Solubility of high melting temperature oxides (CaO, Al2O3, Cr2O3) in copper oxide liquid

Joseph Hamuyuni

Research output: ThesisDoctoral ThesisCollection of Articles


Thermodynamic databases consisting of carefully acquired phase equilibrium and thermochemical data for oxide systems are an invaluable tool towards optimization and improved control of current copper making processes. Fluxing, which is the main control procedure in copper smelting processes can be fully optimized by employing an accurate thermodynamic database. The result of optimization is a controlled process, which is both efficient in utilization of input materials and versatile to continually changing raw materials. Because a thermodynamic database for metal making processes cannot be modelled solely from first principle calculations, experimental phase equilibrium data is critical in obtaining a consistent database relevant for industrial applications. In this study, an equilibration and quenching technique was adapted to acquire experimental phase equilibria data for selected systems in temperature and composition ranges either poorly known or not previously investigated. For the system Cu-O-CaO in oxidizing conditions, new experimental liquidus data between 1300 and 1500 oC are presented in this study. In the system Cu-O-CaO-Al2O3, experimental phase equilibria of the triple points of the system by the quenching technique are presented for the first time. Prior to this study, phase equilibria of the system Cu-O-CaO-Al2O3 has not been experimentally studied, otherwise equilibria of the system was estimated by extrapolations. The liquidus of the system Cu-O-Cr2O3 has also been investigated by the equilibration technique for the first time. Experimental results of this thesis reveal that liquidus data for simple oxide systems of copper are poorly known and currently insufficient to accurately predict higher order systems. The experimental phase equilibria data acquired in this dissertation will improve prediction of high order oxide systems for process metallurgy.
Translated title of the contributionKorkean sulamispisteen oksidien (CaO, Al2O3, Cr2O3) liukoisuus nestemäiseen kuparioksidiin
Original languageEnglish
QualificationDoctor's degree
Awarding Institution
  • Aalto University
  • Taskinen, Pekka, Supervisor
  • Taskinen, Pekka, Advisor
Print ISBNs978-952-60-6929-6
Electronic ISBNs978-952-60-6928-9
Publication statusPublished - 2016
MoE publication typeG5 Doctoral dissertation (article)


  • Phase equilibria
  • liquidus
  • quenching
  • EPMA
  • thermodynamic database
  • MTOX

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