GB／T534-2002 Industrial sulfuric acid
1. General
This standard stipulates the quality requirements and its test methods, rules and signs of industrial sulfuric acid. This standard is applicable to sulfuric acid of sulfur dioxide smelting, industry and its products of absorbed water, qualified product and trade in the market.
2. Product classification
According to the production method, the sulfuric acid produced by sulfur burning is called sulfur burning sulfuric acid; the sulfuric acid produced by sulfur dioxide smelting is called sulfur dioxide smelting sulfuric acid. According to the content of total water, the sulfuric acid produced can be divided into acid water, qualified product and trade.
3. Quality index
3.1 Appearance
The sulfuric acid should appear transparent free flow liquid with the color from yellowish to light reddish brown.
3.2 Density
The mass concentration should satisfy the requirements in the table 1.
Table 1 Mass concentration of sulfuric acid
Mass concentration/ (g/cm3)
Sulfur burning sulfuric acid 1.1750—1.2088
Sulfur dioxide smelting sulfuric acid 1.1680—1.2030
3.3 Free acidity
The free acidity of sulfuric acid should satisfy the requirements in the table 2.
Table 2 Free acidity of sulfuric acid
Free acidity/(%)
Sulfur burning sulfuric acid 85.0 or above
Sulfur dioxide smelting sulfuric acid 85.0 or above
3.4 Iron
The total content of iron should not be higher than 0.003%, the Fe3+ should not be higher than 0.0012% and the Fe2+ should not be higher than 0.0018%.
3.5 Chloride
The total content of chloride should not be higher than 0.005%.
3.6 Non-volatile matter
The non-volatile matter should not be higher than 0.010%.
3.7 Oxidation reaction
The oxidation reaction should produce no gray-black deposits.
3.8 Residue after ignition
The residue after ignition should not be higher than 0.004%.
4. Test methods
4.1 Appearance test
Use the 300ml flask, pour 4ml of acid, carefully examine the appearance and color of acid.
4.2 Density test
Take the 10ml samples respectively from acid water, qualified product and trade. Shake it round and let them stand still, then measure its mass. Measure the temperature of samples, then calculate the mass concentration according to articles 3.2.
4.3 Free acidity test
4.3.1 Take the corresponding samples according to articles 4.2.
4.3.2 Use 0.02N sodium hydroxide solution to neutralize the samples, until the reaction is acidic. The excess sodium hydroxide solution is titrated with basic dichromatic solution. Make the end point of titration turn to violet. Record the volume of sodium hydroxide solution used and calculate the free acidity of acid according to articles 3.3.
4.4 Iron test
4.4.1 Take the samples according to articles 4.2.
4.4.2 Take a certain amount of samples and make denaturation. Add the de-alcalined potassium chromate and sodium arsenite solution and make reaction. Notice the color change and read it on the light yellow line. Filter the solution and titrate the filtrate with 0.01N ferrous sulfate solution, until the sample turns yellow. Record the volume of ferrous sulfate solution used and calculate the total iron and Fe3+ according to articles 3.4.
4.4.3 Take a certain amount of samples and perform denaturation. Add the alkalized potassium dichromate and sodium arsenite solution, and make reaction. Notice the color change and read it on the light yelloe line. Filter the solution and use 0.005N ferric sulfate solution to titrate the filtrate, until the sample turns red or yellow. Then use the 0.005N ferrous sulfate solution to titrate the sample, until the color of sample turns yellow. Record the volume of ferrous sulfate used and calculate the Fe2+ according to articles 3.4.
4.5 Chloride test
Take the sample according to articles 4.2 and perform denaturation. Take an amount of samples according to articles 4.5.1. Then add the silver nitrate solution and nitric acid solution to make reaction. Notice the color change and when the sample turns pale yellow, read it on the light yellow line. Calculate the total chloride in sample according to articles 3.5.
4.6 Non-volatile matter test
Take 10ml of sample and make denaturation. Heat the sample to specific temperature and cool it to room temperature. Take certain amount of samples and filter it. Put the residue on the porcelain plate, put it into oven to dry and then put it into crucible and heat it at 500°C for 3h. Put the tested samples into desiccator and cool it in room temperature, weigh it and then calculate the non-volatile matter according to articles 3.6.
4.7 Oxidation reaction test
Take 10ml of sample and make denaturation. Add 0.2g of copper oxide, a few drops of nitric acid solution and shake round. After heating and cooling, examine the precipitate, if there is no gray-black deposits, then it is qualified and meet the requirements of articles 3.7.
4.8 Residue after ignition test
Take 10ml of sample and make denaturation. Dry the sample on porcelain plate and weigh the sample. Put them into crucible and heat it at 950°C for 1h. Put off the crucible and cool it slowly, put them into desiccator and weigh it and calculate the result according to articles 3.8.
5. Product signs
The sulfuric acid label should contain the engineer, net content of acid and other necessary information. The users should also indicate its production method in the product label.
6. Packaging and storage
The sulfuric acid should be stored in dedicated acid tank and avoid storing it along with combustible and organic materials. The sulfuric acid should also avoid contacting with human skin, eyes, flammable materials, reducing and oxidizing materials, acids and alkalies.
