Wanted to check my thoughts

[user 73157]

Hello all. I have a one liter beaker full of gold plated fingers from ram cards and a good number of cpus with pins. (Should I recycle the rest of the ram card? Idk if there’s gold in the chips, I have close 400) is this enough to be meaningful?

I want to do this :

1. Add 65% Nitric Acid to the scrap until all gold is visibly dissolved.
Au + 4HNO3 → Au(NO3)3 + 2NO2 + 2H2O
2. Remove boards and filter through filter paper into a new beaker.
3. Add HCl (37%) slowly to form AuCl powder.
Au(NO3)3 + 4HCl → AuCl3 + 3HNO3
4. Filter again to separate powder.
5. Add sodium bisulfite to AuCl in water to yield metallic gold.
AuCl3 + 3NaHSO3 + H2O → Au + 3NaHSO4 + 3HCl
6. Filter and smelt.

Does the math and thought process work out? I will clearly do a test run but want to make sure it looks good before I use my works vent hood (my boss is awesome)
Questions: in step one should I have the scrap in water already?
Assumptions all water used will be deionized.

I look forward to any thoughts!

 

[GoIdman]

Hello, and welcome to the forum.
Since this is your first post, please let me guide you to do some reading before you attempt the recovery of gold from your material.

1) download C.M. Hoke`s (Refining precious metal wastes) book ( C.M. Hoke's books here for download )
2) Read the Safety section of the forum ( Safety )
3) Read the Dealing with waste ( Dealing with Waste )

Recovery and refining of RAM stick fingers and IC chips has been discussed many times on this forum, it has precise process steps which are almost failsafe. Please use the search function to read these threads.
RAM fingers are processed easily with the AP (CuCl) process, IC chips with mechanical process.
CPU`s have also well known processes, depending of what kind of CPU`s you are working with.
HNO3 and HCl are used when the material is recovered and refining is the main purpose.

Please do your reading homework before starting the recovery, you need proper safety gear, lab equipment and so on. You will find everything regardind the tools and equipments that is needed to process the e-waste correctly without harming yourself or your environment.

Don`t forget, we are here to help, but we cannot prevent accidents if you do not comply with safety and you do not do your part of educating yourself by reading what you are given.

Pete

 

[FrugalRefiner]

Smity, welcome to the forum.

You have a few things wrong. Nitric acid alone will not dissolve gold in any significant amount. HCl and gold does not form a powder. Sodium bisulfite is added to gold in solution to precipitate it as metallic gold. The metallic gold is melted, not smelted.

Follow the links Goldman gave you. They'll get you going in the right direction. There are links to Hoke's book in my signature line below.

Dave

 

[MGH]

... before I use my works vent hood (my boss is awesome)

What materials are the hood and ductwork made of? Sounds like you have permission to use it, but you should know that unless they are all polymer construction, the gasses you'll be venting are likely to corrode the system, at least to some degree. A stainless steel hood and ductwork could work well with nitric alone, but introducing both nitric and HCl will attack it.

No, you won't eat holes in the sheet metal or kill a blower motor in one day. But neither are all hoods built the same, nor can they all handle the same fumes.

 

[eaglekeeper]

(Should I recycle the rest of the ram card? I

If you want to recycle the trimmed RAM sticks, Boardsort.com is paying $8.50 per Lbs as of today's rate. I'm not sure what your shipping rate will be.

 

[user 73157]

If you want to recycle the trimmed RAM sticks, Boardsort.com is paying $8.50 per Lbs as of today's rate. I'm not sure what your shipping rate will be.

Really? That’s interesting! I’ll have to check that out. I didn’t think they would take the rest after I cut the pins off. Thank you!

 

[user 73157]

What materials are the hood and ductwork made of? Sounds like you have permission to use it, but you should know that unless they are all polymer construction, the gasses you'll be venting are likely to corrode the system, at least to some degree. A stainless steel hood and ductwork could work well with nitric alone, but introducing both nitric and HCl will attack it.

No, you won't eat holes in the sheet metal or kill a blower motor in one day. But neither are all hoods built the same, nor can they all handle the same fumes.

Good question. I will have to find out!

 

[eaglekeeper]

Really? That’s interesting! I’ll have to check that out. I didn’t think they would take the rest after I cut the pins off. Thank you!

Or you can recover the gold from the IC chips yourself. There is just as much gold in the chips as there is in the fingers. There is plenty of info on the forum about that.

 

[Paul Allee]

To my knowledge there is no such thing as gold nitrate. Chat gpt will lie to you if you as the wrong questions, but chlorine is the actual ligand doing the work. The nitric acid is there to strip electrons so the chlorine can go to work.

Someone can correct me if I'm wrong, which is possible.

And yeah don't confuse melting and smelting. A smelt is a full on high temperature liquid phase reaction involving oxidation reduction and pH. Melting is just a physical change.

 

[Thomas M Joseph]

Yes, gold nitrate exists, but your reaction will not proceed as you expect. It takes pure finely powered gold, pure (nearly 100 percent) nitric acid, and high temperatures in specialized rection vessels to produce even small amounts. No water can be present.
Au + 4HNO3 > Au(NO3)3 + NO + 2H2O corrected reaction.
Study and rethink everything.

 

[Pastorman75]

Or you can recover the gold from the IC chips yourself. There is just as much gold in the chips as there is in the fingers. There is plenty of info on the forum about that.

Silver amount is also relevant!

 

[Yggdrasil]

Silver amount is also relevant!

I'm not sure most chips has any appreciate Silver at all.

 

[eaglekeeper]

Silver amount is also relevant!

If they are the BGA type IC's then any reasonable amount of silver would be in the solder balls.

 

[Pastorman75]

I'm not sure most chips has any appreciate Silver at all.

Probably as also @eaglekeeper wrote, it depend on type of RAM you're going to treat.
Some year ago I tested approx 50 kg of RAM that a customer send us for further investigation.
Procedure I made was:
1) pyrolysis and burning of RAM into special furnace we produced. Name was VORAX and was made for goldsmith waste treatment, like spent polish brushes, in which you don't have to drag away ashes into fumes because they contains gold!!
2) put burned RAM into ball mill. Sorting grid was 180mesh.
From it comes out two materials:
A) powder: mixed with borax and some oxidising agents goes into gas furnace to be smelted at 1250 degrees Celsius. After pouted into conical laddle where sedimentation of all heavy metals happens. If temperature had been high enough and right fluxes had been used, all metal goesnin the top edge of the cone and you can collect it.
B) unbreakable part: mainly metal parts (small quantities in RAM) we put it into induction furnace with some fluxes and small quantities of oxidising agents. After strong stirring with silicon carbide rod, we poured into a small ingot die (cast iron).

After this treatment all metals, mainly Cu, Fe, Au, Ag, Ni, Cr are in metal mass A or B. The losses of metal are close to zero.

The metal mass had been tested via cuppelation (fire essay) and ICP.

Whole results had been:
-Au approx 1200 grams/ton
-Ag approx 2650 grams/ton

Of course it depends of input materials.
Please note that procedure exposed above is the procedure used to test batches of E-Waste in some of major PMs refining companies worldwide.
Bye

 

[J.Najam]

Hello everyone,

So I decided to run an experiment of removing some stubborn components on a RAM board that wouldn't want to come off. So, I decided to make a small sample size solder bath to see how it works. I used the solder balls purchased online (claimed99.99% pure) to carry this out and are not recovered from anywhere.

I was expecting a shiny molten tin bath but now can someone explain this phenomenon? The solder balls looked like containing a tinge of gold colour which can't be seen by the camera, but its there. The result of 16 grams melted solder (@85-90C). It is hardened at this point. I tried searching for mulitiple combinations of what could cause tin to go yellow or golden but couldn't find it. Also this colour is mainly from the impurities as can be seen.

P.S I couldn't conitnue with my experiment on this.

 

[Refinerjohn]

Hello everyone,

So I decided to run an experiment of removing some stubborn components on a RAM board that wouldn't want to come off. So, I decided to make a small sample size solder bath to see how it works. I used the solder balls purchased online (claimed99.99% pure) to carry this out and are not recovered from anywhere.

I was expecting a shiny molten tin bath but now can someone explain this phenomenon? The solder balls looked like containing a tinge of gold colour which can't be seen by the camera, but its there. The result of 16 grams melted solder (@85-90C). It is hardened at this point. I tried searching for mulitiple combinations of what could cause tin to go yellow or golden but couldn't find it. Also this colour is mainly from the impurities as can be seen.

P.S I couldn't conitnue with my experiment on this.

Based on why I know from making my own solder for jewelry and different electronic projects.
It’s just oxidation. I’ve had some metal droplets or pieces that stick in the crucible look just like gold when it’s cooled until you cut into it a bit.
Using more flux/a cooler flame might will help to reduce it. More oxygen = more oxidation in my experience.
Thats my two cents. Hope it helps a bit.

 

[J.Najam]

It’s just oxidation.

Believe you me, that is what I thought too. But I searched up multiple times on Google and it resulted in a white/off white colour. I'd even checked for molten tin oxidized state still no luck... I'll take it as an oxidized state for now. If I still suspect something unusual then I may carry on with some tests later on.

Thats my two cents. Hope it helps a bit.

Thanks for your reply btw.

 

[eaglekeeper]

Hello everyone,

So I decided to run an experiment of removing some stubborn components on a RAM board that wouldn't want to come off. So, I decided to make a small sample size solder bath to see how it works. I used the solder balls purchased online (claimed99.99% pure) to carry this out and are not recovered from anywhere.

I was expecting a shiny molten tin bath but now can someone explain this phenomenon? The solder balls looked like containing a tinge of gold colour which can't be seen by the camera, but its there. The result of 16 grams melted solder (@85-90C). It is hardened at this point. I tried searching for mulitiple combinations of what could cause tin to go yellow or golden but couldn't find it. Also this colour is mainly from the impurities as can be seen.

P.S I couldn't conitnue with my experiment on this.

You can take a random sample of the Tin shot and dissolve in hydrochloric. Pure Tin once dissolved should be fairly colorless.

As a bonus you'll have stannous chloride for testing ready to go......if it's not too contaminated.

 

[J.Najam]

You can take a random sample of the Tin shot and dissolve in hydrochloric. Pure Tin once dissolved should be fairly colorless.

As a bonus you'll have stannous chloride for testing ready to go......if it's not too contaminated.

ah, I already got loads of tin dissolved in HCl for stannous, I was thinking should it be pure if I keep removing the drossing as it kept on forming nonetheless?

 

[eaglekeeper]

I used the solder balls purchased online (claimed99.99% pure)

I suggested dissolving some of the Tin to check if it is 99.99% as claimed. If the hydrochloric has any color, then it is contaminated with another metal.