Investigation on fine grinding of marble wastes using a planetary mill

The subject of this study is the grinding of marble waste into fine size using a laboratory-scale planetary mill. The marble waste was reduced to less than 1 mm and then ground to fine size under different grinding conditions using planetary ball mills. Dry grinding experiments were carried out using a planetary ball mill with alubite balls as the grinding medium. The effects of the mill speed, grinding time, and ball/powder ratio, which are critical parameters in grinding, on the grinding particle size were particularly investigated. Experiments were carried out at 5 different mill speeds (150, 200, 250, 300 and 350 rpm); 3 different ball/powder ratios (2.5, 5 and 10) and grinding times ranging from 7.5 to 240 minutes. In addition, some analyses and technological tests were carried out to investigate the natural calcium carbonate properties of the waste. The finest product particle size that could be obtained as a result of the grinding experiments was measured as d90=45, d50=5 and d10=0.2 µm. Unfortunately, finer-grained material could not be reached. However, the obtained fine product was found to be close to natural calcium carbonate (calcite, CaCO3) in terms of mineralogical structure, chemical purity, whiteness and oil absorption values.