High chemical stability of stoneware tiles containing waste metals

Stoneware tiles were produced by the incorporation of galvanic waste to industrial compositions that were processed from kaolinitic clay, feldspar, quartz and recycled domestic glass. The galvanic waste required a calcination step to eliminate the gas forming species prior to its incorporation into industrial processes and crystalline phases were formed. After that, the effective incorporation of metals from the galvanic waste was attained through the formation and the refinement of crystalline phases that acted as pigments. During the fast firing the calcined galvanic waste only got partially dissolved in the liquid phase that developed in spinel phase nanocrystals. The followed procedure allowed to effective immobilization of up to 10 wt% of waste with heavy metals in a porcelain stoneware that satisfy both the mechanical and the chemical standards required to massively commercialize such a product.