Oil shale is included in the category of chemical and fuel and energy raw materials. This mineral lies at a relatively shallow depth. It is part of the group of solid caustobioliths and consists of the mineral part and organic matter. Industrial value is both mineral and organic. The main mineral components of the fossil are aluminosilicates and carbonates.
Oil shales are used in energy. Direct burning of raw materials produces electric and thermal energy. Oil shale is also used for technological purposes. They are raw materials in the metallurgical and chemical industries. Deep processing of oil shale allows you to get liquid fuel.
It should be noted that the definition of "oil shale" has many interpretations. As a rule, these include sedimentary fine-grained clay, siliceous or carbonate rocks, in which the organic matter content is from 15 to 40%. If the organic part is from 5 to 15%, then the breed is classified as kerogen-containing; from 40% and more - to sapropel coal. Some authors include in the group of oil shale rocks with a lower kerogen content of 5 or 10% and an upper of 30-50, and in some cases 60-80%.
Professor Crum Brown in 1912 proposed the use of the term "kerogen." This word denoted the organic matter of oil shale in Scotland. Later, the term began to be used in other countries. When heated, kerogen is capable of forming an oil-like liquid, it is called "shale oil" (or "shale resin").
Some experts believe that the phrase itself, which is used to name the breed, is not entirely successful. The English translation sounds like "oil shales" (oil and oil shale), Latin languages call the breed "bitumineux" (bituminous shale). However, it is reliably known that the so-called fossils practically do not contain bitumoids (crude oil). But rocks can produce a viscous liquid that resembles oil when heated to five hundred or more degrees. At one time, it was supposed to form a special commission that would develop a common terminology. However, all these concepts have already become fairly well-established, so there is no point in correcting the situation.
To more correctly assess the properties of rocks and determine the most rational areas of their use, they study their material composition. A preliminary macroscopic examination is carried out, and then a more detailed one.
To study the material composition of oil shale, thin sections (slices) are made or shale pieces (polished sections) are polished. Thus, a thorough study becomes possible. The particles indistinguishable by the simple eye are called microcomponents. They are examined under a microscope.
Oil shales include microcomponents such as alginite (residues from planktonic algae), sorbomixstinite (a substance that has no structure, which is a mixture of alginite or clay material and the remains of higher plants). Found in breeds, vitrinites (gelified wood residues), liptinite (resin bodies, cuticles, pollen, spores), semivitrinite (a transitional substance from vitrinite to fusinite), fusinite (fusenized (opaque) wood residues with a pronounced cell structure).
The mineral part of shale rocks is composed mainly of finely dispersed, usually hydromicaceous material: chemogenic, pelitomorphic, or organogenic detritus carbonate, chalcedony shells of diatoms.
The most important are such qualities of fossils as the composition of the ash, sulfur content and humidity, resin yield, calorific value and others.