Sulfur is an element of D. I. Mendeleev's periodic system, its atomic number is sixteen. It has non-metallic properties. Denoted by the Latin letter S. The name, presumably, has an Indo-European root - "to burn."
Historical perspective
When sulfur was discovered and its extraction started, 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 rituals, included it in fumigating mixtures. The mineral sulfur was attributed to a product that was produced by the gods, mostly 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For a long time, as evidenced by historical documents, it was used as a constituent element of combustible mixtures that were used for military purposes.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 mineral sulfur. In one of his works, he described "evaporations" that had a detrimental effect on a person when burned.
Historians suggest that sulfur was a constituent element in the so-called "Greek fire", which inspired fear in enemies.
In the eighth century in China, it was used to make pyrotechnicmixtures, including combustible substances resembling gunpowder.
In the Middle Ages, it was one of the three main elements of the alchemists. They actively used the mineral native sulfur in their research. Often this led to the fact that experiments with her were equated with witchcraft, and this, in turn, led to the persecution of ancient chemists and their followers by the Inquisition. 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 devilish manifestations.
Properties
The native mineral sulfur has a molecular lattice that other similar elements do not have. This leads to the fact that it has low hardness, there is no cleavage, it is a rather fragile material. The specific gravity of sulfur is 2.7 grams per cubic centimeter. The mineral has poor electrical and thermal conductivity and a low melting point. Freely ignites when exposed to an open flame, including from a match, the color of the flame is blue. It ignites well 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 varied. It has shades of light yellow, straw, honey, greenish. In sulfur, which has organic substances in its structure, there is a brown, gray or black color. In the photo, the sulfur mineral in a solid, pure, crystalline form always attracts the eye and easilyrecognizable.
Volcanic sulfur is bright yellow, greenish, orange. In nature, you can find it in the form of various masses, dense, earthy, powdery. There are also crystalline overgrown sulfur crystals in nature, but quite rarely.
Sulfur in nature
Natural sulfur in its pure state is rare. But in the earth's crust, its reserves are very significant. These are mainly ores, where sulfur layers are present in large quantities.
Until now, science has not decided on the cause of the occurrence of sulfur deposits. Some versions are mutually exclusive. Taking into account the fact that sulfur exhibits high chemical activity, it is assumed that during the formation of the surface of the earth's crust, it was repeatedly bound and released. How these reactions proceeded has not been established for certain.
According to one of the versions, it is assumed that sulfur is the result of the leaching of sulfates, which have become the waste products of individual bacteria. The latter use the mineral compounds as food.
Researchers are considering various versions of the processes of replacement of sulfur in the earth's crust, which lead to its release and accumulation. But it is not yet possible to unambiguously understand the nature of the occurrence.
Physical and chemical properties of sulfur
The first scientific research was made 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 found that it crystallizes from melts, initially taking needle-shapedkinds. However, this form is not stable. As the temperature decreases, sulfur recrystallizes, forming volumetric translucent formations of lemon yellow or golden hue.
Deposits, sulfur mining
The main source of sulfur mineral production are deposits. According to the calculations of geologists, it follows that its world reserves are about 1.4 billion tons.
Ancient people, as well as the miners of the Middle Ages, mined sulfur by digging a large clay container to the depth. Another was placed on it, in which there was a hole in the bottom. The upper container was filled with rock, which contained sulfur. This structure was heated. The sulfur began to melt and flow into the lower vessel.
Currently, mining is carried out by open pit mining, as well as using smelting methods from underground.
Large deposits of sulfur in Eurasia are found in Turkmenistan, the Volga region, and other places. Significant deposits in Russia have been discovered on the left banks of the Volga River, which stretch from Samara to Kazan.
When developing the sulfur mineral, special attention is paid to safety. This is due to the fact that the ore is always accompanied by the accumulation of hydrogen sulfide, which is very harmful to breathing. The mineral itself tends to ignite and form explosive compounds.
The most common mining method is open pit. At the same time, the upper part of the rocks is removed by mining equipment. Explosive work is carried out crushing the ore part. Thenfractions are sent to the enterprise for the enrichment process, and then to smelting plants to obtain pure sulfur.
If the mineral lies deep and its volumes are significant, the Frasch method is used for extraction.
At the end of 1890, engineer Frasch proposed to melt 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 engineer's idea was successfully tested and the industrial extraction of this mineral began in this way.
In the second half of the 20th century, the method for mining through the use of high-frequency currents began to be actively used. Their impact also leads to the melting of sulfur. The subsequent injection of compressed hot air makes it possible to accelerate its rise in a liquid state to the surface.
Sulfur is found in large quantities in natural gases. The Claus method is suitable for its extraction. 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 produced sulfur goes to the production of sulfuric acid. Also, this mineral is needed for the manufacture of rubber, drugs, as fungicides in agriculture. The mineral has also been used as a structural element in the popular sulfur asph alt and the substitute for Portland cement - sulfur concrete. Actively used in the manufacture of variouspyrotechnic compositions, in the production of matches.
Biological role
Sulfur is an important biogenic element. 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 and is a source of energy. In the human body, there are about two grams of sulfur per kilogram of weight.
Sulfur in its pure form is not a toxic substance, unlike volatile gases, which include sulfur dioxide, sulfuric anhydride, hydrogen sulfide, and so on.
Flame properties
Sulfur is a flammable mineral. Its finely ground fractions are capable of spontaneous combustion 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.
