Abstract
An amorphous silica powder (A2) was mechanically treated using a planetary type mill. Four different rotation speeds (50, 100, 200, 300 rpm), milling times (15, 30, 60 min) and ball sizes (01, 05, 10 mm) were used. The structure and morphology of the powder did not change by milling. The effect of milling conditions on particle size distribution and specific surface area was investigated. By the milling treatment the original particle size of the powder was not effectively reduced. Rotation speeds of more than 200 rpm and prolonged milling causes the formation of a broad range of particles of larger sizes. The surface activity of raw and treated powders was measured as the amounts of dissolved Si4+ ion into ammonia solution. The 10 mm ball size was the most effective for 200 and 50 rpm rotation speeds almost independently of the milling time. Comparison of the effect of milling conditions on particle features of this powder with previously investigated powder is also discussed. The findings indicate that from a technical and economical point of view each powder has its own optimum milling condition, which will be sufficient to considerably increase the specific surface activity of the original amorphous powder making it suitable for different applications in non-firing ceramics processing.
