Chalk is one of the most ancient rocks and has witnessed many events that took place many centuries ago. However, most of us got acquainted with the mineral during the school period
Most of the chalk composition is formed by calcium deposits of shells of prehistoric microorganisms and protozoan plants. Chalk deposits, including processed ones, are used today in various fields-from the production of paints and food additives to cosmetics
Chalk is a natural material and is extracted as a mineral. Basically, it is a calcium deposit formed from the remains of ancient terrestrial organisms.
In the production of chalk and honey-containing products, already processed chalk is used.
Natural Cretaceous deposits often contain various undesirable impurities – stones, sand and various mineral particles. Therefore, the chalk extracted from the deposits is broken and mixed with water in such a way as to obtain a suspension.
In this case, heavy impurities are lowered to the bottom, and light calcium particles are sent to a special tank, where they are dried after adding a special bonding agent, turning them into chalk, with which you can draw.
Untreated chalk from chalk quarries is used for construction purposes to produce lime
It is considered that the chemical formula of chalk coincides with the formula of potassium carbonate CaCO3.
The composition of the chalk includes:
calcium oxides - from 47 to 55%;
carbon dioxide — up to 43%;
silicon dioxide – no more than 6%;
aluminum oxide – up to 4%;
magnesium oxide – no more than 2% of the total mass of chalk;
also, the composition of chalk may include iron, however, its concentration usually does not exceed 0.5%.
The high content of silicon increases the density of chalk, and the presence of red shades can indicate an increased content of iron in it
The accumulation of Cretaceous deposits began in the so-called Cretaceous period, covering a period of 80 million years. About 20% of the Earth's sedimentary rocks include chalk.
The world's largest deposits include the White Cliffs of Dover, the chalk caves in the French city of Champagne and the chalk cliffs of Mons Klint in Denmark.
On the territory of Ukraine, chalk mountain deposits with a thickness of up to 600 meters are located south of Kharkiv.
The largest deposits in the Voronezh Region are Kopanishchenskoye, Rossoshanskoye, and Buturlinskoye. The city of Belgorod, presumably, got its name from the local chalk deposits
Today, chalk is a fairly widespread material for various areas of production.
So, chalk is used in the following areas:
Chalk paints are used for interior decoration during construction and repair work.
Chalk is a part of cement mixes, providing them with softness and elasticity.
Ground natural chalk is actively used for the production of glass.
Chalk is a part of farm feed and is used for fertilizing the soil.
Chalk is the basis for cosmetics-lipstick, foundation, powder, etc. It is the chalk in the foundation that absorbs excess fat and protects the skin from shine.
Chalk is also used for household purposes as an absorbent and bleaching component.
The production of tooth powders and pastes is also not complete without the use of chalk.
The lack of calcium and other useful trace elements can lead to the desire to eat chalk. During pregnancy, with anemia, some people have a strong craving for eating chalk, so the question of the safety of this mineral for the body arises in many.
Of course, one or two small pieces of pure chalk will not bring much harm to the body. However, it must be remembered that chalk without impurities is not available for free sale and it is almost impossible to get it, except in the pharmacy in the form of calcium gluconate.
In the most common product – "school chalk", glue and various dyes are added to the production, which are toxic to the body