Glass-Ceramics with Multibarrier Structure Obtained from Industrial Waste

In order to form a multibarrier structure for wastes, the ecologically incompatible substances may be diluted and chemically bound until their recycling products gain a structure like natural mineral or glass. After that, remineralised materials are converted into a new product by melting or powder technology using an ecological compatible type of waste as a matrix phase. Waste treated in this way could be used to produce ceramic building materials such as floor tiles, pavers and cast products. Industrial waste from a metallurgical factory in Latvia ("Liepajas metalurgs") includes metallurgical slag, filter dust, etching waste and sewage used in technologies. The main constituents of this waste are oxides of Fe, Ca, Si, Mg, Al, Mn, etc. In some types of waste, a small amount of hazardous elements such as Cr, Ni, Zr, Sn and Pb can occur. The combination of metallurgical waste with peat ashes from Riga thermal power station, oil shale ashes or glass waste under controlled sintering gives bulk materials with surface or/and bulk crystallisation. The structure of the glass-ceramics formed may prevent the migration of the harmful elements into the environment due to corrosion or friction. The properties and thermal behaviour (DTA, dilatometry, melting) of the waste define the sintering range for producing glass-ceramics (powder technology) and decorative glass-ceramic materials (melting and powder technology). 5 refs.