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Effect of Inorganic Salts on Direct Mineral Carbonation of
Natural Olivine Silicate Minerals
Kobina Ofori and Lei Pan
Department of Chemical Engineering, Michigan Technological University, Houghton, MI
ABSTRACT: Direct mineral carbonation of magnesium- and iron-bearing silicate minerals is a promising
technology in permanently storing carbon dioxide (CO2) in stable carbonate minerals. It has been shown that
the natural silicate minerals exhibited varying CO2 uptake capacity and reaction kinetics. However, limited
studies were performed to better understand the impact of various inorganic salts on direct mineral carbonation
of natural olivine silicate minerals. Herein, mineral carbonation of magnesium-rich olivine mineral with
different inorganic electrolytes has been investigated at different temperatures. The underlying mechanism was
investigated using scanning electron microscopy (SEM). The present work sheds new lights into the governing
mechanism involved in the direct mineral carbonation of natural silicate minerals.
INTRODUCTION
Enhancing the efficiency of mineral carbonation has
become increasingly crucial for its capacity of fixating atmo-
spheric CO2 in stable compounds. Mineral carbonation
offers a permanent and environmentally friendly solution
for carbon sequestration (Oelkers et al., 2008 Sanna et al.,
2014 Snæbjörnsdóttir et al., 2020). The potential of this
technology to mitigate climate change is significant, as it
addresses the urgent need to reduce CO2 emission rates,
a primary driver of global warming (Mun &Cho, 2013
Olajire, 2013 Thonemann et al., 2022). Mineral carbon-
ation is feasible economically at a large scale, presenting this
technology as a sustainable approach to capture and store
CO2 (O’Connor et al., 2005).
Two major approaches to achieve mineral carbonation
include a) direct carbonation approach and b) indirect
carbonation approach (Saran et al., 2018 B. Wang et al.,
2021). Direct mineral carbonation involves a direct reac-
tion of silicate minerals with CO2 to form stable carbonates
in a single step (Li &Hitch, 2018 O’Connor et al., 2002).
The indirect mineral carbonation involves a two-step
process where carbonate-forming multivalent ions, e.g.,
calcium (Ca) and magnesium (Mg), are released from min-
erals and dissolved in the aqueous solution. The released
divalent ions reacts with CO2 gas to form stable carbon-
ate minerals (Galina et al., 2023). Improving the efficiency
and accelerating the rate of mineral carbonation is essential
to make the carbonation process more economically viable
and acceptable for the implementation at the industrial
scale. Various additives have been studied to enhance this
process (Bodor et al., 2013 Woodall et al., 2019).
Much of research efforts have been devoted to inves-
tigating various strategies and chemical means to release
multi-valent ions from silicate minerals, especially serpen-
tine-type minerals. Park et al. proposed a physical activa-
tion method in the form of grinding and combined with
a pH swing process to dissolve and sequester CO2 in ser-
pentine minerals. The action of physical activation using
internal grinding alone did not enhance the mineral disso-
lution. However, in the presence of an acidic environment,
Effect of Inorganic Salts on Direct Mineral Carbonation of
Natural Olivine Silicate Minerals
Kobina Ofori and Lei Pan
Department of Chemical Engineering, Michigan Technological University, Houghton, MI
ABSTRACT: Direct mineral carbonation of magnesium- and iron-bearing silicate minerals is a promising
technology in permanently storing carbon dioxide (CO2) in stable carbonate minerals. It has been shown that
the natural silicate minerals exhibited varying CO2 uptake capacity and reaction kinetics. However, limited
studies were performed to better understand the impact of various inorganic salts on direct mineral carbonation
of natural olivine silicate minerals. Herein, mineral carbonation of magnesium-rich olivine mineral with
different inorganic electrolytes has been investigated at different temperatures. The underlying mechanism was
investigated using scanning electron microscopy (SEM). The present work sheds new lights into the governing
mechanism involved in the direct mineral carbonation of natural silicate minerals.
INTRODUCTION
Enhancing the efficiency of mineral carbonation has
become increasingly crucial for its capacity of fixating atmo-
spheric CO2 in stable compounds. Mineral carbonation
offers a permanent and environmentally friendly solution
for carbon sequestration (Oelkers et al., 2008 Sanna et al.,
2014 Snæbjörnsdóttir et al., 2020). The potential of this
technology to mitigate climate change is significant, as it
addresses the urgent need to reduce CO2 emission rates,
a primary driver of global warming (Mun &Cho, 2013
Olajire, 2013 Thonemann et al., 2022). Mineral carbon-
ation is feasible economically at a large scale, presenting this
technology as a sustainable approach to capture and store
CO2 (O’Connor et al., 2005).
Two major approaches to achieve mineral carbonation
include a) direct carbonation approach and b) indirect
carbonation approach (Saran et al., 2018 B. Wang et al.,
2021). Direct mineral carbonation involves a direct reac-
tion of silicate minerals with CO2 to form stable carbonates
in a single step (Li &Hitch, 2018 O’Connor et al., 2002).
The indirect mineral carbonation involves a two-step
process where carbonate-forming multivalent ions, e.g.,
calcium (Ca) and magnesium (Mg), are released from min-
erals and dissolved in the aqueous solution. The released
divalent ions reacts with CO2 gas to form stable carbon-
ate minerals (Galina et al., 2023). Improving the efficiency
and accelerating the rate of mineral carbonation is essential
to make the carbonation process more economically viable
and acceptable for the implementation at the industrial
scale. Various additives have been studied to enhance this
process (Bodor et al., 2013 Woodall et al., 2019).
Much of research efforts have been devoted to inves-
tigating various strategies and chemical means to release
multi-valent ions from silicate minerals, especially serpen-
tine-type minerals. Park et al. proposed a physical activa-
tion method in the form of grinding and combined with
a pH swing process to dissolve and sequester CO2 in ser-
pentine minerals. The action of physical activation using
internal grinding alone did not enhance the mineral disso-
lution. However, in the presence of an acidic environment,