CN114380278A - Method for removing trace sulfur dioxide in ultrapure sulfuric acid - Google Patents
Method for removing trace sulfur dioxide in ultrapure sulfuric acid Download PDFInfo
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- CN114380278A CN114380278A CN202111650757.1A CN202111650757A CN114380278A CN 114380278 A CN114380278 A CN 114380278A CN 202111650757 A CN202111650757 A CN 202111650757A CN 114380278 A CN114380278 A CN 114380278A
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- C01B17/00—Sulfur; Compounds thereof
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Abstract
The invention provides a method for removing trace sulfur dioxide in ultrapure sulfuric acid, and relates to the technical field of chemical preparation. The method for removing trace sulfur dioxide in the ultra-pure sulfuric acid comprises the following steps: 1000g of ultrapure concentrated sulfuric acid is weighed through the accuracy, add into 200g 31% ultrapure hydrogen peroxide solution, its concentration is for about 5% to accurate demarcation, survey the sulfur dioxide content in the ultrapure sulfuric acid jar, according to the equal volume reaction principle of mole in the chemistry, calculate strictly required hydrogen peroxide solution molar quantity and required 5% hydrogen peroxide solution sulfuric acid solution volume, slowly add the hydrogen peroxide solution sulfuric acid jar above, the temperature is no longer than 50 degrees, the feeding finishes, it is even with the circulating pump circulation, most trace sulfur dioxide's content in the ultrapure sulfuric acid can be got rid of. By using hydrogen peroxide as an oxidant, a small amount of sulfur dioxide is oxidized into sulfur trioxide or sulfuric acid under certain conditions, so that the method is simple and convenient to operate, low in cost, strong in operability and suitable for industrial application.
Description
Technical Field
The invention relates to the technical field of chemical preparation, in particular to a method for removing trace sulfur dioxide in ultrapure sulfuric acid.
Background
The electronic industry, especially the modern chip industry, uses a large amount of ultra-pure sulfuric acid as a necessary chemical reagent in a process processing room, the control of various impurities, especially harmful impurities, in modern electronic chemicals is more and more strict, and for the ultra-pure sulfuric acid, the content of sulfur dioxide in a product determines the grade of the product and generally requires to be controlled in the range of 1-5PPM, but in the actual manufacturing process of the ultra-pure sulfuric acid, the sulfur dioxide is difficult to control to the level.
In the invention, a scientific and simple method is found: hydrogen peroxide is used as an oxidant, and a small amount of sulfur dioxide is oxidized into sulfur trioxide or sulfuric acid under a certain condition, so that a sulfuric acid product meets the standard requirement.
Disclosure of Invention
Technical problem to be solved
Aiming at the defects of the prior art, the invention provides a method for removing trace sulfur dioxide in ultrapure sulfuric acid, which solves the problem that the sulfur dioxide is difficult to control to the level of 1-5PPM in the manufacturing process of pure sulfuric acid.
(II) technical scheme
In order to achieve the purpose, the invention is realized by the following technical scheme: the method for removing trace sulfur dioxide in the ultra-pure sulfuric acid comprises the following steps:
s1, firstly, accurately weighing 1000g of ultra-special concentrated sulfuric acid, adding the ultra-special concentrated sulfuric acid into 200g of 31% ultra-pure hydrogen peroxide solution, and accurately calibrating the concentration of the ultra-special concentrated sulfuric acid to be about 5%;
s2, determining the content of sulfur dioxide in the ultrapure sulfuric acid tank, and strictly calculating the required molar quantity of hydrogen peroxide and the required 5% hydrogen peroxide sulfuric acid solution quantity according to a chemical molar equivalent reaction principle;
s3, slowly adding the hydrogen peroxide sulfuric acid solution prepared in the step S2 into a sulfuric acid tank, wherein the temperature is not more than 40-50 ℃, and after the addition is finished, circulating for 30-40min by using a circulating pump to be uniform;
and S4, testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S3, wherein if the residual amount is less than 5PPM, the judgment is qualified.
S5, if the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 is more than 5PPM, heating the sulfuric acid product in the step S4 to 120-150 ℃, so that the sulfurous acid is decomposed, the solubility of the sulfur dioxide in the sulfuric acid is reduced, the residual amount of the sulfur dioxide in the sulfuric acid product is further reduced, and the step S4 is repeated to test the residual amount of the sulfur dioxide in the sulfuric acid product.
Preferably, the method for testing the residual amount of sulfur dioxide in the sulfuric acid product in the step S4 comprises the following steps:
s1, precisely measuring 20mL of sulfuric acid product, placing the sulfuric acid product in a two-neck 1000mL round-bottom flask, adding 500mL of water and 600mL of water and 8-10mL of 6mol L-1A neck of the hydrochloric acid solution introduces nitrogen to the bottom of the bottle, the other neck of the hydrochloric acid solution is connected with a reflux condenser tube, the condenser tube is connected with an air duct at the upper end and is introduced to the bottom of a beaker;
s2, adding water and a plurality of drops of starch solution into the beaker, and adding 0.01-0.02mol L-1The iodine standard solution was blue colored and the flask was heated to boil the solution;
s3, distilling and reducing iodine in the beaker, leading the solution to have a fading phenomenon along with the reduction of the iodine concentration in the solution, and then dropwise adding 0.01-0.02mol L-1Supplementing consumed iodine with iodine standard solution to make the solution turn blue, repeating the above steps until the solution in the beaker does not fade within 1-2 min;
and S4, finally, directly calculating the concentration of the sulfur dioxide by using the consumed iodine solution amount.
Preferably, the hydrogen peroxide used in step S1 is an ultra-pure product with a concentration of 30% to 50%.
Preferably, the step S3 of mixing the sulfuric acid-containing oxidizing agent with the ultra-pure sulfuric acid containing sulfur dioxide must be performed in a clean and closed container.
Preferably, the adding amount of the hydrogen peroxide sulfuric acid solution in the step S3 must be strictly calculated, and the adding amount cannot exceed 1-2% of the theoretical amount.
(III) advantageous effects
The invention provides a method for removing trace sulfur dioxide in ultrapure sulfuric acid. The method has the following beneficial effects:
the method comprises the steps of accurately weighing 1000g of ultrapure concentrated sulfuric acid, adding the weighed ultrapure concentrated sulfuric acid into 200g of 31% ultrapure hydrogen peroxide solution, accurately calibrating the concentration to be about 5%, measuring the content (generally 50-100PPM) of sulfur dioxide in an ultrapure sulfuric acid tank, strictly calculating the required molar quantity of hydrogen peroxide and the required 5% of hydrogen peroxide sulfuric acid solution according to a chemical molar equivalent reaction principle, slowly adding the hydrogen peroxide sulfuric acid solution into the sulfuric acid tank at a temperature not exceeding 50 ℃, uniformly circulating for 30-40min by using a circulating pump after the feeding is finished, removing most of trace sulfur dioxide in the ultrapure sulfuric acid, and ensuring that the balance of the sulfur dioxide is less than 5 PPM.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment is as follows:
the embodiment of the invention provides a method for removing trace sulfur dioxide in ultrapure sulfuric acid, which comprises the following steps:
s1, firstly, accurately weighing 1000g of ultra-special concentrated sulfuric acid, adding the ultra-special concentrated sulfuric acid into 200g of 31% ultra-pure hydrogen peroxide solution, and accurately calibrating the concentration of the ultra-special concentrated sulfuric acid to be about 5%;
s2, determining the content of sulfur dioxide in the ultrapure sulfuric acid tank, and strictly calculating the required molar quantity of hydrogen peroxide and the required 5% hydrogen peroxide sulfuric acid solution quantity according to a chemical molar equivalent reaction principle;
s3, slowly adding the hydrogen peroxide sulfuric acid solution prepared in the step S2 into a sulfuric acid tank, wherein the temperature is not more than 40 ℃, and after the addition is finished, circulating for 30min by using a circulating pump to be uniform;
and S4, testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S3, wherein if the residual amount is less than 5PPM, the judgment is qualified.
S5, if the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 is more than 5PPM, heating the sulfuric acid product in the step S4 to 120 ℃, so that the sulfurous acid is decomposed, the solubility of the sulfur dioxide in the sulfuric acid is reduced, and the residual amount of the sulfur dioxide in the sulfuric acid product is further reduced, and repeating the step S4 to test the residual amount of the sulfur dioxide in the sulfuric acid product, wherein the residual amount of the sulfur dioxide in the sulfuric acid product is less than 5PPM, and the judgment is qualified.
The method for testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 comprises the following steps:
s1, precisely measuring 20mL of sulfuric acid product, placing the sulfuric acid product into a two-neck 1000mL round-bottom flask, adding 500mL of water and 8mL of 6molL-1A neck of the hydrochloric acid solution introduces nitrogen to the bottom of the bottle, the other neck of the hydrochloric acid solution is connected with a reflux condenser tube, the condenser tube is connected with an air duct at the upper end and is introduced to the bottom of a beaker;
s2. naturalThen adding water and a plurality of drops of starch solution into the beaker, and adding 0.01mol L-1The iodine standard solution was blue colored and the flask was heated to boil the solution;
s3, distilling and reducing iodine in the beaker, leading the solution to have a fading phenomenon along with the reduction of the iodine concentration in the solution, and then dropwise adding 0.01mol L-1Supplementing consumed iodine with the iodine standard solution to make the solution turn blue, and repeating the steps until the solution in the beaker does not fade within 1 min;
s4, finally, directly calculating the concentration of sulfur dioxide by using the consumed iodine solution amount;
the calculation formula is as follows:
wherein A is the volume of iodine titration solution consumed by the test sample, and is ml;
b is the volume of the blank iodine titrant consumed, ml;
c is the actual concentration of the iodometric solution;
w is the weight of the sample, g;
0.01 is the theoretical concentration of the iodometric solution
0.6406 is the equivalent weight of sulphur dioxide per 1ml of iodometric solution (1mol/L), g.
The hydrogen peroxide used in step S1 is an ultrapure product having a concentration of 30%.
When the sulfuric acid-containing oxidizing agent is mixed with the ultra-pure sulfuric acid containing sulfur dioxide in step S3, it is necessary to perform fusion in a clean closed vessel.
The addition of the hydrogen peroxide sulfuric acid solution in the step S3 must be strictly calculated, and the addition cannot exceed 1% of the theoretical amount.
Example two:
the embodiment of the invention provides a method for removing trace sulfur dioxide in ultrapure sulfuric acid, which comprises the following steps:
s1, firstly, accurately weighing 1000g of ultra-special concentrated sulfuric acid, adding the ultra-special concentrated sulfuric acid into 200g of 31% ultra-pure hydrogen peroxide solution, and accurately calibrating the concentration of the ultra-special concentrated sulfuric acid to be about 5%;
s2, determining the content of sulfur dioxide in the ultrapure sulfuric acid tank, and strictly calculating the required molar quantity of hydrogen peroxide and the required 5% hydrogen peroxide sulfuric acid solution quantity according to a chemical molar equivalent reaction principle;
s3, slowly adding the hydrogen peroxide sulfuric acid solution prepared in the step S2 into a sulfuric acid tank, wherein the temperature is not more than 50 ℃, and after the addition is finished, circulating for 40min by using a circulating pump to be uniform;
and S4, testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S3, wherein if the residual amount is less than 5PPM, the judgment is qualified.
S5, if the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 is more than 5PPM, heating the sulfuric acid product in the step S4 to 150 ℃, so that the sulfurous acid is decomposed, the solubility of the sulfur dioxide in the sulfuric acid is reduced, and the residual amount of the sulfur dioxide in the sulfuric acid product is further reduced, and repeating the step S4 to test the residual amount of the sulfur dioxide in the sulfuric acid product, wherein the residual amount of the sulfur dioxide in the sulfuric acid product is less than 5PPM, and the judgment is qualified.
The method for testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 comprises the following steps:
s1, precisely measuring 20mL of sulfuric acid product, placing the sulfuric acid product into a two-neck 1000mL round-bottom flask, adding 600mL of water and 10mL of 6molL-1A neck of the hydrochloric acid solution introduces nitrogen to the bottom of the bottle, the other neck of the hydrochloric acid solution is connected with a reflux condenser tube, the condenser tube is connected with an air duct at the upper end and is introduced to the bottom of a beaker;
s2, adding water and a plurality of drops of starch solution into a beaker, and adding 0.02mol L-1The iodine standard solution was blue colored and the flask was heated to boil the solution;
s3, distilling and reducing iodine in the beaker, leading the solution to have a fading phenomenon along with the reduction of the iodine concentration in the solution, and then dropwise adding 0.02mol L-1The iodine standard solution replenishes the consumed iodine to make the solution turn blue, and the process is repeated until the solution in the beaker does not fade within 2 min.
And S4, finally, directly calculating the concentration of the sulfur dioxide by using the consumed iodine solution amount.
The hydrogen peroxide used in step S1 is an ultra-pure product with a concentration of 50%.
When the sulfuric acid-containing oxidizing agent is mixed with the ultra-pure sulfuric acid containing sulfur dioxide in step S3, it is necessary to perform fusion in a clean closed vessel.
The addition of the hydrogen peroxide sulfuric acid solution in the step S3 must be strictly calculated, and the addition cannot exceed 2% of the theoretical amount.
1000g of ultrapure concentrated sulfuric acid is accurately weighed and added into 200g of 31% ultrapure hydrogen peroxide solution, the concentration of the ultrapure concentrated sulfuric acid is accurately calibrated to be about 5%, the content (generally 50-100PPM) of sulfur dioxide in an ultrapure sulfuric acid tank is measured, the required molar amount of hydrogen peroxide and the required 5% amount of hydrogen peroxide sulfuric acid solution are strictly calculated according to a chemical molar equivalent reaction principle, the hydrogen peroxide sulfuric acid solution is slowly added into the sulfuric acid tank, the temperature does not exceed 50 ℃, after the feeding is finished, a circulating pump is used for circulating uniformly, most of trace sulfur dioxide content in the ultrapure sulfuric acid can be removed, and the residual amount of sulfur dioxide is smaller than 5 PPM.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (5)
1. The method for removing trace sulfur dioxide in the ultra-pure sulfuric acid is characterized by comprising the following steps: the method comprises the following steps:
s1, firstly, accurately weighing 1000g of ultra-special concentrated sulfuric acid, adding the ultra-special concentrated sulfuric acid into 200g of 31% ultra-pure hydrogen peroxide solution, and accurately calibrating the concentration of the ultra-special concentrated sulfuric acid to be about 5%;
s2, determining the content of sulfur dioxide in the ultrapure sulfuric acid tank, and strictly calculating the required molar quantity of hydrogen peroxide and the required 5% hydrogen peroxide sulfuric acid solution quantity according to a chemical molar equivalent reaction principle;
s3, slowly adding the hydrogen peroxide sulfuric acid solution prepared in the step S2 into a sulfuric acid tank, wherein the temperature is not more than 40-50 ℃, and after the addition is finished, circulating for 30-40min by using a circulating pump to be uniform;
and S4, testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S3, wherein if the residual amount is less than 5PPM, the judgment is qualified.
S5, if the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 is more than 5PPM, heating the sulfuric acid product in the step S4 to 120-150 ℃, so that the sulfurous acid is decomposed, the solubility of the sulfur dioxide in the sulfuric acid is reduced, and the residual amount of the sulfur dioxide in the sulfuric acid product is further reduced, and repeating the step S4 to test the residual amount of the sulfur dioxide in the sulfuric acid product, wherein the residual amount of the sulfur dioxide in the sulfuric acid product is less than 5PPM, and the judgment is qualified.
2. The method for removing trace sulfur dioxide in ultrapure sulfuric acid according to claim 1, wherein: the method for testing the residual amount of the sulfur dioxide in the sulfuric acid product in the step S4 comprises the following steps:
s1, precisely measuring 20mL of sulfuric acid product, placing the sulfuric acid product in a two-neck 1000mL round-bottom flask, adding 500mL of water and 600mL of water and 8-10mL of 6mol L-1A neck of the hydrochloric acid solution introduces nitrogen to the bottom of the bottle, the other neck of the hydrochloric acid solution is connected with a reflux condenser tube, the condenser tube is connected with an air duct at the upper end and is introduced to the bottom of a beaker;
s2, adding water and a plurality of drops of starch solution into the beaker, and adding 0.01-0.02mol L-1The iodine standard solution was blue colored and the flask was heated to boil the solution;
s3, distilling and reducing iodine in the beaker, leading the solution to have a fading phenomenon along with the reduction of the iodine concentration in the solution, and then dropwise adding 0.01-0.02mol L-1Supplementing consumed iodine with iodine standard solution to make the solution turn blue, repeating the above steps until the solution in the beaker does not fade within 1-2 min;
and S4, finally, directly calculating the concentration of the sulfur dioxide by using the consumed iodine solution amount.
3. The method for removing trace sulfur dioxide in ultrapure sulfuric acid according to claim 1, wherein: the hydrogen peroxide used in the step S1 is an ultra-pure product with the concentration of 30-50%.
4. The method for removing trace sulfur dioxide in ultrapure sulfuric acid according to claim 1, wherein: the sulfuric acid-containing oxidizing agent and the ultra-pure sulfuric acid containing sulfur dioxide in step S3 must be mixed in a clean and sealed container.
5. The method for removing trace sulfur dioxide in ultrapure sulfuric acid according to claim 1, wherein: the adding amount of the hydrogen peroxide sulfuric acid solution in the step S3 must be strictly calculated, and the adding amount cannot exceed 1-2% of the theoretical amount.
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| CN115057415A (en) * | 2022-06-13 | 2022-09-16 | 湖北龙祥磷化有限公司 | Production process of high-purity electronic acid |
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| CN115057415A (en) * | 2022-06-13 | 2022-09-16 | 湖北龙祥磷化有限公司 | Production process of high-purity electronic acid |
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