The significance of the serpentinite characteristics in mineral carbonation by “the ÅA Route”

Serpentinite rocks are considered to be a suitable raw material for Carbon Capture and Mineralization (CCM), which has been recognized as a potential method for the management of the industrial CO₂-emissions. Different serpentine minerals, that form serpentinite rocks, feature divergent characteristics that influence the eventual suitability of a serpentinite rock for CCM. The present study focuses on these characteristics, sub-divides them and explains how each characteristic influences the suitability. The carbonation method employed in this study is developed at Åbo Akademi University. The good, yet sometimes inconsistent results gained with this method, gave grounds to a closer mineralogical study. Samples in this study consist of an antigorite dominating serpentinite, a lizardite dominating serpentinite, an antigorite seam, a lizardite rock and a serpentinite rock with high water content (15.15%). A serpentinite tailing is used as a base sample. Mineralogical studies were executed with an optical microscope, Scanning Electron Microscope with Energy Dispersive X-Ray Spectrometer (SEM-EDX) and X-ray Diffraction (XRD).

The results state that the characteristics that influence the suitability of a serpentinite rock for mineral carbonation are the mineralogical structure, parent rock and later transformation of the rock through metamorphosis or other type of alteration. The features that positively influence the suitability are more common in lizardite than in antigorite.

As serpentinite rocks are widely available, additional knowledge on their behavior based on the mineralogical characteristics, and understanding these variables, enables improvement of the method and widens its range of application. The results can also be used as guidelines to other rocks that are found to be possible raw materials for the carbonation method. The results do not apply to carbonation processes only, but also other purposes, for example among industrial exploitations of quarried materials and their further utilization as profitable goods.