Abstract

GONCALVES, Lucy; MORONTA, Delfín; OCANTO, Freddy  and  LINARES, Carlos. Synthesis of ultramarine blue type pigments using several raw materials. Rev. Fac. Ing. UCV [online]. 2010, vol.25, n.1, pp.25-31. ISSN 0798-4065.

The main goal of this study was to synthesize blue ultramarine-type inorganic pigments by using several raw materials. During the synthesis we used a national and Spanish kaolin, a national pirophilite, elemental sulphur, sodium carbonate and carbon. Previously, clays were dehydrated at 700°C for 6, 12 and 24 h, and then they were characterized by EDX analysis, FT-IR and powder-ray X diffraction. After that, pigments were synthesized by using variable S₈/Na₂CO₃ ratio and different reaction times. These solids were also characterized by FT-IR, powder X-ray and EPR. The clay used was a key factor in the synthesis of sodalite-type zeolite due to the fact that a high Si/Al ratio does not allow the formation of the sodalite. The best conditions to synthesize blue ultramarine were a S₈/Na₂CO₃ = 0.3 ratio and a 24 h dehydration time for the raw material

Keywords : Ultramarine blue pigments; Kaolin; Sodalites; Polysulfides; Pirophilite.