Abstract
This study investigates diatomite-based silica ceramics designed for low thermal conductivity, using diatomite from the Utesai deposit (Aktobe region, Kazakhstan) and loam from the Romanovskoye deposit (West Kazakhstan region, Kazakhstan) as a modifying additive. The raw diatomite is characterized by high porosity and low thermal conductivity, while the ground fraction shows favorable technological behavior for ceramic processing, including low drying sensitivity. Calcination at 950 °C increases density and thermal conductivity, indicating partial densification. Silica-ceramic specimens were produced by plastic and semi-dry molding and fired at 950 °C, both from pure diatomite and from a diatomite-loam composition. The results show that 10% loam addition improves the fired structure: density and strength increase, whereas water absorption and total shrinkage decrease, with only minor changes in thermal conductivity. The combined trends demonstrate the feasibility of producing lightweight silica ceramics with improved integrity while maintaining heat-insulating performance.