XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 3049
RESULTS AND DISCUSSIONS
FT-IR Spectroscopy
High-resolution spectra were collected to ascertain the
mechanism by which Orfom ® D8 adsorbs on the chalco-
pyrite surface. From Figure 3, untreated chalcopyrite (blue)
demonstrated two distinct bands at 1039.63 and 1369.45
cm–1. Chalcopyrite treated with Orfom ® D8 (orange)
shows new peaks which can only be attributed to adsorbed
Orfom ® D8 on chalcopyrite that exhibited band vibrations
that changed from 1118.51 and 1233.25 cm–1 to 1101.35
and 1205.51 cm–1, respectively. These are attributed to
C=S vibration of the SCS2– functionality. The interaction
outcome indicates adsorption occurs through the SCS2–
functionality and not through CO2– functionality. Band
vibrations with the chalcopyrite itself are also observed to
shift slightly from 1039.63 and 1369.45 to 1033.84 and
1371.33, respectively, indicating chemical bonds formed
further suggesting that Orfom ® D8 is chemisorbed. Because
this shows Orfom ® D8 chemisorbs through its SCS2– func-
tionality, these results support the mechanism proposed by
Young and Timbillah’s findings that also suggested that, the
carboxylate end pulls chalcopyrite into solution due to its
highly negative polarity [17–20].
Chalcopyrite was treated with potassium ethyl xanthate
(KEX) and Orfom ® D8 to ascertain the adsorption mech-
anism between the reagents and the mineral in Figure 4.
Chalcopyrite treated with KEX (yellow) exhibited three
significant vibrations at 1033.84, 1124.49 and 1199.79
cm–1. Similar to Orfom ® D8 treated chalcopyrite, 1033.84
cm–1 band vibration occurs at the same wave number as
the KEX treated chalcopyrite, and the 1205.51 cm–1 band
shifted to 1199.79 cm–1 with KEX combined with chalco-
pyrite. The Peak vibration 1124.49 cm–1 is specific to KEX
in the fingerprint region indicating that KEX is present
on the chalcopyrite surface. Both KEX and Orfom ® D8
treated chalcopyrite (grey) appears to have nearly similar
vibrations as the individual reagents on chalcopyrite. Bands
of both reagents, 1033.84 and 1205.51 for Orfom ® D8
and 1124.49 for KEX, are observed on the chalcopyrite
surface indicating both reagents are present on the chalco-
pyrite surface. Because these results show Orfom ® D8 does
not cause xanthate desorption, they suggest it masks the
hydrophobicity caused by xanthate thereby supporting the
mechanism proposed by Young and Timbillah [17–20].
Molybdenite interaction with the reagents under same
conditions as collected for chalcopyrite. Untreated molyb-
denite (Mo) exhibited three band vibrations at 468.70,
781.17 and 1093.63 cm–1. Molybdenite when treated with
Orfom ® D8 (Mo+D8), revealed band vibrations occurring
at the same wave number as the untreated mineral because
no new vibrations appeared. Unlike chalcopyrite, no
noticeable Orfom ® D8 adsorption occurred on the molyb-
denite surface. Again, these results support the mechanism
proposed by Young and Timbillah [17–20].
Zeta Potential
Chalcopyrite
It has been confirmed that Orfom ® D8 chemisorbs through
its SCS2– functionality but does not cause xanthate to
desorb so its depressant effect must mask the hydropho-
bicity caused by xanthate. This means the CO2– function-
ality on Orfom ® D8 must protrude into solution thereby
creating surface charge. Zeta potential measurements were
400 900 1400 1900
Wave Number (cm-1)
CuFeS2
CuFeS2 +D8
Figure 3. FT-IR of Chalcopyrite with and without Orfom® D8
Transmit
(%)1039.63
1033.84 1101.35
1369.45
1205.51 1371.33
RESULTS AND DISCUSSIONS
FT-IR Spectroscopy
High-resolution spectra were collected to ascertain the
mechanism by which Orfom ® D8 adsorbs on the chalco-
pyrite surface. From Figure 3, untreated chalcopyrite (blue)
demonstrated two distinct bands at 1039.63 and 1369.45
cm–1. Chalcopyrite treated with Orfom ® D8 (orange)
shows new peaks which can only be attributed to adsorbed
Orfom ® D8 on chalcopyrite that exhibited band vibrations
that changed from 1118.51 and 1233.25 cm–1 to 1101.35
and 1205.51 cm–1, respectively. These are attributed to
C=S vibration of the SCS2– functionality. The interaction
outcome indicates adsorption occurs through the SCS2–
functionality and not through CO2– functionality. Band
vibrations with the chalcopyrite itself are also observed to
shift slightly from 1039.63 and 1369.45 to 1033.84 and
1371.33, respectively, indicating chemical bonds formed
further suggesting that Orfom ® D8 is chemisorbed. Because
this shows Orfom ® D8 chemisorbs through its SCS2– func-
tionality, these results support the mechanism proposed by
Young and Timbillah’s findings that also suggested that, the
carboxylate end pulls chalcopyrite into solution due to its
highly negative polarity [17–20].
Chalcopyrite was treated with potassium ethyl xanthate
(KEX) and Orfom ® D8 to ascertain the adsorption mech-
anism between the reagents and the mineral in Figure 4.
Chalcopyrite treated with KEX (yellow) exhibited three
significant vibrations at 1033.84, 1124.49 and 1199.79
cm–1. Similar to Orfom ® D8 treated chalcopyrite, 1033.84
cm–1 band vibration occurs at the same wave number as
the KEX treated chalcopyrite, and the 1205.51 cm–1 band
shifted to 1199.79 cm–1 with KEX combined with chalco-
pyrite. The Peak vibration 1124.49 cm–1 is specific to KEX
in the fingerprint region indicating that KEX is present
on the chalcopyrite surface. Both KEX and Orfom ® D8
treated chalcopyrite (grey) appears to have nearly similar
vibrations as the individual reagents on chalcopyrite. Bands
of both reagents, 1033.84 and 1205.51 for Orfom ® D8
and 1124.49 for KEX, are observed on the chalcopyrite
surface indicating both reagents are present on the chalco-
pyrite surface. Because these results show Orfom ® D8 does
not cause xanthate desorption, they suggest it masks the
hydrophobicity caused by xanthate thereby supporting the
mechanism proposed by Young and Timbillah [17–20].
Molybdenite interaction with the reagents under same
conditions as collected for chalcopyrite. Untreated molyb-
denite (Mo) exhibited three band vibrations at 468.70,
781.17 and 1093.63 cm–1. Molybdenite when treated with
Orfom ® D8 (Mo+D8), revealed band vibrations occurring
at the same wave number as the untreated mineral because
no new vibrations appeared. Unlike chalcopyrite, no
noticeable Orfom ® D8 adsorption occurred on the molyb-
denite surface. Again, these results support the mechanism
proposed by Young and Timbillah [17–20].
Zeta Potential
Chalcopyrite
It has been confirmed that Orfom ® D8 chemisorbs through
its SCS2– functionality but does not cause xanthate to
desorb so its depressant effect must mask the hydropho-
bicity caused by xanthate. This means the CO2– function-
ality on Orfom ® D8 must protrude into solution thereby
creating surface charge. Zeta potential measurements were
400 900 1400 1900
Wave Number (cm-1)
CuFeS2
CuFeS2 +D8
Figure 3. FT-IR of Chalcopyrite with and without Orfom® D8
Transmit
(%)1039.63
1033.84 1101.35
1369.45
1205.51 1371.33