Production of sulfuric acid. Methods of preparation. Application

Sulfuric acid has found wide application in various branches of human activity. The modern chemical industry includes it in the list of the main products of production, the level of its output is an indirect indicator of the chemical production potential of a particular country. Annually in the world about 160 million tons of this substance are produced.

According to its physical and chemical properties, sulfuric acid is a dibasic acid, in this compound sulfur reaches the highest oxidation state (+6). Under normal conditions in a concentrated state sulfuric acid is a heavy oily liquid, which has neither color nor smell. Sulfuric acid is used in the solution. Both ordinary water and sulfuric anhydride can be used as the solvent. It is customary to consider the solution as aqueous if the ratio of sulfuric anhydride molecules to the amount of water is less than unity. If this value is exceeded, the expression - sulfuric anhydride solution in sulfuric acid or oleum is used.

The production of sulfuric acid provides this valuable product with the technological process of creating mineral fertilizers, it is used as an electrolyte in lead batteries, acid is the main component in the preparation of various mineral salts and acids. Chemical fibers, dyes, smoke-forming and explosives in the technology of their production use sulfuric acid. Without it, it is impossible to imagine oil, metalworking, textile, leather and other industries.

Even the food industry has not managed without the use of this substance - the preparation of food additive E513 (emulsifier). Industrial organic synthesis, dehydration (the process of obtaining esters, diethyl ether), hydration (extraction of ethanol from ethylene), sulfonation (the production of synthetic detergents and intermediates in the preparation of dyes), alkylation (synthesis of isooctane, caprolactam, polyethylene glycol), resins in Filters on production lines of distilled water - none of these processes can not do without the use of sulfuric acid.

The production of sulfuric acid provides the most basic consumer of this substance - the synthesis of mineral fertilizers. For example, to produce a ton of phosphorus fertilizers, it is necessary to use two to three and a half tons of sulfuric acid. For this reason, sulfuric acid enterprises, which are responsible for the production of sulfuric acid, are built in conjunction with plants producing mineral fertilizers.

For the extraction of sulfuric acid, two technological methods are used. The production of sulfuric acid by contact method is the main one and is ninety percent, the nitros (tower) method has become less prevalent. Despite the shortcomings and merits of each, the production of sulfuric acid from pyrite displaced nitroses due to more attractive indicators of cost, purity and high concentration of the finished product at the outlet.

Mastering by sulfuric acid plants contact synthesis method, the production of sulfuric acid can be divided into three stages. In the first stage, pyrites are fired, using special kilns in the so-called "fluidized bed". The second stage involves the oxidation of sulfur dioxide to sulfur oxide (VI), and in the third stage oleum is produced, which is poured into tanks and sent to customers.

The production of sulfuric acid by nitrosis was not widely used due to insufficient purity of the product, which limits its use.

Regardless of methods and methods of production, the production of sulfuric acid requires production workers to pay increased attention to environmental protection.