Malayaite ceramic pigments prepared with galvanic sludge

Autores: Costa, G.|Ribeiro, M.J.|Labrincha, J.A.|Dondi, M.|Matteucci, F.|Cruciani, G.
Fuente: Dyes and pigments
en prensa
2008

The synthesis and characterisation of chrome-tin, red malayaite Ca(Cr,Sn)SiO5 pigments is reported. The novel approach of using a galvanizing sludge from the Cr/Ni plating process as colouring agent is investigated. The ceramic pigments were prepared using a common, solid state reaction process, with optimisation of milling and firing conditions. Characterisation was undertaken using x-ray powder diffraction, diffuse reflectance spectroscopy and application in standard ceramic glazes. The ceramic pigments were of high purity (=96% malayaite) and developed a burgundy colour due to the occurrence of Cr4+ and Cr3+ and also Ni2+ in the sludge-bearing samples. The hue of the pigments agreed with standard expectations and optimal formulations showed better performance than some commercial pigments, perhaps due to the contribution of nickel.