3502 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
grinding media. The sample was sieved to different size frac-
tions for mineral carbonation trials. CO2 gas cylinder was
used to supply CO2 gas to the reactor. Sodium bicarbon-
ate (NaHCO3, ACS grade) was obtained by Macron Fine
Chemicals. Both sodium sulfate (Na2SO4, ACS grade) and
sodium chloride (NaCl, ACS grade) were purchased from
Fisher Scientific. All other chemicals were purchased from
Fisher Scientific, and they were at ACS grade or above.
Deionized (DI) water was used, and it was supplied from a
laboratory water purification system (Thermo Fisher). The
resistance of the DI water was 18.0 MΩ cm or above.
Bulk properties of the feed mineral materials were
characterized to determine elemental composition, min-
eralogical composition, as well as particle size distribution
(PSD) information. The mineralogical composition of the
feed material was analyzed using X-ray diffraction (XRD)
method. The Scintag (Division of Thermo ARL, Dearborn,
MI) XDS-2000/ instrument was used for XRD analysis.
This instrument has 1–2 mm beam slits and 0.3–0.5 mm
receiving slits. Using a copper target tube (λ =1.5405929
Å), the power settings were 45 kV and 35 mA. The samples
were scanned in a 2q range of 20° to 70° using 0.02° step
size. Table 2 shows the mineralogical composition of the
feed olivine minerals. As shown, the feed olivine sample
contains 79.5% forsterite and 19.5% of other forms of ser-
pentine minerals. The elemental composition of the feed
olivine sample was determined using Inductively Coupled
Plasma -Optical Emission Spectrophotometry (ICP-OES)
coupled with X-ray florescence (XRF) method. Table 1
shows both the elemental composition and mineralogical
composition of the feed sample. The particle size distribu-
tion (PSD) of the feed materials was determined using a
particle size analyzer (Microtrac) based on the laser dif-
fraction method. The D50, D80, and D90 size of the feed
materials were determined.
Experimental Configuration
The direct carbonation trials were carried out in a 600-ml
Titanium autoclave reactor (Parr Instrument). Figure 1
shows a photo of the reactor vessel and system used in this
work. Olivine feed materials were grounded prior to the
carbonation experiments and fed to the reaction vessel with
300 ml of deionized (DI) water. Chemical additives were
added. The reactor vessel was stirred at 650 rpm through-
out the period of the reaction. 50 bars of CO2 gas were
added to the reactor at the room temperature. The reac-
tor vessel was heated to a set temperature. The time spent
for the temperature inside the vessel to reach the target
temperature ranged from 20–45 minutes depending on
the targeted temperature. The reaction runs from 1 hr to
10 hours. After the reaction, the vessel was allowed to be
cooled in air to 50°C prior to disassembly of the reactor
vessel. The slurry was vacuum filtered to obtain solid resi-
due, and the filter cake was washed with DI water once to
remove residual soluble salts. The filtered samples are dried
in an oven at 80°C overnight.
Carbonation Efficiency Determination
The mineral carbonation efficiency is measured by the
extent of CO2 captured by the mineral sample, dependent
on the availability of reactive ions. The 100% carbonation
efficiency is defined as all available multivalent ions (Mg2+,
Ca2+, and Fe2+) reacts with CO2 and forms stable carbonate
minerals. The percentage of CO2 in the reacted products
can be determined by the TGA. In TGA analysis, carbonate
minerals are decomposed to oxide mineral at a tempera-
ture of 500 °C or above, releasing CO2. The efficiency is
calculated based on the stoichiometric ratio of the mineral
reacting with CO2, resulting in the formation of carbonates
(mainly magnesite) and silica as the primary products. The
weight loss of 36.67% was calculated to be equivalent to a
Table 1. Elemental composition of the feed olivine minerals
Elements Ca Mg Fe Al Si
Weight, %0.25 23.22 7.92 0.25 19.40
Table 2. Mineralogical composition of the feed olivine
minerals
Mineral
Composition Olivine Actinolite Lizardite
Weight, %79.5 10.3 9.2
Figure 1. Photos of a high-pressure agitated aut°Clave
reactor (Parr) that was used to study the carbonation
efficiency of olivine minerals at different temperatures and
CO
2 partial pressure conditions
grinding media. The sample was sieved to different size frac-
tions for mineral carbonation trials. CO2 gas cylinder was
used to supply CO2 gas to the reactor. Sodium bicarbon-
ate (NaHCO3, ACS grade) was obtained by Macron Fine
Chemicals. Both sodium sulfate (Na2SO4, ACS grade) and
sodium chloride (NaCl, ACS grade) were purchased from
Fisher Scientific. All other chemicals were purchased from
Fisher Scientific, and they were at ACS grade or above.
Deionized (DI) water was used, and it was supplied from a
laboratory water purification system (Thermo Fisher). The
resistance of the DI water was 18.0 MΩ cm or above.
Bulk properties of the feed mineral materials were
characterized to determine elemental composition, min-
eralogical composition, as well as particle size distribution
(PSD) information. The mineralogical composition of the
feed material was analyzed using X-ray diffraction (XRD)
method. The Scintag (Division of Thermo ARL, Dearborn,
MI) XDS-2000/ instrument was used for XRD analysis.
This instrument has 1–2 mm beam slits and 0.3–0.5 mm
receiving slits. Using a copper target tube (λ =1.5405929
Å), the power settings were 45 kV and 35 mA. The samples
were scanned in a 2q range of 20° to 70° using 0.02° step
size. Table 2 shows the mineralogical composition of the
feed olivine minerals. As shown, the feed olivine sample
contains 79.5% forsterite and 19.5% of other forms of ser-
pentine minerals. The elemental composition of the feed
olivine sample was determined using Inductively Coupled
Plasma -Optical Emission Spectrophotometry (ICP-OES)
coupled with X-ray florescence (XRF) method. Table 1
shows both the elemental composition and mineralogical
composition of the feed sample. The particle size distribu-
tion (PSD) of the feed materials was determined using a
particle size analyzer (Microtrac) based on the laser dif-
fraction method. The D50, D80, and D90 size of the feed
materials were determined.
Experimental Configuration
The direct carbonation trials were carried out in a 600-ml
Titanium autoclave reactor (Parr Instrument). Figure 1
shows a photo of the reactor vessel and system used in this
work. Olivine feed materials were grounded prior to the
carbonation experiments and fed to the reaction vessel with
300 ml of deionized (DI) water. Chemical additives were
added. The reactor vessel was stirred at 650 rpm through-
out the period of the reaction. 50 bars of CO2 gas were
added to the reactor at the room temperature. The reac-
tor vessel was heated to a set temperature. The time spent
for the temperature inside the vessel to reach the target
temperature ranged from 20–45 minutes depending on
the targeted temperature. The reaction runs from 1 hr to
10 hours. After the reaction, the vessel was allowed to be
cooled in air to 50°C prior to disassembly of the reactor
vessel. The slurry was vacuum filtered to obtain solid resi-
due, and the filter cake was washed with DI water once to
remove residual soluble salts. The filtered samples are dried
in an oven at 80°C overnight.
Carbonation Efficiency Determination
The mineral carbonation efficiency is measured by the
extent of CO2 captured by the mineral sample, dependent
on the availability of reactive ions. The 100% carbonation
efficiency is defined as all available multivalent ions (Mg2+,
Ca2+, and Fe2+) reacts with CO2 and forms stable carbonate
minerals. The percentage of CO2 in the reacted products
can be determined by the TGA. In TGA analysis, carbonate
minerals are decomposed to oxide mineral at a tempera-
ture of 500 °C or above, releasing CO2. The efficiency is
calculated based on the stoichiometric ratio of the mineral
reacting with CO2, resulting in the formation of carbonates
(mainly magnesite) and silica as the primary products. The
weight loss of 36.67% was calculated to be equivalent to a
Table 1. Elemental composition of the feed olivine minerals
Elements Ca Mg Fe Al Si
Weight, %0.25 23.22 7.92 0.25 19.40
Table 2. Mineralogical composition of the feed olivine
minerals
Mineral
Composition Olivine Actinolite Lizardite
Weight, %79.5 10.3 9.2
Figure 1. Photos of a high-pressure agitated aut°Clave
reactor (Parr) that was used to study the carbonation
efficiency of olivine minerals at different temperatures and
CO
2 partial pressure conditions