Carbon dioxide sequestration using alkaline industrial residues: a focus on recent research activities carried out at DICAAR

Since the beginning of the industrial revolution, the anthropogenic emissions of carbon dioxide, which has been globally recognized as the primary factor determining the ongoing global warming of the surface of the Earth, has increased continuously and significantly. One important technical strategy to reduce CO2 emissions is mineral carbon sequestration, which rest on the reaction of CO2 with alkaline minerals and consequently on the permanent storage of CO2 in the form of calcium and magnesium carbonates (IPPC, 2005). Alkaline industrial residues can be suitable materials for mineral carbonation and they can be used as alternative feedstock to natural minerals, due to their higher reactivity, their availability near CO2 point-emission sites and the possibility to improve some of their environmental properties as a consequence of the process. Within this framework, the research activity carried out at the Department of Civil-Environmental Engineering and Architecture (DICAAR) of the University of Cagliari has been focusing on the application of accelerated carbonation treatment on several alkaline industrial residues, such as bottom ash and air pollution control ash from waste to energy plant, coal ash from combustion plant, Waelz slag from metallurgical industry and Red Mud from Alumina production process, to evaluate their CO2 sequestration capacity and to assess the feasibility of a full scale accelerated carbonation treatment aimed at sequestering the CO2 emitted from the related plants. This paper provides a short background of the topic and resumes the scientific results achieved so far.