Sulfuric acid
Sulfuric acid H2SO4 is a strong dibasic acid, corresponding to the highest degree of sulfur oxidation. Under normal conditions, anhydrous concentrated sulfuric acid is a heavy oily liquid without color and smell, with a strongly acidic “copper” taste, the density at a temperature of 20 ° C is equal to 1.8305 g / m3. In the technique of sulfuric acid is called a mixture of both water and sulfuric anhydride.
Sulfuric acid has been known since antiquity, being found in nature in a free form, for example, in the form of lakes near volcanoes.
In the 18th — 19th centuries, sulfur for gunpowder was produced from pyrite (pyrite) in sulphate plants. Sulfuric acid at the time was called “oil of vitriol”.
The smallest droplets of sulfuric acid can form in the middle and upper layers of the atmosphere as a result of the reaction of water vapor and volcanic ash containing large amounts of sulfur. The resulting suspension, due to the high reflectivity of sulfuric acid clouds, makes it difficult for sunlight to reach the surface of the planet.
Therefore (and also as a result of a large number of the smallest particles of volcanic ash in the upper layers of the atmosphere, which also impede access to sunlight for the planet), after particularly strong volcanic eruptions, significant changes in climate can occur. For example, as a result of the eruption of the Ksudach volcano (Kamchatka Peninsula, 1907), an increased concentration of dust in the atmosphere lasted for about 2 years, and characteristic silvery clouds of sulfuric acid were observed even in Paris.
The explosion of the Pinatubo volcano in 1991, which sent 30 million tons of sulfur into the atmosphere, caused 1992 and 1993 to be much colder than 1991 and 1994.
Sulfuric acid is used:
- in the processing of ores, especially in the extraction of rare elements,
- in the production of mineral fertilizers,
- as an electrolyte in lead accumulators,
- for the production of various mineral acids and salts,
- in the production of chemical fibers, dyes, smoke and explosives,
- in the oil, metalworking, textile, leather and other industries,
- in the food industry,
- registered as a food additive E513 (emulsifier),
- in industrial organic synthesis, sulfonation (detergents and intermediate products in the production of dyes), alkylation (production of isooctane, polyethylene glycol, caprolactam), etc.
Sulfuric acid produced by:
GOST 2184 – 77 Technical sulfuric acid. Technical conditions.
mark “Improved”, mark “Technical”.
Form and packaging:
Sulfuric acid is shipped in special railway tanks or through a piping system.
When shipping sulfuric acid in tanks or containers, no more than 10 tanks or containers are accepted as a batch, and for contact improved acid and improved oleum – no more than one tank or one container. The lot size when shipping products in barrels is not more than 20 tons.
Technical sulfuric acid is produced in accordance with the requirements of GOST 2184 marks: improved and technical (grade 1 and grade 2).
| Name of the indicator | Standard | |||||
|---|---|---|---|---|---|---|
| Improved | Technical | |||||
| 1 mark | 2 mark | |||||
| Mass fraction of monohydrate,% | 92,5-94,0 | No less 92,5 | ||||
| Mass fraction of iron (Fe),% not more than | 0,006 | 0,02 | 0,11 | |||
| Mass fraction of the residue after | 0,02 | 0,05 | Not standardized | |||
| calcination,% not more | 0,00005 | Not standardized | ||||
| Mass fraction of nitrogen oxides (N2O3),% not | 0,00008 | Not standardized | ||||
| More | 0,001 | Not standardized | ||||
| Mass fraction of arsenic (As),% not more than | 0,0001 | Not standardized | ||||
| Mass fraction of lead (Pb),% not more than | 1 | 6 | ||||
| Mass fraction of chloride compounds (Cl), |
transparent without
dilution |
Not standardized | ||||