Abstract Wastes management studies concerning slaker grits, a rich calcium carbonate landfilled residue from the pulp and paper industry, are focused on their application in the construction field due to their calcareous nature. To the best of our knowledge, slaker grits addition in a high calcium content ceramic frit formulation and their behavior as a glaze has not yet been explored, being the aim of this work. Grits were added as a calcium oxide source in 0, 50%, and 100%, and the frits were analyzed regarding their chemical composition, devitrification, sintering behavior, morphology, colorimetric coordinates, and scratch resistance. By means of comparison, the commercial frit was also characterized. The glazes were analyzed by their physical and thermal properties and scratch resistance. Grits did not prevent the vitreous phases obtention and, compared to the commercial frit, presented a similar behavior, although resulted in higher wollastonite devitrification that directly affected glazes’ thermal properties, sintering contraction, linear thermal expansion coefficient, among others. A great outcome was the quartz scratch resistance of the glaze containing the highest grits content, revealing an optimized behavior. Grits residue proved to be a promising alternative raw material capable of generating sustainable and economic perspectives for the ceramic coating sector.

Abstract Palygorskite (Pal) is a natural clay mineral with fibrous morphology and high surface area. Depending on the geological origin, it presents impurities, such as quartz and carbonates, which can harm some of its properties. Therefore, this work seeks to define a viable methodology for the purification of a Brazilian Pal. Two types of mixing processes (sonication and milling) and two types of dispersing agents (sodium silicate and sodium polyacrylate) were investigated. In addition, a subsequent acid activation with hydrogen peroxide and sulfuric acid was performed for complete purification. The viability of the purification of Pal was confirmed by X-ray diffraction, X-ray fluorescence, and thermogravimetric analyses. The sonication mixture process and the use of sodium polyacrylate as a dispersing agent were more effective. In addition, BET analysis showed an increase in the surface area of Pal, and scanning electron microscopy confirmed the permanence of its fibrous morphology after the purification steps.