KATIOX catalytic dioxin destruction for thermal waste treatment (precious metal recycling)

Posing the tasks

During the processing of precious metals in the jewellery industry, dental medicine and microelectronics, the following waste containing precious metals accrue. A thermal heat recovery process is used for the recycling of precious metals. All non-metallic portions of the dross are converted to ash or components of flue gas. Flue gasses must be treated in order to maintain the 17th BimSchV limit values. Essential flue gas components are dust, carbon monoxide and dioxins. The dust contains precious metals, however, and should not be disposed of but should be separately handled for recycling.

Solution / Highlights

In addition to the optimisation of the combustion system for maintenance of CO limit values, a multi-level flue gas purification was installed. Flue gasses were initially cooled with a heat exchanger to 350°C, which also corresponds to the operating temperature of the KATIOX. The greater portion of the company's hot water needs can be met with the energy recovered. A hot gas filter with ceramic filter elements was installed for dust removal, which recovers the precious metals. Through the high degree of separation, the amount of precious metal recovery is significantly increased, which justifies the investment in the system over and above the meeting of legal requirements. The KATIOX was used for oxidation of the dioxins, which could be deployed here without reheating. The effectiveness of the KATIOX is due to multiple active components, such as vanadium pentoxid, which is applied to a honeycomb formed, porous ceramic carrier, extruded from a mixture of titanium oxide and tungsten oxide. Multiple KATIOX modules are arranged next to each other appropriate to the application and installed in one housing.

In this manner, supplemental energy not is necessary and the disposal and dumping of the adsorbent, common during the adsorptive process, are excluded.