Method of reprocessing zinc- and lead-containing residues from metallurgical plants by means of a circulating fluidized bed system

US5162107A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Martin Hirsch · Friedrichsdorf, DE
• Albert Kaune · Königstein, DE
• Alpaydin Saatci · Frankfurt am Main, DE
• Karlheinz Broj · Hattersheim, DE
• Uwe Harter · Dinslaken, DE
• Walter Meichsner · Krefeld, DE

Key dates

• Filing date: Dec 20, 1990
• Grant date: Nov 10, 1992
• Expiry date: Dec 20, 2010

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S423/16
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A zinc- and lead-containing residue from a metallurgical plant is reprocessed by a thermal treatment in a circulating fluidized bed system. A major part of the heat demand is satisfied by a combustion of solid carbonaceous material in the fluidized bed reactor of the circulating fluidized bed system. A reducing fluidizing gas, which is virtually free of free oxygen, is fed to the lower part of the fluidized bed reactor. A solid carbon content of from 5 to 30% is adjusted in the fluidized bed in the lower portion of the fluidized bed reactor, which is supplied in its upper portion with oxygen-containing gases and in which CO.sub.2 is formed only at such a rate that zinc metal is not reoxidized. Substantially all solids are removed in a recycling cyclone from the suspension discharged from the reactor and the removed solids are recycled. The gas is cooled to a temperature at which zinc metal is oxidized to ZnO. The dust-like zinc compounds and lead compounds are removed from the gas.