3058 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
METHODS AND MATERIALS MATERIALS
Synthetic mineral sample: The material to be used in this
study corresponded to a mineral manufactured in the labo-
ratory from mixtures of high purity minerals acquired at
“Wards Science” (chalcopyrite and pyrite) and at commer-
cial quartz. The samples to be floated had the proportions
indicated below: 18 g of chalcopyrite, 120 g of pyrite and
462 g of quartz for each sample. In these proportions, a
grade of 1% of total Cu per sample is approximately
ensured, which is provided only by the chalcopyrite min-
eral that represents 3.6% of the total sample, while pyrite
represents 24% of the total, the remaining percentage of
sterile minerals represented by quartz. The different miner-
als were crushed and ground separately to obtain a particle
size with a P80 of less than 200 µm. Subsequently, signifi-
cant samples were obtained using rolling and quartering,
according to the criteria of the ASTM standard, and then
mixed in the defined proportions.
REAGENTS
Methyl isobutyl carbinol (MIBC) as frother and potas-
sium-amyl-xanthate (PAX) provided by Solvay and Orica,
respectively. The pH was adjusted with lime (Merck S.A.).
The biosolids (BSs) used in this study were obtained from
a local water treatment plant in Chile and characterized by
atomic absorption. Table 1 shows that the sample is formed
mostly by organic matter (67.42%), Carbon (36.34%)
and nitrogen (5.08%) and a lower presence of the other
elements as P, Ca, Mg, P and K. On the other hand, the
ester recycled soybean oil (ERVOs) was obtained from the
University of Talca’s food services and characterized using
gas chromatography in an ionic medium, with a mass spec-
trometer (Thermo Scientific TSQ Duo Triple Quadrupole)
and using a standards mixture (F.A.M.E. Mix RM-2,
Sigma-Aldrich). Table 2 shows that ERVOs is composed
of 51.35% of Methyl linoleate, 21.35% of Methyl oleate,
a value close to 12% of Methyl palmitate and Methyl lino-
lenate and 4.27% of Methyl stearate.
PROCEDURES
Flotation Kinetics and Batch Flotation Tests
Flotation kinetics tests were performed in a laboratory
EDEMET cell of 1.5 L of volume for a period of 20 min.
The tests were done according to the following conditions:
solid percentage in pulp of 31% air flow rate of 5 L/min
stirring speed of 1100 rpm, using 15 g/t of MIBC. The pH
during the kinetic tests was kept at a value of pH 8. It was
established to use 100 g/ton of ERVOs, BSs and PAX col-
lector for the kinetics. On the other hand, the mixtures for
batch flotation tests considered a maximum of 100 g/ton
between ERVOs and BSs.
Kinetic constant is determined using the following
equation:
exp R R kt 1 1 =--
3
-kt b b ll_1 i (1)
To calculate the recovery, the enrichment ratio and the
selectivity index, equations reported in papers related to
the subject were used (Arcos &Uribe, 2021). Also, after
the chemical analysis, the elemental assays for Cu and Fe
for each sample were converted into mineral compositions
using the following mathematical relations based on the
stoichiometric compositions of Chalcopyrite (Cpy) and
Pyrite (Py):
Chalcopyrite .5
.3
63
183 %Cpy %Cu #=b l (2)
Iron as pyrite .5
.8
63
55 %Fe *=%Fe %Cu #-b l (3)
Pyrite .8
.8
55
119 %Py %Fe *#b =l (4)
RESULTS AND DISCUSSION
Flotation Kinetics
The Figure 1a shows the recovery of copper and iron
obtained as a function of time in the presence of ERVOs.
According to this, a maximum flotation time is established
Table 1. Main composition of biosolids (BSs)
Organic Matter (%)C (%)N (%)Ca (%)P (%)Mg (%)K (%)Na (%)
65.42 36.34 2.15 2.88 2.15 0.60 0.12 0.12
Table 2. Composition of the main FAMES presents in ERVOs
Detected Methyl Esters Corresponding Acids FAME-RVO (%)
Methyl palmitate C16:0 11.26
Methyl stearate C18:0 4.27
Methyl oleate C18:1 21.35
Methyl linolenate C18:2 51.35
METHODS AND MATERIALS MATERIALS
Synthetic mineral sample: The material to be used in this
study corresponded to a mineral manufactured in the labo-
ratory from mixtures of high purity minerals acquired at
“Wards Science” (chalcopyrite and pyrite) and at commer-
cial quartz. The samples to be floated had the proportions
indicated below: 18 g of chalcopyrite, 120 g of pyrite and
462 g of quartz for each sample. In these proportions, a
grade of 1% of total Cu per sample is approximately
ensured, which is provided only by the chalcopyrite min-
eral that represents 3.6% of the total sample, while pyrite
represents 24% of the total, the remaining percentage of
sterile minerals represented by quartz. The different miner-
als were crushed and ground separately to obtain a particle
size with a P80 of less than 200 µm. Subsequently, signifi-
cant samples were obtained using rolling and quartering,
according to the criteria of the ASTM standard, and then
mixed in the defined proportions.
REAGENTS
Methyl isobutyl carbinol (MIBC) as frother and potas-
sium-amyl-xanthate (PAX) provided by Solvay and Orica,
respectively. The pH was adjusted with lime (Merck S.A.).
The biosolids (BSs) used in this study were obtained from
a local water treatment plant in Chile and characterized by
atomic absorption. Table 1 shows that the sample is formed
mostly by organic matter (67.42%), Carbon (36.34%)
and nitrogen (5.08%) and a lower presence of the other
elements as P, Ca, Mg, P and K. On the other hand, the
ester recycled soybean oil (ERVOs) was obtained from the
University of Talca’s food services and characterized using
gas chromatography in an ionic medium, with a mass spec-
trometer (Thermo Scientific TSQ Duo Triple Quadrupole)
and using a standards mixture (F.A.M.E. Mix RM-2,
Sigma-Aldrich). Table 2 shows that ERVOs is composed
of 51.35% of Methyl linoleate, 21.35% of Methyl oleate,
a value close to 12% of Methyl palmitate and Methyl lino-
lenate and 4.27% of Methyl stearate.
PROCEDURES
Flotation Kinetics and Batch Flotation Tests
Flotation kinetics tests were performed in a laboratory
EDEMET cell of 1.5 L of volume for a period of 20 min.
The tests were done according to the following conditions:
solid percentage in pulp of 31% air flow rate of 5 L/min
stirring speed of 1100 rpm, using 15 g/t of MIBC. The pH
during the kinetic tests was kept at a value of pH 8. It was
established to use 100 g/ton of ERVOs, BSs and PAX col-
lector for the kinetics. On the other hand, the mixtures for
batch flotation tests considered a maximum of 100 g/ton
between ERVOs and BSs.
Kinetic constant is determined using the following
equation:
exp R R kt 1 1 =--
3
-kt b b ll_1 i (1)
To calculate the recovery, the enrichment ratio and the
selectivity index, equations reported in papers related to
the subject were used (Arcos &Uribe, 2021). Also, after
the chemical analysis, the elemental assays for Cu and Fe
for each sample were converted into mineral compositions
using the following mathematical relations based on the
stoichiometric compositions of Chalcopyrite (Cpy) and
Pyrite (Py):
Chalcopyrite .5
.3
63
183 %Cpy %Cu #=b l (2)
Iron as pyrite .5
.8
63
55 %Fe *=%Fe %Cu #-b l (3)
Pyrite .8
.8
55
119 %Py %Fe *#b =l (4)
RESULTS AND DISCUSSION
Flotation Kinetics
The Figure 1a shows the recovery of copper and iron
obtained as a function of time in the presence of ERVOs.
According to this, a maximum flotation time is established
Table 1. Main composition of biosolids (BSs)
Organic Matter (%)C (%)N (%)Ca (%)P (%)Mg (%)K (%)Na (%)
65.42 36.34 2.15 2.88 2.15 0.60 0.12 0.12
Table 2. Composition of the main FAMES presents in ERVOs
Detected Methyl Esters Corresponding Acids FAME-RVO (%)
Methyl palmitate C16:0 11.26
Methyl stearate C18:0 4.27
Methyl oleate C18:1 21.35
Methyl linolenate C18:2 51.35