7
HPAL test. The residue contained 24.4% Si, 2.6% Fe, and
6.8% Al as major components.
Mineralogical Characterization of Feed and HPAL
Residue
The Feed and HPAL residue samples were investigated with
chemical analyses and TIMA-X to provide a mineralogical
perspective to the metallurgical testwork results. The feed
was stage crushed to a P80 of ca. 40 μm and the residue was
analyzed as produced.
TIMA-X is an acronym for TESCAN Integrated
Mineral Analyzer, which is one of the newest Automated
Scanning Electron Microscopy (ASEM) instruments on the
market. It is based on four Energy Dispersive X-Ray (EDX)
silicon drift detectors (SDD) attached to a TESCAN MIRA
(field-emission gun – FEG) platform which also includes
backscattered electron (BSE) and secondary electron (SE)
detectors. The TIMA system utilizes both the EDX and
BSE signals to identify minerals at each measurement point
(or each homogenous segment of a grain, depending upon
the analysis mode) and it is optimized to deal with rapidly
acquired low-count spectra. These EDX (and BSE) spectra
(and BSE data) are compared to entries in a mineral library
on a first match principle to identify the mineral phase,
where this mineral library is based on theoretical mineral/
phase composition or created by the user based on BSE,
X-ray spectral windows counts, and/or ratios.
Chemical Characterization
The chemical composition of the feed and HPAL leach resi-
due streams is given in Table 7 showing the decrease (from
feed to residue) of well leached elements such as nickel,
cobalt, and copper, along with an increase of elements that
do not leach significantly such as iron, aluminum, and
manganese.
Mineral Abundance
Figure 4 illustrates a summary of the mineral wt% distribu-
tion in the two samples. The compounds are fine grained
and characterized by crypto to microcrystalline intergrowths
yielding mixed chemical analyses, and do not conform to
common rock forming minerals. Therefore, they have been
described based on their elemental composition. For exam-
ple, Mn-(high Si)-oxides consist of Mn-oxides intergrown
with Mn-silicates. Both samples consist of Mn-(high Si)-
oxides, Fe-(Mn)-silicates, Mn(Si,S)-oxides, Mn-(Cu,Ni)
oxides, and other minerals in lower quantifies (ca. 2%).
A notable difference is the presence of significant levels
of Mn-(Cu,Ni) oxides in the feed material (ca. 19%) and
the low level (2%) in the HPAL leach residue, indicative
of efficient leaching. This coincides with the increase in
Mn-(Si,S)-oxide from 2.83% in the feed to 13.7% in the
leach residue
Examples of the occurrence and chemistry of
Mn-(Cu,Ni) particles from the TIMA-X are shown in
Figure 5 from the Feed and Figure 6 from the HPAL resi-
due. They illustrate back scattered electron (BSE) micro-
scope images, the pseudo colour images of the particles,
and X-ray maps of Mn, S, Si, Ni, and Cu, and the cor-
responding spectrum of the minerals. A semi-quantitative
analysis yields 40.7% Mn, 2.4% Ni, 1.7% Cu and 0.6%
Co, and minor other elements.
Grain Size
The P80 of selected minerals is given in Table 8. The P80 of
Mn-(Cu,Ni) ranges from 39 μm to 26 μm in the Feed and
HPAL Residue, Mn-(high Si)-Ox from 31 μm to 150 μm,
respectively. The term “Particle” refers to both liberated and
middling particles, monomineralic and polymineralic. The
P80 of the particle ranges from ca. 39 μm in the Feed to 151
μm in the HPAL Residue.
Exposure of Mn-(Cu,Ni) Oxides
The exposure (exposed surface%) of Mn-(Cu,Ni) is sum-
marized into well exposed particles (exposure ≥80%) which
ranges from 19% to 24%, poorly exposed (30% exposure)
ranging from 20% to 35%, and moderately exposed (80-
≥30%) that ranges from 61% to 41% in the Feed and HPAL
Residue (Figure 6). It is of interest to note that despite the
relatively high levels of poorly exposed Cu/Ni bearing
manganese oxides, leach extraction for copper, nickel, and
cobalt were still high. This is indicative that either the acid
solution was able to penetrate into poorly exposed areas, or
Table 7. Chemical composition of the Feed and HPAL
Residue
Oxide/Element Feed HPAL Residue
Ni 1.27 0.03
Co 0.24 0.02
Cu 1.06 0.08
Fe 5.27 5.67
Mn 28.4 30.9
Si 7.48 8.32
Fe 5.27 5.67
Al 2.52 2.68
Mg 1.89 0.05
Ca 1.43 1.37
Na 2.08 0.64
K 1.25 1.27
Ti 0.30 0.35
P 0.13 0.16
HPAL test. The residue contained 24.4% Si, 2.6% Fe, and
6.8% Al as major components.
Mineralogical Characterization of Feed and HPAL
Residue
The Feed and HPAL residue samples were investigated with
chemical analyses and TIMA-X to provide a mineralogical
perspective to the metallurgical testwork results. The feed
was stage crushed to a P80 of ca. 40 μm and the residue was
analyzed as produced.
TIMA-X is an acronym for TESCAN Integrated
Mineral Analyzer, which is one of the newest Automated
Scanning Electron Microscopy (ASEM) instruments on the
market. It is based on four Energy Dispersive X-Ray (EDX)
silicon drift detectors (SDD) attached to a TESCAN MIRA
(field-emission gun – FEG) platform which also includes
backscattered electron (BSE) and secondary electron (SE)
detectors. The TIMA system utilizes both the EDX and
BSE signals to identify minerals at each measurement point
(or each homogenous segment of a grain, depending upon
the analysis mode) and it is optimized to deal with rapidly
acquired low-count spectra. These EDX (and BSE) spectra
(and BSE data) are compared to entries in a mineral library
on a first match principle to identify the mineral phase,
where this mineral library is based on theoretical mineral/
phase composition or created by the user based on BSE,
X-ray spectral windows counts, and/or ratios.
Chemical Characterization
The chemical composition of the feed and HPAL leach resi-
due streams is given in Table 7 showing the decrease (from
feed to residue) of well leached elements such as nickel,
cobalt, and copper, along with an increase of elements that
do not leach significantly such as iron, aluminum, and
manganese.
Mineral Abundance
Figure 4 illustrates a summary of the mineral wt% distribu-
tion in the two samples. The compounds are fine grained
and characterized by crypto to microcrystalline intergrowths
yielding mixed chemical analyses, and do not conform to
common rock forming minerals. Therefore, they have been
described based on their elemental composition. For exam-
ple, Mn-(high Si)-oxides consist of Mn-oxides intergrown
with Mn-silicates. Both samples consist of Mn-(high Si)-
oxides, Fe-(Mn)-silicates, Mn(Si,S)-oxides, Mn-(Cu,Ni)
oxides, and other minerals in lower quantifies (ca. 2%).
A notable difference is the presence of significant levels
of Mn-(Cu,Ni) oxides in the feed material (ca. 19%) and
the low level (2%) in the HPAL leach residue, indicative
of efficient leaching. This coincides with the increase in
Mn-(Si,S)-oxide from 2.83% in the feed to 13.7% in the
leach residue
Examples of the occurrence and chemistry of
Mn-(Cu,Ni) particles from the TIMA-X are shown in
Figure 5 from the Feed and Figure 6 from the HPAL resi-
due. They illustrate back scattered electron (BSE) micro-
scope images, the pseudo colour images of the particles,
and X-ray maps of Mn, S, Si, Ni, and Cu, and the cor-
responding spectrum of the minerals. A semi-quantitative
analysis yields 40.7% Mn, 2.4% Ni, 1.7% Cu and 0.6%
Co, and minor other elements.
Grain Size
The P80 of selected minerals is given in Table 8. The P80 of
Mn-(Cu,Ni) ranges from 39 μm to 26 μm in the Feed and
HPAL Residue, Mn-(high Si)-Ox from 31 μm to 150 μm,
respectively. The term “Particle” refers to both liberated and
middling particles, monomineralic and polymineralic. The
P80 of the particle ranges from ca. 39 μm in the Feed to 151
μm in the HPAL Residue.
Exposure of Mn-(Cu,Ni) Oxides
The exposure (exposed surface%) of Mn-(Cu,Ni) is sum-
marized into well exposed particles (exposure ≥80%) which
ranges from 19% to 24%, poorly exposed (30% exposure)
ranging from 20% to 35%, and moderately exposed (80-
≥30%) that ranges from 61% to 41% in the Feed and HPAL
Residue (Figure 6). It is of interest to note that despite the
relatively high levels of poorly exposed Cu/Ni bearing
manganese oxides, leach extraction for copper, nickel, and
cobalt were still high. This is indicative that either the acid
solution was able to penetrate into poorly exposed areas, or
Table 7. Chemical composition of the Feed and HPAL
Residue
Oxide/Element Feed HPAL Residue
Ni 1.27 0.03
Co 0.24 0.02
Cu 1.06 0.08
Fe 5.27 5.67
Mn 28.4 30.9
Si 7.48 8.32
Fe 5.27 5.67
Al 2.52 2.68
Mg 1.89 0.05
Ca 1.43 1.37
Na 2.08 0.64
K 1.25 1.27
Ti 0.30 0.35
P 0.13 0.16