# Extracting Gold from Ore by Aqua Regia method



## Dawoody (Oct 1, 2017)

Hi Guys,
Basically, I am from Egypt and our government started permitting people to make mining in gold mines
I am a chemist and have good background about chemicals usage 7 handling
I would like to start doing this business and i want to start refining gold by Aqua Regia method 
Appreciate if you share with me your experience in this field and the guidelines about processing aqua regia in perfect way
Thanks for your help


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## patnor1011 (Oct 1, 2017)

Ore is too complex to be done with AR.


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## Deano (Oct 2, 2017)

The usual reason why people do not leach ore direct with aqua regia is the cost of the process, not just the chemical cost but the equipment cost of plant to handle aqua regia, the health regulations regarding fumes and the disposal requirements of used solutions.

All of the above means that any aqua regia plants are small with low throughput, really only suitable for recalcitrant concentrates.

There are a lot of articles around on running cyanide systems in full scale, these are the industry standard method.

There are many alternative leach systems such as thiocyanate which run in acid pH systems, usually the cost of acid makes these non-viable.

The only alkaline system used commercially apart from cyanide is thiosulfate. This suffers from the lack of a cheap effective adsorbent for the resulting gold complexes, it means that the gold has to be recovered by filtration/zincing, an expensive option.

Neutral pH hypochlorite systems also require acid proof construction and handling systems as well as the addition of 20% salt ifs the ore has much silver present. It does have the advantage that the gold complexes are easily loaded onto both carbon and resins.

Deano


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## Dawoody (Oct 2, 2017)

Thanks Deano for your explanations
Appreciate if you explain to me in details how to refine gold from ore by cyanide process


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## patnor1011 (Oct 2, 2017)

Dawoody said:


> Thanks Deano for your explanations
> Appreciate if you explain to me in details how to refine gold from ore by cyanide process



Click on Deanos name and go through his posts. He made several fantastic threads about this topic where all is explained in great detail. All you need to do is to just go through them and read and read. I do not think he does have time to write the same again and again. Believe me, most of what you need to know is already posted there.


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## Dawoody (Oct 2, 2017)

Dear patnor1011,
Much thanks for your advice
Because I m a beginner in this field, I want to collect accurate info from trusted sources

Thanks again

Dawoody


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## g_axelsson (Oct 2, 2017)

Deano is a trusted source.

Göran


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## Deano (Oct 2, 2017)

I presume from the language used in your enquiry that you are actually seeking information regarding the recovery or extraction of gold from ores, this is quite different from the "refine" terminology you have also used.

If I have presumed wrongly please let me know.

Deano


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## Dawoody (Oct 3, 2017)

Hi Deano,
Thanks for your comment
Actually, there is a gold mine in my region, I am willing to purchase gold dust from miner 
The process they are doing right now is searching for gold in this mine and get the rocks then grind it to fine particles
I will by these fine particles from them then i would like to extract gold from it 
Why i am willing to use aqua regia process, because the chemicals used in this process is available in my area and easy to get them, 
As i mentioned that i am a beginner in this field, I want to start with AR method then i can move to cyanide process after making required arrangement
I hope if you give me the detailed steps of AR process for this type of ores with safety precautions


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## nickvc (Oct 3, 2017)

With nearly all ores acid processes are not recommended as the other elements in the ore can be and frequently are toxic or deadly.
We have stated many many times that it is essential to get a full assay done to know exactly what you are dealing with, if you had a concentrate of free milling gold then perhaps acids could be the way to go but we have no idea exactly what you may have so I would advise not to add acids until you know what you are dealing with.


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## g_axelsson (Oct 3, 2017)

In what form is this "ore concentrate" that you would buy from the miners?

Many gold ores contains arsenic so even smelting the concentrate can create a situation that is fatal. Just as Irons about that.

I would consider if, and only if the gold is already melted once to be safe to go to aqua regia. Then we are talking about refining normal gold. That has been discussed for ten years on this forum. Just check the library or Hoke's book for instructions on how to refine gold.

If the ore concentrate contains unknown parts then I would never treat it with aqua regia at first. Melting gold can also be dangerous (arsenic, mercury,...) so care has to be taken as long there is unknown substances together with the gold.

I hope you understand now why there is no "Extracting Gold from Ore by Aqua Regia method".

Göran


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## Reno Chris (Oct 3, 2017)

Over and over through the years we have advised new operators who come here *NOT* to use aqua regia because of the problems it causes. Many have ignored this advice and then are confused as to why they cannot extract the gold in their ores. I know of *NOT ONE* example where a person inquiring here has been successful extracting gold from ore using AR. In addition to the problems cited by Deanno, nearly all gold ores and even more so gravity type concentrates contain large amounts of iron minerals including pyrite and others. These dissolve in AR and must be dissolved away and oxidized before the Gold will start to go into solution. The Fe+2 - or ferrous ion will drop any dissolved gold out of solution so as you try to dissolve the gold with AR, the ferrous iron will take it back out and prevent the gold going onto solution. So you would need to dissolve all the iron first, then oxidize it to Fe+3 or Ferric ion before any gold could be taken onto solution. 
If you are truly a chemist and understand oxidation-reduction reactions you will understand this and see why using AR to process gold ores is crazy. If you are not a chemist you will likely ignore all the good advice you have received and still try to use AR to extract your gold. Then, like all the others you will be confused and wonder why it didn't work. Consider going back through the threads on extracting gold with AR under this heading and see the failures others have experienced.


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## Blakey (Oct 3, 2017)

Failure is the first step to success! 
Good luck


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## Dawoody (Oct 4, 2017)

Thanks to all for your contributions and advises
I attached here a photo of ores i got from miner and which i am willing to try to get gold from
Please advice me which the best way to extract gold from these stones
Thanks


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## Dawoody (Oct 4, 2017)

Thanks to all for your contributions and advises
I attached here a photo of ores i got from miner and which i am willing to try to get gold from
Please advice me which the best way to extract gold from these stones
Thanks


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## g_axelsson (Oct 4, 2017)

Any visible gold?
How much gold is it in the ore?
Any assays?
Are there any sulfides?
Is the ore oxidized?
Any carbonates?

Ore is a complex issue and you can't just take a picture and get an answer over the internet. You need proper assays of a representative sample or many. Taking a representative sample is an art of it self and has been discussed on the forum.

I'm no expert on ores, I'm just trying to get you to give us the details needed to answer your questions.

Göran


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## Reno Chris (Oct 4, 2017)

Step one is to have the ore tested by Assay. This will tell you if there is actually gold in the ore. What you have is quartz, one of the most common minerals on planet earth because it is formed of the two most common elements in the earth's crust: Silicon and oxygen. There are many, many quartz veins with very little or no gold. Even in a vein which does have gold in some parts of it, there are often portions of the same vein which are barren and have very little or no gold. If an assay shows little gold, there is no point in going farther - its time to quit. 

This type of ore is not a concentrate, it is a raw ore. It must first be crushed to powder to extract the gold. Rock crushing equipment will cost many thousands of dollars even if you purchase small scale crushing equipment from China - At least US $5,000 and more likely closer to US$ 10,000. Although a variety of treatments to extract gold exist, unless you have loads of money to invest (perhaps something closer to US $100,000) - your best bet is to investigate the potential for treating the ore by gravity based methods (gravity methods means the use of gold's high density to separate it from low density materials like quartz). It is the most economic type of plant to set up, the most common for small operators and the easiest to operate. However, not all ores are successfully treated by gravity methods. You must test the ore to see if gravity methods will work on this ore. 

Often there are operators who set up ore processing plants in the gold bearing regions of Africa to process the local ores mined there. They process the ores produced by the miners for a fee. This is a far better business model than the miner selling you ore. If he sells you barren ore, you will process it and get little or no gold - but the loss of money will be yours. If the miners pay a fee to have their ore processed then the responsibility of delivering rich ore to the processing mill is on them - so that if the ore is barren the miner takes the loss. You might consider traveling to the region where the ore is produced and see if these mills exist and see what methods they use to treat the ores. It will likely be a gravity based method, but there are a variety of ways of crushing ores and a variety of ways to process the ore using gravity. I am sure you would find it a worthwhile education.


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## Dawoody (Oct 5, 2017)

Thanks Mr. Reno Chris for your inputs & advice 
Regarding if this ore contains gold or not, Yes it has gold as the miners have a detecting device which indicating if the rocks contains gold or not, normally what they are doing is, they use this device while they are searching for gold, if they got a signal from the device that this area contains gold then they start breaking in the mountain and get rocks
After that, what they are doing is grinding these rocks under granite wheels by mixing it with water then they collect the wet sands and processing through mercury amalgamation 
As per my knowledge, extracting by this way is not effective and a lot of waste is occurred 
Now, I am looking for better way to get gold from these rocks
I can ask the miners to grind these rocks for me and get it in dry sand form

Appreciate your advice to find the best and effective way to get gold from these rocks
all necessary chemicals are available in my area and i can get them easily 

Thanks to all


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## Reno Chris (Oct 6, 2017)

Crushing with a granite wheel is especially primitive - it is a method known as a Chilean Wheel and is slow and expensive compared to other methods of rock crushing - but it is cheap to implement as far as the starting capital cost. 
You left out a step in how the miners process the sand - I do not know if you are unaware of this step or if you just left it out. The miners take the sand after crushing and run it as a wet slurry through a trough with water. There is carpet on the bottom of the trough which catches the heavier materials in the sand (this is a gravity based method as I mentioned previously). This trough is known as a sluice. The heavier materials are captured in the trough/ sluice and these are then treated with mercury - the bulk of the sand is not treated with mercury. I have been to Africa and seen it done. It is a primitive way to capture part of the gold in the ore. Important amounts of gold are left behind in both the sand after it is treated and in the concentrates after they are treated with mercury. It is an inefficient method used all over Africa and elsewhere in many countries because it can be done cheaply and recovers something around half to maybe 3/4 of the gold (depending on the exact nature of the ore and other factors). To extract the remaining gold from the remaining sand and from the concentrates can be done, but it is much more expensive. The sand would normally be treated by cyanide solutions in vats. The concentrate is normally rich in gold bearing sulfides and would be treated by oxidation using roasting or oxidation treatment under pressure in an autoclave with cyanide treatment after the oxidation step is complete.
Many thousands of Scientists and Engineers around the world have studied the best ways of how to extract gold from ores for more than 100 years. It is a complex topic and not a study with one simple, easy, cheap and efficient answer as you are seeking. Information on how to treat gold ores using cyanide can be found on the internet. Best of luck to you.


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## richoc (Nov 9, 2017)

If they are running the old ways like with the wheel, the sluice slide will not have carpet.
It will be lined with a copper or brass sheet coated in mercury, than grabs the gold as it sides on top of it.
This is a used in a third of the world and they are trying to stop this practice.
There is a system that uses palm fibers to collect even the very fine gold and then it has to be separated from the rest of the " black sands ".
"The Manado Method (English Version)" put this in the search line on YouTube and you will see the safest
way to recover the gold from the ore.
Watch this video to see the safest ore processing method I have ever seen.
But really you need assay done, will tell you of all the values in the ore.
Is this a hand held XRF they are using to locate the gold or just a metal detector?
Hope you All watch this video, Rich


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