Technical & economic evaluation of a mineral carbonation process using southern Québec mining wastes for CO2 sequestration of raw flue gas with by-product recovery

This paper focuses on an energy and economic analysis of a mineral carbonation process developed to treat raw flue gas issued from an industrial plant. The process uses Serpentinite based mining residues available in very large quantities close to an industrial center in southern Quebec. A model based on a mass balance obtained from laboratory scale experiments allowed the evaluation of the energy requirements of the process. The integration of these results to the particular situation of the Québec province showed the process feasibility. In addition, economic investigations illustrated the profitability of such plant because of the high potential sale value of the carbonates produced. This work aims to give a particular focus on a technology developed for a niche problem but also gives valuable information for the development of other potential mineral carbonation processes elsewhere in the world. Results show that 7.8 GJ/t CO2 is required to sequester 234 kg of CO2 per tonne of rocks. Calculations showed that a plant with a capacity of 200 t of rocks treated per hour, using biomass for the heat requirements and train for the rock transportation would treat 387 000 tCO2 per year. The global process cost is estimated at 144 $/tCO2 (146 $/tCO2 avoided). Based on the incomes generated by the by-product sale and the carbon credit tax, revenues of 644 $/tCO2 are generated, giving a profitable balance. With a payback period of 1.4 years the process is highly beneficial from an economic point of view.