The most solid substance on Earth is diamond. Many materials differing in big hardness cut these stones, but it is possible to cut diamond other diamond. Appreciate this mineral not only hardness, but also beauty.
On the chemical composition diamond – "close relative" of coal and graphite. It consists of the same chemical element – carbon, but differs in the structure of a crystal lattice. That the lattice changed, having turned thereby graphite into diamond, temperature from 1100 to 1300 wasps and pressure about 5000 atmospheres is necessary. Such conditions happen at a depth from 100 to 200 km.
Diamond fields
When through earth crust gases break, in a crack volcanic magma which bears with itself diamonds from terrestrial depths directs. Magma stiffens, forming special breed – a kimberlite, there is a kimberlite tube which is narrowed from top to down. Its diameter can vary from 10 to 20 meters, and the area – from 0.01 to 140 hectares. So primary, or radical diamond field looks.
The kimberlite, as well as other breeds, is subject to aeration and destruction as a result of chemical reactions with water, carbon dioxide and other substances. At expansion and deepening of river valleys, diamonds from the collapsing kimberlite tubes were taken water streams and appeared in the lower part of river deposits. So there were secondary diamond fields, they are called scatterings. To the 2nd half of the 19th century diamonds were mined only in scatterings, but now 85% of diamonds are mined in kimberlite tubes. Diamond fields are found on all continents, excepting Antarctica. However, even splinters of the meteorite containing diamonds are found there. Especially there are a lot of diamond fields in Siberia and Africa.
Process of extraction of diamonds
Extraction of diamonds – process difficult and expensive. It begins with search of the field, on it decades leave. When the field is found, the preparation of the platform which is defined by specific conditions begins. So, if the kimberlite tube is deeply underground, the closed underground mines are equipped and if at the bottom of the sea – special robots are used. After preparation of the platform the concentrating factory which will be engaged in extraction of diamonds from rock is under construction. The technology of extraction of diamonds consists of three stages. At the first stage ore is crushed and divided into a diamond kimberlite and the accompanying breed. It is done directly on the mine on special installations. At the second stage ore is crushed again, sort a clean diamond kimberlite on 4 categories depending on the size of particles and exempt diamonds from the accompanying breed. It occurs at factory.
Ways of separation of the accompanying breed from diamonds.
The most primitive way – fat installations: on the table covered with fat the kimberlite mixed with water moves. Water carries away the accompanying breed, and diamonds stick to fat, collect them. Electromagnetic installations are more perfect. Their action is based that diamonds are not attracted by magnets, and the accompanying breed is attracted quite strongly. In X-ray machines ore is exposed to radiation as a result of which diamonds shine blue light. The special sensors fixing this luminescence put the mechanism cutting diamonds from the accompanying breed in action. When diamonds are separated from the accompanying breed, the third stage of processing begins. Diamonds go to the sorting shop where they are examined and select on the weight, diameter and a class.