Ceramic pigments based on chain-structure silicates

• Published in: Glass and ceramics 1992, Vol.49 (1-2), p.43-44
• Main Authors: SIRAZHIDDINOV, N. A, AKRAMOVA, N. N, VELIKANOVA, F. I, PULATOVA, L. Z, AKHMEDOV, B. M
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Chemical industry and chemicals; Exact sciences and technology; Glazes, enamels
• ISSN: 0361-7610; 1573-8515
• DOI: 10.1007/BF00676675

The Voronezh Earthenware Factory supplies pigments for use in bodies and glazes for colouring the surfaces of ceramic tiles. Pigment supply is very limited, however, and does not satisfy the growing demands in the Uzbekistan region. The use of local raw materials, e.g. wollastonite concentrate, which is very resistant at high temperatures, was investigated. CaO.SiO2 contains chains of bonded Si-O tetrahedra; the position of these tetrahedra is distorted due to the Ca cations, and the possibility of isomorphic substitution arises in which colouring oxides (Co, Ni, Cr, Fe, etc.) may take part. A mixture of 93-98% wollastonite concentrate containing 78% wollastonite, together with 2-7% cobalt oxide, was fired at 1150-1250 C for 1 h. X-ray phase analysis indicated that the optimum firing temperature for the wollastonite-based cobalt pigments was 1250 C. The pigments have good chromophore properties. Addition of 2-7% to production glazes gave a glazed tile surface with colours ranging from pale to intense purple. The pigments are resistant to the solvent action of glazes and to high temperatures.