Today sulfuric acid is produced mainly by two commercial processes: contact and nitrous.Contact way more progressive and in Russia it is used more extensively than nitrous, ie tower.
sulfuric acid starts with burning sulfur raw materials, such as iron pyrites.In special pyrite furnaces get the so-called kiln gas, which contains about 9% of sulfur dioxide.This step is the same for both the pin and for nitrous method.
next step is to oxidize the resulting sulfur dioxide in sulfur.However, it must be pre-cleaned of some impurities that interfere with the further process.Kiln gas cleaned of dust in the electrostatic precipitators or cyclone-machine, and then submit it to a device containing a solid contact mass, where the sulfur dioxide SO2 is oxidized to sulfur trioxide SO3.
This exothermic reaction is reversible - increase in temperature leads to the decomposition of the resulting sulfur trioxide.On the other hand, when the temperature decreases the speed of the forward reaction is very small.Therefore, the temperature in the contactor is maintained within 480oS adjusting its speed of passage of the gas mixture.
Afterwards, when the contact sulfuric acid process is formed when the compound of sulfur trioxide with water.
nitrous method is characterized in that the sulfur dioxide is oxidized by nitric oxide.Preparation of sulfuric acid by this method is started the formation of sulfurous acid by reaction of sulfur dioxide from roasting gas with water.Subsequently, the resulting sulfurous acid is oxidized with nitric acid, resulting in the formation of nitric oxide and sulfuric acid.
This reaction mixture is fed into a special tower.Thus, by adjusting the gas flow, achieve that the gas mixture fed to a absorption tower dioxide and nitrogen monoxide contained in a ratio of 1: 1 is necessary to obtain the nitrogenous anhydride.
Finally, by reacting sulfuric acid and nitrous anhydride formed NOHSO4 - nitrosyl sulfuric acid.
nitrosylsulfuric The resulting acid is applied to the production tower, where it decompose water, nitrogen dioxide releases:
2NOHSO4 + H2O = N2O3 + 2N2SO4,
which oxidizes and sulfurous acid, resulting in the tower.
Nitric oxide, select from the reaction returns to the oxidation tower and enter into a new cycle.
Currently, the Russian sulfuric acid is produced mainly by contact.Nitrous method is rarely used.
The use of sulfuric acid is very wide and varied.
Most of it goes to the production of chemical fibers and chemical fertilizers, it is necessary in the production of drugs and dyes.Using sulfuric acid, the ethyl and other alcohols, detergents and pesticides.
Its solutions are used in the textile, food industry, in the nitration process for the production of explosives.Sulphuric acid battery electrolyte is to fill in the lead-acid batteries, which are widely used in public transport.
