DEVELOPMENT OF A NEW CO_2 FIXATION/UTILIZATION PROCESS (1): RECOVERY OF CALCIUM FORM STEELMAKING SLAG AND CHEMICAL FIXATION OF CARBON DIOXIDE BY CARBONATION REACTION

摘要

A new process of CO_2 fixation via carbonation of calcium contents in waste concrete or slag by using a solution of weak base - strong acid salt was proposed. The process is composed of two steps: (1) extraction of calcium ions by a solution of weak base - strong acid salt from the waste materials, such as waste concrete and slag, or natural ore which containing Ca and/or Mg, (2) deposition of calcium carbonate (CaCO_3) from the solution by the reaction with dissolved CO_2. In the new process, selective extraction of alkaline earth metal ions from steelmaking slag and fixation as CaCO_3 was carried out under 333-363K.