(560d) Low Intensity Pathways for Carbon Mineralization: Utilizing Mafic Resources in Arizona

Natural mineral resources in abundant quantities, geologic stability, and relatively quick reaction rates make mineral carbonation a promising pathway for long-term carbon sequestration (Lackner, 1995). High pressure and temperature carbonation of mafic and ultramafic mineral in CO2 saturated environments is a known and demonstrated method of stable carbon sequestration. (Gadikota, 2014) Ex-situ applications of undisturbed materials have largely been deemed cost-prohibitive due to the economics of crushing and transporting large-scale quantities of hard rock, particularly compared to the lower costs of in-situ methods. (National Acadamies Press, 2018) The performance of mafic resources under comparably low intensity conditions remains relatively unstudied, and highly glassy and porous scoria from Arizona shows promise for ex-situ processes due to inherently high surface area and lower crushing costs, arising from the naturally porous and glassy structure formed by the rapid cooling and young age of the associated volcanic events. (Valentine, 2021)

This work explores the reaction rates of local mafic and ultramafic resources in an ambient temperature, CO2 saturated aqueous solution; materials show considerable carbonation extent over monthslong timespans. Benchmarked using an ultramafic San Carlos (Arizona) olivine/pyroxene specimen samples demonstrate a reaction extent exceeding 10 wt% CO2 (100g CO2/1kg rock) over 128+ day experiments. Consistent magnesite, siderite, and dolomite carbonate phases are observed under thermogravimetric analysis (TGA) which are not seen under in-situ conditions. The combination of mild conditions and preferable rock characteristics indicate greater economic feasibility and potential for new carbon mineralization pathways.

References

Klaus S. Lackner, Christopher H. Wendt, Darryl P. Butt, Edward L. Joyce, David H. Sharp, Carbon dioxide disposal in carbonate minerals, Energy, Volume 20, Issue 11, 1995, Pages 1153-1170, ISSN 0360-5442, https://doi.org/10.1016/0360-5442(95)00071-N. (https://www.sciencedirect.com/science/article/pii/036054429500071N)

Gadikota G, Matter J, Kelemen P, Park AH. Chemical and morphological changes during olivine carbonation for CO2 storage in the presence of NaCl and NaHCO3. Phys Chem Chem Phys. 2014 Mar 14;16(10):4679-93. doi: 10.1039/c3cp54903h. PMID: 24469156.

National Academies of Sciences, Engineering, and Medicine; Division on Earth and Life Studies; Ocean Studies Board; Board on Chemical Sciences and Technology; Board on Earth Sciences and Resources; Board on Agriculture and Natural Resources; Board on Energy and Environmental Systems; Board on Atmospheric Sciences and Climate; Committee on Developing a Research Agenda for Carbon Dioxide Removal and Reliable Sequestration. Negative Emissions Technologies and Reliable Sequestration: A Research Agenda. Washington (DC): National Academies Press (US); 2018 Oct 24. PMID: 31120708.

Greg A. Valentine, Michael H. Ort, Joaquín A. Cortés; Quaternary basaltic volcanic fields of the American Southwest. Geosphere 2021;; 17 (6): 2144–2171. doi: https://doi.org/10.1130/GES02405.1