Glass ceramics and mineral materials for the immobilization of lead and cadmium

Abstract : Waste management is one of the major global environmental issues. Incineration is an efficient treatment since it offers both a reduction of mass and volume and a possibility of energy recovery. One of the problems of incineration is the production of fly ash which is considered as hazardous waste with obligation of final disposal into a specific landfill. The objective of the present study is to investigate glass ceramics and sintered ceramics as new mineral materials for a sustainable immobilization and possible recycling of these incineration wastes. Toxic elements can be incorporated into crystals embedded in a glass matrix which has a function of the second barrier, or in highly resistant crystalline structure in a sintered ceramic. Based upon cations size considerations, this study is focused on Ca-rich or Ba-bearing minerals as possible hosts of lead and cadmium. Promising results have been obtained for CaMgSi2O6 diopside-bearing glass ceramics and sintered Ba1.5Mg1.5Ti6.5O16 hollandite, both in terms of toxic elements incorporation and of chemical resistance.