Substantial Potential of Adamawa State Silicates for Stoneware Glaze Formulation: A Quadriaxial Blending Approach

Nigerian ceramic practitioners face persistent challenges accessing reliable, affordable glaze materials, creating dependencies on imported supplies that inflate costs and constrain local innovation. This study investigated whether minerals sourced from Adamawa State could produce functional stoneware glazes suitable for educational and small-scale production contexts. We collected feldspar and quartz from Murke' community (Song LGA) and ball clay from Vunoklang (Girei LGA), processed them through standard beneficiation procedures, and formulated 157 test glazes using systematic quadriaxial blending---36 compositions in an initial exploration, followed by 121 refined formulations. Samples were applied to bisque-fired test tiles and evaluated at 1200°C in an electric kiln under oxidizing conditions. Chemical analysis via X-ray fluorescence revealed the raw materials contained SiO₂ (55-68%), Al₂O₃ (18-32%), K₂O (2-8%), and Fe₂O₃ (1-4%). Results from the first batch showed 30.6% of compositions achieved complete fusion with strong adhesion, though high alumina content (>20%) favored matte rather than glossy surfaces. Two compositions produced excellent glossy finishes: Recipe 11 (16% feldspar, 64% quartz, 4% kaolin, 16% ball clay) and Recipe 12 (0% feldspar, 80% quartz, 0% kaolin, 20% ball clay). Recipe 12 was successfully applied to a functional washbasin. The second 121-tile batch, exploring broader compositional space, showed 14.9% fusion success but predominantly matte outcomes. Unity Molecular Formula calculations for successful glazes indicated Al₂O₃:SiO₂ ratios of 1:5.0 to 1:7.4, typical of stable stoneware systems. While the predominance of matte finishes initially surprised us, this actually aligns with contemporary design preferences favoring satin surfaces. The study demonstrates that Adamawa State possesses adequate mineral resources for viable local glaze production, potentially reducing import dependency for regional ceramists and educational institutions. We recommend adoption of validated recipes, particularly Recipes 11 and 12, with suggestions for flux optimization to expand surface finish variety.