New technologies and compositions for recycling non-ferrous metallurgical waste into acid-resistant ceramics without using traditional natural raw materials

This study investigates non-ferrous metallurgy waste – specifically, the clay fraction of zircon-ilmenite ore gravity separation tailings (ZIGT) – with the aim of using it as both a clay component and a non-plastic additive (chamotte derived from ZIGT) in the production of acidresistant ceramic tiles. It was found that samples made solely from ZIGT (without any additives), fired at temperatures of 1250–1300 °C, do not meet regulatory requirements for acid resistance. Introducing 40 wt. % chamotte into the ceramic body was found to be optimal for producing acid-resistant tiles at 1300 °C that comply with all requirements of GOST 961-89 Acid-Resistant and Thermo-Acid-Resistant Ceramic Tiles, grade KSh (chamotte-based acid-resistant tiles). Increasing the chamotte content beyond 40 wt.% reduces the clay binder fraction, which in turn lowers the plasticity index (to below 11), causing cracks to form in the samples during shaping. The phase composition of four tile samples with varying ZIGT and chamotte contents was analyzed. X -ray diffraction patterns of the samples fired at 1300 °C revealed prominent peaks corresponding to mullite, cristobalite, quartz, and hematite, which were also confirmed by IR spectroscopy. The formation of mullite is crucial in the production of acid-resistant ceramics, as mullite is the primary phase determining the operational properties of the material. As a result, new ceramic compositions were developed and acid-resistant tiles were obtained from non-ferrous metallurgy waste without the use of conventional natural raw materials.