A Novel Indirect Wollastonite Carbonation Route for CO2 Sequestration

A new CO₂ sequestration approach through indirect wollastonite carbonation is proposed to mitigate anthropogenic CO₂ emissions from fossil fuel combustion. The wollastonite carbonation process includes three steps: (1) dissolution of wollastonite in hydrochloric acid to leach Ca²⁺ from mineral matrix; (2) reaction of the resulting CaCl₂ solution with CO₂ in triisooctylamine (TIOA) at low temperature, producing CaCO₃ and an amino acid complex; (3) regeneration of the extractant and acid by backextraction through a temperature swing process and recycling to the dissolution and carbonation steps. It was found that the wollastonite dissolution rate was accelerated by hydrochloric acid and a maximum Ca²⁺ dissolution extent of 95 % was obtained.