Pyrometallurgy Innovation Centre (PYROSEARCH)

  • 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.

  • High-temperature experimental and thermodynamic modelling research on the pyrometallurgical processing of copper

    Hidayat, Taufiq; Shishin, Denis; Decterov, Sergei A.; Hayes, Peter C.; Jak, Evgueni (2017). Uncertainty in the metal price and competition between producers mean that the daily operation of a smelter needs to target high recovery of valuable elements at low operating cost. Options for the improvement of the plant operation can be examined and decision making can be informed based on accurate information from laboratory experimentation coupled with predictions using advanced thermodynamic models. Integrated high-temperature experimental and thermodynamic modelling research on phase equilibria and thermodynamics of copper-containing systems have been undertaken at the Pyrometallurgy Innovation Centre (PYROSEARCH). The experimental phase equilibria studies involve high-temperature equilibration, rapid quenching and direct measurement of phase compositions using electron probe X-ray microanalysis (EPMA). The thermodynamic modelling deals with the development of accurate thermodynamic database built through critical evaluation of experimental data, selection of solution models, and optimization of models parameters. The database covers the Al-Ca-Cu-Fe-Mg-O-S-Si chemical system. The gas, slag, matte, liquid and solid metal phases, spinel solid solution as well as numerous solid oxide and sulphide phases are included. The database works within the FactSage software environment. Examples of phase equilibria data and thermodynamic models of selected systems, as well as possible implementation of the research outcomes to selected copper making processes are presented.

  • The synergistic copper process - a new process route for low-energy copper production

    Hawker, William; Vaughan, James; Jak, Evgueni; Hayes, Peter C. (2016). A new process concept has been developed that will enable significant increases in productivity to be achieved from existing copper smelting and converting operations. Key to the Synergistic Copper Process is the utilisation of the excess enthalpy currently available from the sulphide oxidation reactions that take place pyrometallurgical processing. The process involves the preparation of precipitated oxide forms of copper and their introduction of this intermediate product into copper smelting and converting reactors. The precipitated oxide can be prepared using any leaching technology to recover copper ions in aqueous solution. The solution is treated to increase the pH of the solution and produce selective precipitation of firstly iron and then copper. The intermediate copper product can be then be pre-treated utilising low grade waste heat to remove residual free or chemically-bound water before being introduced directly into the pyrometallurgical reactors as a supplemental copper feed source. The process can be used in conjunction with all presently-used pyrometallurgical copper production process technologies. This process route provides an attractive alternative to the SX/EW route currently employed industrially to recover copper from oxidised and some sulphide ores. The process can be adapted to any virtually method of obtaining leach copper. The precipitated intermediate product has grades comparable with conventional sulphide concentrates and can be blended with other copper smelter feedstocks or used directly as a high-copper, low-iron feedstock in the smelting or converting stages. The process enables smelter productivity to be increased with minimal capital expenditure on smelter upgrades; provides an alternative method of preparation and of utilising new copper-containing intermediate products to improve overall copper recovery.