The presence of heavy metals in tile surface coating has an effect on the surrounding environment and anti-pollution measures has been taken at different levels, one of which consists in using materials with low content in harmful components. In particular Pb, Cd and Sb limits are indicated in Ecolabel, a labelling system for ceramic tiles. This paper describes the validation of method used to determine the percentage of the three oxides in a ceramic glaze because a standard generally accepted procedure does not yet exist. Three commercial glazes samples and one glass certified reference material have been investigated. The dissolution of samples is carried out by acid digestion by heating a known amount of powder with HNO3 and HF additions. The solution is investigated by Inductively Coupled Plasma Atomic Emission Spectrometry. Detection limit, recovery, repeatability and the uncertainty of measurement were calculated. The results seem to underline that the calculated uncertainty fits the method parameters requested, but the problem is not the compliance with the permissible limits. The fact of the matter is that the limits are so low that the aim of the method is to confirm if the banned elements is present or not in the ceramic glaze.
DETERMINATION OF LEAD, CADMIUM AND ANTIMONY CONTENT IN A CERAMIC GLAZE
TIMELLINI, GIORGIO
2010
Abstract
The presence of heavy metals in tile surface coating has an effect on the surrounding environment and anti-pollution measures has been taken at different levels, one of which consists in using materials with low content in harmful components. In particular Pb, Cd and Sb limits are indicated in Ecolabel, a labelling system for ceramic tiles. This paper describes the validation of method used to determine the percentage of the three oxides in a ceramic glaze because a standard generally accepted procedure does not yet exist. Three commercial glazes samples and one glass certified reference material have been investigated. The dissolution of samples is carried out by acid digestion by heating a known amount of powder with HNO3 and HF additions. The solution is investigated by Inductively Coupled Plasma Atomic Emission Spectrometry. Detection limit, recovery, repeatability and the uncertainty of measurement were calculated. The results seem to underline that the calculated uncertainty fits the method parameters requested, but the problem is not the compliance with the permissible limits. The fact of the matter is that the limits are so low that the aim of the method is to confirm if the banned elements is present or not in the ceramic glaze.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
