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Semi-Empirical Modelling for Dissolution of Calcium from Ironmaking Slag in Ammonium Acetate for CO2 Utilisation
* 1 , 1 , 1 , 2 , 1
1  Clean Technology and Applied Materials Research Group, Department of Chemical and Metallurgical Engineering, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1911, South Africa
2  Centre for Minerals Research, Department of Chemical Engineering, University of Cape Town, South Africa
Academic Editor: Antoni Sánchez


It is a great technique to use iron and steel slags as feedstock for a mineral carbonation reaction to use carbon dioxide gas because they are easily accessible, contribute to land pollution, and have a reasonable quantity of lime and magnesia. The rate at which ironmaking blast furnace ironmaking slag dissolves in an aqueous solution of ammonium acetate was investigated in relation to pH, stirring speed, solvent concentration, and temperature. A one-factor-at-a-time experiment was conducted, and pH was monitored to the maximum value of 13, stirring speed ranged from 100 to 200 rpm, solvent concentration was between 0.01 and 1M, whereas the reaction temperature was maintained between 25 and 80°C. The dissolution kinetics of ironmaking slag was calculated by fitting experimental data to a model of a diminishing core. Using BET, XRF, XRD, and FTIR, the leaching residue was characterized under various experimental conditions. The formation of the aluminoakermanite phase was ascribed to the residue slag, which had an average specific surface area of 19.58 m2g-1. In addition, FTIR analysis revealed that the residue mainly consists of Si-O-Si and Si-O-Al bonds. The results of the trial revealed that this reaction is driven by chemical reaction model equation. A semi-empirical model was also developed from the experimental data to better describe the dissolution kinetics.

Keywords: Dissolution Reaction, CO2 fixation, Ironmaking Slag, Shrinking Core Models, Semi-Empirical Modelling