Sulfur — chemical element VI of group of a periodic system, it is carried to chalcogens. The average content of sulfur in earth crust is 0.05% of all weight, and in the seas and oceans — 0.09%. In the form of connections it is present at slates, oil and natural gases, is a part of vitamins and proteins.
Instruction
1. In the nature sulfur is presented by four isotopes, its numerous minerals are also known. Among sulphidic minerals — antimonite, blende, chalcosine, pyrite, kowellin, cinnabar, a galenite and many others. Sulfur sulfates — anhydrite, barite, mirabilite, plaster and others.
2. Cera is capable to form cyclic molecules with different number of atoms, the cycle with 8 atoms is preferable, others — are less stable, in particular cycles from four and five atoms. Metastable modifications differ in the color, it varies from orange to citreous.
3. Metastable nacreous sulfur can be received at fast cooling of benzene solution of sulfur. Rubber-like plastic sulfur is received at sharp cooling, for example, pouring out fusion at a temperature of 190 °C in cold water.
4. Many modifications distinguish the fact that fusion before crystallization contains only one grade of molecules. Near temperature of board it represents yellow mobile liquid, cyclic molecules with the number of atoms equal 8, and in insignificant degree - molecules with other number of atoms generally are its part.
5. When temperature reaches 187 °C fusion of sulfur becomes almost not fluid, it dark brown color. If to continue to heat it further, chains of molecules are broken off and shortened, liquid becomes mobile again.
6. Sulfur is received from native ores, restoration of oxide of sulfur or oxidation of sulfide of hydrogen. There are several ways of extraction of sulfur from ores, one of them — a geotechnological method of processing when in sulfur-containing layer water vapor under pressure moves. At a thermal way of processing sulfur are sublimated in the rotating furnaces or melt from shredded ore.
7. The steam-and-water method is applied to ores with the high content of sulfur, at the same time shredded ore process the ferry in autoclaves. The floatation way consists in enrichment of ores and extraction of sulfur with a steam-and-water method. For receiving sulfur by a flocculation method the concentrate is sent at first in a plavilnik, and then to the flocculator in which add the high-boiling liquid containing water to suspension. After that from liquid sulfur separate flocculi of dead rock.
8. About a half of the produced sulfur is applied to receiving sulfuric acid, a quarter — to sulfides, and 10-15% - to pest control of crops. Sulfur is used in rubber industry as the vulcanizing agent and also in production of dyes and artificial fiber.