Extraction of Gold
gold recovery and refining methods employ a variety of mechanical and
chemical operations to produce precious metals of commercial purity.
Depending on the quality of the gold source and its composition, any
one of several different refining methods can be used to recover and
refine gold to high purity.
use of solvent extraction to recover metals is a greatly underutilized
technology. Solvent Extraction can provide significant reductions in
operational costs in comparison to more traditional methods of metals
recovery and refining.
CDE 9 Gold collector is:
and not biotoxic
to handle-low volatility (bp. 254.6C); low flammability in part
because of a high flash point (118C)
solubility in water
process that delivers nearly quantitative yields of high purity
selective for gold chloride
for small and large operations
integrated into existing refining processes
Digest your ore with CDE
Leach converting any AU complexes to Au(lll)Cl
Extract the AuCl from
the pregnant solution as chlorauric acid with CDE 5
Reduce the AU(lll) with
CDD9 to Au0 (metallic gold)
Recycle the CDE 5 back
into the process
Solution of CDE Leach
that has digested enough of your ore to get a yellow/orange/gold
color. (See our leaching video and primer.)
Acid Solution (HCl Sol). You
make this solution by purchasing 38% Muriatic Acid (available from
most hardware stores) and dilute three times with distilled or
reverse osmosis water. If you buy one quart of Muriatic Acid, you
will make 4 quarts of HCl
42 Whatman Filters or equivalent
5 Gold Collector
9 Gold Stripper
Hydrochloric Acid as made according to directions above.
– When testing
we use units of 25 ml. We have substituted the word part
for each 25ml we use. This will allow you to adjust the arithmetic
for your setup no matter the size.
can readily scale-up to any size set-up
beaker marked “Gold”- 400
beaker marked “Step 2”
beaker marked “Step 2”- 400
Stirring Hotplate and stir bar.
Prepare 1 parts of clear leach by filtering pregnant solution
through a # 42 Whatman filter into the beaker marked Gold.
[NOTE: You may rinse the debris from the filtering back into your
original leaching container to retain any unleached metals.]
Add 1 parts of distilled
water and stir manually (stirring rod or agitating the beaker)
Add 2 parts of CDE 5 Gold
Place beaker on a magnetic stirring hotplate, place stir bar in
the beaker and agitate strongly for 45 minutes at 98 degrees F.
Transfer the solution to a separatory funnel and allow it to
settle into two layers. The gold will be in the top layer.
Drain the bottom layer into a beaker marked “Pregnant
solution minus Au”
and set it aside. [This “waste” liquid will be processed later for
possible platinum group metals. The procedure is the same, but the
collectors and strippers and different for each metal. Supplies may be
purchased from Rocky Ledge.]
Place the CDE 5 into a beaker and add an equal amount of CDE
9 gold separator.
Agitate vigorously while bringing the solution to 180 F. This
could take as long as 90 minutes depending on the volume as well as your
heating and stirring equipment.
As the temperature rises a color change in the liquid will become
At approximately 180 F any gold present will appear to be
“black” particulate floating in the solution. When the color is no
longer modifying stop the heating and stirring.
Place the solution into a separatory funnel and allow to
Drain the bottom solution through a # 42 Whatman filter to
collect the gold particulate.
Rinse the particulate from the filter paper into an appropriate
beaker. Add a small amount of HCL to the liquid and stir
An amount of the gold will be “in the vortex” created by the
stirring. Slowly add isopropyl alcohol—store-bought cheap rubbing
alcohol—to the dilute HCL solution. When the mix is approximately
50/50 the gold will fall out of the vortex and settle in the bottom.
Air dry the powder in a protected area. You can be assured the
material remaining is an ultra high quality gold in sponge form. This
sponge gold is sale-able as it is.
Contact Rocky Ledge Mining Supply for further information. We can
be a broker for your sponge gold under certain circumstances.
method is extremely effective even when the pregnant solution is quite
complex. Selective recovery of high quality Gold and PGM’s is possible
and therefore has great value with many ores.
careful, neat and thorough.
quality of the results is dependent on the quality of the procedures.
use a fume hood.
method is what I use on my own ores.
you follow the procedures it never misses.