A Novel Collector 5–(Butylthio)–1,3,4–Thiadiazole–2–Thiol …
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weighed, and assayed for flotation recoveries and metal grades. Each flotation test
was repeated three times, and the average value was obtained.
Actual Ore Flotation Tests
Actual ore flotation tests were conducted on an XFG flotation machine with a 1.5-L
Plexiglass [18] at a spindle speed of 1600 rpm. In each flotation test, firstly, the mineral suspension was prepared by adding actual ore (500 g) to the flotation cell (with
1.5 L tap water). Secondly, if necessary, NaOH or HCl stock solution (0.1 mol/L)
was added to regulate pulp pH. Then, CSC-1 (or EX) and terpineol of desired concentration were added in sequence, and floatation products were collected for 3 min
after inflating (8 L/min) for 3 min. Finally, flotation concentrates and tailings were
collected, filtered, dried, and weighed. Flotation recoveries and metal grades were
calculated and assessed by weighing and chemical analysis, respectively. The recovery and grade were averaged from three repeated actual ore flotation tests in a certain
condition.
Contact Angle Measurement
Contact angle measurement is a common method to detect the wettability on mineral
surface [19, 20]. Contact angles of pyrite, sphalerite, and galena in DI water, EX
solution (1 × 10
−5 mol/L), and CSC-1 collector solution (1 × 10
−5 mol/L) were
measured by Zetasizer Nano contact angle tester (England). The prepared samples
of pyrite, sphalerite, and galena were initially immersed and stirred for 20 min in a
beaker (250 mL) filled with a given solution (150 mL) at 20 °C. Subsequently, the
samples were taken out, gently washed with DI water, and dried in a vacuum oven
(40 °C). The contact angles were measured by suspension droplet method. At each
contact angle test, droplets of 3.5 μL DI water were added to reach a stable state
after 30 s. Then, the contact angle was calculated based on the shape of the droplet
(Windrop++ Software). Under various test conditions, three contact angle tests were
performed to obtain the average value. After each measurement, sample surfaces
were washed repeatedly with alcohol and DI water. Finally, samples were polished
with 0.05 μm alumina powder solution for the next measurement.
Zeta Potential Measurement
Zeta potential measurement is another method to further investigate the mechanism
of flotation separation [21, 22]. Zeta potential measurements were carried out at 20 °C
by Malvern Zeta Sizer Nano Series. In each measurement, the mineral suspension was
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weighed, and assayed for flotation recoveries and metal grades. Each flotation test
was repeated three times, and the average value was obtained.
Actual Ore Flotation Tests
Actual ore flotation tests were conducted on an XFG flotation machine with a 1.5-L
Plexiglass [18] at a spindle speed of 1600 rpm. In each flotation test, firstly, the mineral suspension was prepared by adding actual ore (500 g) to the flotation cell (with
1.5 L tap water). Secondly, if necessary, NaOH or HCl stock solution (0.1 mol/L)
was added to regulate pulp pH. Then, CSC-1 (or EX) and terpineol of desired concentration were added in sequence, and floatation products were collected for 3 min
after inflating (8 L/min) for 3 min. Finally, flotation concentrates and tailings were
collected, filtered, dried, and weighed. Flotation recoveries and metal grades were
calculated and assessed by weighing and chemical analysis, respectively. The recovery and grade were averaged from three repeated actual ore flotation tests in a certain
condition.
Contact Angle Measurement
Contact angle measurement is a common method to detect the wettability on mineral
surface [19, 20]. Contact angles of pyrite, sphalerite, and galena in DI water, EX
solution (1 × 10
−5 mol/L), and CSC-1 collector solution (1 × 10
−5 mol/L) were
measured by Zetasizer Nano contact angle tester (England). The prepared samples
of pyrite, sphalerite, and galena were initially immersed and stirred for 20 min in a
beaker (250 mL) filled with a given solution (150 mL) at 20 °C. Subsequently, the
samples were taken out, gently washed with DI water, and dried in a vacuum oven
(40 °C). The contact angles were measured by suspension droplet method. At each
contact angle test, droplets of 3.5 μL DI water were added to reach a stable state
after 30 s. Then, the contact angle was calculated based on the shape of the droplet
(Windrop++ Software). Under various test conditions, three contact angle tests were
performed to obtain the average value. After each measurement, sample surfaces
were washed repeatedly with alcohol and DI water. Finally, samples were polished
with 0.05 μm alumina powder solution for the next measurement.
Zeta Potential Measurement
Zeta potential measurement is another method to further investigate the mechanism
of flotation separation [21, 22]. Zeta potential measurements were carried out at 20 °C
by Malvern Zeta Sizer Nano Series. In each measurement, the mineral suspension was