Evaluation of Activation Efficiency and Quality of Slag Carbonation

The capacity of some industrial waste to sequester carbon dioxide is well known and it is also noted that to achieve the carbonation reaction it is necessary to activate the precursors overcoming the initial energy barrier through processes of dissolution in an autoclave at high temperature and pressure. To develop the direct carbonation, without autoclaving, our research group uses the mechanical activation of precursor minerals realized through an intense grinding made with friction mill (ring mill). We can estimate the timing of activation of mineral phases using a calculation model realized by us. Knowing the mechanical parameters of the grinding machines, the thermodynamic parameters of the material and the amount of radicalic sites obtained by grinding, we can evaluate the rate of carbonation for each type of mineral. The results show a good correlation between the activation level of the materials and the efficiency of carbon dioxide fixation: at ambient temperature and pressure a yield of up to 98% can be achieved.