Metallgesellschar Aktiengeselschaft

Guenter Boening

Gernot Mayer-Schwinning

Hansjoerg Herden

The process of purifying oxygen-containing exhaust gases produced by combustion of waste materials including garbage, industrial waste and sewage sludge includes reacting an exhaust gas containing pollutants in a gas-solids suspension at a temperature of 120.degree. to 140.degree. C. and at a gas velocity from 3 to 20 m/s for a reaction time of 0.5 to 10 seconds with a mixture containing naturally occurring zeolites to remove mercury, mercury compounds and polyhalogenated hydrocarbons pollutants from the exhaust gas. The naturally occurring zeolites have a median particle size (d.sub.50) from 5 to 50 micrometers and the gas-solids suspension has a mean suspension density from 0.020 to 10 kg of solids per sm.sup.3 of exhaust gas. The mixture contains from 10 to 20% by weight mordenite, from 60 to 70% by weight clinoptilolite, from 0 to 5% by weight montmorillonite and a remaining balance of SiO.sub.2. The purified gas contains &lt;50 micrograms of mercury per sm.sup.3, &lt;0.1 ng TE per sm.sup.3 of polyhalogenated dibenzodioxins and dibenzofurans and of &lt;1 microgram of PCB, PCP and PCA per sm.sup.3.

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Frankfurt am Main, Germany

Guenter Boening