XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2491
Å (Pt2–S2), while the Pt1–S1 and As1–N1 does not form
any bond under neutral condition and the acidic condi-
tion did not form any bond with the surface. The adsorp-
tion energies for the most exothermic adsorption as shown
in Table 3 depicted that SDTBAT on dry and hydrated
PtAs2 surface under neutral conditions had strong exo-
thermic adsorption. In addition, the HNBDTC showed
strong adsorption under acidic condition for both dry and
hydrated sperrylite surface. Interestingly, after relaxation of
HNBDTC on hydrated sperrylite surface for acidic condi-
tion, one water molecule dissociated, where its hydrogen
migrated to bond with the nearest water molecule forming
a hydronium (H3O), while the OH bonded on As atom
(As–OH =1.872 Å) on the surface (see Figure 4). This
confirmed that the acidic condition was well simulated
since the formation of hydronium is one of the species that
form in acidic conditions. The adsorption of SDTBAT on
dry PtAsS surface also gave the most exothermic adsorp-
tion under neutral and acidic condition (see Table 3 as also
depicted in Figure 6). The simulated adsorption energies
on platarsite (100) surface followed the decreasing order as:
DTBAT NBDTC NBX, under both neutral and acidic
conditions indicating that the DTBAT had strong exother-
mic adsorption (Figure 6).
Microcalorimetry and Microflotation Tests
Microcalorimetry titration and microflotation were per-
formed for each collector on sperrylite, and the enthalpies
of adsorption are displayed in Figure 7 and 8, in com-
parison with the computational adsorption energies. The
adsorption energies on dry and hydrated sperrylite surface
followed the decreasing order as: DTBAT NBDTC
NBX under neutral condition, and under acidic condition
the order followed as: NBDTC DTBAT NBX. The
neutral condition adsorption trends of dry and hydrated
surface were in agreement with the microcalorimetry trend
as shown in Figure 7. Furthermore, it was noted that the
adsorption energies for dry surface were higher than those
for hydrated surface under neutral condition, which dem-
onstrated the effect of water to reduce the binding strength
of collector on mineral surface. It was observed that the
simulated acidic condition collector adsorption agreed well
with the microflotation recoveries for acidic condition (pH
=4, 2SPW). This showed that sperrylite float better under
acidic conditions.
CONCLUSIONS
This study adopted the computational, microcalorimetry
and microflotation experimental approaches to determine
the performance of NBX, NBDTC and DTBAT collec-
tors onto sperrylite and platarsite minerals at different pH
conditions that could be applicable in a wide range of arse-
nide minerals. The tested collectors were computationally
adsorbed on dry and hydrated surface under neutral and
acidic conditions. From the adsorption of NBX, NBDTC
and DTBAT on dry sperrylite and platarsite (100) surface,
it was observed that all collectors preferred to bridge bond
on the Pt and As atoms through the S and N atoms. The
adsorption energies on dry platarsite surface followed the
decreasing order as: DTBAT NBDTC NBX, under
both neutral and acidic conditions indicating that the
DTBAT had strong exothermic adsorption. It was found
Figure 6. Bar graph showing the adsorption trend for NBX, NBDTC and DTBAT collector adsorptions on platarsite surface
Å (Pt2–S2), while the Pt1–S1 and As1–N1 does not form
any bond under neutral condition and the acidic condi-
tion did not form any bond with the surface. The adsorp-
tion energies for the most exothermic adsorption as shown
in Table 3 depicted that SDTBAT on dry and hydrated
PtAs2 surface under neutral conditions had strong exo-
thermic adsorption. In addition, the HNBDTC showed
strong adsorption under acidic condition for both dry and
hydrated sperrylite surface. Interestingly, after relaxation of
HNBDTC on hydrated sperrylite surface for acidic condi-
tion, one water molecule dissociated, where its hydrogen
migrated to bond with the nearest water molecule forming
a hydronium (H3O), while the OH bonded on As atom
(As–OH =1.872 Å) on the surface (see Figure 4). This
confirmed that the acidic condition was well simulated
since the formation of hydronium is one of the species that
form in acidic conditions. The adsorption of SDTBAT on
dry PtAsS surface also gave the most exothermic adsorp-
tion under neutral and acidic condition (see Table 3 as also
depicted in Figure 6). The simulated adsorption energies
on platarsite (100) surface followed the decreasing order as:
DTBAT NBDTC NBX, under both neutral and acidic
conditions indicating that the DTBAT had strong exother-
mic adsorption (Figure 6).
Microcalorimetry and Microflotation Tests
Microcalorimetry titration and microflotation were per-
formed for each collector on sperrylite, and the enthalpies
of adsorption are displayed in Figure 7 and 8, in com-
parison with the computational adsorption energies. The
adsorption energies on dry and hydrated sperrylite surface
followed the decreasing order as: DTBAT NBDTC
NBX under neutral condition, and under acidic condition
the order followed as: NBDTC DTBAT NBX. The
neutral condition adsorption trends of dry and hydrated
surface were in agreement with the microcalorimetry trend
as shown in Figure 7. Furthermore, it was noted that the
adsorption energies for dry surface were higher than those
for hydrated surface under neutral condition, which dem-
onstrated the effect of water to reduce the binding strength
of collector on mineral surface. It was observed that the
simulated acidic condition collector adsorption agreed well
with the microflotation recoveries for acidic condition (pH
=4, 2SPW). This showed that sperrylite float better under
acidic conditions.
CONCLUSIONS
This study adopted the computational, microcalorimetry
and microflotation experimental approaches to determine
the performance of NBX, NBDTC and DTBAT collec-
tors onto sperrylite and platarsite minerals at different pH
conditions that could be applicable in a wide range of arse-
nide minerals. The tested collectors were computationally
adsorbed on dry and hydrated surface under neutral and
acidic conditions. From the adsorption of NBX, NBDTC
and DTBAT on dry sperrylite and platarsite (100) surface,
it was observed that all collectors preferred to bridge bond
on the Pt and As atoms through the S and N atoms. The
adsorption energies on dry platarsite surface followed the
decreasing order as: DTBAT NBDTC NBX, under
both neutral and acidic conditions indicating that the
DTBAT had strong exothermic adsorption. It was found
Figure 6. Bar graph showing the adsorption trend for NBX, NBDTC and DTBAT collector adsorptions on platarsite surface