A STUDY ON THE EFFECT OF PHYSICAL AND MECHANICAL PROPERTIES OF ROCKS ON THEIR GRINDABILITY

Abstract

Grinding processes are very costly because of significant energy requirements to achieve particle reduction. It was estimated that about 5-6% of the power generated all over the world is consumed in size reduction of raw materials necessary for mineral, cement, and ceramics industries. Mineral processing comminution is always the most energy intensive operation. The energy consumption may vary considerably for different ore types and flowsheets with values ranging from 10 kwh/t to 30 kwh/t and corresponding to 30 to 50% of the total energy cost. Factors affecting the process of comminution include the design and operating parameters of the comminuting machine as well as the physical and mechanical properties of the comminuted rock.Consequently, the main objective of this work is to study the effect of the most important physical and mechanical properties of rocks on their grindability. It is applied on marble, ilmenite ore and granite samples using a laboratory scale ball mill. The performance of each experiment is measured by the percentage of -1.25 mm in the product. 2n factorial method is applied as an experimental design method on each studied rock. Optimum values of the studied operating parameters and their gradation according to their effect on the process are achieved for each studied rock it is concluded that the performance decreases as the compressive strength and hardness of the studied rocks increase and increases as the abrasion value increases. It is also found that optimum values of the studied operating parameters and their gradation depend on the mechanical properties of the studied rocks.