CO2 Sequestration Using Fly Ash from Lignite Power Plants

Carbon dioxide sequestration by calciumor magnesium-containing minerals has been recognized as a promising processing route for the permanent and safe storage of carbon dioxide. In this study, the wet carbonation of lignite fly ash containing approximately 39 wt.% of total calcium oxide was attempted in an autoclave at pressure 1–15 bar, temperature 25–150 ◦C, liquid to solid ratio equal to 10 L/kg and retention time 24 h. Carbon content in treated fly ash was increased due to carbonation from 1.76% to 4.84–6.15% with the maximum value obtained at temperature 100 ◦C and pressure 15 bar. The analytical techniques applied confirmed the elimination of free lime and the formation of CaCO3. Based on the carbon content in untreated and treated samples it is estimated that under the optimum conditions 212,57 kg CO2 are sequestered in 1 tn of fly ash.