure sulfuric acid into sulfur trioxide or sulfuric acid, does not generate industrial wastewater, is clean and environment-friendly, has a simple and reliable operation process, greatly saves the production cost, and is suitable for industrial production.)

1. A method for removing sulfur dioxide in ultrapure sulfuric acid is characterized in that a sulfuric acid solution of hydrogen peroxide is used as an oxidizing agent, and the sulfur dioxide in the ultrapure sulfuric acid is oxidized in a closed container, so that the content of the sulfur dioxide in the ultrapure sulfuric acid is lower than 5 ppm.

2. The method for removing sulfur dioxide in ultrapure sulfuric acid according to claim 1, wherein the mass concentration of hydrogen peroxide in the sulfuric acid solution of hydrogen peroxide is 5-10%.

3. The method for removing sulfur dioxide from ultrapure sulfuric acid according to claim 2, wherein said hydrogen peroxide sulfuric acid solution is prepared by the method comprising: adding the ultrapure hydrogen peroxide solution into ultrapure concentrated sulfuric acid to prepare the catalyst.

4. The method for removing sulfur dioxide in ultrapure sulfuric acid according to claim 3, wherein the mass concentration of the ultrapure hydrogen peroxide solution is 30-50%.

5. The method for removing sulfur dioxide in ultrapure sulfuric acid according to claim 3, wherein the mass concentration of the ultrapure concentrated sulfuric acid is 60-80%.

6. The method of claim 1, wherein the oxidation is carried out under the process conditions of: the temperature is 10-50 ℃, and the mixture is stirred and mixed for 20-40 min.

7. The method for removing sulfur dioxide in ultrapure sulfuric acid according to claim 6, wherein the time of stirring and mixing is 20-30 min.

8. The method of claim 7, wherein the stirring and mixing method is stirrer stirring or circulating pump circulation.

Technical Field

The invention relates to the technical field of preparation of ultrapure chemicals, in particular to a method for removing sulfur dioxide in ultrapure sulfuric acid.

Background

The electronics industry is increasingly controlling various impurities, particularly harmful impurities, in chemical reagents. The ultra-pure sulfuric acid is one of eight common ultra-pure chemical materials in the semiconductor industry, is one of essential key chemical reagents in the development process of microelectronic technology, is widely applied to the assembly and processing processes of semiconductors and ultra-large scale integrated circuits, is mainly used for diffusion, corrosion, cleaning and other processes of silicon wafers, and can effectively remove impurity particles, inorganic residues and carbon deposits on the wafers. The purity and cleanliness of electronic-grade sulfuric acid have important influences on the yield, electrical properties and reliability of electronic components.

For ultra-pure sulfuric acid, the sulfur dioxide content therein determines the grade of the ultra-pure sulfuric acid. Generally, the sulfur dioxide content in the ultra-pure sulfuric acid is required to be controlled within a range of 1-5 ppm to meet the use requirement, but the use requirement is difficult to achieve in practice.

In the prior art, the method for controlling the content of sulfur dioxide in ultrapure sulfuric acid is mostly realized by vaporizing sulfur trioxide in the preparation process of the ultrapure sulfuric acid, absorbing the vaporized sulfur trioxide by a multi-stage absorption tower and stripping tower gas, and the process has the following defects: 1. the operation process is complex, the used equipment is more, the equipment investment is large, and the energy consumption is high; 2. after multi-stage absorption and steam stripping, the removed sulfur dioxide forms process wastewater, which pollutes the environment and has high treatment cost. In addition, for the simple removal of trace sulfur dioxide (the content is usually 50-100 ppm) in ultrapure sulfuric acid, no effective removal means is available at present.

Disclosure of Invention

The invention mainly solves the technical problem of providing the method for removing the sulfur dioxide in the ultrapure sulfuric acid, can directly oxidize the sulfur dioxide in the ultrapure sulfuric acid, is energy-saving and environment-friendly, and solves the defects of the existing treatment process.

In order to solve the technical problems, the invention adopts a technical scheme that: a method for removing sulfur dioxide in ultrapure sulfuric acid is provided, wherein a sulfuric acid solution of hydrogen peroxide is used as an oxidizing agent, and the sulfur dioxide in the ultrapure sulfuric acid is oxidized in a closed container, so that the content of the sulfur dioxide in the ultrapure sulfuric acid is lower than 5 ppm.

In a preferred embodiment of the present invention, the hydrogen peroxide solution in sulfuric acid has a mass concentration of 5-10%.

In a preferred embodiment of the present invention, the preparation method of the sulfuric acid solution of hydrogen peroxide comprises: adding the ultrapure hydrogen peroxide solution into ultrapure concentrated sulfuric acid to prepare the catalyst.

In a preferred embodiment of the present invention, the mass concentration of the ultrapure hydrogen peroxide solution is 30 to 50%.

In a preferred embodiment of the present invention, the mass concentration of the ultrapure concentrated sulfuric acid is: 60-80%.

In a preferred embodiment of the present invention, the oxidation process conditions are as follows: the temperature is 10-50 ℃, and the mixture is stirred and mixed for 20-40 min.

In a preferred embodiment of the present invention, the time for stirring and mixing is 20 to 30 min.

In a preferred embodiment of the invention, the stirring and mixing method is stirrer stirring or circulating pump circulation.

The invention has the beneficial effects that: the method for removing sulfur dioxide in the ultrapure sulfuric acid takes the sulfuric acid solution of hydrogen peroxide as an oxidant, directly oxidizes the sulfur dioxide in the ultrapure sulfuric acid into sulfur trioxide or sulfuric acid, does not generate industrial wastewater, is clean and environment-friendly, has a simple and reliable operation process, greatly saves the production cost, and is suitable for industrial production.

Drawings

FIG. 1 is a schematic diagram illustrating a process of removing sulfur dioxide from ultrapure sulfuric acid according to a preferred embodiment of the present invention;

the parts in the drawings are numbered as follows: 1. an ultra-pure sulfuric acid tank, 2, a circulating pump, 3, a condenser.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention, and to clearly and unequivocally define the scope of the present invention.

The embodiment of the invention comprises the following steps:

the invention discloses a method for removing sulfur dioxide in ultrapure sulfuric acid, which comprises the steps of taking a sulfuric acid solution of hydrogen peroxide as an oxidant, stirring and mixing for 20-40 min in a closed container at the temperature of 10-50 ℃, and oxidizing sulfur dioxide in the ultrapure sulfuric acid to enable the content of the sulfur dioxide in the ultrapure sulfuric acid to be lower than 5 ppm.

The preparation method of the sulfuric acid solution of hydrogen peroxide comprises the following steps: adding an ultrapure hydrogen peroxide solution with the mass concentration of 30-50% into an ultrapure concentrated sulfuric acid with the mass concentration of 60-80% to prepare the hydrogen peroxide solution, wherein the mass concentration of hydrogen peroxide in the prepared sulfuric acid solution of hydrogen peroxide is 5-10%.

The stirring and mixing method is stirrer stirring or circulating pump circulation.

Example 1

1000g of ultrapure concentrated sulfuric acid with the mass concentration of 70% is accurately weighed, added into 200g of ultrapure hydrogen peroxide solution with the mass concentration of 31%, and stirred and mixed uniformly, so that the mass concentration of hydrogen peroxide in the mixed solution is accurately 0.81%.

As shown in fig. 1, ultrapure sulfuric acid from which sulfur dioxide is to be removed is fed into an ultrapure sulfuric acid tank 1 through a station 1, the content of sulfur dioxide in the ultrapure sulfuric acid tank 1 is determined to be 80ppm, the molar quantity of sulfur dioxide contained therein is 0.00125mol, the molar quantity of hydrogen peroxide required is strictly calculated to be 0.00125mol (corresponding to 0.0425g in mass) according to the principle of a chemically equivalent molar reaction, and the amount of hydrogen peroxide solution having a required mass concentration of 0.81% is 5.25 g.

As shown in fig. 1, 5.25g of a sulfuric acid solution of hydrogen peroxide with a mass concentration of 0.81% is accurately measured, and is slowly added into a closed ultrapure sulfuric acid tank 1 through a station 2, the feeding is completed at 35 ℃, and the sulfuric acid solution is circulated through a condenser 3 by a circulating pump 2 at room temperature, and is finally returned into the ultrapure sulfuric acid tank 1, and the oxidizing reaction is completed after the circulation is performed for 35 minutes to be uniform.

After the reaction was completed, the residual amount of sulfur dioxide in the ultrapure sulfuric acid tank 1 was measured to be 1.5 ppm.

Compared with the prior art, the method for removing sulfur dioxide in ultrapure sulfuric acid has the following advantages:

1. the process flow is simple, the equipment investment is low, and the production cost is greatly saved;

2. the oxidation condition is mild and reliable, and energy is saved;

3. the sulfur dioxide is directly oxidized and then converted into sulfuric acid, so that no process wastewater is generated, and the method is clean and environment-friendly.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.