Process for thermal treatment of residual materials containing heavy metal and iron oxide

US6451086B2 · kind B2 · utility

Assignee

• PAUL WURTH S.A. · LU

Inventors

• Thomas Hansmann · Trier, DE
• Romain Frieden · Beidweiler, LU
• Marc Solvi · Schifflange, LU

Key dates

• Filing date: Feb 12, 2001
• Grant date: Sep 17, 2002
• Expiry date: Feb 12, 2021

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S75/961
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A process for thermal treatment of residual materials containing heavy metal and iron oxide, including providing a multiple-hearth furnace having hearths provided one above the other, depositing the residual materials continuously on a top hearth of the hearths, gradually transferring the residual materials to lower hearths of the hearths, introducing reducing agents to at least one of the hearths and reacting the residual materials to form heavy metals and directly reduced iron, exhausting gases containing heavy metals from below hearths of the hearths where the heavy metals are being vaporised, re-injecting at least a part of the gases into the multiple-hearth furnace from above the hearths of the hearths where the heavy metals are being vaporised, and discharging the directly reduced iron together with residues of the reducing agents in an area of a bottom hearth of the hearths in the multiple hearth furnace.