AbstractZircon is the most used opacifier for ceramic glazes. Zircon sands of different beach placers have been investigated for their mineralogical, morphological and chemical characteristics. Mineralogical investigations have been carried out by SEM, polarizing microscope and XRD. In particular the refractive index has been determined by immersion in liquids at the polarizing microscope. While the morphometric characteristics have been established using both grain size distribution and automatic image analysis, the morphotropic ones have been elaborated directly from their image analyses. The chemical composition has been detected using XRF, ICP-AES, NAA (for the rare earths) and EPR. The zircon sands resulted to be very good or excellent opacifiers: the values of refractive indices are high, the content of Ti02 is low (XRF), Nd and Co are less than the detection limits (ICP-AES and NAA) and Mn is absent (EPR). The distribution of the U-content is strictly correlated with the grain size distribution and with the refractive index.
|Only available as a scanned copy|