Direct chemical characterisation of clay suspensions by WD-XRF

摘要

This study was performed to develop a method for directly controlling the chemical composition of clay slurries used in preparing ceramic floor and wall tile bodies by wavelength-dispersive X-ray fluorescence (WD-XRF) spectrometry, without the prior need to dry and prepare the samples as fused beads or pellets for WD-XRF measurement, owing to the importance of knowing the suspension chemical composition in real time for appropriate control of the industrial process. The study was conducted on a wide range of ceramic floor and wall tile bodies, which are used to prepare different suspensions. The influence of suspension viscosity (from 300 to 7000 cp), of suspension solids content (between 66 and 69%), and of the type of body composition (floor or wall tile) on the WD-XRF measurement was determined. In these viscosity and solid content ranges, no appreciable differences were observed in the WD-XRF measurement results, indicating that the possibly arising variations in viscosity and solids content in such clay suspensions in industrial practice do not influence the WD-XRF measurement. In contrast, the type of body composition did influence the WD-XRF measurement. The developed method is rapid, reproducible, and accurate, which was verified by analysis of the materials using the customary method of WD-XRF measurement on fused beads. In addition, this method is cheaper and more harmless to the environment; it minimises waste generation, since no sample preparation is required and the plastic sample holders can be reused, thanks to the reusable sample holder system designed at the Instituto de Tecnologia Ceramica laboratories.