Impact of Hardness on Specific Crushing Energy and Product Size of Jaw Crusher

The crushing of the mineral raw material is the most essential mechanical operation within mineral processing. It is also an inefficient, energy intensive process that consumes billions of kilowatt-hours (kWh) per year. In fact only 1% of the total energy input into size reduction processes is used in individual particles breaking and changing of solid material dispersion state. Since the technology is well known, improvements in comminution are dependent upon optimizing the application and operation of that technology. The quality of building crushed stone is evaluated on the basis of the physical and mechanical characteristics, the grain size distribution and the grain shape. Schmidt rebound hardness of rocks is the characteristic which is due to its speed and simplicity of testing often applied in practice. The paper presents results of the testing of hardness impact on the crushing energy and product size of the laboratory jaw crusher. Results show that the Schmidt rebound hardness of rock mass does not have significant influence on the jaw crusher power consumption. The high correlation (R2=0, 876) between grain size distribution parameter t10 and Schmidt rebound hardness has been established.