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Debayan Pyne

Member
Joined
Jul 31, 2020
Messages
9
I've tried to conduct the experiment of gold recovery from electronic waste. I used 3kgs of Intel Pentium 4 processors along with others for this purpose and initially the material seemed descent just for this experiment and not for any profit motive. I dismantled the whole lot and washed them properly with hot water. Then I gave them the first chemical bath with 32% hydrochloric acid and 3% hydrogen peroxide in 2:1 ratio (about 1lt hcl and 500ml h202) to detach the gold coated foils and pins and kept it for 48 hours. Then I prepared my stuff for aqua regia. I dipped the residue in a solution of 32% hydrochloric acid and 70% nitric acid in 3:1 ratio (about 150ml of hcl and 50ml of hno3 along with 50ml of distilled water) and kept it for 24 hours after which I added some urea to neutralize hno3 and poured in a solution of sodium metabisulfite (mixed with hot water). Drained the rest solution and I got some brown mud like stuff sitting at the bottom of the beaker. Then I washed the thing with hot water, boiled it, filtered it and dried the filter paper. I got some black dust. I don't know what it is and where the gold went? I don't know what went wrong, I'm new to this and this is my first experiment on gold extraction. Can anyone please help me. :(
 

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You need to stop trying to refine from youtube videos and study on this forum a lot. Learn about how to deal with your wastes. There is a search function you can find it in the drop down menu tab. Search by type of material you are processing. You need to spend a lot of time reading or you will just lose your gold and harm yourself and others.
 
Debayan Pyne said:
I've tried to conduct the experiment of gold recovery from electronic waste. I used 3kgs of Intel Pentium 4 processors along with others for this purpose and initially the material seemed descent just for this experiment and not for any profit motive. I dismantled the whole lot and washed them properly with hot water. Then I gave them the first chemical bath with 32% hydrochloric acid and 3% hydrogen peroxide in 2:1 ratio (about 1lt hcl and 500ml h202) to detach the gold coated foils and pins and kept it for 48 hours. Then I prepared my stuff for aqua regia. I dipped the residue in a solution of 32% hydrochloric acid and 70% nitric acid in 3:1 ratio (about 150ml of hcl and 50ml of hno3 along with 50ml of distilled water) and kept it for 24 hours after which I added some urea to neutralize hno3 and poured in a solution of sodium metabisulfite (mixed with hot water). Drained the rest solution and I got some brown mud like stuff sitting at the bottom of the beaker. Then I washed the thing with hot water, boiled it, filtered it and dried the filter paper. I got some black dust. I don't know what it is and where the gold went? I don't know what went wrong, I'm new to this and this is my first experiment on gold extraction. Can anyone please help me. :(
What did you do with your waste chemicals, where are they now, what are you planning to do with them? And about how much gold are you expecting from your lot? 1g?
 
niks neims said:
Debayan Pyne said:
I've tried to conduct the experiment of gold recovery from electronic waste. I used 3kgs of Intel Pentium 4 processors along with others for this purpose and initially the material seemed descent just for this experiment and not for any profit motive. I dismantled the whole lot and washed them properly with hot water. Then I gave them the first chemical bath with 32% hydrochloric acid and 3% hydrogen peroxide in 2:1 ratio (about 1lt hcl and 500ml h202) to detach the gold coated foils and pins and kept it for 48 hours. Then I prepared my stuff for aqua regia. I dipped the residue in a solution of 32% hydrochloric acid and 70% nitric acid in 3:1 ratio (about 150ml of hcl and 50ml of hno3 along with 50ml of distilled water) and kept it for 24 hours after which I added some urea to neutralize hno3 and poured in a solution of sodium metabisulfite (mixed with hot water). Drained the rest solution and I got some brown mud like stuff sitting at the bottom of the beaker. Then I washed the thing with hot water, boiled it, filtered it and dried the filter paper. I got some black dust. I don't know what it is and where the gold went? I don't know what went wrong, I'm new to this and this is my first experiment on gold extraction. Can anyone please help me. :(
What did you do with your waste chemicals, where are they now, what are you planning to do with them? And about how much gold are you expecting from your lot? 1g?

I dumped the waste chemicals as the stannous chloride test was negative. I tested all the solution for at least 3 to 4 times before disposing off, got negative result all the time. And I haven’t been expecting much, around 0.2-0.3g output from the material I processed. I have used a ready made stannous chloride powder which I bought from a local chemist. Now I'm doubting whether the test showed the accurate result or not.
 

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jarlowski1 said:
You need to stop trying to refine from youtube videos and study on this forum a lot. Learn about how to deal with your wastes. There is a search function you can find it in the drop down menu tab. Search by type of material you are processing. You need to spend a lot of time reading or you will just lose your gold and harm yourself and others.

You're absolutely right. I have a lot to learn. Corrections are warmly welcomed :)
 
Debayan Pyne said:
I dumped the waste chemicals

What, like on the ground in your back yard or down the drain in your apartement?

Maybe you could share your adress or contact information, I'm sure some of our members from India would take a special interest in your case...
 
What the members are saying is that the solution that you tested for gold was still loaded with toxic elements that need treating to make harmless before disposal, if you poured it into the ground it will slowly make it into the water table and maybe back into your drinking water, if your poured it down the drain it will kill all the good bacteria that breaks down human waste and again possibly enter rivers and streams that people or animals use for water.
We are pretty heavy about proper disposal as we under watch from many agencies and the last thing anyone wants is trouble with them, there are many chemicals many can’t source and any further restrictions would probably make our hobby/ business impossible.
 
nickvc said:
What the members are saying is that the solution that you tested for gold was still loaded with toxic elements that need treating to make harmless before disposal, if you poured it into the ground it will slowly make it into the water table and maybe back into your drinking water, if your poured it down the drain it will kill all the good bacteria that breaks down human waste and again possibly enter rivers and streams that people or animals use for water.
We are pretty heavy about proper disposal as we under watch from many agencies and the last thing anyone wants is trouble with them, there are many chemicals many can’t source and any further restrictions would probably make our hobby/ business impossible.

No, I haven’t dumped the waste chemicals down the drain or anywhere else. I simply collected it by pouring into a big hdpe container which I bought for this purpose.
I know the waste chemical is various metals contaminated hazardous waste, so I kept it at a safe place. The thing which I cannot figure out now is whether the gold content in those processors dissolved in chemicals or not. And if yes I'm trying to figure out how to retrive the gold from that solution.
 
Well I’m sure we are all pleased you have stored your waste for future safe disposal.
The mud as you call it is where your gold is as I believe Lino told you, precipitated gold is normally a brown tan color which your powder seems to show, as Lino suggested redissolve filter and precipitate.
 
nickvc said:
Well I’m sure we are all pleased you have stored your waste for future safe disposal.
The mud as you call it is where your gold is as I believe Lino told you, precipitated gold is normally a brown tan color which your powder seems to show, as Lino suggested redissolve filter and precipitate.

Yes I re-dissolved that dust material again in aqua regia. I got a yellow solution. I don't know whether it's chloroauric acid or what. Maybe stannous test will clarify things this time. Thank you very much for your time and help. I really appreciate all of your advices. :)
 

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Note: Stannous chloride is a reducing agent, similar to the other reducing agents we use (copper or zinc, SMB Copperas...) before we can reduce the gold from the solution we must remove the free oxidizing agent from solution (free nitric acid and nitrate salts in the case of aqua regia), before we can reduce the gold to metal (brown to black powders) or to a purple colloid in the case of the stannous chloride test.

The test will not work if you cannot reduce the gold (or break its bond with the chloride ions), in order to do so you must remove the oxidizer that will keep gold in solution or redissolve it as fast as your reducing agent is trying to work...

Urea will not remove free or excess nitric from a solution, although if you did not overuse nitric acid it can be effective in removing the gasses of decomposition of the nitric from a solution such as nitrous acid HNO2.
Urea is useless to remove free nitric from the solution, for that reason, I do not recommend its use to anyone for this purpose.

Sulfamic acid not only removes the nitrous acid HNO2 from solution, but unlike urea will also decompose the free nitric in solution, so it not only deNOx the solution but also decompose the free nitric (from using more nitric than needed to dissolve the gold) thus sulfamic works better and does the job where urea may not...

Do not dump your waste treat it properly to recover the values, remove as much of the toxic metals from the solution and convert them to hydroxides or oxides, before properly disposing of the still somewhat toxic salt solutions or the dangerous metal powders...
It is simple to learn and to do and this can insure you are not poisioning the land where you live or poisioning you or your neighbors drinking and bathing waters...
 
butcher said:
Note: Stannous chloride is a reducing agent, similar to the other reducing agents we use (copper or zinc, SMB Copperas...) before we can reduce the gold from the solution we must remove the free oxidizing agent from solution (free nitric acid and nitrate salts in the case of aqua regia), before we can reduce the gold to metal (brown to black powders) or to a purple colloid in the case of the stannous chloride test.

The test will not work if you cannot reduce the gold (or break its bond with the chloride ions), in order to do so you must remove the oxidizer that will keep gold in solution or redissolve it as fast as your reducing agent is trying to work...

Urea will not remove free or excess nitric from a solution, although if you did not overuse nitric acid it can be effective in removing the gasses of decomposition of the nitric from a solution such as nitrous acid HNO2.
Urea is useless to remove free nitric from the solution, for that reason, I do not recommend its use to anyone for this purpose.

Sulfamic acid not only removes the nitrous acid HNO2 from solution, but unlike urea will also decompose the free nitric in solution, so it not only deNOx the solution but also decompose the free nitric (from using more nitric than needed to dissolve the gold) thus sulfamic works better and does the job where urea may not...

Do not dump your waste treat it properly to recover the values, remove as much of the toxic metals from the solution and convert them to hydroxides or oxides, before properly disposing of the still somewhat toxic salt solutions or the dangerous metal powders...
It is simple to learn and to do and this can insure you are not poisioning the land where you live or poisioning you or your neighbors drinking and bathing waters...

Thank you very much Sir. Your information is really helpful
 
Copperas or ferrous sulfate FeSO4 (which you can easily make your own) using dilute sulfuric acid (10% H2SO4) and iron.

The copperas will also test for gold, unlike stannous chloride, the ferrous sulfate will work even if there is some free nitric acid still left in solution (where stannous chloride will not).

The copperas itself can deNOx the solution during the test where stannous chloride will not work to reveal gold in solution.

When properly dealing with waste, we can recover gold or other values from the solution during that proceedure , gold that we may have missed or did not see with our stannous chloride testing solutions...
 
butcher said:
Copperas or ferrous sulfate FeSO4 (which you can easily make your own) using dilute sulfuric acid (10% H2SO4) and iron.

The copperas will also test for gold, unlike stannous chloride, the ferrous sulfate will work even if there is some free nitric acid still left in solution (where stannous chloride will not).

The copperas itself can deNOx the solution during the test where stannous chloride will not work to reveal gold in solution.

When properly dealing with waste, we can recover gold or other values from the solution during that proceedure , gold that we may have missed or did not see with our stannous chloride testing solutions...

Thank you Sir @butcher :) I'll follow these instructions in my subsequent experiments
 
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