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| Leaching Gold |
| Updated 11/5/2006 |
Negatively-Charged Metallic Salts
Aluminum -1.71 volts
Zinc -0.76 volts
Iron -0.44 volts
Cadmium -0.40 volts
Indium -0.34 volts
Cobalt -0.28 volts
Nickel -0.23 volts
Tin -0.14 volts
lead -0.12 volts
Hydrogen -0.00 volts
Positively-Charged Metallic Salts
Copper + 0.52 volts
Ruthenium +0.49 volts
Palladium +0.62 volts
Rhodium +0.68 volts
Mercury +0.78 volts
Silver +0.80 volts
Platinum +0.90 volts
Uranium +1.01 volts
Iridium +1.02 volts
Gold +1.36 volts
Aluminum -1.71 volts
Zinc -0.76 volts
Iron -0.44 volts
Cadmium -0.40 volts
Indium -0.34 volts
Cobalt -0.28 volts
Nickel -0.23 volts
Tin -0.14 volts
lead -0.12 volts
Hydrogen -0.00 volts
Positively-Charged Metallic Salts
Copper + 0.52 volts
Ruthenium +0.49 volts
Palladium +0.62 volts
Rhodium +0.68 volts
Mercury +0.78 volts
Silver +0.80 volts
Platinum +0.90 volts
Uranium +1.01 volts
Iridium +1.02 volts
Gold +1.36 volts
Now that our Gold is in solution...(it may take some time)...we select to recover that Valuable Portion.
How do you know when the Leaching is done?
It can take 2 hours or 2 days, depending on the ore...
If you have the time, most of us do a "Roll-test" or extract samples of the ore in question first...so we know fairly well,
in advance.
Remember, below 400mv ORP, your leach stops working. To a great degree, the iodine will prevent this total
collapse of the process, but it may not move forward, gathering more PM's. try to keep the ORP as high as possible,
without exceeding 900mv if it contains iron, higher if not.
The 400 to 900 range will extract the higher valence metals (precious), but little else.
This methodology applies to most un-complicated quartz-based ores. Complexed ores, containing sulfates,
carbonates and other difficult elements may require pre-treatment and another type of leaching formulation.
This formula is PERFECT however, for all of the sediment collection that our units perform, and extracts and reduces
it easily to 999.9 Fine Gold, ready for smelting.
Complexed Ores
Sulfurous, Pyrites, Black sands, etc. are Complexed Ores, and MUST be treated first, otherwise the sulfur/iron will
eat the leach faster than you can renew it, making it very difficult to extract anything!
If Black sands are the issue, read our Black Sands section on the website at: www.goldmineworld.net
Take your ore outside, fire up the family BBQ, and place the ore powder into a large iron frypan or container. Crank
up the heat, stand upwind, and it will drive off the sulfur, arsenic and mercury and organic contaminants.
DO NOT DO THIS INDOORS!
Iron oxide coatings, plant oils and other garbage can and does interfere with the leaching. For tough cases, tumble
with citric or other weak acid to remove these in our poly mixer. Be sure to neutralize all leach solutions and washes
before returning them to the environment.
For those working indoors, please observe standard laboratory procedures, use fume hoods, etc. For the rest of us
Yahoos...do this outdoors, for heaven's sake, where it wont' bother anyone. Keep all chemicals locked up when not
in use...and don't pollute, please. Respect your Mother (Earth)
*NOTE: Carbonaceous ores require specialized leach formulas. Please contact us for information concerning them.
THIS LEACH WILL NOT WORK ON CARBON ORES
ok, we have our "Pregnant Leach".
It has the precious metals now in solution.
What now?
It is still very acid.
We need to bring up the PH to near 7.0
To get the gold out of the leach solution, the Nitric Acid must be eliminated.
The little-known shortcut to that is to add prilled Urea, which will neutralize the Nitric Acid, by degrees. As you slowly
add it, it will fizz and off-gas. Stir it in well, until the PH nears 7.0
You can additionally use Ammonia, to fine tune or bring the PH up, but DO NOT USE AMMONIA if silver was in
the ore. When it dries, it becomes Fulminate of Silver, an explosive powder as tempermental as Nitro Glycerin!
How do you know when the Leaching is done?
It can take 2 hours or 2 days, depending on the ore...
If you have the time, most of us do a "Roll-test" or extract samples of the ore in question first...so we know fairly well,
in advance.
Remember, below 400mv ORP, your leach stops working. To a great degree, the iodine will prevent this total
collapse of the process, but it may not move forward, gathering more PM's. try to keep the ORP as high as possible,
without exceeding 900mv if it contains iron, higher if not.
The 400 to 900 range will extract the higher valence metals (precious), but little else.
This methodology applies to most un-complicated quartz-based ores. Complexed ores, containing sulfates,
carbonates and other difficult elements may require pre-treatment and another type of leaching formulation.
This formula is PERFECT however, for all of the sediment collection that our units perform, and extracts and reduces
it easily to 999.9 Fine Gold, ready for smelting.
Complexed Ores
Sulfurous, Pyrites, Black sands, etc. are Complexed Ores, and MUST be treated first, otherwise the sulfur/iron will
eat the leach faster than you can renew it, making it very difficult to extract anything!
If Black sands are the issue, read our Black Sands section on the website at: www.goldmineworld.net
Take your ore outside, fire up the family BBQ, and place the ore powder into a large iron frypan or container. Crank
up the heat, stand upwind, and it will drive off the sulfur, arsenic and mercury and organic contaminants.
DO NOT DO THIS INDOORS!
Iron oxide coatings, plant oils and other garbage can and does interfere with the leaching. For tough cases, tumble
with citric or other weak acid to remove these in our poly mixer. Be sure to neutralize all leach solutions and washes
before returning them to the environment.
For those working indoors, please observe standard laboratory procedures, use fume hoods, etc. For the rest of us
Yahoos...do this outdoors, for heaven's sake, where it wont' bother anyone. Keep all chemicals locked up when not
in use...and don't pollute, please. Respect your Mother (Earth)
*NOTE: Carbonaceous ores require specialized leach formulas. Please contact us for information concerning them.
THIS LEACH WILL NOT WORK ON CARBON ORES
ok, we have our "Pregnant Leach".
It has the precious metals now in solution.
What now?
It is still very acid.
We need to bring up the PH to near 7.0
To get the gold out of the leach solution, the Nitric Acid must be eliminated.
The little-known shortcut to that is to add prilled Urea, which will neutralize the Nitric Acid, by degrees. As you slowly
add it, it will fizz and off-gas. Stir it in well, until the PH nears 7.0
You can additionally use Ammonia, to fine tune or bring the PH up, but DO NOT USE AMMONIA if silver was in
the ore. When it dries, it becomes Fulminate of Silver, an explosive powder as tempermental as Nitro Glycerin!
As the PH in your pregnant Leach now climbs towards PH7.0, stop short just before 7.0, and you will note the leach
liquor has turned from its dark color, through yellow and even to clear in some cases, and the Gold and PM's will
start to gel in the liquid.
Precipitants
Some of the common precipitants are:
1. Ferrosulfate
2. Oxalic acid
3. "Storm"
4. Sodium Nitrite
5. Stannous Chloride
6. Sodium Metabisulfite
7. Zinc (bars-chunks-powder)
Now add your precipitant
With slow additions of the selected precipitant...try to match it to the amount of gold you think it contains...
As the precipitant is stirred in, the magic begins...As the gold starts to clump together in larger and larger masses.
Keep swirling it every few minutes, until the darker portion starts to descend.
Now leave it alone to separate out on its own...the brown powdery layer will consolidate on the bottom, leaving the
empty, clear leach on the top; containing the iodine, salt and water...as ready to use again, with new Nitric Acid
Separation may take overnight to cleanly separate the precious metals out as the dark layer on the bottom. Pour off
the clear layer into a carboy or plastic bucket, and cover. Save this "Clear" water...It becomes your new leach base.
Now take the dark potion you saved, and pour it through 3 to 4 , 12" coffee filters, pre-wetted, in a 12", plastic funnel,
set over a clean glass jar.
The Gold will be caught in the filter, the cleaned leach pass through. If it is a bit cloudy below...re-run it through the
same filters to recover the remaining fine Gold.
Leave the filters to drip to relative dry, then place them carefully into an electric fry pan and turn the thermostat down
to dry the whole filter and powder. This may take hours....Or place into a windproof area in a sunny spot.
The dried filter now contains Pure Gold!
This filter weighed (minus a clean filter weight) will give you a "How many Ounces of Gold per Ton" figure.
liquor has turned from its dark color, through yellow and even to clear in some cases, and the Gold and PM's will
start to gel in the liquid.
Precipitants
Some of the common precipitants are:
1. Ferrosulfate
2. Oxalic acid
3. "Storm"
4. Sodium Nitrite
5. Stannous Chloride
6. Sodium Metabisulfite
7. Zinc (bars-chunks-powder)
Now add your precipitant
With slow additions of the selected precipitant...try to match it to the amount of gold you think it contains...
As the precipitant is stirred in, the magic begins...As the gold starts to clump together in larger and larger masses.
Keep swirling it every few minutes, until the darker portion starts to descend.
Now leave it alone to separate out on its own...the brown powdery layer will consolidate on the bottom, leaving the
empty, clear leach on the top; containing the iodine, salt and water...as ready to use again, with new Nitric Acid
Separation may take overnight to cleanly separate the precious metals out as the dark layer on the bottom. Pour off
the clear layer into a carboy or plastic bucket, and cover. Save this "Clear" water...It becomes your new leach base.
Now take the dark potion you saved, and pour it through 3 to 4 , 12" coffee filters, pre-wetted, in a 12", plastic funnel,
set over a clean glass jar.
The Gold will be caught in the filter, the cleaned leach pass through. If it is a bit cloudy below...re-run it through the
same filters to recover the remaining fine Gold.
Leave the filters to drip to relative dry, then place them carefully into an electric fry pan and turn the thermostat down
to dry the whole filter and powder. This may take hours....Or place into a windproof area in a sunny spot.
The dried filter now contains Pure Gold!
This filter weighed (minus a clean filter weight) will give you a "How many Ounces of Gold per Ton" figure.