Stabilization of carbon dioxide and chromium slag via carbonation

As the main greenhouse gas, CO₂ is considered as a threat in the context of global warming. Many available technologies to reduce CO₂ emission was about CO₂ separation from coal combustion and geological sequestration. However, how to deal with the cost-effective storage of CO₂ has become a new challenge. Moreover, chromium pollution, the treatment of which requires huge energy consumption, has attracted people's widespread attention. This study is aimed to develop the sequestration of CO₂ via chromium slag. A dynamic leaching experiment of chromium slag was designed to testify the ability of CO₂ adsorption onto chromium slag and to release Cr(VI) for stabilization. The results showed that the accumulative amounts of Cr(VI) were ca. 2.6 mg/g released from the chromium slag after 24 h of leaching. In addition, ca. 89 mg/g CO₂ was adsorbed by using pure CO₂ in the experiment at 12 h. Calcite is the only carbonate species in the post-carbonated slag analyzed by powder X-ray diffraction and thermal analysis. The approach provides the feasibility of the utilization of chromium slag and sequestration of the carbon dioxide at the same time at ordinary temperatures and pressures.