The effect of certain operating parameters on the grinding efficiency in grinding the Kokaksu bauxite in a stirred mill and comparison of the grinding efficiency with that of the bond mill

This paper presents grindability of the Kokaksu (Zonguldak) bauxite crushed below -3.35 mm in a stirred mill. It was established that the operating parameters of the stirred mill such as the ball size, stirring time and the stirring speed have a considerable effect on the fineness of the product and these parameters are directly related to energy consumption. For grinding in a unit time, increasing the ball size yielded finer products and also increased the energy consumption. It was determined from the balls of various diameters tested that the optimal ball size for the feeding size was 6.5 mm. On the other hand, an increase in stirring time and stirring speed both yielded finer products and increased the energy consumption. To conclude, the yield of finer products by means of the stirred mill was established to be directly related to the energy consumed per unit time. In the last stage, the bauxite sample was ground in a conventional Bond mill and the grinding efficiency was compared with that of the stirred mill. It was established that the stirred mill is more advantageous in grinding fine particles (140 μm) in terms of energy consumption. However, for both size groups, the stirred mill was established to be advantageous in terms of grinding time. The stirred mill yielded products of a few micrometers in a few minutes.