THE STUDY OF PREPRATION OF BLUE V ZIRCON PIGMENT BY USING ZIRCON AND SULPHURIC ACID

Depending on the type of dopant metal, many kinds of zircon based pigments are produced and blue vanadium pigment is the most important one of them. In this study, blue zircon ceramic pigments were synthesized from intermediate product, resulting from decomposition of zircon sand with NaOH. In this regard, various amounts of sulfuric acid, water, NH(4)VO(3) as colorant, NaF as mineralizer and extra quartz were added to the prepared Na(2)ZrSiO(5). Role of quartz was to omit the repercussions of presence of free zirconia in the composition. The main objective of this work is to assess various reactions at different temperatures during blue pigment synthesis. Phase analysis was done by X ray diffraction and infrared spectroscopy. Color quality was determined by CIE Lab. The best composition was studied by DTA to determine temperatures of the reactions. Powders heated at various temperatures were studied by X ray diffraction and infrared spectroscopy to investigate crystallization behavior. It was concluded that V(+5) doped tetragonal zirconia has first been formed at temperatures lower than 600 degrees C. Then, from 820 to 890 degrees C, an endothermic reaction of formation of monoclinic zirconia from tetragonal zirconia and an exothermic reaction of formation of zircon from monoclinic zirconia and quartz occur, respectively.