The role of particle size distribution in CO2 sequestration by BOF slag

The paper reports the results of slurry-phase accelerated carbonation experiments using basic oxygen surface steel slag as the source of alkalinity for CO2 sequestration. In particular, the effect of particle size distribution was specifically investigated here. To this aim, different size classes of the slag were separately subjected to accelerated carbonation, and the CO2 uptake performance, the mineralogical changes and the final particle size distribution were studied. While the total content of potentially reactive elements in the different size fractions of the slag exerted only a minor influence on the carbonation performance, particle size was found to play a relevant role during the process, and likely in particular during the dissolution stage. Changes of up to two orders of magnitude in CO2 sequestration (which varied from 4.7 to 465 g of CO2 sequestered per kg of slag) were observed for the different size classes investigated. © 2015 The Authors