Juergen Antrekowitsch

Abstract:

Slags from primary lead industry are well known as potential resource for zinc which is accumulated in the slag during lead smelting. At some of the smelters a subsequent fuming process is installed to recover zinc which is usually present in a range between 4 to 16 %.

However, at many lead producers this is not the case and the slag is landfilled. Out of this, over the years, a huge number of dumps was generated worldwide. The Chair of Nonferrous Metallurgy at Montanuniverstaet Leoben has developed possible strategies to treat such slags in a way that zinc and lead can be recovered and the remaining mineral phase containing first of all typical slag components can also be utilized. These concepts allow a full remediation of a dumpsite or a zero waste treatment of slag from ongoing smelter operations.

The present paper describes the reduction process which is performed under CO₂-neutral conditions, utilizing either hydrogen or charcoal. Furthermore, possibilities for slag modification and optimization are explained, allowing a utilization of the slag in building and construction industry. Results from various test campaigns in lab- and technical scale are discussed.

Finally, an overview of the worldwide potential and some process scenarios including economic considerations are presented.