XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 295
credits, potentially covering 37–60% of capital costs from
2022–2030 and 18–30% from 2031–2040 (“Canada
Nickel Confirms Value of Carbon Storage Capacity,” 2023).
While government tax incentives assist infrastructure
development, this method’s long-term commercial poten-
tial hinges heavily on delivering value-added products, such
as enhanced nickel recovery and marketable magnesium
carbonates.
Ultramafic Nickel Laterites Carbonation
As laterite ore processing relies on hydrometallurgy, ultra-
mafic laterite ores acid leaching provides the Mg2+ ions in
addition to nickel in the pregnant leach solution (PLS).
The flowsheet employs sulfuric acid (H2SO4) to leach
nickel from laterites, which also leaches the magnesium
ions (Figure 3). Although magnesite (MgCO3) has simi-
lar neutralizing properties to calcite, magnesite is relatively
rare and expensive, while calcite is more common. As such,
locally sourced calcite (CaCO3) could be used as a cost-
effective neutralization reagent. Utilizing calcite will lead to
the neutralization reactions below:
s CaCO3 H SO CaSO CO H2O
2 4 4 2 "+++^h (7)
Mg unreactedh 2+ ^(8)
CaSO4 should remain neutral during the carbonation
reaction without side reaction from other impurities
(Equation 7). The CO2 evolved during the reaction is col-
lected, scrubbed, compressed, and sent for the carbonation
reaction, which follows reactions (Eqns. 1–4). The Mg2+
ions from neutralization will be present in the PLS, which
can then be used in the carbonation reaction. The carbon-
ation reaction occurs in the presence of Mg2+ in the slurry,
and CO32– ions formed from the CO2 dissolution in liquid.
Figure 2. High-level block diagram for CO
2 sequestration in
nickel tailings processing
Figure 3. High-level block diagram for CO
2 sequestration in
nickel laterite processing
credits, potentially covering 37–60% of capital costs from
2022–2030 and 18–30% from 2031–2040 (“Canada
Nickel Confirms Value of Carbon Storage Capacity,” 2023).
While government tax incentives assist infrastructure
development, this method’s long-term commercial poten-
tial hinges heavily on delivering value-added products, such
as enhanced nickel recovery and marketable magnesium
carbonates.
Ultramafic Nickel Laterites Carbonation
As laterite ore processing relies on hydrometallurgy, ultra-
mafic laterite ores acid leaching provides the Mg2+ ions in
addition to nickel in the pregnant leach solution (PLS).
The flowsheet employs sulfuric acid (H2SO4) to leach
nickel from laterites, which also leaches the magnesium
ions (Figure 3). Although magnesite (MgCO3) has simi-
lar neutralizing properties to calcite, magnesite is relatively
rare and expensive, while calcite is more common. As such,
locally sourced calcite (CaCO3) could be used as a cost-
effective neutralization reagent. Utilizing calcite will lead to
the neutralization reactions below:
s CaCO3 H SO CaSO CO H2O
2 4 4 2 "+++^h (7)
Mg unreactedh 2+ ^(8)
CaSO4 should remain neutral during the carbonation
reaction without side reaction from other impurities
(Equation 7). The CO2 evolved during the reaction is col-
lected, scrubbed, compressed, and sent for the carbonation
reaction, which follows reactions (Eqns. 1–4). The Mg2+
ions from neutralization will be present in the PLS, which
can then be used in the carbonation reaction. The carbon-
ation reaction occurs in the presence of Mg2+ in the slurry,
and CO32– ions formed from the CO2 dissolution in liquid.
Figure 2. High-level block diagram for CO
2 sequestration in
nickel tailings processing
Figure 3. High-level block diagram for CO
2 sequestration in
nickel laterite processing