TY - JOUR

T1 - Carbon dioxide fixation within chrysotile mining residues from the Ak-Dovurak asbestos mine, Tuva Republic (Southern Siberia): Retrospective and prospective assessment

AU - Denisov, Stepan

AU - Trutnev, Matvey

AU - Goryajnov, Dmitry

AU - Tsvetkov, Sergey

AU - Kasprzhitskii, Anton

AU - Bortnikova, Svetlana

AU - Lazorenko, Georgy

N1 - The authors acknowledge the support by the Ministry of Science and Higher Education of the Russian Federation (grant No. FSUS-2024-0027).

PY - 2026/9

Y1 - 2026/9

N2 - This study provides the first integrated retrospective and prospective assessment of CO2 fixation within the historic tailings of the Ak-Dovurak chrysotile asbestos mine (Tuva Republic, Southern Siberia). Mineralogical (XRD, FTIR), petrographic, SEM-EDS, and stable isotope data show that near-surface tailings have undergone natural carbonation, forming hydromagnesite-rich [Mg5(CO3)4(OH)2·4H2O] crusts up to 20 cm thick, while brucite and pyroaurite [Mg6Fe3+2(CO3)(OH)16·4H2O] persist at depth. Isotopic signatures indicate an atmospheric CO2 source. Quantitative phase analysis shows that at least 9.5 kg CO2 m-2 is stored within the upper 1 m of tailings, corresponding to an average long-term sequestration rate of 0.3 kg CO2 m-2 yr-1 and a minimum of 4.7 kt CO2 sequestered since mine closure in 1992. Kinetic modelling with a shrinking core model estimates 100-year CDR potentials of up to 141 g CO2 kg-1 via alkalinity generation and 94 g CO2 kg-1 via mineral carbonation, well below stoichiometric capacities because of kinetic limitations. Among three in situ enhancement scenarios, irrigation with weak organic acids or biocatalysts gives the highest modeled acceleration, whereas surface scarification and phytoremediation provide lower-risk complementary options. The results identify Ak-Dovurak tailings as a previously unquantified carbon sink and a relevant natural analogue for engineered CO2 removal in chrysotile mine wastes.

AB - This study provides the first integrated retrospective and prospective assessment of CO2 fixation within the historic tailings of the Ak-Dovurak chrysotile asbestos mine (Tuva Republic, Southern Siberia). Mineralogical (XRD, FTIR), petrographic, SEM-EDS, and stable isotope data show that near-surface tailings have undergone natural carbonation, forming hydromagnesite-rich [Mg5(CO3)4(OH)2·4H2O] crusts up to 20 cm thick, while brucite and pyroaurite [Mg6Fe3+2(CO3)(OH)16·4H2O] persist at depth. Isotopic signatures indicate an atmospheric CO2 source. Quantitative phase analysis shows that at least 9.5 kg CO2 m-2 is stored within the upper 1 m of tailings, corresponding to an average long-term sequestration rate of 0.3 kg CO2 m-2 yr-1 and a minimum of 4.7 kt CO2 sequestered since mine closure in 1992. Kinetic modelling with a shrinking core model estimates 100-year CDR potentials of up to 141 g CO2 kg-1 via alkalinity generation and 94 g CO2 kg-1 via mineral carbonation, well below stoichiometric capacities because of kinetic limitations. Among three in situ enhancement scenarios, irrigation with weak organic acids or biocatalysts gives the highest modeled acceleration, whereas surface scarification and phytoremediation provide lower-risk complementary options. The results identify Ak-Dovurak tailings as a previously unquantified carbon sink and a relevant natural analogue for engineered CO2 removal in chrysotile mine wastes.

KW - CO2mineralization

KW - Carbon dioxide removal

KW - Carbon sequestration

KW - Mine tailings

UR - https://www.scopus.com/pages/publications/105044291017

UR - https://www.mendeley.com/catalogue/738611c9-6a88-3a6a-adea-29eb3b252a30/

U2 - 10.1016/j.ijggc.2026.104740

DO - 10.1016/j.ijggc.2026.104740

M3 - Article

VL - 155

JO - International Journal of Greenhouse Gas Control

JF - International Journal of Greenhouse Gas Control

SN - 1750-5836

M1 - 104740

ER -