Specific surface area and chemical reactivity of quartz powders during mechanical processing

The present work focuses on the specific surface area increase, and on the related chemical reactivity enhancement of quartz powders submitted to mechanical processing. The mechanical treatment was carried out in a suitably developed ball mill allowing the control of the frequency and energy of the impacts between ball and reactor. The specific surface area was directly measured by nitrogen physisorption, whereas electron microscopy was used to determine the size distribution of powder particles. Based on the experimental results, a simplified mathematical model was developed to describe the process of specific surface area increase on a phenomenological basis. The model permits to gain valuable information on the amount of powder processed in individual impacts. The density of reactive centers at the surface of powder particles was also estimated by using the neutralization of a free radical as a test reaction. It is shown that the surface density of reactive centers increases with the energy of collisions.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Quartz powders were submitted to mechanical processing. ► The specific surface area and the chemical reactivity increased. ► A model was developed to describe the observed processes. ► The amount of powder processed at impact was estimated. ► The surface density of reactive centers was also estimated by using a test reaction.