Silicon Depletion in Ceramic Foam Filters (CFFs) during Aluminium Melt Filtration

Filtration is a widely used methodMethod for removing non-metallic inclusionsInclusions/bifilms from molten aluminiumAluminium, where Ceramic Foam Filters (CFFs)Ceramic Foam Filters (CFFs) dominate due to their cost-effectiveness and easy use. While many CFFs are phosphate-bonded and have been considered inert when in contact with molten aluminiumAluminium, recent studies have shown that this is not the case, making it necessary to study even non-phosphate-bonded CFFs. Through aluminiumAluminium melt pilot-scale filtration trials using a 60826082 alloyAlloys and commercial CFFs based on sintered aluminaAlumina (Al2O3) and silica (SiO2), the present study reveals that even these filters can react with the molten aluminiumAluminium. Microscopic characterizationCharacterization of unused/used CFFs confirmed two notable observations: (i) indications of silicon depletion in the used filters and (ii) minimal reactivity. Based on the microscopic evaluation and LiMCALiMCA data, the silicon depletion and the conditions leading to silicon depletion are discussed in view of its effect on filtration efficiencyFiltration efficiency.