Mineral carbonation of gaseous carbon dioxide using a clay-hosted cation exchange reaction

Abstract

The mineral carbonation method is still a challenge in practical application owing to: (1) slow reaction kinetics, (2) high reaction temperature, and (3) continuous mineral consumption. These constraints stem from the mode of supplying alkaline earth metals through mineral acidification and dissolution. Here, we attempt to mineralize gaseous carbon dioxide into calcium carbonate, using a cation exchange reaction of vermiculite (a species of expandable clay minerals). The mineralization is operated by draining NaCl solution through vermiculite powders and continuously dropping into the pool of NaOH solution with CO₂ gas injected. The mineralization temperature is regulated here at 293 and 333 K for 15 min. As a result of characterization, using an X-ray powder diffractometer and a scanning electron microscopy, two types of pure CaCO₃ polymorphs (vaterite and calcite) are identified as main reaction products. Their abundance and morphology are heavily dependent on the mineralization temperature. Noticeably, spindle-shaped vaterite, which is quite different from a typical vaterite morphology (polycrystalline spherulite), forms predominantly at 333 K (∼98 wt%).

Keywords:

• CO₂ sequestration
• mineral carbonation
• vermiculite
• cation exchange
• calcium carbonate

This research was supported by the General Research Project of the Korea Institute of Geoscience and Mineral Resources (KIGAM), funded by the Ministry of Trade, Industry and Energy (MOTIE).