34 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
The selectivity of MHP precipitation can be enhanced
by using two stage MHP precipitation. The second stage
precipitate is recovered and recycled to discharge from the
main leaching step (where acid is present to redissolve the
Ni/Co and other metals from the second stage precipitate).
Manganese Removal. Manganese is an undesirable
impurity in magnesium hydroxide and cannot be selec-
tively precipitated as a hydroxide in the presence of magne-
sium hydroxide. Accordingly, oxidation and precipitation
are used to remove manganese from solution.
MnCl2 +NaOCl +2NaOH =
MnO2 +H2O +3NaCl (19)
The manganese dioxide precipitate is filtered and washed.
Magnesium hydroxide precipitation. The remain-
ing magnesium in solution is precipitated by addition of
NaOH to form Mg(OH)2.
MgCl2 +2NaOH =Mg(OH)2 +2NaCl (20)
Brine Recycle
HCl Solution
suohpromA hsaW Silica Residue
rof retaW Cement Manufacture
NaOH Soln To Cement
Olivine +NaOCl
rC/lA/eF hsaW Olivine
Water for Cement Manufacture
oC/iN HOaN Mixed Hydroxide
(to battery manufacture)
NaOCl+
nM HOaN Precipitate
NaOH
Brine Recycle
NaOH Soln
gM hsaW Hydroxide
etatipicerP retaW
Electricity
NaOH
Mg Hydroxide
Precipitation
S/L Separation Washing
of Precipitate
Chlor Alkali Plant to
make HCl and NaOH for
Recycle
Nickel Saprolite Ore
Crushing and Grinding
HCl Leaching
S/L Separation Washing
of Residue
Iron and Aluminum
Precipitation
S/L Separation Washing
of Residue
Ni/Co MHP Production
Manganese Removal
Figure 7. The NEM Simplified Process Flowsheet
The selectivity of MHP precipitation can be enhanced
by using two stage MHP precipitation. The second stage
precipitate is recovered and recycled to discharge from the
main leaching step (where acid is present to redissolve the
Ni/Co and other metals from the second stage precipitate).
Manganese Removal. Manganese is an undesirable
impurity in magnesium hydroxide and cannot be selec-
tively precipitated as a hydroxide in the presence of magne-
sium hydroxide. Accordingly, oxidation and precipitation
are used to remove manganese from solution.
MnCl2 +NaOCl +2NaOH =
MnO2 +H2O +3NaCl (19)
The manganese dioxide precipitate is filtered and washed.
Magnesium hydroxide precipitation. The remain-
ing magnesium in solution is precipitated by addition of
NaOH to form Mg(OH)2.
MgCl2 +2NaOH =Mg(OH)2 +2NaCl (20)
Brine Recycle
HCl Solution
suohpromA hsaW Silica Residue
rof retaW Cement Manufacture
NaOH Soln To Cement
Olivine +NaOCl
rC/lA/eF hsaW Olivine
Water for Cement Manufacture
oC/iN HOaN Mixed Hydroxide
(to battery manufacture)
NaOCl+
nM HOaN Precipitate
NaOH
Brine Recycle
NaOH Soln
gM hsaW Hydroxide
etatipicerP retaW
Electricity
NaOH
Mg Hydroxide
Precipitation
S/L Separation Washing
of Precipitate
Chlor Alkali Plant to
make HCl and NaOH for
Recycle
Nickel Saprolite Ore
Crushing and Grinding
HCl Leaching
S/L Separation Washing
of Residue
Iron and Aluminum
Precipitation
S/L Separation Washing
of Residue
Ni/Co MHP Production
Manganese Removal
Figure 7. The NEM Simplified Process Flowsheet