Sulfur is an element of the periodic system of D. I. Mendeleev, its atomic number is sixteen. It has non-metallic properties. It is denoted by the Latin letter S. The name, presumably, has an Indo-European root - “burn”.
Historical perspective
When sulfur was discovered and its production began, it is not clear. It is only known that ancient people knew about it long before our era. The early priests used it in their cult rites, included in the composition of fumigation mixtures. Mineral sulfur was attributed to the product that the gods produced, mainly living in the underworld.
For a long time, as evidenced by historical documents, it was used as a constituent element of combustible mixtures that were used for military purposes. Homer also did not ignore the sulfur mineral. In one of his works, he described the "evaporation", which had a detrimental effect on humans when burned.
Historians suggest that sulfur was an integral element in the so-called "Greek fire", which instilled fear in enemies.
In the eighth century in China, it began to be used for the preparation of pyrotechnic mixtures, including in combustible substances resembling gunpowder.
In the Middle Ages, it was one of the three main elements among the alchemists. They actively used the native sulfur mineral in their research. Often this led to the fact that experiments equated witchcraft with it, and this, in turn, led to persecution by the inquisition of ancient chemists and their followers. It was from those times, from the Middle Ages and the Renaissance, that the smell of burning sulfur, their gases, began to be associated with acts of evil spirits and diabolical manifestations.
The properties
The native mineral sulfur has a molecular lattice, which is not found in other similar elements. This leads to the fact that it has low hardness, no cleavage, this is a rather fragile material. The specific gravity of sulfur is 2.7 grams per centimeter cubic. The mineral has poor electrical, low thermal conductivity and a low melting point. Lights up freely when exposed to an open flame, including from a match, the color of the flame is blue. It is highly flammable at a temperature of about 248 degrees Celsius. When burning, it emits sulfur dioxide, which has a sharp, suffocating odor.
Descriptions of the sulfur mineral are diverse. It has shades of light yellow, straw, honey, greenish. In sulfur, which has organic matter in its structure, there is brown, gray or black color. In the photo, the mineral sulfur in a solid, pure, crystalline form always attracts the eye and is easily recognizable.
Volcanic sulfur is bright yellow, greenish, orange. In nature, you can meet it in the form of various masses, dense, earthy, powder. Crystalline overgrown sulfur crystals are also found in nature, but rarely enough.
Sulfur in nature
Natural sulfur in its pure state is rare. But its reserves in the earth's crust are very significant. These are mainly ores, where sulfur layers are present in large quantities.
To date, science has not decided on the cause of the occurrence of sulfur deposits. Some versions are mutually exclusive. Given the fact that sulfur exhibits high chemical activity, it is assumed that in the process of forming the surface of the earth's crust, it was repeatedly bound and released. How these reactions went is not known for certain.
According to one version, it is assumed that sulfur is the result of leaching of sulfates, which became the waste products of individual bacteria. The latter use mineral compounds as food.
Researchers are considering various versions of the processes of sulfur substitution in the earth's crust, which lead to its release and accumulation. But it is not yet clear to understand the nature of the occurrence.
Physical and chemical properties of sulfur
The first scientific studies were carried out only in the XVIII century. A thorough study of the properties of the sulfur mineral was carried out by the French scientist Antoine Lavoisier. So, he established that it crystallizes from melts, initially taking on needle-like forms. However, this form is not stable. With decreasing temperature, sulfur recrystallizes, forming volumetric translucent formations of a lemon yellow or golden hue.
Deposits Sulfur Mining
The main source of sulfur mineral extraction are deposits. According to the calculations of geological researchers, its global reserves amount to about 1.4 billion tons.
Ancient people, as well as miners of the Middle Ages, mined sulfur by digging a large clay tank to the depths. Another was placed on it, in which there was a hole in the bottom. The upper tank was filled with rock, which contained sulfur. This design was heated. Sulfur began to melt and drain into the lower vessel.
Currently, mining takes place through open-cast mining, as well as using methods of smelting from underground.
Large deposits of sulfur in Eurasia are available in Turkmenistan, in the Volga region, and other places. Significant deposits in Russia were found on the left banks of the Volga River, which stretched from Samara to Kazan.
When developing the sulfur mineral, special attention is paid to safety. This is due to the fact that ore is always accompanied by the accumulation of hydrogen sulfide, which is very harmful to breathing. The mineral itself has the property to ignite and form explosive compounds.
The most common mining method is open. At the same time, the upper part of the rocks is removed by mining equipment. Blasting operations are carried out crushing of the ore part. Then the fractions are sent to the enterprise for the enrichment process, and then to the smelting plants to obtain pure sulfur.
If the mineral lies deep and its volumes are significant, use the Frash method for mining.
At the end of 1890, engineer Frasch proposed melting sulfur underground, and after turning it into a liquid state, pump it out. This process is comparable to oil production. Given the rather low melting point of sulfur, the idea of the engineer successfully passed the tests and industrial production of this mineral began in this way.
In the second half of the 20th century, the method for production by using high frequency currents began to be actively used. Their effect also leads to the melting of sulfur. Subsequent injection of compressed hot air allows you to accelerate its rise in a liquid state to the surface.
Sulfur is found in large volumes in natural gases. For its extraction, the Klaus method is suitable. Special sulfur pits are used in which degassing is carried out. The result is a solid modified product with a high sulfur content.
Application
About half of all extracted sulfur goes to the production of sulfuric acid. Also, this mineral is needed for the manufacture of rubber, medicines, as fungicides in agriculture. The mineral has also found application as a structural element in the popular sulfur asphalt and Portland cement substitute - sulfur concrete. Actively used in the manufacture of various pyrotechnic compositions, in the production of matches.
Biological role
Sulfur is an important nutrient. It is part of a significant number of amino acids. An integral element in the formation of protein structures. In bacterial photosynthesis, the mineral takes part in the redox reactions of the body, is a source of energy. In the human body, one kilogram of weight accounts for about two grams of sulfur.
Pure sulfur in its pure form is not a toxic substance, unlike volatile gases, which include sulfur dioxide, sulfuric anhydride, hydrogen sulfide, and so on.
Fire hazard properties
Sulfur is a flammable mineral. Its finely ground fractions are able to ignite spontaneously in the presence of moisture, in the presence of contacts with oxidizing agents, and also when creating mixtures with coal, fats, oils. Extinguish sulfur with sprayed water and air-mechanical foam.