The International Metals Reclamation Company, Inc.

John K Pargeter

John A MacDougall

Richard H Hanewald

Francisco Olano

A technique for rendering toxic metals (chromium, lead, cadmium and arsenic) contained in steel plant furnace dust innocuous and suitable for burial with minimal adverse environmental impact. Pelletized iron oxide containing dust is introduced into a rotary hearth furnace under a reducing atmosphere in excess of 600.degree. C. The higher iron oxides are reduced to FeO which in turn complexes with the toxic metals to form relatively benign products.

Process for the detoxification of steel plant wastes

A radiantly heated, travelling hearth furnace having a supplementary feed means positioned intermediate the initial loading point and the final take-off point to increase the capacity of the furnace for treating objects fed thereto. When the objects are pellets of iron oxide and carbonaceous reductant the provision of supplementary feed means about half-way along the travel path of the hearth promotes uniformity of product by inhibition of reoxidation of reduced iron by exposure to a fossil-fuel-fired furnace atmosphere.

Radiantly heated furnace

A countercurrent fluid cooled conveying screw is disclosed. Suitable for furnace applications, the screw includes an outer shaft spatially circumscribing an inner tube. A plurality of hollow, fluid cooled flights are affixed to the outer shaft and are in fluid flow communication with coolant coursing through the screw. The coolant is first directed through the flights and then back through the outer shaft before exiting through the inner tube.

Conveying screw for furnace

Discloses an improvement in furnacing objects on the top surface of an impervious rotating hearth in a directly fired rotary hearth furnace by the use of fuel burning with a luminous flame e.g., coal.

Furnacing

A rotary hearth adapted to rotate in horizontal plane having a top surface made of a loose granular refractory material, advantageously dead burned dolomite grain.

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Ellwood City, PA, United States of America

John K Pargeter