Investigation of milling energy input on structural variations of processed olivine powders for CO2 sequestration

• Milling energy input in kJ/g determines the microstructure of olivine powders.
• The optimum energy input for a minimum olivine particle size is about 14 kJ/g.
• The crystallite size of olivine decreases up to 55 kJ/g energy input and then saturates.
• The effect of structural strain on material’s disorder is negligible above 55 kJ/g energy input.
• The overall energy input for producing desirable olivine microstructure absorbing CO2 is about 55 kJ/g.

This study aims to identify the correlation between microstructure of mechanically processed olivine powders and the milling energy input, for an ultimate purpose of optimizing the ball milling approach for achieving the best CO2 sequestration characteristics. Powders were processed in a high energy magneto ball mill. A variety of instrumental techniques such as scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) and X-ray diffraction (XRD) were utilized to characterize the particle size, specific surface area, pore volume, crystallinity and crystallite size of processes powders obtained with different levels of milling energy input. In each case, the variation of microstructural parameters with milling energy is compared for different milling devices extracted from the literature. Structural parameters of activated powders are correlated as a function of milling energy input, regardless of the ball mill type. The optimal range of milling energy input, expected to achieve the most desirable microstructure for CO2 sequestration is found to be about 55 kJ/g.