Proceedings of the 4th International Conference on Accelerated Carbonation for Environmental and Materials Engineering pages:235-244
ACEME 2013 location:Leuven, Belgium date:9-12 April 2013
Process limitations have thus far prevented mineral carbonation of alkaline wastes from being widely applied. These barriers are caused by inefficient processing, but also by mineralogical aspects inherent to the materials. Better understanding and predictability of the effects of mineral carbonation on alkaline materials could be obtained by separately studying the constituent minerals carbonation susceptibility, allowing for detailed and accurate analysis of their reaction kinetics, maximal conversions and formed carbonate products.
For this purpose, this paper presents the synthesis and carbonation of the seven most abundant alkaline minerals found in AOD, CC and BOF slags, namely: Åkermanite (Ca2MgSi2O7), Bredigite (Ca7MgSi4O16), Cuspidine (Ca4Si2O7F2), β– and γ–C2S (Ca2SiO4), Merwinite (Ca3MgSi2O8), and Srebrodolskite (Ca2Fe2O5). Two experimental approaches to mineral carbonation of increasing levels of process severity are utilized: (mild) incubator carbonation, and (accelerated) pressurized slurry carbonation. In addition, the slags and two free oxides (CaO and MgO) are equally carbonated and evaluated. Data regarding CO2 uptake, mineral conversion and formed carbonate and non-carbonate products in the samples were obtained through TGA, QXRD and SEM techniques. Reduction in material basicity and evolution of particle morphology were also assessed.