In the quest to mitigate climate change, scientists are exploring innovative ways to capture and store carbon dioxide (CO2). One promising avenue is mineral carbonation, a process that transforms CO2 into stable carbonate minerals. Recent research published in the Journal of CO2 Utilization sheds new light on this technique, with significant implications for the energy sector.
At the heart of this study is serpentinized peridotite, a type of rock rich in forsterite, a magnesium iron silicate mineral. These rocks are not only abundant but also highly effective at sequestering CO2. However, they also contain nickel, a potentially harmful metal whose behavior during carbonation has been poorly understood—until now.
Dr. Błażej Cieślik, a geologist from the University of Wrocław, led a team that investigated nickel mobilization during single-stage aqueous mineral carbonation. Their findings, published in the Journal of CO2 Utilization, reveal a complex interplay between CO2 sequestration and nickel release.
The researchers subjected powdered serpentinized peridotite to high temperatures and pressures, mimicking conditions suitable for mineral carbonation. Over 96 hours, they observed the dissolution of forsterite and the formation of magnesite, a carbonate mineral. “The serpentinized peridotite proved to be highly effective for permanent CO2 storage,” Cieślik noted, highlighting the potential of this natural material for large-scale carbon capture and storage (CCS) projects.
However, the story doesn’t end with successful carbon sequestration. The team also tracked the fate of nickel during the process. They found that about half of the nickel in the rock was released during forsterite dissolution. Most of this nickel (over 98%) was incorporated into newly formed nickel-rich phyllosilicates, a type of clay mineral. A small fraction (less than 2%) ended up in the post-carbonation fluid, reaching a concentration of approximately 18 mg/kg.
While the amount of nickel mobilized into the fluid is relatively low, it’s not negligible. “The behavior of nickel during single-stage mineral carbonation is complex and requires careful monitoring,” Cieślik cautioned. The presence of nickel in the post-carbonation fluid could pose ecotoxicological risks, potentially impacting the natural environment.
So, what does this mean for the energy sector? Mineral carbonation is gaining traction as a viable CCS technique, with several pilot projects already underway. The findings of Cieślik and his team underscore the need for a nuanced understanding of the process. While serpentinized peridotite shows promise for CO2 storage, the potential mobilization of metals like nickel must be carefully managed.
As the energy sector continues to explore and invest in CCS technologies, this research serves as a reminder that the devil is in the details. The path to a low-carbon future is paved with complex challenges, and each step forward brings new insights and considerations. The work published in the Journal of CO2 Utilization, translated from Polish as ‘Journal of CO2 Utilization,’ is a testament to the ongoing efforts to navigate these challenges and pave the way for a more sustainable energy landscape.