The heterogeneity and anisotropy of the rock is the major factor that distinguishes rock from metal. A piece of metal contains uniformly mixed material, but the material of a rock is not uniformly mixed. Somewhere may contain large amount of certain chemicals. This is known as heterogeneity of rock in the industrial, which determines the difficulty of ore beneficiation operations. A big ore can be pided into several parts, and each part needs to use different crushing equipment and crushing process.
In accordance with this situation, the common rule in industry is that crushing the loose part of rocks first, which is corresponding to our stone production line. In the crushing line, we use PE jaw crusher coarse break the stone first, then sent qualified raw materials to the fine crusher by belt conveyor.
The heterogeneity shows that the physical, chemical and mechanical properties of the rocks are not the same, and test data has obvious fluctuation. For example, for the same mine and the same rock, the deviation factor of compression strength is 15% to 40%, tensile strength is 20% to 60%. The metal mineral is only 4%-7%, therefore, we must adopt the methods of mathematical statistics when we deal with the test data of rock.
Everything has two sides, and the heterogeneity of the rock is no exception. When crushing rocks, the soft part will be crushed first, and the hard part will be broken later for the heterogeneity, which is helpful to promote the crushing efficiency. However, when we drilling the rocks, it is eay to cause skew of drilling and result in poor drill hole quality.