# Unable to precipitate gold



## Malc84 (Feb 13, 2022)

Hi all, I am new to this forum so hello . I am hoping that someone will be able to help me. I have followed the instructions from this post Gold Recovery Correctly exactly. I tested the gold solution as described, which instantly turned black. When it came to adding the sodium bisulfite there was no reaction, the liquid remained yellow, I continued to add sodium bisulfite hoping for a reaction however this didn’t happen and I overloaded it . I ended up with roughly a 1 cm layer of sodium bisulfite, not knowing what to do I added more hydrochloric acid. I now have roughly 4cm of crystals in the liquid. The solution still tests positive for gold but I don’t know how to extract the gold.

Any suggestions/help would be greatly appreciated!

Thanks,
Malc


----------



## Martijn (Feb 13, 2022)

Welcome to the forum. 









When In Doubt, Cement It Out


When In Doubt, Cement It Out This is advice I often give to new members who find they've created a bit of a mess, and they're wondering how to recover their values (gold, silver, PGMs, etc.). Perhaps they've followed a process they've seen on YouTube that left out some important details...




goldrefiningforum.com





How much plated items did you dissolve to begin with? How much foils did you have?

Martijn.


----------



## galenrog (Feb 13, 2022)

Sodium bisulfite? Why?

Time for more coffee.


----------



## Malc84 (Feb 13, 2022)

Thank you Martin. I started with 485g of ram fingers, I probably at a guess had around 4-5 grams of foils.
I have seen that I should have used sodium metabisulfite however I have also read that I can use sodium bisulphite, I know chemically they are different but without the necessary knowledge of chemistry I didn’t know what would happen.


----------



## FrugalRefiner (Feb 13, 2022)

Malc84 said:


> I have seen that I should have used sodium metabisulfite however I have also read that I can use sodium bisulphite, I know chemically they are different but without the necessary knowledge of chemistry I didn’t know what would happen.


Malc, welcome to the forum. I hope you find the information here to make you successful.

Now, I know this will be harsh, but if you don't have "the necessary knowledge of chemistry" to know what will happen, *DON'T DO IT!* Follow the tried and true processes detailed here on the forum. There are many ways to recover and refine precious metals. We recommended certain processes here because they are nearly foolproof. If you don't have a particular chemical described in a process here, substituting something that sounds close could kill you.

Dave


----------



## Malc84 (Feb 13, 2022)

Hi Dave, thank you for your response. The link I posted in my original post detailed everything I needed and he made reference to this site as his go to place for information so I followed it very carefully until I had no reaction to precipitate the gold, that’s where it seemed to go wrong even when following the instructions. If you could advise how to resolve this issue it would be greatly appreciated.


----------



## Martijn (Feb 13, 2022)

From the article: 
_4. Stumpout by Bonide. or Sodium bisulfate - 99.9% as specified in the Msds or Sodium Meta Bisulfite_

The second one mentioned, is wrong_. _
I did not read the rest for errors.
But it shows chemistry has to be exact. Little typo's can have big consequences or do nothing at all in the reaction. 

Martijn.


----------



## Malc84 (Feb 13, 2022)

So it should have have been metabisulphite? Is there any way to reverse what I have done?

malc


----------



## Stibnut (Feb 13, 2022)

Bisulfite and metabisulfite exist in an equilibrium with each other in solution, so it does not make a difference whether you use bisulfite or metabisulfite to precipitate gold. However if you used bisulfate, which the post you linked to seems to confuse with bisulfite, nothing would happen - that contains sulfur in the +6 oxidation state rather than the needed +4. So that's one possibility - make sure you have bisulfite rather than bisulfate.

Since you put a whole lot of the bisulfite in your solution, does it smell pungent, like burnt matches, burning sulfur, or volcanoes? This is sulfur dioxide and would indicate that you had the right compound. It's the release of sulfur dioxide in solution that does the work of reducing gold salts to the metal. If you can't smell any sulfur odor, this would be a good indication that you had bisulfate instead.

The other thing I noticed about the Instructables post is that they never heat their bleach + HCl solution or do anything else to drive off the excess chlorine after the gold is dissolved. If you have too much chlorine remaining in solution, gold will tend not to drop because it is re-oxidized and put back into solution by the chlorine. A similar thing happens with excess nitric acid in aqua regia. However, bisulfite is good at reducing chlorine to chloride so you likely reduced it when you added a large amount of it to your solution. For that reason I think this isn't your problem.


----------



## Malc84 (Feb 14, 2022)

Thanks for the above. I have rechecked and it is sodium hydrogensulphate that I have used, I believe this is the same as bisulphate. I have just ordered some sodium metabisulphite to use instead. Do you think I can just filter the liquid off to remove the crystals and then add the metabisulphite to drop the gold or do you think that the gold could have been locked into the crystals? If the gold could have been affected by me adding the bisulphate are there additional steps I need to take to remove it other than filtering it? Many thanks.


----------



## orvi (Feb 14, 2022)

Malc84 said:


> Thanks for the above. I have rechecked and it is sodium hydrogensulphate that I have used, I believe this is the same as bisulphate. I have just ordered some sodium metabisulphite to use instead. Do you think I can just filter the liquid off to remove the crystals and then add the metabisulphite to drop the gold or do you think that the gold could have been locked into the crystals? If the gold could have been affected by me adding the bisulphate are there additional steps I need to take to remove it other than filtering it? Many thanks.


Yes, you can filter the crystals, rinse them with some water.
Then you proceed with sulfite.

As Stibnut mentioned, it is relatively up to you which form of sulfite you use. You can use sodium metabisulfite (SMB), sodium sulfite or sodium bisulfite. Sulfur dioxide gas will also work perfectly.
If you cannot get some sort of sulfite, use ferrous sulfate for precipitation. It also work well.

*"Nose testing" for SO2 is very easy, but SO2 is not healthy at all. Just be sure you do not stick your nose to the beaker, or it will knock you down pretty certainly. *Very pungent smell, sulfurous, unbearable.
Learn how to properly sniff chemicals as chemist. Fan the fumes with your hand towards your nose SLOWLY, be sure you do not stand closer than half meter from the beaker. Do not inhale much, just to the "tip of your nose". SO2 is clearly evident when present, it is unmistakeable. And if you are able to cautiously smell it, there is enough in the solution.

Please be careful with chemistry. As Dave said, if you do not know what is happening with your experiment, and you do not know for sure what addition of this and that will cause, DO NOT DO IT. It could easily be your last addition. Chlorine is very toxic, one accidental whiff could leave you disabled for life with pulmonary problems and "dissolved" lung tissue. No jokes.


----------



## orvi (Feb 14, 2022)

Stibnut said:


> The other thing I noticed about the Instructables post is that they never heat their bleach + HCl solution or do anything else to drive off the excess chlorine after the gold is dissolved. If you have too much chlorine remaining in solution, gold will tend not to drop because it is re-oxidized and put back into solution by the chlorine. A similar thing happens with excess nitric acid in aqua regia. However, bisulfite is good at reducing chlorine to chloride so you likely reduced it when you added a large amount of it to your solution. For that reason I think this isn't your problem.


Unlike nitric acid, reaction of chlorine with sulfite/SO2 is quite quick. And chlorine is soluble in the aqueous solutions just to some extent. Heating up the solution will certainly minimize it´s content in the mixture, but one excess spoon of sulfite usually kill every last bit of Cl2 present (in my experience).

I used sulfite excessively also in my organic chemistry career, to purposefully kill traces of bromine and iodine, left in reaction mixtures. Reaction is instant. And so it is with chlorine.

So, as you said  not very problematic.


----------



## Malc84 (Feb 16, 2022)

Thanks all. I managed to filter the crystals off and then added metabisulfite which then did drop the gold to the bottom of the beaker. I dried the residual black powder off and then melted it with a Map torch and a little borax however the attached is what I have ended up with! Very little gold in amongst something else. I tested the gold solution as the instructions described all the way and had a positive reaction to suggest there was gold in the solution. The only other thing I noticed was during the process of dissolving the gold foils I ended up with a white sludge at the bottom of the solution which looked like salt, I have taken this out and put it to one side. Can anyone suggest why I haven’t managed to get much gold from this process? Could it be in the sludge etc? I used 485g of ram fingers so was expecting to at least have 2-3 grams of gold.


----------



## Malc84 (Feb 16, 2022)

This is the sludge and also the crystals that were left/produced.


----------



## Martijn (Feb 16, 2022)

Dilute until crystals are dissolved, filter, and: Cement it out. Study and start over (start small until you know what to do and what to expect) 
Test the filtered solution and the cemented solution with stannous.

If you want to melt gold: only do so with clean light brown powder. if it's not clean light brown powder: do not melt. It wil not be pure gold. 
Melting black stuff with ??? in it?? can do anything, because of the ??? Even gold can go up in smoke.

Powders are easy to clean, a blob of Au + ??? is not. 

Trash in, trash out.


----------



## kurtak (Feb 16, 2022)

Malc84 said:


> I used 485g of ram fingers so was expecting to at least have 2-3 grams of gold.



454 grams equals 1 pound - so 485 is very close to 1 pound & for all practical purposes you can call it a pound

1 pound of *close cut fingers* (from RAM) will give you "*about*" 1.5 grams gold (*if you do everything right*)

Kurt


----------



## kurtak (Feb 16, 2022)

Malc84 said:


> *This is the sludge* and also the crystals that were left/produced.


Per the bold print - the *sludge* looks to me like meta stannic acid which is the result of processing boards with tin solder on them

That means the "fingers" you processed were NOT clean close cut (from the RAM) 

That means you would not even get the expected 1.5 grams gold from the 485 grams of fingers

Question - did you actually cut the fingers off the RAM sticks (& cut them VERY close to the fingers) or process them as whole RAM sticks &/or not cut them very close to the fingers ?

Kurt


----------



## kurtak (Feb 16, 2022)

Malc84 said:


> I tested the gold solution as the instructions described all the way and had a positive reaction to suggest there was gold in the solution.


What color was your stannous test ?

A true positive stannous test (for gold) will range in color from purple to black (depending on how much gold is in solution)

There is such a thing as a *false* positive - which is often the result of using to much SMB to drop your gold

A false positive test will be *brown* in color --- not the purple/black you are looking for

Kurt


----------



## Malc84 (Feb 16, 2022)

The photo I sent with my final results were a bit misleading as it contained little fragments of the graphite crucible as I had difficulty in removing the so called resultant gold, when I removed it parts of the crucible broke off. The powder I was left with was a light brown colour at the start of the melting process. 

Hi Kurt,
I processed RAM fingers only, but they were not as clean cut as they should have been so quite a few of the individual finger cuts included a small portion of the board with components still on them. If this is what caused the sludge then I will have to spend more time cutting them closer to the fingers and washing the boards off before proceeding to ensure they are clean. The instructions I used as listed above stated that I needed to use 6% sodium hypochlorite but I used 14-15%, would this also have caused an issue I.e. the sludge?
Below is a photo of the stannous test results, it was definitely dark purple/black as opposed to a brown.
Thank you for the clarification regarding what I should expect from the 1 pound of fingers. I also have about 2.2 lbs of RAM chips to process which I have burnt, crushed, sieved and removed all of the metallic parts using a magnet. Could I follow the same process I have for the fingers to process the chips? If not could you recommend how to process these please? Also do you know how much gold I should expect to recover from 2.2 lbs of RAM chips?

Also, what is meant by cementing it out?

I have a further 30kgs of RAM boards to process but I want to get it right before stripping everything down.

Many thanks,

Malcolm


----------



## FrugalRefiner (Feb 16, 2022)

Malc84 said:


> Also, what is meant by cementing it out?


See When In Doubt, Cement It Out.

Dave


----------



## orvi (Feb 16, 2022)

Malc84 said:


> The photo I sent with my final results were a bit misleading as it contained little fragments of the graphite crucible as I had difficulty in removing the so called resultant gold, when I removed it parts of the crucible broke off. The powder I was left with was a light brown colour at the start of the melting process.
> 
> Hi Kurt,
> I processed RAM fingers only, but they were not as clean cut as they should have been so quite a few of the individual finger cuts included a small portion of the board with components still on them. If this is what caused the sludge then I will have to spend more time cutting them closer to the fingers and washing the boards off before proceeding to ensure they are clean. The instructions I used as listed above stated that I needed to use 6% sodium hypochlorite but I used 14-15%, would this also have caused an issue I.e. the sludge?
> ...


Processing RAM chips is much more difficult than fingers. Fingers are easy money if you can do it right. RAM chips need some extra care for good recovery. There are just a ton more things that could go wrong.

You say that you burned chips. It need to be done diligently, and there should be no carbon left in the incinerated chips. All nice white, in worst case greyish white colour. No dark grey or blackish when scraped through upper layer of ash. Properly incinerated chips do not require excessive grinding, they disintegrate right away to powdery residue and legs/dies with some shaking inside closed box.

Carbon absorb dissolved gold. It is used in mining industry to scavenge gold from leaching vats with cyanide gold leach. From AR solution, it have much less affinity to bond to carbon, but still pretty strongly. Bear that in mind.

If there isn´t much carbon, recovery with acid is relatively straightforward. You will appreciate good filtering apparatus as soon as you will be going few pounds for a run.

From the start, do not go with more than few hundred grams of material. Build up steadily, and scale up only if you are confident with your skill and persuaded that you are doing everything as you should.
I advise you to not invent your "procedures" from the start and stick to the proven and tested ones.

Search here on the forum, all you want to know was discussed numerous times in numerous threads here. In the moment, I cannot provide you link for the one that come to my mind, but I think other members would focus you in the right direction.

Stay safe


----------



## kurtak (Feb 17, 2022)

Malc84 said:


> Hi Kurt,
> I processed RAM fingers only, but they were not as clean cut as they should have been *so quite a few of the individual finger cuts included a small portion of the board with components still on them.*


Per the bold print ---The tin solder used to solder those components to the board is what caused the sludge problem (as I said yesterday)

Tin is considered a *refiners nightmare* - therefore we make every effort to remove tin first/before going to actual refining 


Malc84 said:


> . The instructions I used as listed above stated that I needed to use 6% sodium hypochlorite but I used 14-15%, would this also have caused an issue I.e. the sludge?


No - the tin was/is the problem


Malc84 said:


> I also have about 2.2 lbs of RAM chips to process which I have burnt, crushed, sieved and removed all of the metallic parts using a magnet. *Could I follow the same process* I have for the fingers to process the chips?


Per the bold print --- NO - processing IC chips is a completely different process


Malc84 said:


> If not could you recommend how to process these please?


I see you just joined the forum - start do some research here on the forum (I don't have time to right a book) there is a HUGE amount of info about processing IC chip here on the forum you just need to start using the search functions provided here --- be aware that there is a HUGE amount of BAD info out there on the internet (although there is some good info - but only *some* good info) - this forum is one of the best sources of info you can/will find 


Malc84 said:


> Also do you know how much gold I should expect to recover from 2.2 lbs of RAM chips?


depends on what type of chips - different ram has different type chips


Malc84 said:


> Also, what is meant by cementing it out?


Read the link Dave (FrugalRefiner) provided


Malc84 said:


> I have a further 30kgs of RAM boards to process but I want to get it right before stripping everything down.
> 
> Many thanks,
> 
> Malcolm


It will serve you well to take the time to start doing *LOTS* of research here on this forum before you move forward with more refining/processing

I am not trying to put you off - rather I am tell you the best thing you can do is to start with doing research

That is part of the "learning" process - which comes before the processing process 

research/learn will serve you well - much better then just diving in & making a LOT of mistakes - which we then need to try & fix

Kurt


----------



## kurtak (Feb 17, 2022)

orvi said:


> You say that you burned chips. It need to be done diligently, and *there should be no carbon left in the incinerated chips. All nice white*, in worst case greyish white colour. No dark grey or blackish when scraped through upper layer of ash. Properly incinerated chips do not require excessive grinding, they disintegrate right away to powdery residue and legs/dies with some shaking inside closed box.


Per the bold print - although "somewhat" true - not entirely true

When processing chips - it's not until you get to the final leaching process that you need to worry about the carbon - until then the carbon is not a problem & there are MANY steps before you get to the actual leaching process

I have posted about this MANY times - here is just one of those posts (about 1/3 down on page 12)









Gold inside chips (black, flatpacks - not CPU)


I have finally started a small test run with RAM chips: Just 22 single and double sided SDRAM and DDR sticks carrying 130g of chips. Using the coffee tin method with a few holes punched above the bottom and placed into the coals of a wood fire, only about half of them burned to white. I am now...




goldrefiningforum.com





Kurt


----------



## kurtak (Feb 17, 2022)

Here is a link to my IC chip *milled carbon* run on a shaker table



Kurt


----------



## Martijn (Feb 17, 2022)

Malc84 said:


> Also, what is meant by cementing it out?


Dude.. read the info that's given.



Martijn said:


> Welcome to the forum.
> 
> 
> 
> ...


----------



## Martijn (Feb 17, 2022)

Something went wrong...can't seem to edit anymore or remove a post. Is that turned off?


----------



## FrugalRefiner (Feb 17, 2022)

The new owners limited the time members are able to edit posts. I think it's 24 hours, but I could be wrong. Was it a new post or an old one you wanted to edit?

Dave


----------



## Martijn (Feb 17, 2022)

Minutes old. Probably just an internet glitch. Kept giving the error message. I'll pm you if it happens again.


----------



## FrugalRefiner (Feb 17, 2022)

Probably. It was running a little funny for me this morning too. I clicked on a topic, it took quite a long time, then gave me an error massage. I clicked the back button, clicked on a different topic, and it took a while but got me there. Went back to the topic it errored on and it worked fine.

Dave


----------



## Dougplogan (Feb 18, 2022)

Malc84 said:


> Thanks all. I managed to filter the crystals off and then added metabisulfite which then did drop the gold to the bottom of the beaker. I dried the residual black powder off and then melted it with a Map torch and a little borax however the attached is what I have ended up with! Very little gold in amongst something else. I tested the gold solution as the instructions described all the way and had a positive reaction to suggest there was gold in the solution. The only other thing I noticed was during the process of dissolving the gold foils I ended up with a white sludge at the bottom of the solution which looked like salt, I have taken this out and put it to one side. Can anyone suggest why I haven’t managed to get much gold from this process? Could it be in the sludge etc? I used 485g of ram fingers so was expecting to at least have 2-3 grams of gold.


Gold fingers usually have less than 2 grams per pound. I've personally never gotten over 1.4 grams per pound. But everywhere I read says upto two pounds. The foils always look like alot of gold but remember they aren't 24 karat gold. I've done alot of ram fingers but not much else and only for last two years or so.


----------



## Dougplogan (Feb 18, 2022)

Malc84 said:


> The photo I sent with my final results were a bit misleading as it contained little fragments of the graphite crucible as I had difficulty in removing the so called resultant gold, when I removed it parts of the crucible broke off. The powder I was left with was a light brown colour at the start of the melting process.
> 
> Hi Kurt,
> I processed RAM fingers only, but they were not as clean cut as they should have been so quite a few of the individual finger cuts included a small portion of the board with components still on them. If this is what caused the sludge then I will have to spend more time cutting them closer to the fingers and washing the boards off before proceeding to ensure they are clean. The instructions I used as listed above stated that I needed to use 6% sodium hypochlorite but I used 14-15%, would this also have caused an issue I.e. the sludge?
> ...


Ram boards usually get me around or just over a half gram per pound total. That's chips and foils and all. The more bga type chips the better I find they have more gold than ic chips. Material I've done has been mixed bga type and leg ic type. Make sure to cleanly trim your gold foil fingers. No component and avoid getting the soldier in with those. It will save you headache and waist acids. Just to be clear 10 pounds unshielded ram gonna be 4 to 5 grams total gold.


----------



## orvi (Feb 18, 2022)

kurtak said:


> Per the bold print - although "somewhat" true - not entirely true
> 
> When processing chips - it's not until you get to the final leaching process that you need to worry about the carbon - until then the carbon is not a problem & there are MANY steps before you get to the actual leaching process
> 
> ...


Yes, that is true, if he will mill the pyrolyzed/incinerated chips and then separate gold bonding wires by gravitational means (pan, shaker table, sluice etc.).
Since he asked about original process (eg dissolving everything in AP/AR), i responded just to this, not considering gravity separation.
Good point.

PS: nice collaboration with mbmmllc  "thickest line of gold we have ever seen"


----------



## Malc84 (Mar 5, 2022)

Hi all, I have done as you all said and have done a lot of reading over the last few weeks. With so much information to take in regarding the reactions, the resultant crystals/salts/brown_black precipitates, how to identify what these are and how to treat them unfortunately I am back for further advice if I may.

I followed the advice here and have adjust my process ie: trimming the fingers as close as possible/cleaning the fingers etc. 

Here is where I am at now, this is the process I have followed:

1- I started off by washing 100g closely cut fingers in distilled water.

2- I put them in 700ml of 36% hydrochloric acid - brick acid -muriatic acid north star and 200ml NCS hydrogen peroxide 3% food grade and left them for 48 hours.

3- Filtered to leave gold foils, washed using distilled water and dried them.

4- Put gold foils in 300ml HCI and 50-75ml liquipak sodium hypochlorite 14-15%. This dissolved the gold foils.
Salts appeared.

5- Stannous test resulted dark black 

6- I dissolved the salts with distilled water. I repeated stannous test again and it was still dark black. 

7- I then added 8-10g of SMB, I was left with this (see pictures 1,2 and 3) repeated stannous test and it was clear.

8- I dissolved salts in distilled water and then poured off excess liquid to leave dark brown residue.

9- I repeated the hydrochloric acid and sodium hypochlorite at 100ml:9ml to dissolved dark brown residue. 

10- Stannous test resulted dark black. 

11- I added 1g of SMB which sank straight to the bottom with no precipitation occurring. I have left this overnight but it still has not precipitated. And the stannous test results is still dark black. See pictures 4, 5 and 6.

can someone please advise me on where I am going wrong?
Thank you.


----------



## Yggdrasil (Mar 5, 2022)

Check if you have overdone the bleach addition.
It has to be acidic, preferable pH 1-2


----------



## Malc84 (Mar 5, 2022)

hi Yggdrasil, I have tested my solution and I have a pH of 1.


----------



## Yggdrasil (Mar 5, 2022)

Heat it gently to 50 ish centigrade for a while and let it rest over night. Stir it from time to time.
This will drive off excess chlorine.


----------



## Malc84 (Mar 5, 2022)

I have it on the heat now so will let you know how it goes tomorrow, thank you.


----------



## Malc84 (Mar 6, 2022)

So after heating for about 3 hours and letting it settle overnight this is now what I am left with.


----------

