Upgrading copper slag cleaning tailings for re-use

Keiran Holland, R. Hürman Eriç, Pekka Taskinen*, Ari Jokilaakso

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

23 Citations (Scopus)
147 Downloads (Pure)


Tailings from an industrial copper slag cleaning milling and flotation circuit have been pre-reduced at low temperatures, well below its melting point, using CH4-H2-Ar mixtures with the aim of metallizing its iron oxide component to metallic iron. The treatment carried out at 700–900 °C, with a duration of up to 90 min, indicated a complete transformation of magnetite within the first 30 min of the process. At the same time, significant fractions of its harmful impurities, antimony, arsenic, bismuth, lead and zinc, present as oxides in the slag were reduced from magnetite and the glassy inter-granular phase, and removed from the slag as flue dust in the process off-gas. The obtained fine slag powder with low impurity contents can be melted after the pre-reduction to synthetic rock or to fast cooled slag granules for further use.

Original languageEnglish
Pages (from-to)35-42
Number of pages8
JournalMinerals Engineering
Publication statusPublished - 15 Mar 2019
MoE publication typeA1 Journal article-refereed


  • Hydrocarbons
  • Reduction kinetics
  • Slag utilization
  • Smelting
  • Volatilization


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