Mass and energy balance of NH4-salts pH swing mineral carbonation process using steel slag

A basic evaluation of the entire NH4-salts pH swing mineral carbonation process steel slag based system including CO₂ capture, ammonia absorption and regeneration of additives, has been investigated to evaluate its feasibility at industrial scale. Heat released from mineral dissolution, pH adjustment and precipitation of impurities, carbonation reaction and CO₂ capture was 2.3 MWh/tCO₂ and could be recovered using heat exchangers and reused within the mineralization process to heat-up the incoming streams of steel slag, ammonium sulphate and water. Heat required, mainly from water evaporation and regeneration of additives, is reported to be 20 MWh/tCO₂.