QSL procedure
The QSL process is a metallurgical process for extracting lead . The process, named after its inventors Queneau and Schuhmann and the Lurgi company , was initially patented in 1973 for the production of copper and nickel .
Process description
Input materials can be lead concentrates, but also secondary raw materials such as ash or sludge. These feedstocks, which are mixed with slag formers such as sand, are continuously fed in the form of pellets to a cylindrical molten bath reactor lined with refractory bricks . These fall into the melt pool in the oxidation zone and are melted at 950 ° C to 1000 ° C. By oxygen injection contained in the lead are sulphides partially oxidized, so sulfur dioxide escapes. In a subsequent reduction zone, the lead oxide slag coming from the oxidation zone is reduced at a temperature of approximately 1250 ° C. by injecting coal dust . The metallic lead obtained in this way leaves the reactor via a siphon.
Others
In addition to sulfuric acid recovery, the separation of arsenic and cadmium are of particular importance for reducing emissions .
Zinc- rich slag that is produced in the QSL process is used for zinc extraction.
literature
- VDI 2597: 2004-07 emission reduction; Plants for the production of lead and lead alloys. Beuth Verlag, Berlin. ( Summary and table of contents online )
Individual evidence
- ^ A b Franz Joseph Dreyhaupt (editor): VDI-Lexikon Umwelttechnik. VDI-Verlag Düsseldorf 1994, ISBN 3-18-400891-6 , p. 948.
- ↑ Jürgen Falbe, Manfred Regitz (Ed.): Römpp Chemie Lexikon . Thieme Verlag, Stuttgart 1995, ISBN 3-13-102759-2 , p. 5138.