XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 2335
The grades of Cu, Ni, and S in the NK copper nickel
ore in South Africa are 0.18%, 0.52%, and 5.76%, respec-
tively. The copper and nickel bearing minerals are mainly
chalcopyrite and pentlandite. Other sulfides mainly include
pyrrhotite and pyrite. And the main gangue minerals are
diopside, enstatite, mica, chromite, talc, etc. The grades of
Cu, Ni, and S in JC copper nickel ore in China are 1.08%,
1.19%, and 5.20%, respectively. The copper and nickel
bearing minerals are mainly chalcopyrite and pentlandite.
Other sulfides mainly include pyrrhotite, and the main
gangue minerals are serpentine, pyroxene, olivine, mica,
etc.
Milling and Flotation
The ore samples were crushed to –2 mm, and each
sample was milled using a laboratory cast iron mill with
cast iron balls and a stainless steel mill with stainless steel
balls, at a milled concentration of 50%. The diameters of
the cast iron balls and stainless steel balls are 30, 25, and
20 mm, with their number of 24, 31, and 30, respectively.
Based on the optimal milled fineness in the plant operation
of the two mines, the fineness of JC ore and NK ore milled
products was controlled at –75 µm, with a content of 70%
and 80%, respectively.
A comparison of flotation tests was conducted on
products milled under different milling conditions and
the optimal reagent conditions in their respective produc-
tion. The reagent scheme used for the two ores are shown
in Table 2. Batch flotation tests were conducted using a
500 mL self-aeration mechanical batch flotation cell. The
impeller speed was maintained at 1750 rpm and the aera-
tion rate at 2.5 l/min. In the flotation, the flotation froth
was scraped every 10 s and the total flotation time was
10 minutes. Four sequential timed concentrates were taken
at minutes 1, 3, 6, and 10 respectively.
For each test, the mass of solids and water recovery
were evaluated, and all samples of flotation concentrates
and tailings were analyzed for Cu, Ni, Mg content in dry
powder form using ICP -AES. A Leco S632 sulfur analyzer
was used to determine the sulfur content of the samples.
A sulphur balance calculation enabled the pyrrhotite (FeS)
content to be determined. PH, Eh and DO were measured
inside the flotation cell using YSI Multi-Probe System. The
measurement was made after the ore had been transferred
to the flotation cell and the pulp conditioned for 2 min-
utes, before any reagents were added.
Table 1. Mineral compositions of two Cu-Ni ores, %
NK Ore JC Ore
Minerals Contents Minerals Contents
Diopside 21.87 Serpentine 33.81
Enstatite 16.63 Pyroxene group 17.15
Pyrrhotite 11.27 Fayalite 11.19
Mica 11.11 Pyrrhotite 8.56
Chromite 9.37 Pentlandite 4.00
Talc 7.22 Mica group 3.98
Serpentine 6.48 Chlorite 3.77
Hortonolite 6.02 Magnetite 3.54
Tremolite 3.58 Chalcopyrite 3.31
Quartz 2.77 Feldspar group 2.53
Pyrite 1.71 Quartz 2.44
Chalcopyrite 0.72 Calcite 1.16
Pentlandite 1.23 Amphibole group 0.81
Dolomite 0.70
Pyrite 0.38
Andradite 0.33
Apatite 0.08
Other 2.16
Table 2. The reagents scheme for the tests /(g·t–1)
Ore Collectors Frothers
JC Ore (China) Amyl xanthate 120
903G 48
None
NK Ore (South Africa) Isobutyl xanthate 50 DOW200 20
The grades of Cu, Ni, and S in the NK copper nickel
ore in South Africa are 0.18%, 0.52%, and 5.76%, respec-
tively. The copper and nickel bearing minerals are mainly
chalcopyrite and pentlandite. Other sulfides mainly include
pyrrhotite and pyrite. And the main gangue minerals are
diopside, enstatite, mica, chromite, talc, etc. The grades of
Cu, Ni, and S in JC copper nickel ore in China are 1.08%,
1.19%, and 5.20%, respectively. The copper and nickel
bearing minerals are mainly chalcopyrite and pentlandite.
Other sulfides mainly include pyrrhotite, and the main
gangue minerals are serpentine, pyroxene, olivine, mica,
etc.
Milling and Flotation
The ore samples were crushed to –2 mm, and each
sample was milled using a laboratory cast iron mill with
cast iron balls and a stainless steel mill with stainless steel
balls, at a milled concentration of 50%. The diameters of
the cast iron balls and stainless steel balls are 30, 25, and
20 mm, with their number of 24, 31, and 30, respectively.
Based on the optimal milled fineness in the plant operation
of the two mines, the fineness of JC ore and NK ore milled
products was controlled at –75 µm, with a content of 70%
and 80%, respectively.
A comparison of flotation tests was conducted on
products milled under different milling conditions and
the optimal reagent conditions in their respective produc-
tion. The reagent scheme used for the two ores are shown
in Table 2. Batch flotation tests were conducted using a
500 mL self-aeration mechanical batch flotation cell. The
impeller speed was maintained at 1750 rpm and the aera-
tion rate at 2.5 l/min. In the flotation, the flotation froth
was scraped every 10 s and the total flotation time was
10 minutes. Four sequential timed concentrates were taken
at minutes 1, 3, 6, and 10 respectively.
For each test, the mass of solids and water recovery
were evaluated, and all samples of flotation concentrates
and tailings were analyzed for Cu, Ni, Mg content in dry
powder form using ICP -AES. A Leco S632 sulfur analyzer
was used to determine the sulfur content of the samples.
A sulphur balance calculation enabled the pyrrhotite (FeS)
content to be determined. PH, Eh and DO were measured
inside the flotation cell using YSI Multi-Probe System. The
measurement was made after the ore had been transferred
to the flotation cell and the pulp conditioned for 2 min-
utes, before any reagents were added.
Table 1. Mineral compositions of two Cu-Ni ores, %
NK Ore JC Ore
Minerals Contents Minerals Contents
Diopside 21.87 Serpentine 33.81
Enstatite 16.63 Pyroxene group 17.15
Pyrrhotite 11.27 Fayalite 11.19
Mica 11.11 Pyrrhotite 8.56
Chromite 9.37 Pentlandite 4.00
Talc 7.22 Mica group 3.98
Serpentine 6.48 Chlorite 3.77
Hortonolite 6.02 Magnetite 3.54
Tremolite 3.58 Chalcopyrite 3.31
Quartz 2.77 Feldspar group 2.53
Pyrite 1.71 Quartz 2.44
Chalcopyrite 0.72 Calcite 1.16
Pentlandite 1.23 Amphibole group 0.81
Dolomite 0.70
Pyrite 0.38
Andradite 0.33
Apatite 0.08
Other 2.16
Table 2. The reagents scheme for the tests /(g·t–1)
Ore Collectors Frothers
JC Ore (China) Amyl xanthate 120
903G 48
None
NK Ore (South Africa) Isobutyl xanthate 50 DOW200 20