Iron ore is a specialmineral formation, including iron, as well as its compounds. Ore is considered iron if it contains this element in sufficient quantities to be economically profitable to extract.
The main type of iron ore ismagnetic iron ore. It contains almost 70% of oxide and ferrous oxide. This ore has a black or gray-steel color. Magnetic iron ore on the territory of Russia is mined in the Urals. It occurs in the depths of the Magnetic, High, Grace and Kachkanar mountains. On the territory of Sweden, he is found in the vicinity of Falun, Dannemore and Gellivar. In the USA it is Pennsylvania, and in Norway - Arendal and Persberg.
In ferrous metallurgy iron ore products are divided into three types:
- Separated iron ore (low iron content);
- sinter ore (with an average iron content);
- pellets (raw iron-containing mass).
Rich are such deposits of iron ore,which contain more than 57% of iron in its composition. The poor ores include those in which at least 26% of iron. Scientists divided iron ore into two morphological types: linear and planar.
Iron ore of a linear type is aore wedge-shaped bodies in zones of bends and earth faults. This type is characterized by an especially high content of iron (from 50 to 69%), but sulfur and phosphorus in such ore is contained in a small amount.
Ploskoopodobnye deposits are found on the tops of the layers of ferruginous quartzites, which represent a typical weathering crust.
Iron ore. Application and extraction
A rich iron ore application is found forreceiving pig iron and mainly goes to smelting in converter and open-hearth production or directly to iron reduction. A small amount is used as a natural paint (ocher) and a weighting agent for clay muds.
The volume of world reserves of explored depositsmake 160 billion tons, and iron in them contains about 80 billion tons. Iron ore is found in Ukraine, and Russia and Brazil have the largest reserves of pure iron.
The volume of world ore mining is growing every year. In most cases, iron ore is extracted by an open method, the essence of which is that all the necessary equipment is delivered to the deposit, and a quarry is also built there. The pit depth is an average of about 500 m, and its diameter depends on the features of the discovered deposit. After that, with the help of special equipment, they extract iron ore, put them on machines adapted for carrying heavy loads, and are delivered from the quarry to the enterprises that are processing.
The disadvantage of the open method is the possibilityto extract ore only at shallow depths. If it lies much deeper, you have to build mines. At first, the barrel is made, resembling a deep well with well-fortified walls. In different directions from the trunk pass corridors, the so-called drifts. The ore found in them is blown up, and then its pieces are lifted to the surface with the help of special equipment. The extraction of iron ore in this way is effective, but is associated with serious danger and costs.
There is another way with whichthey extract iron ore. It is called SRS or borehole hydraulic mining. The ore is extracted from the ground in such a way: a bore hole is drilled, pipes with a hydromonitor are lowered into it and a very powerful water jet crushes the rock, which is then raised to the surface. The extraction of iron ore in this way is safe, but, unfortunately, it is inefficient. So it is possible to extract only 3% of ore, and 70% is mined with the help of mines. However, the development of the SRS method is being improved, and there is a high probability that in the future this option will become the main one, replacing the mines and quarries.