Solubility of Oxygen in PbO-SiO<sub>2</sub> Melts

Grau, A. E.; Masson, C. R.

doi:10.1179/cmq.1977.16.1.82

Cited by 6 publications

(6 citation statements)

References 8 publications

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“…Richardson reported the possibility of dissolution of Pb 0 in PbO–SiO 2 slags, especially at high temperatures and high silica concentrations. Grau reported small solubility of oxygen in the PbO–SiO 2 slags and attributed this to traces of Pb 4+ with the ratio Pb 4+ /Pb 2+ never exceeding 0.01 in the range close to pure PbO, and further decreasing with the addition of silica or with the increase in temperature. Kuxmann reported the solubilities of Pb 0 in PbO below 1 mol% in the range 900°C‐1150°C; Isecke reported Pb 0 concentrations double this value, and no excess of oxygen in molten PbO.…”

Section: Introductionmentioning

confidence: 99%

Experimental phase equilibria studies of the PbO–SiO₂ system

Shevchenko

Jak

2017

J Am Ceram Soc

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Phase equilibria of the PbO-SiO 2 system have been established for a wide range of compositions: (i) liquid in equilibrium with silica polymorphs (quartz, tridymite, and cristobalite) between 740°C and 1580°C, at 60-90 mol% SiO 2 ; (ii) with lead silicates (PbSiO 3 , Pb 2 SiO 4 , and Pb 11 Si 3 O 17 ) and lead oxide (PbO) between 700°C and 810°C. A high-temperature equilibration/quenching/electron probe X-ray microanalysis (EPMA) technique has been used to accurately determine the compositions of the phases in equilibrium in the system. Significantly, no liquid immiscibility has been found in the high-silica range, and the liquidus in this high-silica region has been accurately measured. The phase equilibria information in the PbO-SiO 2 system is of practical importance for the improvement of the existing thermodynamic database of lead-containing slag systems (Pb-Zn-Fe-Cu-Si-Ca-Al-Mg-O).

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Section: Introductionmentioning

confidence: 99%

Experimental phase equilibria studies of the PbO–SiO₂ system

Shevchenko

Jak

2017

J Am Ceram Soc

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“…To enable the approach to equilibrium to be tested from different starting compositions and to reduce the extent of lead oxide vaporization, a master slag of composition Pb 4 Si 6 O 16 was prepared by mixing an appropriate ratio of Pb 3 O 4 and dried SiO 2 powders and heating initially for 2 hours at 600 °C and then for a further 2 hours at 900 °C in Pt crucible in air. Excess oxygen from Pb 3 O 4 was released to atmosphere during heating, so that the final master slag contained only Pb 2+ [48] ; direct use of PbO reagent was avoided to protect the Pt substrate from accidental destruction due to local reducing conditions, observed in some previous studies. [23] The initial compositions of the mixtures were selected to ensure that, following equilibration, at least one crystalline phase would be present.…”

Section: Experimental Methodologymentioning

confidence: 99%

Integrated Experimental and Thermodynamic Modeling Investigation of Phase Equilibria in the PbO–MgO–SiO2 System in Air

Abdeyazdan

Shevchenko

Hayes

et al. 2022

Metall Mater Trans B

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Magnesium oxide-based refractory materials are used industrially to contain the chemically aggressive slags present in lead smelting systems. In the present study an integrated experimental and thermodynamic modeling approach was taken to provide fundamental information on the chemical reactions taking place in these systems. New experimental phase equilibria and liquidus data were obtained for the PbO–MgO–SiO2 system in air in the temperature range 750 °C to 1740 °C. In the MgO–SiO2 binary, new experimental results were obtained at 1550 °C to 1740 °C and compared to the available thermodynamic data in the literature. The experiments were carried out using the high-temperature equilibration of oxide powder mixtures followed by rapid quenching of the samples. Electron probe X-ray microanalysis (EPMA) was used to determine the compositions of the solid and liquid phases present at equilibrium conditions. Phase equilibria and liquidus isotherms in the cristobalite and tridymite (SiO2), pyroxene (protoenstatite MgSiO3), olivine (forsterite Mg2SiO4), barysilite (Pb8MgSi6O21), massicot (PbO) and periclase (MgO) primary phase fields were measured, and the extent of the high-silica two-liquid immiscibility gap in equilibrium with cristobalite was determined. The experimental results were used to optimize the parameters in a thermodynamic database that was subsequently used to describe this multi-component, multi-phase system and predict the liquidus for the PbO–MgO–SiO2 system. The new data were used to characterize the chemical interactions of magnesia-based refractory with PbO–MgO–SiO2 slags.

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“…The apparatus used to measure the uptake of oxygen by the slag-metal system was similar to that used previously [7] for determining the solubility of oxygen in PbO-Si0 2 melts. The volume of oxygen taken up by the system was measured directly by means of a gas burette and a differential dibutylphthalate manometer, with the system maintained at constant pressure.…”

Section: Methodsmentioning

confidence: 99%

“…Mullite tubes were replaced frequently due to volatilization of PbO. The tube was attached, via a water-cooled brass flange and glass-metal seal to an all-glass vacuum apparatus equipped with mercury and dibutylphthalate manometers and a gas burette [7]. The ensemble of tube and brass flange was subjected to helium leakdetection tests with a mass spectrometer before each series of measurements.…”

Section: Methodsmentioning

confidence: 99%

“…In the presence of an electronic conductor the rate of transfer of oxygen is enhanced by the flow of current in the cell (+ )Ir, 02(g)/(PbO + Si0 2 )(1 )/Pb(l), Ir ( -) rate = E/4 x 96500 (R t + r) moles O 2 S-1 (7) over the time interval during which current flows. The increase in rate due to the conductor is thus directly proportional to E and inversely proportional to (R t + r).…”

Section: Nduced Transport Of Oxygenmentioning

confidence: 99%

See 1 more Smart Citation

Diffusion and Electrochemical Transport of Oxygen in Pbo–SiO₂Melts

Caley¹,

Marple²,

Masson³

1981

Canadian Metallurgical Quarterly

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The diffusion of oxygen from the gas phase through PbO-Si0 2 melts to an underlying phase of liquid Pb is considerably enhanced when the metal phase is connected to the slag-gas interface by an electronic conductor. The connection may be made either internally, by a conductor which passes through the three phases, or by an external circuit. When the connection is made externally the increased transfer of oxygen is equivalent to the number of coulombs which pass. The increase in rate due to the electronic conductor is governed by the flow of current in the cell M, 02(g)/(PbOwhere M is the conductor and depends on the resistance in the circuit. The transport of oxygen may be enhanced, supp"essed or reversed by applying an appropriate EMF across the slag and metal phases. Resume-La diffusion d'oxygene a partir de l'etat-gaz, par la dissolution de PbO-Si02,jusqu'a un etat-liquide de base, est considerablement accrue quand l'etat-metal est relie a l'interface scorie-gaz par un conducteur electronique. La liaison peut etre realisee soit interieurement, par un conducteur passant par les trois etats, soit par un circuit exterieur. Quand cette liaison est realisee exterieurement, Ie transfer accru d'oxygene est equivalent au nombre d'ampere-secondes qui s'ecoule. L'augmentation en taux due au conducteur electronique est regie par Ie passage du courant dans la pile M, 02(g)/(PbO + Si02)(I)/Pb(I), M OU M est Ie conducteur et depend de la resistance dans Ie circuit. Le transport d'oxygene peut etre accru, supprime ou inverse en appliquant une FEM appropriee entre la scorie et les phases-metal.

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Solubility of Oxygen in PbO-SiO₂ Melts

Cited by 6 publications

References 8 publications

Experimental phase equilibria studies of the PbO–SiO₂ system

Experimental phase equilibria studies of the PbO–SiO₂ system

Integrated Experimental and Thermodynamic Modeling Investigation of Phase Equilibria in the PbO–MgO–SiO2 System in Air

Diffusion and Electrochemical Transport of Oxygen in Pbo–SiO₂Melts

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Solubility of Oxygen in PbO-SiO2 Melts

Cited by 6 publications

References 8 publications

Experimental phase equilibria studies of the PbO–SiO2 system

Experimental phase equilibria studies of the PbO–SiO2 system

Integrated Experimental and Thermodynamic Modeling Investigation of Phase Equilibria in the PbO–MgO–SiO2 System in Air

Diffusion and Electrochemical Transport of Oxygen in Pbo–SiO2Melts

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Solubility of Oxygen in PbO-SiO₂ Melts

Experimental phase equilibria studies of the PbO–SiO₂ system

Experimental phase equilibria studies of the PbO–SiO₂ system

Diffusion and Electrochemical Transport of Oxygen in Pbo–SiO₂Melts