23/10/2024: Phase diagrams in pyrometallurgy

Phase diagrams and principles of slag and matte in metallurgy

This session has its focus on phase diagrams for slag and matte. Starting from the basic phase diagrams, the structure of slag and matte is explained. It is shown how their structure influences their properties, and how the properties can be linked to the composition. For slag, the concept of basicity is introduced and the link to viscosity, refractory wear and affinity for certain metal oxides is shown. Several examples of slag and matte metallurgy are included, and it is shown how the phase diagram can be used to draw guidelines for the process.


  • 09.00: Registration
  • 09.30: Slag: structure and basic phase diagrams
    • CaO-SiO2 and FeO-SiO2, types of slags
    • The structure of silicate slag and glass
    • The miscibility gap between metals and oxides
    • Basicity as a concept and influence on viscosity
    • Chemical behaviour of slag depending on basicity
  • 11.30: Matte: structure and basic phase diagrams
    • The miscibility gap between metals and sulphides
    • The structure of matte
  • 12.30: Sandwich lunch
  • 13.30: Different elements and their tendencies
    • Ellingham diagram for oxides
    • Ellingham diagram for sulphides
    • How to approach three phase metal-slag-matte systems
  • 14.30: Applications of phase diagrams
    • Melting points of slags and determining a safe working window
    • Stability and formation of mattes
    • Higher order diagrams for complex slag systems
    • Solubility of oxygen in matte
    • Refractory wear by slag
  • 15.45: Opportunity for discussion


After the course all participants know how to interpret a phase diagram and are able to use it in industrial applications involving slag or matte. They know about the structure of slag and matte and the influence of basicity on the properties of slag.


The course will tackle the theory of the topics listed above and several exercises will be made to  ensure that everything was understood. It is advisable to bring a pencil, ruler, and calculator.

Who should attend

The course will be given in English and aims at people active in the metal processing industry. The course can be a refreshment of the metallurgical principles for engineers, or give hands-on metallurgists a solid theoretical background.

This session assumes you have sufficient knowledge about thermodynamics and that you can read a phase diagram. If this is not the case, we strongly suggest to follow this training only in combination with day 1 and/or 2.


600 € per person per day (excl. VAT)
2000 € per person for the full course program (4 days) (excl. VAT)

WhenWednesday 23 October 2024
Registration deadlineMonday 14 October 2024 (cancellation is possible before this date)
Participantsmin. 6 – max. 12
LocationInsPyro, Ambachtenlaan 54, 3001 Leuven, Belgium
RegistrationBy email: Els.Nagels@inspyro.be
By phone: +32/16.298.491 (Els Nagels)
or through the form on this page


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