**Abstract**

Casting, glass, ceramic, construction, plastic, dyeing, and abrasive industries are the main consumption areas of quartz sand, which are formed as a result of the weathering of igneous metamorphic rocks. In such industries, it is very important to select the correct ball size in order to grind the raw material to the desired particle size in optimum time. In this study, the changes in the specific rate of breakage of the quartz sand sample were investigated by using alloy steel balls of five different sizes. For this purpose, three different mono-size samples were prepared according to <sup>4</sup> √2 series in the range of 0.090–0.053 mm. The quartz sand prepared in these three intervals was ground with 6.35, 7.94, 9.52, 12.70, and 19.05 mm alloy steel balls for different durations. The specific rate of breakage values was obtained from the particle size distributions acquired after various grinding periods. As a result of grinding tests, an increase in the rate of breakage is observed due to the increase in ball diameter.

**Keywords:** quartz sand, breakage, ball size, comminution, Şile, İstanbul
