Experimental study and thermodynamic modelling of the phase equilibria in the FeO-FeO1.5-SbO1.5-SbO2.5-SiO2 system in air and 1 atm oxygen, and in equilibrium with liquid Sb or Sb-Ag metal has been undertaken. New experimental phase equilibria data at 575-1600°C were obtained for this system using high-temperature equilibration of synthetic mixtures with predetermined compositions in sealed silica ampoules, Fe3O4 basket/MgO crucible in sealed silica ampoule, Re or Pt-Ir foils, followed by a rapid quenching technique, and electron probe X-ray microanalysis of the equilibrated phase compositions. The primary phase fields of quartz/tridymite/cristobalite (SiO2), two high-SiO2 immiscible liquids, olivine (Fe2SiO4), wustite (FeO1+x), spinel (Fe3O4), schafarzikite (FeSb2O4) and valentinite/senarmontite (Sb2O3) were identified in the binary “FeO”-Sb2O3, Sb2O3-SiO2 and ternary “FeO”-Sb2O3-SiO2 systems in equilibrium with Sb metal, as well as in more oxidizing conditions in equilibrium with Sb-Ag metal. The primary phase fields of quartz/tridymite/cristobalite (SiO2), two high-SiO2 immiscible liquids, hematite (Fe2O3-Sb2O5), spinel (Fe3O4), tripuhyite (FeSbO4) and cervantite (SbO2 = Sb2O4) were studied in air and at 1 atm O2. All data were described with a thermodynamic model in attempt to incorporate minor Sb2O5 contributions to liquid slag.

Metals commonly found in electronic components, mine waste, natural minerals, slag, and soil are often related to the iron-tin-arsenic system. Understanding its phase equilibria is essential for advancing pyrometallurgical processing and the recycling from these complex feedstocks. The iron-tin-arsenic system was investigated to improve thermodynamic description of the Cu-Fe-Sb-Sn-Ni-S-As matte/speiss/liquid metal system and enhance the predictive accuracy of the FactSage-based 20-component system. Vacuum-sealed samples were equilibrated at specified temperatures, quenched to preserve microstructures, and subsequently analyzed using an electron probe microanalyzer. Liquidus and solidus projections from 500 to 1500 degrees C revealed a miscibility gap extending from the Fe-Sn binary to the centre of the diagram. Identified phases include liquid metals, BCC-Fe (Sn- and Ascontaining), Fe5(Sn,As)3-Me5X3, "Fe3(As,Sn)2", FeSn-MeX, FeSn2, Fe2As, Fe3Sn, FeAs, and FeAs2, along with their primary phase fields. Incongruently melting Fe5(Sn,As)3 at 904 degrees C and "Fe3(As,Sn)2" are newly identified ternary phases. Sub-solidus experiments performed in equilibrium with liquid Pb flux in the Fe-Sn system confirm Fe3Sn stability. Three saddle points and seventeen invariant reactions were identified. Monotectic and syntectic reactions were observed at two sets of invariant points within the miscibility gap.

Phase equilibria of the "CuO0.5"-"FeO"-MgO-SiO2 system in equilibrium with copper metal were investigated as part of the thermochemistry characterization of copper electric slag cleaning furnace (EF) operation using a high-temperature equilibration, quenching, and electron probe microanalysis (EPMA) technique integrated with thermodynamic modeling using FactSage computer package. Experiments were conducted under conditions relevant to the EF operation: at temperatures of 1200-1300 degrees C and a wide range of oxygen partial pressures (log(pO2) = -5, -6, -7, -8, -9, -10 atm, and in equilibrium with iron Fcc). The present investigation focuses on establishing the pyroxene/olivine-tridymite and olivine-monoxide/spinel phase boundaries at different p(O2). The relationship between p(O2) and slag, metal, and solid solutions composition was studied and compared with FactSage prediction. The experimental results are used for the optimization of the thermodynamic database of the system.

Phase equilibria in the NiO-ZnO-"SnO2" system in air were experimentally studied to support the optimization of thermodynamic model parameters of the system. High-purity oxide powders were equilibrated at high temperatures and rapidly quenched to preserve phase relationships, followed by detailed compositional analysis using electron probe X-ray microanalysis (EPMA). Silica (SiO2) was added to the mixtures to promote liquid phase formation and equilibration of the NiO-ZnO-"SnO2" phases. The phase equilibria in the system were examined across a range of temperatures to gather comprehensive data. The experimental results, in combination with literature data, were used to refine thermodynamic modeling parameters and produce a self-consistent set of data for all phases. This work presents the first high-temperature investigation of phase equilibria in this ternary system and provides essential input for improving process control in multi-metal recycling applications. This study is part of a broader experimental and modeling study focused on phase equilibria in the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co, Na) gas/oxide liquid/matte/speiss/metal/solids system, aimed at improving the design and efficiency of pyrometallurgical processes.

The Cu-Fe-Ni-Sn-Sb-As-S system is essential for recycling electronic components, energy storage devices, brass, solders, flue dust, black copper, lead bullion, and final products like Cu, Ni, Pb metals, etc., and for the extraction of metals from different grades of concentrates. Bulk mixtures were equilibrated at target temperatures, quenched in brine, and directly analyzed using an electron probe X-ray microanalyzer. A miscibility gap (matte and two liquid speisses) was identified and projected on the Fe-Cu-S and Fe-Cu-As compositional triangles, and compared with a recently updated internal thermodynamic database. Three liquid phases (matte, Fe-rich speiss and Cu-rich speiss) were found to exist between 955 and >= 1375 degrees C; above 1375 degrees C, they were estimated to merge into two liquids - matte and liquid speiss. Cu- and As-containing BCC-Fe, digenite (Cu, Ni, Fe0.5, Va)2S, Me2X (Cu, Fe, Ni)2(As, Sb), and Me3X (Cu, Ni, Fe)3 +/- x(Sb, Sn, As) solid solutions were identified. The distribution and concentration of different elements were briefly discussed. The crystallization behavior of a bulk composition was briefly noted. The discovery of three immiscible metallic liquid phases has been considered essential for advancing metal production technologies.

The thermochemistry of the Cu-Ni-S system largely determines the recovery of nickel, copper, and platinum group metals from sulfide ores and the production of nickel speiss in polymetallic recycling through lead bullion route. This study evaluates the accuracy of the FactSage 8.3 FTsulf thermodynamic database for predicting phase equilibria and element distribution within this system and provides data for further model improvements. Existing experimental data from literature were critically assessed against model predictions, identifying key areas where data were either lacking or controversial. New experiments were designed in these areas. Experimental investigation focused on two key areas: the matte-metal miscibility gap at 1100 and 1200 degrees C, and the solubility of copper sulfide in the (3-Ni3S2 solid phase, often referred to as high-temperature heazlewoodite. The experimental method of equilibration and quenching, followed by Electron Probe X-ray Microanalysis (EPMA) was refined to apply it for highly fluid matte and liquid metal phases. While the FactSage 8.3 FTsulf database generally agreed with most literature data, our results revealed a systematic underestimation of the nickel distribution coefficient, ratio of wt% Ni in liquid Cu2S-rich matte to wt % Ni in liquid copper metal. The solubility of copper sulfide in the (3-Ni3S2 solid phase was underestimated by the model compared to the experimental results of this study. These findings will inform future thermodynamic model optimizations and contribute to a broader research program focused on characterizing phase equilibria, heat balance, and elemental distribution in complex nickel-, copper-, and lead-based polymetallic processes.

The compositional ranges of SFCA series and the phase equilibrium relationships were reevaluated in the iron-rich corner of the CaO-Fe2O3-Al2O3 system at 1 240 degrees C in air using powder and single crystal XRD as well as EPMA: The liquidus line was reexamined using the samples with initial compositions close to the liquidus line. The observed liquidus line was shifted to the Fe2O3 rich side from the previous one reported by the present authors. The liquidus compositions of the samples, the initial compositions of which were far from the liquidus line, may be affected by CF (CaFe2O4), CFF (Ca2Fe15.51O25) and C2F (Ca2Fe2O5) precipitated during quenching. Some of the limits of compositional range of SFCA-I, SFCA-II and SFCA were determined by newly prepared samples with the three-phase equilibriums such as liquid + SFCA-I + hematite. It has been found that the Al2O3 concentration is the smallest for SFCA-I and the largest for SFCA: The Al/(Al + Ca + Fe) ranges from 5.61% to 17.55% for SFCA-I in equilibrium with a liquid phase, from 14.75% or even lower to 25.00% for SFCA-II and from 19.93% to 31.42% or even higher for SFCA. It has been found that the phases of a sample having the initial composition of 10.04CaO-63.47FeO1.5-26.49AlO1.5 (mol%) equilibrated at the oxygen partial pressure of 0.1 atm and at 1 390 degrees C are SFCA-I and SFCA-III. The value of Fe2+/Fe in SFCA-III has been calculated to be 20.36% assuming that the structural formula of M26O36 (M = Ca, Fe, Al) is satisfied by the presence of Fe2+: (Ca2+1-xFe2+x)6(Fe3+1-yAl3+y)20O36 (x = 0.57, y = 0.33).

Phase equilibria studies were undertaken on the CaO-MgO-SiO2 system using equilibration and quenching technique followed by the electron probe X-ray microanalysis (EPMA). The primary phase fields of periclase (MgO), olivine ([Mg,Ca]2SiO4: low-Ca forsterite and high-Ca monticellite), merwinite (Ca3MgSi2O8), akermanite (Ca2MgSi2O7), rankinite (Ca3Si2O7), dicalcium silicate (alpha- and alpha '-C2S) ([Ca,Mg]2SiO4), pseudowollastonite (CaSiO3), wollastonite ([Ca,Mg]SiO3), pyroxenes ([Mg,Ca]SiO3: proto-, ortho- and two immiscible clino-), tridymite/cristobalite (SiO2) and the area of a two liquid miscibility gap were experimentally characterized. Experiments in the CaO-MgO-FeO-FeO1.5-SiO2 system were conducted to confirm stability of bredigite Ca7MgSi4O16 and solubility of Mg in alpha- and alpha '-C2S. The experimental data obtained in the present study, as well as available literature data on the phase equilibria and thermodynamics of the CaO-MgO-SiO2 system were used for the optimisation of the model parameters of the discussed system in agreement with the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-OS-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co and Na) gas/oxide liquid/matte/speiss/metal/solids system to obtain a selfconsistent set of parameters of the thermodynamic model for all phases in support of the development and optimisation of pyrometallurgical processes.

ABSTRACT Integrated experimental and thermodynamic modeling study of the phase equilibria in the Na 2 O–SnO–SnO 2 –SiO 2 system in air and in equilibrium with liquid metal has been undertaken for characterizing the thermochemistry of slag in smelting side streams enriched in Sn and optimizing the fuming process. New experimental phase equilibria data at 800°C–1635°C in air, and 610°C–1300°C in equilibrium with liquid metal were obtained using high‐temperature equilibration of synthetic mixtures with predetermined compositions in sealed silica ampoules or Re / Pt‐Ir foils, rapid quenching, and electron probe X‐ray microanalysis of the equilibrated phase compositions. Phase equilibria and liquidus isotherms in the quartz/tridymite (SiO 2 ), cassiterite (SnO 2 ), sodium silicates (Na 2 Si 2 O 5 , Na 2 SiO 3 ), sodium stannates (Na 2 SnO 3, Na 4 Sn 3 O 8 ) and sodium tin silicates (Na 8 SnSi 6 O 18 , and three new phases Na 4 SnSi 2 O 8 , Na 4 Sn 2 Si 3 O 12 , Na 2 Sn 2 Si 2 O 7 ) primary phase fields in the NaO 0.5 –“SnO 2 ”–SiO 2 and NaO 0.5 –“SnO”–SiO 2 systems were revealed. New experimental data were used to develop a thermodynamic database describing the Na 2 O–SnO–SnO 2 –SiO 2 system.

The Cu-Sn-S system applies to describe the chemistry of electronic components, low-high-grade minerals, energy storage devices, slag, solders, brass, lead bullion, flue dust, black copper, etc. Its phase equilibria are essential for modeling complex Cu-Sb-Sn-Ni-S-Fe-As matte, speiss, and metal system. Mixtures were equilibrated at 500-1300 degrees C, quenched in brine, and analyzed by an electron probe microanalyzer. Open- and closed-system experiments of the Cu-S and Cu-Sn-S systems revealed the miscibility gaps. Liquidus and solidus projections, isotherms, and primary phase fields of each phase were constructed. Identified phases include matte, liquid metal, Cu2-xS, SnS, Sn2S3, SnS2, Cu3Sn, Cu4SnS4 (550-800 degrees C), Cu2SnS3 (600-900 degrees C), and Cu2Sn3S7 (700-800 degrees C) phases. A sub-solidus inconclusive solid-solution phase was discovered at 500-650 degrees C. Cu4SnS4 and Cu2SnS3 melt congruently, while Cu2Sn3S7 shows uncertain melting behavior. All ternary solid phases, except the inconclusive phase, form only above atmospheric pressure, with primary phase-field stability extending from 1 atmosphere to > 10 atmospheres. Nineteen invariant points and five saddle points were identified. Sn distribution between matte and liquid metal was investigated to support sustainable Sn removal during recycling of complex feedstocks. The CuS0.5-SnS quasi-binary and CuS0.5-SnS1.5 pseudo-binary systems were also evaluated.

Phase equilibria studies were undertaken on the FeO-FeO1.5-MgO and FeO-FeO1.5-MgO-SiO2 systems using equilibration and quenching technique followed by the electron probe x-ray microanalysis (EPMA). The primary phase fields of spinel (Fe,Mg)Fe2O4, monoxide (Mg,Fe)O1+ x, olivine (Mg,Fe)2SiO4, pyroxene (Mg,Fe)SiO3 (proto, ortho, and clino-), tridymite, cristobalite (SiO2), and two-liquids miscibility gap were experimentally characterized at oxygen partial pressures of 10-4, 10-6 atm, and in equilibrium with metallic iron. The experimental data obtained in the present study, as well as available literature data on the phase equilibria and thermodynamics of the FeO-FeO1.5-MgO-SiO2 system, were used for the optimization of the model parameters of the discussed system as a part of the Cu-Pb-Zn-Fe-Ca-Si-Al-Mg-O-S-(As, Sn, Sb, Bi, Ag, Au, Ni, Cr, Co, and Na) gas/oxide liquid/matte/speiss/metal/solids system to obtain a self-consistent set of parameters of the thermodynamic model for all phases in support of the development and optimization of pyrometallurgical processes.

Experimental and thermodynamic modelling investigation of the phase equilibria in the CaO-"FeO"-AlO1.5 system in equilibrium with Fe metal has been undertaken to characterise the thermochemistry of slag in pyrometallurgical processes. Phase equilibria data at 1100-1615 degrees C were obtained using equilibration of synthetic mixtures with predetermined compositions in Fe foil/wire or Al2O3 crucibles, quenching, and electron probe Xray microanalysis of the phases. Phase equilibria and liquidus isotherms in the lime (CaO), wustite (FeOx), spinel (FeAl2O4), corundum (Al2O3), calcium aluminates (CaAl2O4 = CA, CaAl4O7 = CA2, CaAl12O19 = CA6, Ca3Al2O6 = C3A, Ca12Al14O33 = mayenite), dicalcium ferrite (Ca2(Fe,Al)2O5 = C2F, brownmillerite), and calcium iron aluminate (Ca3FeAl4O10 = C3FA2, found for the first time) primary phase fields were revealed. The experimental results were used to develop a thermodynamic database for describing the CaO-"FeO"-AlO1.5 system. Also, the composition of solid phases versus slag composition was analysed through the experimental results and thermodynamic database developed in this study.

Experimental investigation and thermodynamic modeling of the phase equilibria in the FeO-Fe2O3-SnO-SnO2-SiO2 system have been undertaken to characterize Sn behavior in iron silicate slags for recycling of waste electrical and electronic materials (WEEE) through black copper process. Phase equilibria data at 865-1740 degrees C were obtained through equilibration of synthetic mixtures in sealed silica ampoules or open crucibles, on Ir wires, or Pt-Ir foils, followed by rapid quenching and electron probe x-ray microanalysis. Phase equilibria and liquidus isotherms of the "FeO"-"SnO"-SiO2 system in equilibrium with Sn metal, "Fe2O3"-"SnO2"-SiO2 system in air and 1 atm oxygen, FeO-Fe2O3-SnO-SnO2-SiO2-Au2O in equilibrium with Au-Fe-Sn metal, and hematite(spinel)-cassiterite equilibria in the Fe-Sn-O system at various p(O2) in the presence of CaO-SiO2 or PbO-SiO2 flux were measured in the tridymite/cristobalite SiO2, cassiterite SnO2, hematite (Fe,Sn)2O3, spinel (Fe,Sn)3O4+ x, and fayalite Fe2SiO4 phase fields. New data were used for developing a self-consistent set of thermodynamic parameters for all phases to describe the Pb/Zn/Cu/Fe-containing complex system for characterizing Sn behavior in industrial primary smelting and recycling slags.

The Ni-Sn-S system can be used to describe the chemistry of Ni-based battery materials, printed circuit boards, and other waste from electrical and electronic equipment. Therefore, understanding the phase equilibria of the Ni-Sn-S system is essential for managing and recycling these metals effectively. This study was focused on the high-temperature phase equilibria in the Ni-Sn-S system. The experimental techniques used in the present study included high-temperature equilibration and quenching, followed by direct measurement of compositions of phases present in the samples using the electron probe X-ray microanalysis (EPMA). Primary phase fields of the following phases were experimentally characterized in the temperature range of 500 to 1100 degrees C: two mattes (NiS- and SnS-rich), liquid metal, FCC-Ni, Ni3Sn (high- and low-temperature), Ni1+xSn, Ni3Sn4, Sn-rich beta-Ni3S2, Ni1-xS, NiS2, SnS, Sn2S3, SnS2, and Ni3Sn2S2. Incongruently melting Ni3Sn2S2 was the only ternary compound identified to be present under the liquidus conditions. Invariant reactions and saddle points present under the liquidus conditions were accurately identified. This study was a part of the integrated experimental and thermodynamic modeling study of phase equilibria in the Cu-Sb-Sn-Ni-S-Fe-As matte/speiss/liquid metal system. It is a small part of the 20-component gas/oxide liquid/matte/speiss/liquid metal/salt/solid system supporting the metallurgical operations.

The Fe-Si-O system is important in understanding the slag chemistry of copper production which involves fayalite slags. It is also an important part of a 20-component Cu-Pb-Zn-Fe-Ca-Si-O-S-Al-Mg-Cr-Na-As-Sn-Sb-Bi-Ag-Au-Ni-Co thermodynamic database being developed for multiple processes and applications of ferrous and nonferrous metallurgy. The present work presents experimental data on high-temperature silica liquidus/miscibility gap in the Fe-Si-O system measured by equilibration/quenching/electron probe X-ray microanalysis (EPMA) method as well as a thermodynamic reassessment of the Fe-Si-O system within the 20-component database. The slag phase has been modeled within the modified quasichemical formalism to account for short-range ordering phenomena. The heat capacities of liquid endmembers have been updated in a way consistent with the physical principles of liquid slag cooling and glass transition, potentially opening a way for lower-temperature applications of the database regarding the leaching of minor elements from partially crystallized slags. Recent developments in thermodynamic modeling and optimization allowed us to perform the assessment of the system in a consistent way as a part of a multicomponent experimental dataset, leading to a superior prediction quality of the resulting thermodynamic database for industrial applications.

The Ca-Fe-O system is essential for understanding the chemical equilibria involved in copper production using calcium ferrite slags. It forms a core component of a complex 20-component Cu-Pb-Zn-Fe-Ca-Si-O-S-Al-Mg-Cr-NaAs-Sn-Sb-Bi-Ag-Au-Ni-Co system developed for diverse applications in ferrous and non-ferrous metallurgy. This study re-evaluates the Ca-Fe-O system using recent experimental phase equilibrium data acquired by the authors (Cheng et al., 2024) [1] through advanced equilibration, quenching, and Electron Probe X-ray Microanalysis (EPMA) techniques. Thermodynamic properties of solid phases have been revised in accordance with the recommendations for the third generation of Calphad databases. Liquid endmember heat capacities have been refined to describe glass transition behaviour in supercooled liquids. The updated properties of liquid end- members significantly extend the applicability of the database, enabling lower-temperature applications related to toxic element leaching from amorphous and partially crystallized slags. The revised, higher melting temperature of CaO enhances predictive accuracy in multicomponent systems. Liquid slag phase has been modelled within the Modified Quasichemical Formalism to account for short-range ordering phenomena. Recent advances in modelling and optimization technique made it possible to assess experimental data within the Ca-Fe-O system as an integral part of a large multicomponent dataset, applicable for industrial conditions.

The present work aims to elucidate the influence of the iron oxidation state on the electrical conductivity of iron silicate slags through a combined approach of electrical conductivity measurements and iron redox state determination. Electrical conductivity experiments were combined with stepped potential chronoamperometry measurements to distinguish between the ionic and electronic conduction mechanism. Contrary to previous studies, the Fe3+/Fe2+ ratio was also experimentally determined via both Mössbauer spectroscopy and wet chemistry. A continuous decrease in Fe3+/Fetot ratio was found which varies accordingly to the different atmospheres applied during each experiment which confirmed that the changes in the electrical conductivity are attributed to a difference in the sample’s iron redox state. The ionic and electronic conductivity showed a linear and parabolic dependency, respectively, as a function of Fe3+/Fetot. The experimental data were compared with two models, namely, the structural ionic model of Thibodeau et al. and the electronic Diffusion-Assisted Charge Transfer (DACT) model from Barati and Coley. Regarding the former, it is found that the model overestimates the ionic conductivity due to an overestimation of the Fe2+ diffusion coefficient. The latter model was unable to reproduce the experimental data using the original model’s original r* parameter of 3.87 Å, but adaptation of this parameter to 4.67 Å provided a better fit. This suggests that the DACT model also needs to consider a slag composition dependency to accurately reproduce experimental data.

Phase equilibria information are significant for optimizing recovery of Sb in industrial Cu production. An integrated experimental and thermodynamic modeling investigation of the phase equilibria in the CuO0.5-SbO1.5-SiO2 system has been undertaken to characterize the distribution of Sb between high-Cu slags and matte/metal phase in the Cu processing reactors. New experimental phase equilibria data at 600-1500 degrees C were obtained for this system using high-temperature equilibration of synthetic mixtures with predetermined compositions in sealed silica ampoules or Cu foils, a rapid quenching technique, and electron probe x-ray microanalysis of the equilibrated phase compositions. Phase equilibria and liquidus isotherms in the cuprite Cu2O, quartz/tridymite/cristobalite SiO2, valentinite Sb2O3, and cervantite Sb2O4 primary phase fields were measured, and the extent of the high-SiO2 2-liquid immiscibility gap in equilibrium with cristobalite was determined. Experimental results were used to fix thermodynamic parameters in the CuO0.5-SbO1.5 binary and the CuO0.5-SbO1.5-SiO2 ternary systems. Moreover, the solubility of Sb in the metal phase (predominantly Cu) was predicted reasonably through the thermodynamic database. The information obtained in this study is important for recycling critical metal Sb with increasing demand in the ceramic and glass applications as well as low-carbon energy production.

Characterisation of thermochemistryThermochemistry of iron in blisterIron in blister and copper in slagCopper in slag in the copperCopper electric slag cleaning furnaceSlag Cleaning Furnace is important to improve copper slagCopper slag processingSlag processing in BHP Olympic DamOlympic Dam direct-to-blisterBlister processDirect-to-blister. Phase equilibriaPhase equilibria investigation in the “CuO0.5”–“FeO”–MgO–SiO2 system in equilibrium with copperCopper metalMetal was undertaken using a high-temperature equilibration, quenching, and electron probe microanalysisAnalysis (EPMAElectron Probe X-ray Microanalysis (EPMA)) technique integrated with thermodynamicThermodynamics modellingModelling using FactSageFactSage computer package. Experiments were conducted at conditions relevant to the industrial electric furnaceElectric furnace operationOperation, at 1300 °C and log (pO2) = −5, −6, −7, −8, −9, −10, and in equilibrium with ironIron metalMetal. The experimental results are used for optimizationOptimization of the thermodynamic databaseThermodynamic database of the system. Furthermore, an industrial electric furnaceElectric furnace slagSlag sample was collected and analysed systematically, including analysisAnalysis of macro and micro-features, phase identification and measurement, and FactSageFactSage prediction. The microanalysis of the electric furnaceElectric furnace slagSlag samples was compared to the currently available thermodynamic databaseThermodynamic database. Phase equilibriaPhase equilibria findings showed that copperCopper concentration in slagSlag and ironIron partitioning in blisterBlister are greatly influenced by oxygen partial pressure, and the thermodynamicThermodynamics modelModel agrees reasonably with the experimental results. Microanalysis of the industrial electric furnaceElectric furnace slagSlag sample suggested differences between the industrial slagSlag phases and chemical partitioning compared to the currently available thermodynamic databaseThermodynamic database. Differences are analysed, and possible causes are found to be non-equilibrium condition in furnaceFurnace related to kineticKinetics factors and analytical uncertainties in EPMAElectron Probe X-ray Microanalysis (EPMA).