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VIDEO: Gold cyanidation research at Queen's
Hello, I am Rina Kim in the hydrometalurgy
group under the supervision of Professor
I am studying the effect of oxygen on
gold cyanidation especially in the presence
of sulfidic ores.
In my study, oxygen can give positive effects
in two aspects. The first one is oxidation
of sulfide minerals in the ore.
Generally, sulfur and some metal components in
the sulfide minerals can give negative effects
on gold cyanidation, such as the side reaction
concerning leeching chemicals like cyanide
the formation of passive film on gold
surface and so on.
However, once the sulfide minerals are oxidized
then the negative effects can be reduced and finally
the gold oxidation can be improved.
Secondly, gold leeching in cyanide solution is
an oxidative reaction.
So, if we increase the oxygen concentration, the
gold cyanidation can be improved, too.
Additionally, the oxygen can substitute
one of the oxidants, the lead, which is currently
being used in gold processes.
Finally, the environmental problems caused
by the use of lead an be reduced.
To do my study, I'm mainly using the electro-chemical
methods such as cyclic voltammetry, chronoamperometry,
and Electrochemical quartz crystal microbalance (EQCM).
In this fume hood I am running the electro-chemical test
with cyanide solution and some sulfidic ore slurry
and with gold electrodes, another reference electrode and
In here this gold electrode is leeched by the cyanide
solution and the slurry contains some sulfidic minerals
and some sulfidic ores so it gives a positive effect or
negative effect. At the same time I want to see the
effect of oxygen, so I'm injecting oxygen through this
tube and we can see some bubbles of oxygen gas.
All of these electrodes are connected to this
potentiostat which measures the potential and current
so we can get potential-current curves and another
one is by the chronoamperometry we can get the
current-time curves. These are the curves acquired by the
running test. This curve shows current change over time.
So, it shows that this current is decreased by the time because
of some of the effects of sulfide minerals in the ore slurry.
In here, we can see another plot. this is current and
potential curve. In this plot there are some current
peaks. These peaks shows which potential cuases
gold oxidation and how much gold oxidation has occurred.
With the height of this current, we can measure the
amount of gold oxidation.