| abstract |
In a new procedure for the treatment of ceramic catalysts which are coated or impregnated with a noble metal, honeycomb catalyst elements are chopped and ground to about 100 microns and metallic particles are then separated in a rotating permanent magnet separator. The separation is performed under a vacuum. Also claimed is an installation for carrying out the procedure, consisting of a press (4), a ball, hammer or roller mill (10) and a separator (20) with magnetic rollers (23). The separator is located inside a vacuum vessel (25) with an airlock system (29) and the press and mill are also of a dust-tight construction. The pulverised catalyst is fed into the vacuum system in a batch-wise manner. The separated metal is smelted and further treated separately from the ceramic material. The vacuum is maintained by a continuous suction system (32), such as a water jet (33) or water ring pump, with an inlet filter (34), and the exhaust gas is cleaned and vented to the atmosphere. The mill and press are connected to suction devices (9, 14) with an exhaust gas cleaner (8) in the form for example of an activated carbon filter. The separator vessel has an integral inlet airlock (19) which is connected to the vacuum pump (32). Alternatively, the entire treatment process may take place inside a sealed enclosure with a circulating air system, a make-up air system and inlet and outlet airlocks. USE/ADVANTAGE - For processing used catalysts and especially catalysts used for removing nitrogen oxides from combustion exhaust gases. The catalysts are processed in an environment-friendly manner and the valuable metal content is recovered for further use. |