Microwave Emission During the Impact Compaction of Particle Bed

Abstract

Cost, quality and productivity in comminution processes depend on the portion of consumed energy directly applied to the particle size. Especially particle bed grinding is an inefficient process and has great potential to improve its efficiency. The modelling of the stress and breakage behavior provides complex solutions that are very difficult to apply in terms of real grinding problems. An experimental technique to detect the crack formation in particle may be helpful to obtain the real parameters for modelling. Low sized, not expansive and wireless sensors, based on microwave emission, are promising for this application. In the first step, the microwave emission from Lead zirconate titanate Pb[ZrxTi1−x]O3 (PZT) induced by mechanical stressing was investigated. The mechanical stressing occurs by impact of a sharp tungsten indenter on the upper surface of PZT-ceramics. In the second step, the microwave emission from PZT-ceramics was used for investigations of stressing behavior of particle beds. The PZT-particles were incorporated in beds of glass particles. Variable impact conditions were used to obtain the microwave response of PZT-particles located in different layers of particle bed. An acoustic sensor was used to obtain the mechanical force acting on particles bed during the impact. Based on this microwave response the stressing and breakage behavior of particle beds was characterized. The proposed method allows a direct optimization of particle size reduction in particle beds.