MILLING DERIVED-CHANGES IN ZRO2 SIO2 REVEALED BY THE PERTURBED ANGULAR CORRELATIONS (PAC) SHORT RANGE TECHNIQUE

M.C. CARACOCHE; J. A. MARTINEZ; PATRICIA C. RIVAS; F. ANDREOLA; L. BARBIERI; F. BONDIOLI; A. M. FERRARI; I. LANCELLOTTI

Verona, Italia

Congreso; 2nd. International Congress on Ceramics; 2008

Zircon sand is by far the largest source of zirconium minerals used in industrial applications; most commercial zirconium minerals originate from Australia, South Africa, India and the United States of America representing about 80% of worldwide commercial zircon production. All zircon sand contains radionuclides of natural origin, primarily those in the uranium (U) and thorium (Th) decay series.  The uranium and thorium atoms and their decay elements are bound within the zircon crystal structure, substituting for a small number of zirconium atoms. The nature of the zircon crystal is such that the removal of uranium and thorium is not easily accomplished without destruction of the crystal lattice. As the concentrations of these radionuclides are low but significantly higher than those in normal rocks and soil, all operations involving zircon need to be considered for regulation. Milling is one of them since most of the zircon sand used in industrial applications has to be first milled to smaller particle sizes into two basic types: zircon flour and micronized zircon. In ceramic industry, zircon sand is widely used in different applications because zirconia plays a role as common opacifier constituent.  Normally it is added in glazes for tiles and sanitaries and it is also used as an opacifier in porcelain stoneware body. In this research were determined the nanoconfigurations present in the starting damaged zircons and also in the micronized zircons in order to investigate possible changes caused by the milling procedure.