XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3 1793
silver recovery tests. The extractions of gold and silver in the
leaching tests were calculated according to the equation (1):
%%Ex, c V c m
c V 100
1 2
1 #=+(1)
where: Ex is gold extraction from the leaching step, %c1 is
gold concentration in leachate, mg/L V is leachate volume,
L c2 is gold content in leach residue, mg/kg, m is weight of
leach residue, kg.
Gold and Silver Cementation Test
The gold and silver replacement test were carried out in a
250 mL beaker, and the volume of the leaching solution
used in each test was 100 mL, which was fully stirred for
a certain period with a magnetic stirrer and then filtered,
and the concentration of gold in the solution before and
after the replacement was determined using atomic absorp-
tion spectrometry (AAS). The recovery of gold and silver
in the replacement test was calculated according to the
equation (2):
%%Rec,
c
c0
c
100 0 #=
-
(2)
where: Rec is gold precipitation percentage, %,c0 is gold
concentration before cementation, mg/L, c is gold concen-
tration after cementation, mg/L.
RESULTS AND DISCUSSION
Cyanide Leaching Test
To evaluate the leaching difficulty of the raw materials used
in this test, the cyanide leaching test was carried out first
before the cyanide-free leaching test, and the results of the
cyanide leaching test are shown in Table 2. As shown in
Table 2, the variation of gold extraction with sodium cya-
nide dosage was not obvious, and the gold extraction was
94.93% when the sodium cyanide dosage was 2.5 g/L. The
results of cyanide leaching show that if the raw materials
in this test are not treated intensively, the theoretical maxi-
mum extraction is only about 95%, and a large part of the
gold in the raw materials is still lost.
Conventional Cyanide Free Leaching
In thiocyanate leaching system, thiocyanate can easily form
a complex with gold and exist stably in solution, but the
Figure 2. Raw material microscopy and backscattering results: (a-b) microscopy (c-d) backscattering
silver recovery tests. The extractions of gold and silver in the
leaching tests were calculated according to the equation (1):
%%Ex, c V c m
c V 100
1 2
1 #=+(1)
where: Ex is gold extraction from the leaching step, %c1 is
gold concentration in leachate, mg/L V is leachate volume,
L c2 is gold content in leach residue, mg/kg, m is weight of
leach residue, kg.
Gold and Silver Cementation Test
The gold and silver replacement test were carried out in a
250 mL beaker, and the volume of the leaching solution
used in each test was 100 mL, which was fully stirred for
a certain period with a magnetic stirrer and then filtered,
and the concentration of gold in the solution before and
after the replacement was determined using atomic absorp-
tion spectrometry (AAS). The recovery of gold and silver
in the replacement test was calculated according to the
equation (2):
%%Rec,
c
c0
c
100 0 #=
-
(2)
where: Rec is gold precipitation percentage, %,c0 is gold
concentration before cementation, mg/L, c is gold concen-
tration after cementation, mg/L.
RESULTS AND DISCUSSION
Cyanide Leaching Test
To evaluate the leaching difficulty of the raw materials used
in this test, the cyanide leaching test was carried out first
before the cyanide-free leaching test, and the results of the
cyanide leaching test are shown in Table 2. As shown in
Table 2, the variation of gold extraction with sodium cya-
nide dosage was not obvious, and the gold extraction was
94.93% when the sodium cyanide dosage was 2.5 g/L. The
results of cyanide leaching show that if the raw materials
in this test are not treated intensively, the theoretical maxi-
mum extraction is only about 95%, and a large part of the
gold in the raw materials is still lost.
Conventional Cyanide Free Leaching
In thiocyanate leaching system, thiocyanate can easily form
a complex with gold and exist stably in solution, but the
Figure 2. Raw material microscopy and backscattering results: (a-b) microscopy (c-d) backscattering