Pyrometallurgy Innovation Centre (PYROSEARCH)

  • 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.

  • Selected phase equilibria studies in the Al2O3-CaO-SiO2 system

    Haccuria, Elien; Crivits, Tijl; Hayes, Peter C.; Jak, Evgueni (2016). The AlO-CaO-SiO system provides the basis for describing many important chemical processes. Although the system has previously been extensively studied, recent advances in experimental technique have provided the opportunity to obtain accurate liquidus measurements in the low-silica region at fixed temperatures. The experimental procedures involve equilibration of high-purity oxide powder mixtures at selected temperatures, rapid quenching, and accurate measurement of phase compositions using electron probe X-ray microanalysis. The liquidus isotherms have been determined at selected temperatures between 1503 and 1873 K in the anorthite, gehlenite, pseudowollastonite, corundum, CaAlO, CaAlO, lime, CaSiO, and CaSiO primary phase fields. The results are compared with currently available thermodynamic model predictions of the phase chemistry.

  • Solubility of MgO in high Cu2O slags in equilibrium with Cu metal

    Crivits, T.; Hayes, P. C.; Jak, E. (2016).

  • Integrated experimental and modelling research on copper-making slags

    Hidayat, T.; Shishin, D.; Decterov, S.; Hayes, P. C.; Jak, E. (2016).

  • Fundamental Studies in Ironmaking Slags to Lower Operating Temperatures and to Recover Titania from Slag

    Zhao, Baojun; Jak, Evgueni; Hayes, Peter C. (2016). The eutectic temperature between iron and carbon is 1150 °C. This is the lowest temperature in which Fe-C solution can be tapped from a blast furnace. Current operating temperatures of iron blast furnace are much higher than 1150 ° Cand limited bymelting temperature of the slag. There is room to lower the operating temperature of the iron blast furnace. As a result, coke consumption and CO2 gas emissions can be reduced and campaign length of the furnace can be increased. Akey factor in achieving the low operating temperature of the blast furnace is to use an optimum slag composition that can be tapped at low temperature. Phase equilibria studies have been undertaken in the system "TiO2"-CaO/MgO-Al2O 3SiO2 at carbon saturation. Extensive experimental data are presented in the form of pseudoternary "TiO2"-(CaO+MgO) - (Al2O3+SiO2) at fixedMgO/CaO and Al 2O3/SiO2 ratios.Melting temperatures of complex slag are described as functions of basicity weight ratio (CaO+MgO)/(SiO 2+Al2O3) and TiOx concentration. The phase diagrams determined in this study explain the behaviour of titanium-containing slag such as Panzhihua ironmaking slag. These diagrams will be used for selection of optimum slag composition with low liquidus temperature for both Ti-free and Ticontaining slag. The possibility of lowering ironmaking temperature by adding titania has been discussed based on the experimental data determined in this study. A large amount of iron blast furnace slag containing 20-25 wt% "TiO2" are produced in Panzhihua Iron & Steel. "TiO2" has to be concentrated before it can be efficiently extracted from the slag. It was found in this study that titanium is present in the blast furnace slag mainly in two minerals, perovskite CaTiO 3 and pseudobrookite (Mg2+,Al3+,Ti 3+,Ti4+)3O5. Electron probe X-ray microanalysis (EPMA) has been used to determine phase assemblage of the slag quenched from high temperature and the compositions of the phases. It was found that "TiO2" is 58 wt% in perovskite and 80-90 wt% in pseudobrookite. The particle size of the pseudobrookite is much larger than that of the perovskite. It was found that the composition of the current Panzhihua ironmaking slag is located in the perovskite primary phase field. The maximum "TiO2" concentration in the recovered materials is only 58 wt% if the crystal phase is perovskite. With the information provided in this study it may be possible to recover "TiO2" from the Panzhihua slag in the form of pseudobrookite so that recovered materials contains 80-90 wt% "TiO2" and can be used directly for production of pure TiO2.