Journal of Mining and Metallurgy, Section B: Metallurgy 2013 Volume 49, Issue 2, Pages: 153-159
https://doi.org/10.2298/JMMB120812009Z
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Effects of CaO, Al2O3 and MgO on liquidus temperatures of copper smelting and converting slags under controlled oxygen partial pressures
Zhao B. (The University of Queensland, School of Chemical Engineering, Brisbane, Australia)
Hayes P. (The University of Queensland, School of Chemical Engineering, Brisbane, Australia)
Jak E. (The University of Queensland, School of Chemical Engineering, Brisbane, Australia)
Phase equilibria of silicate slags relevant to the copper smelting/converting
operations have been experimentally studied over a wide range of slag
compositions, temperatures and atmospheric conditions. Selected systems are
of industrial interest and fill the gaps in fundamental information required
to systematically characterise and describe copper slag chemistry. The
experimental procedures include equilibration of synthetic slag at high
temperatures, rapid quenching of resulting phases, and accurate measurement
of phase compositions using electron probe X-ray microanalysis (EPMA). The
effects of CaO, Al2O3 and MgO on the phase equilibria of this slag system
have been experimentally investigated in the temperature range 1200 to 1300
oC and oxygen partial pressures between 10-5 and 10-9 atm. It was found that
spinel and silica are major primary phases in the composition range related
to copper smelting/converting slags. In addition, olivine, diopside and
pyroxene also appear at certain conditions. The presence of CaO, MgO and
Al2O3 in the slag increases the spinel liquidus and decreases the silica
liquidus. Liquidus temperatures in silica primary phase field are not
sensitive to Po2; Liquidus temperatures in spinel primary phase field
increase with increasing Po2. At 1300 oC and low Po2, the spinel
(Fe2+,Mg2+)O.(Al3+,Fe3+) primary phase field can be replaced by wustite
(Fe2+,Mg2+)O.
Keywords: copper smelting, copper converting, liquidus temperature, slag