JUSTIFICATION FOR THE USE OF GRANITOID ROCK SCREENINGS IN CERAMIC BRICK PRODUCTION WITH KAOLIN ADDITION

Abstract

A comprehensive scientific and technical justification for the implementation of fine fractions (screenings) of granitoid rocks into ceramic brick production with kaolin addition was conducted. The methodology included a theoretical comparison of the physical properties of the screenings with the requirements of the SSU (State Standards of Ukraine) and a quantitative comparison of the critical fine fraction content (over 29%) with the maximum permissible norms for concrete (< 5%). On this basis, it was theoretically proven that the critical physical drawback of the screenings (excess dust) can be converted into a technological advantage (an active flux) in ceramic brick production. A theoretical energy efficiency model was developed based on chemical analysis, which confirmed the high content of alkali oxides K2O and Na2O – approximately 8.0%. Due to the high concentration of fluxing oxides (total 18.7%), it was theoretically justified that granite sludge can substitute refractory kaolin and act as an effective flux. Significant technological advantages were predicted: a reduction in the optimal firing temperature to 1000–1150°C (vs. >1200°C), theoretically providing a fuel saving of 10–20%, along with an expected increase in compressive strength and a sharp decrease in water absorption. Based on the theoretical justification, specific final formulations of ceramic compositions (series E1–E4) with the systematic introduction of granite screenings (from 10% to 40%) and a thermal step firing scheme (950°C – 1150°C) were proposed, which are the necessary basis for the experimental confirmation of the low-temperature sintering hypothesis.