Recycling of slag from steel industry for CO2 sequestration

In recent years the need to mitigate emissions of greenhouse gases in the atmosphere increased the number of studies on the use of slag for the capture of CO2: the use of mining and steel industry waste to capture carbon dioxide permanently is a method well known[1][2][3]; the question concerning the efficiency of these materials, however, is not solved[4]. In this paper we present the results obtained from tests on the carbonation of steel slag, studied by type, size class and composition, in order to verify the possibility of providing products to recover as much CO2 as possible. It was verified that most of the light and dark steel slag of blast furnace have a reactivity that, with the same content of alkaline oxide, depends on the particle size. This reactivity is expressed clearly with exothermic reactions, which can be emphasized if are used certain procedures that increase the reactivity, as agitation in ultrasound. The results show that we can achieve efficiencies of capture and reaction speed very high, but low energy consumption.