XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 33
Mixed Hydroxide Precipitation. The MHP product
obtained during a typical period was analyzed as 44.1% Ni,
0.75% Co, 2.47% Mg, 0.035% Al, 0.044% Fe, 0.139%
Cu and 0.04% Zn. The MHP contained typically 2–3.5%
S as sulfate due to formation of some basic nickel and cobalt
sulfate precipitation.
Secondary Hydroxide Precipitation. A typical final
SHP thickener overflow solution analysis showed 0.005
g/L Ni, 0.01 g/L Co, 0.005 g/L Cu, 0.002 g/L Zn,
10.5 g/L Mg, 0.54 g/L Ca. The SHP thickener U/F sol-
ids analyzed 1.47% Ni, 7.64% Mg, 0.13% Co, 0.024%
Al, 7.4% Mg and 20.4% Ca. The solids represented a gyp-
sum precipitate with significant Mg(OH)2 coprecipitation.
These solids were recycled to be mixed with the autoclave
discharge slurry before thickening in order to maximize the
re-extraction of Ni, Co and Cu.
The development of a process to make MHP pre-
cipitate containing nickel and cobalt hydroxides from the
West Musgrave nickel concentrate has been successfully
completed. The concentrate was pressure leached at about
150 °C with oxygen in an acid, metal salt solution in the
presence of a surfactant (ligninsulfonate) and low concen-
trations of chloride to extract about 98% of the Ni, 96%
of the Co and 84% of the Cu from the concentrate. The
resulting leach solutions are purified to remove an iron
precipitate and a copper sulfide product and finally a high
grade MHP precipitate for further refining to produce bat-
tery metal salts for lithium ion battery manufacture.
THE ATLAS MATERIALS PROCESS FOR
LATERITE PROCESSING
Atlas Materials was founded to develop innovative tech-
nologies for critical materials supply, with by-products to
enable an overall “carbon negative” outcome. Technology
development has focused on treatment of nickel saprolite
ores. Nickel saprolite ores contain magnesium silicate or
magnesium hydroxy silicate minerals in addition to nickel
and cobalt, iron, and other minor elements. The vision of
Atlas is to process these materials for nickel and cobalt bat-
tery material supply, silica products carrying iron and alu-
minum for material substitution in the cement industry,
and magnesium hydroxide. Magnesium hydroxide from
the NEM process may be used in the future to sequester
atmospheric carbon dioxide using a variety of processes.
The NEM general process flowsheet is shown below
(Figure 7). The process involves a series of mineral process-
ing and hydrometallurgical steps.
Crushing and Grinding. Crushing and grinding in
recycle brine solution containing a variety of chloride salts
including magnesium chloride and sodium chloride.
HCl Leaching. This process uses 36% HCl to leach
raw materials contain a variety of silicate minerals includ-
ing magnesium, iron, nickel, cobalt, and minor impurity
elements.
The chemistry is therefore comprised of the following
major reactions:
Mg2SiO4 +4HCl =2MgCl2 +SiO2 +2H2O (1)
Ni2SiO4 +4HCl =2NiCl2 +SiO2 +2H2O (2)
Fe2SiO4 +4HCl =2FeCl2 +SiO2 +2H2O (3)
The leaching temperature is close to the boiling point
to ensure rapid extraction. Acid addition is around 650 kg
HCl per dry tonne of saprolite feed.
The products of HCl leaching are a weakly acidic solu-
tion containing various chloride salts and a silica rich resi-
due recovered as a solid product.
Iron and Aluminum Removal. The iron and alumi-
num content in the solution is precipitated by addition of
ground olivine mineral to precipitate the metal impurities.
Olivine is essentially a basic magnesium silicate.
4HCl +Mg2SiO4 =2MgCl2 +2H2O (13)
4FeCl3 +3Mg2SiO4 +2H2O =
4FeO(OH) +6MgCl2 +3SiO2 (14)
4AlCl3 +3Mg2SiO4 +2H2O =
4AlO(OH) +6MgCl2 +3SiO2 (15)
4CrCl3 +3Mg2SiO4 +2H2O =
4CrO(OH) +6MgCl2 +3SiO2 (16)
Olivine often contains nickel, cobalt and iron. These ele-
ments will also react with the acidic leachate. Nickel and
cobalt extraction from olivine is beneficial to the produc-
tion of nickel and cobalt as hydroxide. Iron may extract as
ferrous iron from olivine and with the addition of sodium
hypochlorite may be oxidized to precipitate. Finally, the
extraction of magnesium will lead to a higher overall pro-
duction of magnesium hydroxide.
Nickel and Cobalt Recovery. Nickel and cobalt are
present in solution as NiCl2 and CoCl2 salts. The recovery
of Ni/Co can be done in many ways including the direct
precipitation of mixed hydroxide precipitate. This can
be done directly from the solution coming from the iron
precipitation.
NiCl2 +2NaOH =Ni(OH)2 +2NaCl (17)
CoCl2 +2NaOH =Co(OH)2 +2NaCl (18)
Mixed Hydroxide Precipitation. The MHP product
obtained during a typical period was analyzed as 44.1% Ni,
0.75% Co, 2.47% Mg, 0.035% Al, 0.044% Fe, 0.139%
Cu and 0.04% Zn. The MHP contained typically 2–3.5%
S as sulfate due to formation of some basic nickel and cobalt
sulfate precipitation.
Secondary Hydroxide Precipitation. A typical final
SHP thickener overflow solution analysis showed 0.005
g/L Ni, 0.01 g/L Co, 0.005 g/L Cu, 0.002 g/L Zn,
10.5 g/L Mg, 0.54 g/L Ca. The SHP thickener U/F sol-
ids analyzed 1.47% Ni, 7.64% Mg, 0.13% Co, 0.024%
Al, 7.4% Mg and 20.4% Ca. The solids represented a gyp-
sum precipitate with significant Mg(OH)2 coprecipitation.
These solids were recycled to be mixed with the autoclave
discharge slurry before thickening in order to maximize the
re-extraction of Ni, Co and Cu.
The development of a process to make MHP pre-
cipitate containing nickel and cobalt hydroxides from the
West Musgrave nickel concentrate has been successfully
completed. The concentrate was pressure leached at about
150 °C with oxygen in an acid, metal salt solution in the
presence of a surfactant (ligninsulfonate) and low concen-
trations of chloride to extract about 98% of the Ni, 96%
of the Co and 84% of the Cu from the concentrate. The
resulting leach solutions are purified to remove an iron
precipitate and a copper sulfide product and finally a high
grade MHP precipitate for further refining to produce bat-
tery metal salts for lithium ion battery manufacture.
THE ATLAS MATERIALS PROCESS FOR
LATERITE PROCESSING
Atlas Materials was founded to develop innovative tech-
nologies for critical materials supply, with by-products to
enable an overall “carbon negative” outcome. Technology
development has focused on treatment of nickel saprolite
ores. Nickel saprolite ores contain magnesium silicate or
magnesium hydroxy silicate minerals in addition to nickel
and cobalt, iron, and other minor elements. The vision of
Atlas is to process these materials for nickel and cobalt bat-
tery material supply, silica products carrying iron and alu-
minum for material substitution in the cement industry,
and magnesium hydroxide. Magnesium hydroxide from
the NEM process may be used in the future to sequester
atmospheric carbon dioxide using a variety of processes.
The NEM general process flowsheet is shown below
(Figure 7). The process involves a series of mineral process-
ing and hydrometallurgical steps.
Crushing and Grinding. Crushing and grinding in
recycle brine solution containing a variety of chloride salts
including magnesium chloride and sodium chloride.
HCl Leaching. This process uses 36% HCl to leach
raw materials contain a variety of silicate minerals includ-
ing magnesium, iron, nickel, cobalt, and minor impurity
elements.
The chemistry is therefore comprised of the following
major reactions:
Mg2SiO4 +4HCl =2MgCl2 +SiO2 +2H2O (1)
Ni2SiO4 +4HCl =2NiCl2 +SiO2 +2H2O (2)
Fe2SiO4 +4HCl =2FeCl2 +SiO2 +2H2O (3)
The leaching temperature is close to the boiling point
to ensure rapid extraction. Acid addition is around 650 kg
HCl per dry tonne of saprolite feed.
The products of HCl leaching are a weakly acidic solu-
tion containing various chloride salts and a silica rich resi-
due recovered as a solid product.
Iron and Aluminum Removal. The iron and alumi-
num content in the solution is precipitated by addition of
ground olivine mineral to precipitate the metal impurities.
Olivine is essentially a basic magnesium silicate.
4HCl +Mg2SiO4 =2MgCl2 +2H2O (13)
4FeCl3 +3Mg2SiO4 +2H2O =
4FeO(OH) +6MgCl2 +3SiO2 (14)
4AlCl3 +3Mg2SiO4 +2H2O =
4AlO(OH) +6MgCl2 +3SiO2 (15)
4CrCl3 +3Mg2SiO4 +2H2O =
4CrO(OH) +6MgCl2 +3SiO2 (16)
Olivine often contains nickel, cobalt and iron. These ele-
ments will also react with the acidic leachate. Nickel and
cobalt extraction from olivine is beneficial to the produc-
tion of nickel and cobalt as hydroxide. Iron may extract as
ferrous iron from olivine and with the addition of sodium
hypochlorite may be oxidized to precipitate. Finally, the
extraction of magnesium will lead to a higher overall pro-
duction of magnesium hydroxide.
Nickel and Cobalt Recovery. Nickel and cobalt are
present in solution as NiCl2 and CoCl2 salts. The recovery
of Ni/Co can be done in many ways including the direct
precipitation of mixed hydroxide precipitate. This can
be done directly from the solution coming from the iron
precipitation.
NiCl2 +2NaOH =Ni(OH)2 +2NaCl (17)
CoCl2 +2NaOH =Co(OH)2 +2NaCl (18)