CO sub(2) sequestration by mineral carbonation of steel slags under ambient temperature: parameters influence, and optimization

This work focuses on the influence of different parameters on the efficiency of steel slag carbonation in slurry phase under ambient temperature. In the first part, a response surface methodology was used to identify the effect and the interactions of the gas pressure, liquid/solid (L/S) ratio, gas/liquid ratio (G/L), and reaction time on the CO sub(2) removed/sample and to optimize the parameters. In the second part, the parameters' effect on the dissolution of CO sub(2) and its conversion into carbonates were studied more in detail. The results show that the pressure and the G/L ratio have a positive effect on both the dissolution and the conversion of CO sub(2). These results have been correlated with the higher CO sub(2) mass introduced in the reactor. On the other hand, an important effect of the L/S ratio on the overall CO sub(2) removal and more specifically on the carbonate precipitation has been identified. The best results were obtained L/S ratios of 4:1 and 10:1 with respectively 0.046 and 0.052 gCO sub(2) carbonated/g sample. These yields were achieved after 10 min reaction, at ambient temperature, and 10.68 bar of total gas pressure following direct gas treatment.