The Replacement of Seashells with Calcite in White Ceramic Glaze Preparation

Authors : Levent KOROGLU, Ceren PEKŞEN

Pages : 956-964

Doi:10.16984/saufenbilder.728340

View : 24 | Download : 10

Publication Date : 2020-10-01

Article Type : Research Paper

Abstract :In this study, the effect of seashell utilization as a replacement for calcite on the surface features and optical properties of white ceramic glazes was investigated. As received seashells collected from Black Sea beaches of Samsun, Turkey and purified seashells at 700°C for 1 h were used as calcite replacement by 15 wt.%. Seashell powders were incorporated to white glaze compositions which are applied on the surface of different fired clay bodies such as red clay, chamotte, white and porcelain by dipping technique. Next, the glazed green bodies were sintered at 1100ºC for 8 h. Following to TG-DTA, heating microscope, XRD and optical analysis, the obtained results exhibited that as received seashell powder insert ignore into journalissuearticles values(SP-1); was composed of calcite insert ignore into journalissuearticles values(CaCO3);, whereas purified seashell powder insert ignore into journalissuearticles values(SP-2); comprised aragonite insert ignore into journalissuearticles values(CaCO3); and calcium oxide insert ignore into journalissuearticles values(CaO);. The iron insert ignore into journalissuearticles values(hematite); content in red clay and the impurities in seashells composition caused specks and crawlings on the surface of glazed red clay bodies and of some glazes containing seashell, respectively. In generally, the higher CaO content in SP-2 enhanced gloss insert ignore into journalissuearticles values(60°); values, and whiteness values of most glazed surfaces were closed to each other. The color of chamotte bodies increased redness-greenness values. The variations in optical parameters were mainly associated with the difference in body compositions. SP-1 contained glaze, applied on porcelain body, was selected as optimal because that had 33 gloss value, high whiteness insert ignore into journalissuearticles values(87); and no surface defect. Therefore, the utilization of as received seashells by 15 wt.% as calcite replacement allows eco-friendly and cost-effective production of white ceramic glazes without any additional heat treatment.
Keywords : White Ceramic Glazes, Seashells, Calcite, Optical Properties, Clay Products