(1245) Mineral sequestration of CO2 by indirect aqueous carbonation of ladle furnace(LF) refining slag

摘要

Mineral carbonation of CO2 is an effective way of long-term storage of CO2. Ladle furnace (LF) waste slag contains about 60% CaO. It can be potentially used to fix CO2 with advantages of large volume, cheap and close to CO2 emission sources, and it is, therefore, of great significance of CO2 fixation and waste slag disposal. In this study, the LF waste slag was leached and the leachate was carbonation at atmospheric pressure, the effects of pH of the leaching solution, CO2 gas concentration and flow rate, carbonation reaction time and temperature on the Ca2+ conversion rate in the leachate were studied. The results show that the high purity precipitated CaCO3 can be obtained using ammonium salts (such as NH4Cl) as the leaching agent without purifying the leaching solution. At pH values of the are greater than 11, the pH of the solution has had no effect on the carbonation reaction. It is conducive to the carbonation reactions with an increase of reaction temperature and CO2 gas reaction time and concentration. In addition, the CO2 gas flow rate (0.2ml/min~0.6ml/min) has little effect on the formation of precipitated CaCO3.