The effect of milling and percentage dissociation of plasma dissociated zircon on the colour of Pr-yellow and V-blue zircon pigments

The effect of milling and percentage dissociation of plasma dissociated zircon (PDZ) on the colour of Pr-yellow and V-blue zircon pigments were investigated. A solid-state reaction process was used to produce zircon pigments and the Pr-yellow and V-blue pigments were calcined at 1050 and 950 °C, respectively in a conventional muffle furnace. Using pre-milled PDZ material, prior to the calcining process, the influence on the colour intensity of the pigments after application on a ceramic tile were compared to that of a PDZ material with no prior pre-milling before the calcination stage. Pr-yellow and V-blue zircon pigments produced from PDZ with different percentages dissociation, were also evaluated in this study. The different percentages dissociation of the PDZ material was achieved by only changing the zircon feed rate through a non-transfer arc plasma system, keeping all the other plasma parameters constant.The colour of the pigment samples was characterized on the grounds of the Commission Internationale de l’Eclairage (CIE) standard procedure (CIE L*a*b* measurements) after application on a bisque ceramic tile.