Direct mineral carbonation of steelmaking slag for CO2 sequestration at room temperature
2016
Rushendra Revathy, T. D. | Palanivelu, K. | Ramachandran, A.
Rapid increase of CO₂ concentration in the atmosphere has forced the international community towards adopting actions to restrain from the impacts of climate change. Moreover, in India, the dependence on fossil fuels is projected to increase in the future, implying the necessity of capturing CO₂ in a safe manner. Alkaline solid wastes can be utilized for CO₂ sequestration by which its disposal issues in the country could also be met. The present work focuses to study direct mineral carbonation of steelmaking slag (SS) at room temperature and low-pressure conditions (<10 bar). Direct mineral carbonation of SS was carried out in a batch reactor with pure CO₂ gas. The process parameters that may influence the carbonation of SS, namely, CO₂ gas pressure, liquid to solid ratio (L/S) and reaction time were also studied. The results showed that maximum sequestration of SS was attained in the aqueous route with a capacity of 82 g of CO₂/kg (6 bar, L/S ratio of 10 and 3 h). In the gas-solid route, maximum sequestration capacity of about 11.1 g of CO₂/kg of SS (3 bar and 3 h) was achieved indicating that aqueous route is the better one under the conditions studied. These findings demonstrate that SS is a promising resource and this approach could be further developed and used for CO₂ sequestration in the country. The carbonation process was evidenced using FT-IR, XRD, SEM and TG analysis.
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