Gold from copper ore

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jaan777zaibs

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Jun 28, 2020
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I collected copper ores from different mines. Grinded them with a handheld hammer while putting that powder in a glass beaker and poured some nitric acid in it. then added some salt. Kept it for 10 minutes while stirring it with a rod. After that, I poured HCL into the solution. Again, I kept it for 10 minutes and then filtered the solution into another beaker. I then dissolved some ammonia into water and added that water to the previous solution. After a while, I added urea and after that, I dissolved iron sulfate into the water and added that water into the original solution. Kept the solution for 24 hours and the gold dust was dropped in the bottom of the backer. I collected that dust and washed it with water and HCL again. The dust looked like golden mud, a picture is attached which is taken from the net but the mud I obtained was very similar to the attached picture. I then put the mud into a crucible, heated it with a gas flame. The mud turned like red coal and after I released the heating process, it converted into black carbon, not gold. My questions here are: Whether I did the process correctly/ Whether the mud I obtained was gold/ Whether I did something wrong during the melting process? Or any other method, recommendation from members? I would highly appreciate all your valuable comments.
Kind regards
 

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If you suspected gold simply dissolving your powders in nitric should have left that in the bottom of your beaker with any other materials that wouldn’t dissolve, then decant the solution off and rinse the sediment well with water and again decant, add enough HCl to cover and add a small amount of nitric, allow anything that can dissolve to do so and then test using stannous and if gold was present you will have your answer.
 
Do you mean that I should first treat the powder with nitric to dissolve anything that can be dissolved with nitric? Then I should rinse the sediment and treat those sediments with aqua regia? Have I comprehended your message correctly?
 
In a word yes that’s exactly what I’m suggesting but you need to test your AR solution to see if indeed you have gold.
 
Thank you sir for your guidance. After testing and having gold powder, can you please guide me further on the final step of melting?
 
Let’s see if you really do have gold in solution first and then we can move on to the next steps.
 
Yet another question of "Hey I treated some ore with Aqua Regia and it didn't work. What happened?"
Over the years, this forum has had many, many questions of this type, and they are all questions of why it didn't work.
First, treating ore with Aqua Regia is a terrible idea. DON'T DO IT.
Before you do any type of treatment, find out if you actually have any gold in the rock. Copper sometimes is associated with gold, sometimes not, sometimes there are only tiny Parts Per Billion traces of gold in copper ores.
Lots of precipitates can be light brown in color - most of them are not gold. Just because something is of a certain color does not prove it to be gold. Iron oxides are the same color as the "gold" you precipitated. Ammonia is a base, and you added iron sulfate, I would expect a precip. of iron oxide. Iron hydroxides will darken on heating as water is driven off, just as you observed with your "gold".
Gold is a material with low reactivity. Acids will react with high reactivity materials first. So anything in the ore that is more reactive than gold (including many different minerals, especially copper minerals) will consume the acid and none will be left even if there is gold present.
 
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copper gold ore (persumably sulfidic ore) is a complex thing, already very complicated mixture of elements in various oxidation states, so putting it in acid does not the magic trick of resolving the parts of it.
firstly, proper assay is needed to determine if there is some recoverable gold. most basic thing would be roasting the concentrates to drive off sulfur from sulfides as SO2. that way you convert your feedstock to oxides and hopefully (if is present), liberate the gold from sulfide matrix. this roasted concentrate could be then smelted with proper flux to obtain metal button. if metal content is low, you can add collector metal such as lead to it.
pour the melt, separate the metal and get it assayed.
or with metal button in hand, you can NOW dissolve in nitric acid. if gold is present in some substantial concentration, you are left with undissolved micro gold powder. it could be done, but i dont know if i would reccomend it as an procedure to obtain some reasonable results.
best you can do is to do the proper assay from established lab. saves you ton of time and frustration with unconclusive results of amateur testing.
when gold is confirmed in the sample in quantity that satisfy you, then starts the tedious part of elaborating the best process of its recovery :)
 
Yet another question of "Hey I treated some ore with Aqua Regia and it didn't work. What happened?"
Over the years, this forum has had many, many questions of this type, and they are all questions of why it didn't work.
First, treating ore with Aqua Regia is a terrible idea. DON'T DO IT.
Before you do any type of treatment, find out if you actually have any gold in the rock. Copper sometimes is associated with gold, sometimes not, sometimes there are only tiny Parts Per Billion traces of gold in copper ores.
Lots of precipitates can be light brown in color - most of them are not gold. Just because something is of a certain color does not prove it to be gold. Iron oxides are the same color as the "gold" you precipitated. Ammonia is a base, and you added iron sulfate, I would expect a precip. of iron oxide. Iron hydroxides will darken on heating as water is driven off, just as you observed with your "gold".
Gold is a material with low reactivity. Acids will react with high reactivity materials first. So anything in the ore that is more reactive than gold (including many different minerals, especially copper minerals) will consume the acid and none will be left even if there is gold present.
Thank you Sir for your reply. I have watched a lot of your videos on youtube and I did,t know it was you until I found it today. Again, I am really happy that I have your advice.
 
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