Pyrometallurgy Innovation Centre (PYROSEARCH)

  • Experimental investigation of gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si System in controlled gas atmospheres: Experimental results at 1473 K (1200 A degrees C) and P(SO2)=0.25 atm

    Fallah-Mehrjardi, Ata; Hidayat, Taufiq; Hayes, Peter C.; Jak, Evgueni (2017). Experimental studies were undertaken to determine the gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system at 1473 K (1200 A degrees C), P(SO2) = 0.25 atm, and a range of P(O-2)'s. The experimental methodology involved high-temperature equilibration using a substrate support technique in controlled gas atmospheres (CO/CO2/SO2/Ar), rapid quenching of equilibrium phases, followed by direct measurement of the chemical compositions of the phases with Electron Probe X-ray Microanalysis (EPMA). The experimental data for slag and matte were presented as a function of copper concentration in matte (matte grade). The data provided are essential for the evaluation of the effect of oxygen potential under controlled atmosphere on the matte grade, liquidus composition of slag and chemically dissolved copper in slag. The new data provide important accurate and reliable quantitative foundation for improvement of the thermodynamic databases for copper-containing systems.

  • Experimental investigation of gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system in controlled atmospheres: Development of technique

    Fallah-Mehrjardi, Ata; Hidayat, Taufiq; Hayes, Peter C.; Jak, Evgueni (2017). The majority of primary pyrometallurgical copper making processes involve the formation of two immiscible liquid phases, i.e., matte product and the slag phase. There are significant gaps and discrepancies in the phase equilibria data of the slag and the matte systems due to issues and difficulties in performing the experiments and phase analysis. The present study aims to develop an improved experimental methodology for accurate characterisation of gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system under controlled atmospheres. The experiments involve high-temperature equilibration of synthetic mixtures on silica substrates in CO/CO/SO/Ar atmospheres, rapid quenching of samples into water, and direct composition measurement of the equilibrium phases using Electron Probe X-ray Microanalysis (EPMA). A four-point-test procedure was applied to ensure the achievement of equilibrium, which included the following: (i) investigation of equilibration as a function of time, (ii) assessment of phase homogeneity, (iii) confirmation of equilibrium by approaching from different starting conditions, and (iv) systematic analysis of the reactions specific to the system. An iterative improved experimental methodology was developed using this four-point-test approach to characterize the complex multi-component, multi-phase equilibria with high accuracy and precision. The present study is a part of a broader overall research program on the characterisation of the multi-component (Cu-Fe-O-S-Si-Al-Ca-Mg), multi-phase (gas/slag/matte/metal/solids) systems with minor elements (Pb, Zn, As, Bi, Sn, Sb, Ag, and Au).

  • An investigation of factors influencing freeze lining behaviour

    Crivits, Tijl; Hayes, Peter C.; Jak, Evgueni (2017). Recent studies have indicated that the steady state thicknesses and interface temperatures of freeze linings can be influenced by factors other than the thermal parameters of the systems. To explore these possibilities further cold modelling of freeze linings was undertaken in the CaCl–HO system using an experimental apparatus that enabled the variation of both the bath temperature and the fluid flow rate. Through in situ experimental observations, it was shown that the phases formed, the deposit/liquid interface temperature and the freeze lining thicknesses depend strongly on chemical parameters and elementary reaction steps, which are not considered by the conventional thermal treatment of freeze linings. These results indicate the need for further systematic investigation of various process parameters that influence the elementary reaction steps that may be active in these systems under dynamic steady state conditions.

  • The integration of plant sample analysis, laboratory studies, and thermodynamic modeling to predict slag-matte equilibria in nickel sulfide converting

    Hidayat, Taufiq; Shishin, Denis; Grimsey, David; Hayes, Peter C.; Jak, Evgueni (2017). The Kalgoorlie Nickel Smelter (KNS) produces low Fe, low Cu nickel matte in its Peirce–Smith converter operations. To inform process development in the plant, new fundamental data are required on the effect of CaO in slag on the distribution of arsenic between slag and matte. A combination of plant sample analysis, high-temperature laboratory experiments, and thermodynamic modeling was carried out to identify process conditions in the converter and to investigate the effect of slag composition on the chemical behavior of the system. The high-temperature experiments involved re-equilibration of industrial matte-slag-lime samples at 1498 K (1225 °C) and P(SO) = 0.12 atm on a magnetite/quartz substrate, rapid quenching in water, and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA) and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). A private thermodynamic database for the Ca-Cu-Fe-Mg-Ni-O-S-Si-(As) system was used together with the FactSage software package to assist in the analysis. Thermodynamic predictions combined with plant sample characterization and the present experimental data provide a quantitative basis for the analysis of the effect of CaO fluxing on the slag-matte thermochemistry during nickel sulfide converting, in particular on the spinel liquidus and the distribution of elements between slag and matte as a function of CaO addition.

  • The Synergistic Copper Process concept

    Hawker, William ; Vaughan, James ; Jak, Evgueni; Hayes, Peter C. (2017). A new process concept is proposed, one that combines the inherent advantages of conventional hydro- and pyro-metallurgical processes to provide opportunities for significant increases in resource utilisation and smelter productivity. The process involves first leaching copper minerals in aqueous solution, separation of undesirable impurity elements from the solution using conventional hydrometallurgical technologies, and then preparation of a precipitated solid copper compound product. The product can then be used directly as a high-copper, low-iron feedstock in the smelting and/or converting stages of pyrometallurgical copper production. The solid precipitated copper product can be transported to the smelter and used as a separate feed, or can be used to enhance copper concentrations in sulphide concentrate blends. This new tradeable copper product provides an effective way of increasing copper concentrate grades, and the opportunity to more efficiently utilise the excess enthalpy available from the sulphide mineral oxidation reactions in current copper matte smelting and converting process technologies.

  • Experimental study of slag/matte/metal/tridymite four phase equilibria and minor elements distribution in “Cu-Fe-Si-S-O” system by quantitative microanalysis techniques

    Chen, Jeff (Jiang); Allen Charlotte; Hayes, Peter C.; Jak, Evgueni (2017). Laboratory studies have been carried out to determine the slag/matte/metal/tridymite four condensed-phase equilibria in the “Cu-Fe-Si-S-O” system and the minor element distributions between the equilibrated phases at 1200°C. A combined quantitative microanalysis technique including electron probe X-ray microanalysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been developed to accurately characterize the equilibrated system for both major and minor elements. Analysis precision, estimated accuracy and current limitations are discussed. The resulting elemental distributions are plotted against matte grade and compared to FactSage predictions. It was found that the experimental results for major elements are in good agreement with FactSage predictions. The simultaneous distributions of Ag and Au between slag, matte and metal phases are reported for the first time.

  • Integrated experimental and modelling research for non-ferrous smelting and recycling systems

    Jak, E.; Hidayat, T.; Shishin, D.; Mehrjardi, A. F.; Chen, J.; Decterov, S.; Hayes, P. (2017). The chemistries of industrial pyrometallurgical non-ferrous smelting and recycling processes are becoming increasingly complex. Optimisation of process conditions, charge composition, temperature, oxygen partial pressure, and partitioning of minor elements between phases and different process streams require accurate description of phase equilibria and thermodynamics which are the focus of the present research. The experiments involve high temperature equilibration in controlled gas atmospheres, rapid quenching and direct measurement of equilibrium phase compositions with quantitative microanalytical techniques including electron probe X-ray microanalysis and Laser Ablation ICP-MS. The thermodynamic modelling is undertaken using computer package FactSage with the quasi-chemical model for the liquid slag phase and other advanced models. Experimental and modelling studies are combined into an integrated research program focused on the major elements Cu-Pb-Fe-O-Si-S system, slagging Al, Ca, Mg and other minor elements. The ongoing development of the research methodologies has resulted in significant advances in research capabilities. Examples of applications are given.

  • Experimental study of liquidus of the “FeO”-SiO2-PbO slags in equilibrium with air and with metallic lead

    Shevchenko, Maksym; Hidayat, Taufiq; Hayes, Peter C.; Jak, Evgueni (2017).

  • Experimental study of gas/slag/matte/spinel equilibria and minor elements partitioning in the Cu-Fe-O-S-Si system

    Hidayat, Taufiq ; Mehrjardi, Ata F.; Hayes, Peter C.; Jak, Evgueni (2017).

  • Phase chemistry study of the interactions between slag and refractory in coppermaking processes

    Mehrjardi, Ata Fallah; Hayes, Peter C.; Azekenov, Turarbek; Ushkov, Leonid; Jak, Evgueni (2017). The molten oxides (slag), matte and metal charges during smelting, converting and refining stages of the pyrometallurgical coppermaking processes are contained in refractory-lined vessels. The refractory materials are selected so as to provide resistance to corrosion by molten phases and thermal insulation to minimize heat losses while maintaining the charge in a molten state. However, high process temperature, highly agitated and chemically aggressive melts in furnaces can result in rapid degradation of the refractory and premature shutdown of the reactor for relining; imposing additional costs on processes in the form of planned and unplanned maintenance. The focus of the present study is on detailed characterization of the phase chemistry and slag interactions with refractories. The rate of reactions between refractories and liquids depends on the phase equilibria. Post-mortem analysis of the spent brick from Isa smelter was followed by isothermal finger laboratory test under controlled conditions. Electron probe X-ray microanalysis (EPMA) is used to measure the compositions of the phases across the samples. This information is linked to the phase equilibria. Thermodynamic modelling is carried out by FactSage to assist in interpretation of the results. Phase analysis of used refractory and laboratory tests for Isa smelter indicate formation of a protective spinel layer on the hot face slowing refractory dissolution.