Development of experimental approach for the phase equilibria study of arsenic-containing systems

The technique of arsenic-contained compounds synthesis has been developed. The experimental samples synthesis is proposed to be divided in\ua0two stages. The first stage includes the long-term heating of samples in specially developed high-pressure furnace with the excessive pressure to 50\ua0bar at 900\ua0°C. The second stage relates to conventional heating process at 1\ua0atm pressure and 1200\ua0°C. Results of differential thermal analysis, scanning electron microscopy and energy-dispersive x-ray spectroscopy has shown the consistency of obtained data to the preset phases and their compositions. The developed method can be used for studies of phase equilibria in multicomponent arsenic-contained systems or any complex systems with volatile compounds

Experimental investigation of slag/matte/metal/ tridymite equilibria in the Cu-Fe-O-S-Si system at 1 473 K (1200°C), 1 523 K (1250 °C) and 1573 K (1300 °C)

Laboratory experimental study was undertaken to characterise the four-phase slag/matte/metal/tridymite equilibria of the Cu-Fe-O-S-Si system at 1 473 K [1 200 8C], 1 523 K [1 250 8C] and 1 573 [1 300 8C] in a "closed" system without interaction with gas phase. The research methodology involved high temperature equilibration, ultra-fast quenching of the equilibrated samples followed by quantitative measurement of the equilibrated phases by electron probe X-ray microanalysis. Attainment of chemical equilibrium was carefully checked by the 4-points test approach. The results obtained in the present study provide reliable fundamental experimental information, which is crucial for the development and optimisation of the multicomponent thermodynamic database for copper-containing systems

Phase equilibria and minor element distributions in complex copper/slag/matte systems

To address the increasing complexity of feed materials to pyrometallurgical processes, an integrated experimental and thermodynamic modeling research program is in progress to accurately characterize the multi-phase gas-slag-matte-speiss-metal-solids 17-component Cu/Pb-(CuO-PbO-ZnO-CaO-FeO-FeO-SiO)-(AlO-MgO)-S-(As-Bi-Sb-Sn-Ag-Au-Ni) system. New experimental data are used to continuously improve the thermodynamic database using FactSage. An example is provided on the slag-matte distributions of Bi, Pb, and Zn in equilibrium with tridymite in the Cu-Fe-O-S-Si system under copper smelting conditions. A closed system equilibration experimental technique with rapid quenching was used. Major element concentrations in phases were measured with electron probe x-ray microanalysis. A laser ablation inductively coupled plasma mass spectrum technique was used for determination of Bi, Pb, and Zn concentrations in slag. New experimental data contributed to the optimization of thermodynamic model parameters. Improved thermodynamic databases can be used to accurately predict the elemental distributions in multi-component systems; an example is given for the minor element distributions between slag and matte for industrial conditions

Experimental investigation of gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si-Al-Ca-Mg system in controlled gas atmosphere: experimental results at 1473\ua0K (1200\ua0°C), 1573\ua0K (1300\ua0°C) and p(SO2) = 0.25\ua0atm

The effect of temperature, CaO, MgO and AlO on important technological copper smelting parameters, such as the chemically dissolved copper in slag and the composition of the liquid phase in equilibrium with tridymite, are experimentally characterised as a function of copper concentration in matte. Two series of experiments for the gas/slag/matte/tridymite equilibria in the Cu-Fe-O-S-Si system at p(SO) = 0.25\ua0atm have been carried out. The effect of CaO at 1573\ua0K (1300\ua0°C), and the combined effect of AlO + CaO + MgO at 1473\ua0K (1200\ua0°C) and 1573\ua0K (1300\ua0°C) have been measured in the first and second series of experiments respectively. The experimental methodology involves high temperature equilibration of samples on a substrate made from the primary phase under controlled gas atmosphere (CO/CO/SO/Ar), followed by rapid quenching of the equilibrium condensed phases and direct measurement of the phase compositions using the Electron Probe x-ray Microanalysis. The resulting data are used in the optimization of the thermodynamic database for the copper-containing systems