Investigations of the suitability of K-feldspar modified by milling for CO2 sequestration

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Abstract

Nowadays, carbon dioxide (CO₂) emissions are one of the main factors of global warming and climate change. Controlling CO₂ levels in the atmosphere and limiting global warming requires urgent action. Some minerals can be used to capture and store CO₂ from the air or other sources. Mechanochemically modified K-feldspar (with KOH, Ca(OH)₂, and CaO) was used for ex situ and in situ CO₂ capture. In the ex situ experiment (in a thermoanalytical apparatus at 150 °C, 5 h), infrared spectroscopy indicated that mechanochemically modified feldspar was capable of CO₂ sequestration via carbonate formation. The in situ CO₂ capture experiment consists of two steps. The first step involved the mechanochemical modification of feldspar using Ca(OH)₂ and CaO as additives during milling. The second step consisted of direct in situ CO₂ sequestration in the milling chamber. X-ray diffraction patterns demonstrated the formation of the calcite phase, and thermal analysis confirmed the decomposition of such created calcite. Elemental analysis has found the binding of approximately 1.6% of carbon, and 5.23% carbonation ratio of modified feldspar was achieved. In addition, the use of the mineral vermiculite as a natural additive for in situ sequestration of feldspar was investigated using the above-mentioned analytical techniques.