The Possibilities of Reusing the Ceramic ...

The application of automobile catalytic converter has significantly helped to reduce air pollution of the exhaust gas released to the atmosphere. The main aim of auto catalytic converter installed in a car is to reduce the carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxide (NOx) emissions below the legislated levels. They are converted into harmless nitrogen, carbon dioxide and water. These catalytic converters responsible for the catalytic function contain precious metals such as platinum, palladium and rhodium. Catalytic converter is built based on metallic or ceramic carrier with porous structure of honeycomb shape, covered by the layer of PGM metals (Platinum Group Metals). Such construction increases the active surface which is the contact zone of precious metals with fumes. Catalytic carrier is wrapped by fibrous material and closed to stainless steel shell. As the lifetime of catalytic converters is limited; converters should be periodically maintained and after some working time, updated. Therefore, more and more used auto catalytic converters (both from exchanged and exploited cars) are placed on the scrap disposal sites. Due to high value of materials used in catalytic converters and necessity of waste management, there is an increasing interest in their recovery from waste (not only metallic part but concurrently ceramic part) to ensure the profitability of this process. The paper presents possibility of reusing ceramic parts e.g. in obtaining alumina which is important in Bayer`s method.