Metallgesellschaft Aktiengesellschaft

Dirk Hankel

Fred Erich Cappel

Hans Beisswenger

Friedrich Rosenstock

Walter Koch

Gurudas Samant

Gebhard Bandel

Erhard Weilandt

Johann Renner

Heinrich Meiler

Stephan Becker

Organic and/or inorganic substances and water are thermally separated from contaminated materials, solid aggregates, the contaminated material is pretreated and is subsequently heated in a directly or indirectly heated furnace, which includes a rotary kiln, a fluidized bed furnace or a floating zone reactor, and during the heating the material is treated with recycled hot gases or recycled hot steam and with oxidizing agents. The exiting processing gases, which contain water vapor, are dedusted, and 80 to 90% by volume of the water vapor-containing processing gases are recycled to the furnace to act as entraining gas. The remaining water vapor-containing processing gases are condensed, the resulting liquid phase is withdrawn, and pollutants are removed from the withdrawn liquid phase by a wet chemical or physical processing.

Process for thermally separating organic and/or inorganic substances

For a separation into a purified fraction and a polluant concentrate, contaminated soils are ground in a drum to which loose pieces acting like grinding elements have been added and with a net energy input of 4 to 16 kWh per 1000 kg throughput. The speed is 50 to 90% of the critical speed ##EQU1## The suspension discharged from the drum is separated by sieving into a relatively coarse fraction and a relatively fine fraction. The relatively coarse fraction is discharged as a purified fraction and the relatively fine fraction is desludged. The separated sludge is dewatered and is subsequently delivered as a polluant concentrate. The desludged remainder of the finer fraction is dewatered and is subsequently delivered as purified soil.

Process of dressing contaminated soils

Disclosed is a process for burning cattle dung at a temperature of from 500.degree. to 780.degree. C., preferably from 650.degree. to 780.degree. C., in the presence of one or more aluminum-containing substances selected from the class consisting of bauxite, kaolin and aluminum compound-containing ash from furnaces for firing solid fuels. A major part of the alkalies contained in the cattle dung and a substantial part of the chlorine are retained in combined form in the resulting furnace ash.

Process of burning cattle dung

Calcine which has been obtained by roasting in a fluidized bed and contains zinc oxide is briquetted at elevated temperatures. To produce briquettes having desirable properties for processing in a zinc-producing shaft furnace, the calcine is provided with metallic lead and/or lead oxide in an amount corresponding to at least 3% lead, non-caking coal having a low content of volatile constituents is admixed to the calcine, the Pb:C weight ratio is adjusted to at least 1, and the mixture is briquetted at a compacting temperature of 250.degree. to 470.degree. C. and under an applied pressure amounting to 4 to 20 metric tons per centimeter or roll width when said pressure is dynamically measured.

Process of producing briquettes to be charged to zinc-producing shaft

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Muhlheim, Germany

Dirk Hankel