Feldspathic fluxes for ceramics: Sources, production trends and technological value

Feldspathic fluxes are fundamental ingredients of many ceramic products, but little is known about the sources actually utilized by industry and the evolution over time. This paper reviews the sourcing of feldspathic raw materials over a long timespan (1971-2016) including viable substitutes (particularly recycled materials and end-of-life products). A large set of data was collected, critically assessed and elaborated to get an original insight into market dynamics. In addition, the technological value, based on composition and technological properties of different fluxes, is referred to ceramic use and batch design. A detailed analysis of ongoing trends, mainly driven by the technological innovation in the ceramic tile industry, disclosed possible criticalities in the medium-term supply of key raw materials, principally sodium feldspar from albitites. To mitigate this risk, three actions are envisaged to improve the resource efficiency and sustainability of feldspathic fluxes: 1) full valorization of primary deposits, 2) increasing recourse to alternative sources, 3) relaxing the technological constraints in ceramic applications.