Search

Abstract Phase equilibria of the binary PbO-ZnO and ternary PbO-ZnO-SiO 2 systems have been experimentally investigated at 1033–1898 K (760–1625 °C) for oxide liquid in equilibrium with air and solid oxide phases: tridymite or cristobalite (SiO 2), willemite (Zn 2 SiO 4), zincite (ZnO), larsenite (PbZnSiO 4) and lead-zinc melilite (Pb 2 ZnSi 2 O 7) covering the ranges of concentrations not studied before. High-temperature equilibration on primary phase or inert metal (platinum) substrates, followed by quenching and direct measurement of the Pb, Zn and Si concentrations in the phases with the electron probe X-ray microanalysis (EPMA) has been used. Liquidus phase equilibrium data is essential for the development of the thermodynamic model. [ABSTRACT FROM AUTHOR]

Phase equilibria of the binary PbO-CaO and ternary PbO-CaO-SiO2 systems have been investigated at 870-1655 °C for oxide liquid in equilibrium with air and solid oxide phases: tridymite or cristobalite SiO2, pseudowollastonite CaSiO3, dicalcium silicate (Ca,Pb)2SiO4, tricalcium silicate (Ca1−xPbx)3SiO5 (x < 0.03), new phase tricalcium-lead silicate (Ca0.8Pb0.2)3SiO5 (Ca12Pb3Si5O25), lime CaO, and calcium plumbate Ca2PbO4, covering the ranges of concentrations not studied before. High-temperature equilibration on primary phase or inert metal (platinum, gold) substrates, followed by quenching and direct measurement of the Pb, Ca and Si concentrations in the phases with the electron probe x-ray microanalysis (EPMA) has been used to accurately characterize the system. Liquidus phase equilibrium data of the present authors for the PbO-CaO-SiO2 system are essential to obtain a self-consistent set of parameters of thermodynamic models for all phases. [ABSTRACT FROM AUTHOR]

Abstract Liquidus phase equilibrium data of the present authors for the PbO-ZnO and the PbO-ZnO-SiO 2 systems (as a part of multicomponent PbO-ZnO-FeO-Fe 2 O 3 -Cu 2 O-CaO-SiO 2), combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases. The modified quasichemical model is used for the liquid slag phase. From these model parameters, the optimized ternary phase diagram is back calculated. [ABSTRACT FROM AUTHOR]

The phase equilibria of the "CuO 0.5 "-"FeO"-SiO 2 slag system in equilibrium with metallic copper and tridymite/cristobalite (SiO 2), and the "FeO"-SiO 2 slag system in equilibrium with metallic iron and tridymite/cristobalite (SiO 2) were investigated between 1400 and 1680 °C. High temperature equilibration in closed silica ampoules, followed by quenching and the direct measurement of the phase compositions with the electron probe X-ray microanalysis (EPMA) was used. The liquidus isotherms in the tridymite and cristobalite (SiO 2) primary phase fields were measured, and the shape of the two liquid slags miscibility gap over cristobalite was determined for the "CuO 0.5 "-"FeO"-SiO 2 and "FeO"-SiO 2 systems in equilibrium with metallic copper and iron respectively. The two liquid slags miscibility gap over cristobalite was found to be present at all Cu/(Cu+Fe) molar ratios in the slag. However, the difference in the SiO 2 concentration between the low- and high-SiO 2 slag was found to decrease as the Cu/(Cu+Fe) molar ratio in slag approached 0.5, with the minimal difference assessed to be approximately 4 mol.%. Additionally, new phase equilibria data obtained for the "FeO"-SiO 2 subsystem in equilibrium with metallic iron suggested that the monotectic temperature of the subsystem is 1673 ± 3 °C, and that the low- and high- SiO 2 slags contain 59.7 mol.% and 96.4 mol.% SiO 2 respectively. The present study was a continuation of previous investigations by the authors into the Cu-Fe-Si-O multicomponent slag system, aimed at providing information for improving the thermodynamic models for all phases in this system. • (Cu-)Fe-Si-O slags in equilibrium with metal were studied between 1400 and 1680 °C. • "FeO" and "CuO 0.5 " had negligible solubility in tridymite/cristobalite. • Two-liquid miscibility gap over cristobalite was present at all Cu/Fe ratio in slag. • Charge compensation effect narrowed the miscibility gap as Cu/Fe ratio approached 1. [ABSTRACT FROM AUTHOR]

Phase equilibria of the AgO 0.5 -"FeO 1.5 "-SiO 2 system was investigated in the range of 1563–1913 K (1290–1640 °C) for oxide liquid (slag) in equilibrium with the gas with controlled oxygen partial pressure, Ag metal or Ag-Au alloy, and solid oxide phases: (a) tridymite, cristobalite (SiO 2); (b) hematite (Fe 2 O 3), spinel (Fe 3 O 4) and wüstite (FeO 1+x). High-temperature equilibration on silica, iridium or iron substrates, followed by quenching and direct measurement of the Ag, Au, Fe and Si concentrations in the liquid and solid phases with the electron probe X-ray microanalysis (EPMA) or laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) were used for accurate characterization of the system. Present data were used to develop the thermodynamic models for all phases in this system using FactSage computer package. The present study is a part of the investigation of the thermochemistry of complex multicomponent pyrometallurgical systems. • As a part of the recycling process, the copper and lead smelters require a reliable thermodynamic database for successful recovery of the precious metals such as Ag. • This article demonstrates the high temperature phase equilibria of the AgO 0.5 -"FeO 1.5 ″-SiO 2 ternary system. • This system is a part of the complex multicomponent pyrometallurgical systems (PbO-ZnO-Cu 2 O-FeO-Fe 2 O 3 -CaO-SiO 2 -Al 2 O 3 -MgO-S-As, Sn, Sb, Bi, Ag, Au, Ni, Cr) for the copper and lead smelting and recycling industries. • The data obtained in this study were used for developing FactSage thermodynamic database. [ABSTRACT FROM AUTHOR]

Liquidus phase equilibrium data from the recent study for the PbO–CaO and the PbO–CaO–SiO 2 systems (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–Fe 2 O 3 -"Cu 2 O"-CaO-SiO 2 system), combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases: liquid, (Ca,Pb) 2 SiO 4 , (Ca,Pb) 3 SiO 5 , (Ca,Pb)SiO 3 (wollastonite and pseudowollastonite), Pb 3 (Ca,Pb) 2 Si 3 O 11 (ganomalite) solutions, SiO 2 (quartz, tridymite, cristobalite), Ca 3 Si 2 O 7 (rankinite), CaO (lime), PbSiO 3 (alamosite), Pb 2 SiO 4 , Pb 11 Si 3 O 17 , Pb 5 SiO 7 lead silicates, PbO (massicot), Ca 2 PbO 4 , Pb 8 CaSi 6 O 21 (barysilite), PbCa 2 Si 3 O 9 (margarosanite) and Pb 3 Ca 12 Si 5 O 25 compounds. Analysis of available data has shown the lack of data in the two immiscible liquids range over cristobalite, where several new experiments were done to support the model. The modified quasichemical model is used to describe the liquid slag phase. From these model parameters, the optimized ternary phase diagram is back calculated. [ABSTRACT FROM AUTHOR]

Liquidus phase equilibrium data of the present authors for the CaO–ZnO–SiO 2 system (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–Fe 2 O 3 -"Cu 2 O"-CaO-SiO 2 system), combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases. The modified quasichemical model is used for the liquid slag phase; lime (Ca,Zn)O, zincite (Zn,Ca)O, α- and α′-dicalcium silicate (Ca,Zn) 2 SiO 4 and tricalcium silicate (Ca,Zn) 3 SiO 5 are described within Bragg-Williams formalism; tridymite, cristobalite SiO 2 , wollastonite, pseudowollastonite CaSiO 3 , rankinite Ca 3 Si 2 O 7 , willemite Zn 2 SiO 4 , melilite (hardystonite) Ca 2 ZnSi 2 O 7 and Ca–Zn feldspar CaZnSi 3 O 8 are treated as stoichiometric compounds. From these model parameters, the optimized ternary phase diagram is back calculated. [ABSTRACT FROM AUTHOR]

Liquidus phase equilibrium data obtained in the recent study by the authors for the binary PbO–"Cu 2 O", "Cu 2 O"–SiO 2 and the ternary PbO–"Cu 2 O"–SiO 2 systems in equilibrium with metallic Cu or Pb–Cu alloy (as a part of research program on the characterization of the multicomponent PbO–ZnO–FeO–Fe 2 O 3 –"Cu 2 O"–CaO–SiO 2 system), combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases. The modified quasichemical model is used for the liquid slag phase. From these model parameters, the optimized ternary phase diagram is back calculated. Liquidus surface with cristobalite, tridymite and quartz (SiO 2), two immiscible liquids, cuprite (Cu 2 O), lead silicates (PbSiO 3 , Pb 2 SiO 4 , Pb 11 Si 3 O 17 , Pb 5 SiO 7), massicot (PbO) and copper plumbite Cu 2 PbO 2 primary phase fields has been constructed. Available experimental data are described within uncertainties. Oxygen partial pressures and distribution of lead between slag and metal have been calculated. [ABSTRACT FROM AUTHOR]

Liquidus phase equilibria experimental data of the present authors for the ZnO–"Fe 2 O 3 "–SiO 2 system in air, ZnO–"FeO"–SiO 2 in equilibrium with metallic Fe, and ZnO–"FeO"–SiO 2 –minor Cu 2 O at p(O 2) ~10−7 ... 10−8 atm (obtained as a part the research on the multicomponent PbO–ZnO–FeO–Fe 2 O 3 –Cu 2 O–CaO–SiO 2 system), combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases in the ZnO–FeO–Fe 2 O 3 –SiO 2 system for the whole range of compositions, p(O 2) between ~10−13 to 1 atm, and temperature range corresponding to liquid slag existence (1150–1700 °C). The modified quasichemical model is used for the liquid slag phase. From these optimized model parameters, the ternary phase diagrams are back calculated. The model based on the present set of parameters is in a good agreement with previous and new experimental data, and can be used for predictions of the ZnO–FeO–Fe 2 O 3 –SiO 2 phase equilibria over wide ranges of p(O 2), compositions and temperatures, as well as multicomponent systems. [ABSTRACT FROM AUTHOR]

Liquidus phase equilibrium data of the present authors for the PbO–FeO–Fe 2 O 3 system at various oxygen potentials, PbO–"Fe 2 O 3 "–SiO 2 system in air, and PbO–"FeO"–SiO 2 in equilibrium with metallic Pb, combined with phase equilibrium and thermodynamic data from the literature, have been used to obtain a self-consistent set of parameters of the thermodynamic models for all phases in the PbO–FeO–Fe 2 O 3 –SiO 2 system. The modified quasichemical model is used for the liquid slag phase. For the liquid phase, the PbO–FeO, PbO–Fe 2 O 3 , PbO–FeO–Fe 2 O 3 , PbO–FeO–SiO 2 and PbO–Fe 2 O 3 –SiO 2 parameters are optimized in the present study. From these model parameters, the optimized ternary phase diagram is back calculated. Present set of parameters describe previous and new experimental data well, and can be used for predictions of the PbO–FeO–Fe 2 O 3 –SiO 2 phase equilibria over wide ranges of oxygen partial pressured, compositions and temperatures, as well as multicomponent systems. [ABSTRACT FROM AUTHOR]