Unable to precipitate gold

[orvi]

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

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]

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

. 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

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

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

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

Also, what is meant by cementing it out?

Read the link Dave (FrugalRefiner) provided

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]

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)

https://goldrefiningforum.com/threads/gold-inside-chips-black-flatpacks-not-cpu.23285/page-12
Kurt

 

[kurtak]

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



Kurt

 

[Martijn]

Also, what is meant by cementing it out?

Dude.. read the info that's given.

Welcome to the forum.

https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
How much plated items did you dissolve to begin with? How much foils did you have?

Martijn.

 

[Martijn]

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

 

[FrugalRefiner]

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]

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

 

[FrugalRefiner]

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]

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]

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

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]

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)

https://goldrefiningforum.com/threads/gold-inside-chips-black-flatpacks-not-cpu.23285/page-12
Kurt

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]

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]

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

 

[Malc84]

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

 

[Yggdrasil]

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]

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

 

[Malc84]

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

 

[jailes Norato de Jesus jú]

Bom dia alguém sabe me dizer como fazer a precipitação nesse produto

 

[Yggdrasil]

Bom dia alguém sabe me dizer como fazer a precipitação nesse produto

Welcome to us.
But you will have a better chance of an answer if you post in English.

And since you are new we encourage you to study these things:
We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: Screen Readable Copy of Hoke's Book
2. Then read the safety section of the forum: Safety
3. And then read about "Dealing with waste" in the forum: Dealing with Waste

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