Phase Equilibria of “Cu2O”-“FeO”-CaO-MgO-Al2O3 Slags at PO2 of 10-8.5 atm in Equilibrium with Metallic Copper for a Copper Slag Cleaning Production

Abstract

Limited data are available on phase equilibria of the multicomponent slag system at the oxygen partial pressures used in the copper smelting, converting, and slag-cleaning processes. Recently, experimental procedures have been developed and have been applied successfully to characterize several complex industrial slags. The experimental procedures involve high-temperature equilibration on a substrate and quenching followed by electron probe X-ray microanalysis. This technique has been used to construct the liquidus for the ''Cu 2 O''-''FeO''-SiO 2 -based slags with 2 wt pct of CaO, 0.5 wt pct of MgO, and 4.0 wt pct of Al 2 O 3 at controlled oxygen partial pressures in equilibrium with metallic copper. The selected ranges of compositions and temperatures are directly relevant to the copper slag-cleaning processes. The new experimental equilibrium results are presented in the form of ternary sections and as a liquidus temperature vs Fe/SiO 2 weight ratio diagram. The experimental results are compared with the FactSage thermodynamic model calculations.

Experimental Study of Ferrous Calcium Silicate Slags: Phase Equilibria at $$ {\text{P}}_{{{\text{O}}_{2} }} $$ Between 10−5 atm and 10−7 atm

“…[7] The approach has been used successfully in the investigation of various complex ferrous calcium silicate slags, for example, ''FeO''-CaO-SiO 2 -''Cu 2 O'', [8] ''FeO''-CaO-SiO 2 -Al 2 O 3 -MgO, [9] and ''FeO''-CaO-SiO 2 -''Cu 2 O''-Al 2 O 3 -MgO. [10] In the current study, the equilibration/quenching/ EPMA techniques have been applied to determine accurately the phase equilibria of ferrous calcium silicate slags at intermediate oxygen partial pressures. Following the study by the previous authors, [6,7] the oxygen partial pressure range has been extended from 10 À5 atm to 10 À7 atm between temperatures of 1473 K and 1623 K (1200°C and 1350°C).…”

Phase Equilibrium Investigation for CaO-SiO₂-5wt.%MgO-20wt.%Al₂O₃-TiO₂ System Relevant to Ti-bearing Slag System

“…The platinum crucibles, holding specific oxide mixtures, were suspended by a platinum wire (0.5-mmdiameter) in the hot zone of the furnace. All samples were pre-melted again before equilibration at temperature 1 650°C for 3 hours, after which the temperature was cooled down to the equilibration temperature (1 300°C or 1 400°C), an equilibration time of 24 hours based on the results from preliminary experiments and experience reported by previous authors [31][32][33] was employed to ensure equilibrium had been achieved. Ar (99.99 pct pure) gas was passed through the furnace during the whole experiment to avoid potential contamination sources.…”

Liquidus and Phase Equilibrium in CaO-SiO₂-Nb₂O₅-10%La₂O₃ System

“…Graphical representation for pseudo-melting temperature determination. and 1 573 K. The equilibration time lasted 86 400 s based on experiences reported by other studies, [18][19][20][21][22] repeat experiments with 172 800 s were performed for some samples to check whether the equilibrium was achieved. There was no significant difference between the equilibrium phases with longer equilibration time.…”