The Viscous Behavior of FeOt-Al2O3-SiO2 Copper Smelting Slags

Abstract

HYUN-SHIK PARK, SU SANG PARK, and IL SOHNUnderstanding the viscous behavior of copper smelting slags is essential in increasing the process efficiency and obtaining the discrete separation between the matte and the slag. The viscosity of the FeO t -SiO 2 -Al 2 O 3 copper smelting slags was measured in the current study using the rotating spindle method. The viscosity at a fixed Al 2 O 3 concentration decreased with increasing Fe/SiO 2 ratio because of the depolymerization of the molten slag by the networkmodifying free oxygen ions (O 2À ) supplied by FeO. The Fourier transform infrared (FTIR) analyses of the slag samples with increasing Fe/SiO 2 ratio revealed that the amount of large silicate sheets decreased, whereas the amount of simpler silicate structures increased. Al 2 O 3 additions to the ternary FeO t -SiO 2 -Al 2 O 3 slag system at a fixed Fe/SiO 2 ratio showed a characteristic V-shaped pattern, where initial additions decreased the viscosity, reached a minimum, and increased subsequently with higher Al 2 O 3 content. The effect of Al 2 O 3 was considered to be related to the amphoteric behavior of Al 2 O 3 , where Al 2 O 3 initially behaves as a basic oxide and changes to an acidic oxide with variation in slag composition. Furthermore, Al 2 O 3 additions also resulted in the high temperature phase change between fayalite/hercynite and the modification of the liquidus temperature with Al 2 O 3 additions affecting the viscosity of the copper smelting slag.

Reduction Behavior of Carbon Composite Pellets Including Alumina and Silica at 1273 K and 1373 K

“…In the study, from 5 wt% to 20 wt% of alumina was added and the minimum viscosity was measured at around 10 wt%. 32) Likewise, in the present composite pellet system, alumina content up to 10 wt% acts as basic oxide that is considered to be repulsive with Fe 2+ ion. However, alumina content above 15 wt% plays an acidic role in carbon composite pellet which demonstrates an attractive force towards Fe 2+ ion.…”

“…The fastest reaction rate at 10 wt% of alumina is due to the amphoteric characteristics of alumina. 30) A viscosity study on FeOt-Al2O3-SiO2 ternary slag system 32) shows that alumina acts as basic as well as acidic oxide depending on the basicity of the melts. In the study, from 5 wt% to 20 wt% of alumina was added and the minimum viscosity was measured at around 10 wt%.…”

Effect of Alumina and Silica on the Reaction Kinetics of Carbon Composite Pellets at 1473 K

“…From the CaOSiO2-FeOt ternary phase diagram, 19) increasing silica contents from 5 to 15 wt% confirmed to formulate the fayalite phase (Fe2SiO4) at a fixed CaO / Fe2O3 ratio (CF2). Due to its low melting point of 1 478 K (1 205°C) and low viscosity (≤10 Pa·s), 20) fayalite lowered the surface area of pellets by increasing liquid phases in the structure. When silica is introduced in the oxide system, the fayalite phase increases the stability of oxides.…”

Influence of Al₂O₃ and MgO on the Viscosity and Stability of CaO–MgO–SiO₂–Al₂O₃ Slags with CaO/SiO₂=1.0

“…8,9) Al 2 O 3 behave as either a basic oxide or an acidic oxide depending on the slag composition. [10][11][12][13][14][15] In order to improve the properties of slag containing high Al 2 O 3 content, some researchers have investigated the effect of MgO addition on the viscosity. 16) In CaO-MgO-SiO 2 -Al 2 O 3 slag system, the viscosity decreases firstly and then increases with increasing MgO content.…”