The Orthosilicate‐Iron Oxide Portion of the System CaO‐“FeO”‐SiO₂

Abstract

The phase equilibrium diagram has been determined for the liquidus surface of the portion of the system CaO-"FeO"-SiOz between fayalite, dicalcium silicate, wustite, and lime. Five ternary peritectic points have been located, but no true eutectics have been found. The primary fields of wustite and dicalcium silicate cover most of the area studied (ignoring free iron, which is actually the primary phase in all compositions investigated). The boundaries of smaller fields of olivine solid solution, a paralleltwinned modification of dicalcium silicate, tricalcium silicate, lime, and calciowustite solid' solutions also are delineated. X-ray data show that lime may contain up to 10% "FeO" in solid solution, whereas wiistite may contain as much as 28% CaO in solid solution. Equilibria involving tricalcium silicate explain earlier observations on open-hearth slags and furnacebottom refractories.

Experimental Study and Thermodynamic Re-optimization of the FeO-Fe2O3-SiO2 System

“…composition of axis is to be interpreted as [37] ), obtained using an equilibration/quenching/EPMA technique was assumed to be more reliable than other data; more preference was given to this data. The calculated liquid-wüstite-fayalite eutectic temperature of 1456 K (1183°C) is higher than that reported by Allen and Snow [4] ; their work appears to be affected by the sulfur contamination in the samples. The monotectic temperature and the composition of the SiO 2 -rich slag by Greig [8] at the miscibility gap are reproduced well.…”

“…The slag liquidus compositions from experimental data, [1][2][3][4]8,10,16] from previous optimizations and from the calculation using the present model parameters for the FeO-Fe 2 O 3 -SiO 2 system in equilibrium with metallic iron were projected onto the FeO-SiO 2 pseudo-binary plane in Fig. 5.…”

“…The isothermal sections of the FeO-Fe 2 O 3 -SiO 2 system determined from the calculations using the present model parameters are compared with experimental data [1,3,4,6,11,12,[14][15][16] and with calculation results of the previous models [35][36][37] in Fig. 11.…”

“…Several researchers investigated the liquidus of the slag in equilibrium with metallic iron [1][2][3][4] and air, [5,6] and the miscibility gap of the slag at high temperatures. [7,8] Experimental data were reported by various researchers on the equilibria between gas and fully liquid slag; [6,9,10] between gas and two condensed phases (slag ?…”

“…two solids). [1,3,10,16,[18][19][20][21][22][23][24][25][26][27][28][29] The experimental data were obtained using various experimental techniques including: (a) gas equilibration and quenching, followed by microstructural analysis, wet chemistry or EPMA; [1][2][3][4][5][6][7][8][10][11][12][13]15,17,20,[23][24][25] and (b) gas equilibration and various types of online measurement, such as, thermogravimetric technique, e.m.f. technique with zirconia solid electrolytes or gas analysis technique.…”