A METHOD FOR THE MANUFACTURE OF AQUEOUS SOLUTION OF METAL COMPLEXES AND A METHOD OF MANUFACTURING HIGH TEMPERATURE COLOURED VITREOUS GLASS-CERAMIC TILES

摘要

Disclosed herein is a method for the manufactunng of aqueous solutions of metal complexes comprising the step of adding the selected metal compound to a solution of one or more organic acids; heating the mixture formed to near boiling temperatures wherein redox reactions take place to form stable complexes with the organic complexing agents, removing the complex so formed by conventional methods. The said solution is suitable for use as a colouring formulation for vitrified glass-ceramic tiles, for obtaining excellent shades. There is also described a method of manufacturing high temperature coloured vitreous glass-ceramic tiles using aqueous solutions of metal complex comprising the steps of: a. pre drying of the pressed, unfired (green) tile so as to reduce the moisture content to less than 0.5%; b. treating the surface of the ceramic with an aqueous solution of metal complexes specially prepared by the method such as herein described, so as the colour penetratcs into the tile to a predetermined depth; c. firing the tiles to enable reaction between the said ions and tile matrix to form the required colours; and d. the desired shade and depth of colour in reflectance are adjustable varied by mixing different metal ions complexes and controlling the multivalent states of metal ions.