Use of waste from mineral processing of a pegmatite with albite and spodumene in the development of frits and ceramic glazes

The use of waste incorporated into the ceramic bodies has become common in recent decades as a means to reduce production costs and to preserve mineral resources. This study aimed to evaluate the use of waste from mineral processing of a rock. The waste composed of quartz, albite and spodumene was used to produce frits and ceramics glazes to traditional ceramics. These materials were characterized by chemical composition, fusion, and thermal expansion. In a commercial transparent frit composition, increasing percentage of residue (7 to 30%) was added, and then the fusion of the new compositions was evaluated. With these frits, a ceramic glaze formulation was developed, evaluating the thermal expansion coefficient, firing defects, and aesthetic of the final product (transparency, gloss, no bubbles, and insoluble crystals). In the second step, a ceramic glaze was development, with the addition of residue on a commercial matte glaze formulation, and evaluating the gloss, opacity and color development. The results showed reduction in thermal expansion and softening temperature of the developed glaze. By adjusting the chemical composition, decreasing alkaline oxides and increasing alkaline earth oxides, it was possible to prepare formulations with product properties widely accepted in the market, with the technical and desired aesthetic characteristics. The lithium oxide acted as flux in the new formulations, with little influence on the final properties. Additionally, there was the reduction of the colorant amount, decreasing the cost associated with raw materials. (author)