Ok, I'm planning on ashing few kilograms of IC chips collected from old phones, digital cameras, sat navs, computers and other electronic waste.
Literally thousands of each type all in one batch.
I'm not skilled enough to do Wet ashing as I see it to dangerous to do my self.
First you need to remove ICs from boards.
Then I removing the tin from chips by doing a displacement reaction with organic copper salts, displacing copper with tin on the chips.
Ok next step is ashing... I know places where you can get tons of dry logs for free... Pyrolyze chips outside first.
Then in a my village house on stove burn out all the carbon in the chips to white powder... Crashing the ashes with baseball bat time to time and
sieving through sieve. Wearing the correct PPE respirator and goggles recommended. Also I looking to buy a massive crucible because burning it in a
Stainless steal pot will alloy a lot of gold with the bottom of the pot and stick to the sides too. And I don't want to waste my time electrolyzing
massive pot or dissolving it completely. What about Silicon can gold aloy with it at all?
Next step is to dissolve it all straight in to a diluted AR... boiling for few hours a few times... Here comes the filtering through a Buchner funnel
and flask using a vacuum pump. I understand that there will be a lot of acidic vapors which will brake my pump. To prevent this I need to set up a
trap and I don't know how. Maybe there's is a video on Youtube... or some one here have few spare minutes to explain to me how to do it correctly.
I know what to do after... Drop gold with FeSO4, acids were diluted so there's really no need in removing the excess nitric... Add FeSO4 and stir
good, all gold drops out in seconds. Then wash the gold powder in HCl to remove rust and redissolve in concentrated AR this time and drop pure Gold
with NaSO3 and melt it after drying.
[Edited on 5-9-2022 by Romix]B(a)P - 4-9-2022 at 19:56
I use one of these between my filter outlet and pump inlet. Typically I would have it filled with ice cold dH2O.
Edit - this time with the image
[Edited on 5-9-2022 by B(a)P]
[Edited on 5-9-2022 by B(a)P]
Romix - 4-9-2022 at 20:40
Romix - 4-9-2022 at 21:32
B(a)P I'm really sorry, could you upload the picture here please. You can do that by posting this photo to one of your friends on facebook and
downloading it then from chat there, and posting back here after... Or just converting from your format into JPG.
I am paranoid that the file that you posted contains virus, and it'll fuck up my new clean laptop.
[Edited on 5-9-2022 by Romix]Romix - 4-9-2022 at 22:11
Thank you.Romix - 7-9-2022 at 09:14
B(a)P how this piece of glassware that you've recommended called??Romix - 7-9-2022 at 09:15
Bought electric vacuum pump this morning.
[Edited on 7-9-2022 by Romix]
Romix - 7-9-2022 at 11:03
Also need an adapter to connect hose to the pump.
Similar to that on this link. https://www.ebay.co.uk/itm/174636539385
Not getting it from America, to expensive and will need to pay import fees.
Maybe someone here have it in UK or know where I can get it?
Last resort will be ordering from China, as their delivery usually is free and never paid any import fees ordering from there.Romix - 7-9-2022 at 11:27
B(a)P how this piece of glassware that you've recommended called??
If it's too expensive, might just use a juice bottle with wide lid and two screw in pens. numos - 7-9-2022 at 13:58
Gas wash bottle... can be found for under $100Sulaiman - 7-9-2022 at 17:57
Gas wash bottle = Dreschel bottle.
If you 'release' the vacuum on the pump side of the wash bottle,
the liquid contents of the wash bottle wil be drawn into your equipment, typically into your hard earned product.
So you may need (should have) a suckback trap, of enough capacity.
This commonly means two Dreschel bottles (or equivalent) in-line.
As you will probably have vacuum-capable flasks, you could buy just the heads.
The typical large id tube and low capacity, and high cost, make these commercial Dreschel bottles a good target for diy. Romix - 7-9-2022 at 18:03
Dear Sulaiman.
Thank you for the advice, much appreciated.
That's what I been thinking about all night tonight.
As I have some experience with distilling things and filtering the gases into water.
I thought that the same could happen here.
[Edited on 8-9-2022 by Romix]
Sulaiman - 7-9-2022 at 18:29
I'm too lazy to draw it but imagine;
A similar (empty) bottle inserted between the flask and the bottle in the diagram.
The top/head/adapter should face the opposite direction.
Long tubes in the centre, connected together,
short tubes to filter flask and vacuum pump.
This way no liquid can be sucked or blown out in either direction.
[Edited on 8-9-2022 by Sulaiman]Romix - 7-9-2022 at 18:30
So if I release it from one side it'll go in to filtering flask and dilute my solution.
And if I release from the other side, it'll break my vacuum pump.
Correct? Just thoughts... Sulaiman - 7-9-2022 at 18:44
pinch the tube that goes to the filter flask,
Carefully pull the tube off of the filter flask - now the filter cake and filtrate are 'safe'
Turn off the vacuum pump and slowly release the tube - done
[Edited on 8-9-2022 by Sulaiman]Romix - 7-9-2022 at 18:46
Ok Thanks, so there is no need in the second trap then, if you do it correctly ? Sulaiman - 7-9-2022 at 18:50
True...
if nothing could possibly go wrong arkoma - 8-9-2022 at 02:16
Be careful pulling vacuum on any glass that you don't KNOW is made to take it. I DO know better and pulled vac on an Erlenmeyer one day (oh heck, was
using a "leaky" set up and was gonna be quick...) and WHUMP. Was filtering hot aqua regia/platinum metal group solution. BAD, BAD idea.
If you are using anything "sketchy", put it in a wooden crate or something that will contain the shards and fluids just in case and for goodness sake
wear eye protection.Rainwater - 8-9-2022 at 02:59
I use one of these between my filter outlet and pump inlet. Typically I would have it filled with ice cold dH2O.
A dry ice/ethanol bath would filter your gas stream much better.
I don't have a good vacuum gauge but I can freeze water with my pump.
I have heard the brand of oil you use makes a big difference but cheap mineral oil( pharmacy laxative) is what I use.
If your pumping a netural ph then just keep an eye on the oil level and change it when its full or finished as water vapor will collect in the pump
For anything else use a cold trap or a neutralizing filter.
A little plastic wrap will go a long way if you have an implosion. You cant heat the wrapped flask very hot but when it does go wrong, its worth the
trouble.
[Edited on 8-9-2022 by Rainwater] added picture
Edit:
Quote:
What about Silicon can gold aloy with it at all?
Not to my knowledge but it can get trapped inside the crystal structure as it cools. Use of flux and a collector metal will stop this.
Quote:
Next step is to dissolve it all straight in to a diluted AR...
Nope. After making the finest power reasonable, burn it again to strip out more carbon. Carbon is bad for the next step.
You need to leach out the base metals. Hot nitric acid baths.
Save all your decanted solutions and test with a stannous chloride-based indicator.(youtube "streetips" to watch a professional amateur do it. That
dudes awesome)
Quote:
boiling for few hours a few times... Here comes the filtering through a Buchner funnel and flask using a vacuum pump.
Yes nitric acid boils, then boil in water to remove the left over acids.
After your done. Test your solution from your acid boils for precious metals. 8f 8n dought, reduce the volume of solution and repeat.
Do you want to recover all the metals or just the gold?
[Edited on 8-9-2022 by Rainwater]Romix - 8-9-2022 at 08:16
Could there be something other than gold? Most chips had gold bonding wires, few newer blackberry phones had silvery bonding wires.Rainwater - 8-9-2022 at 15:37
Owww ya.. gold will be the 3rd of the most valuable recovered metals from old cell phones.
The amount recovered will be depressing.
If the phones are free, the reagents will cost an arm and leg.
Most recycled electronics are parted out. After that is incineration and processing as a consentrated ore.
The screen is ruby doped with indium, gold brazing inside the IC's. The ic's silicon is doped with all sorts of tasty metals. The pcb's have a fine
layer of palladium.
Maybe 15-25 precious/rare metals.
The problem is purification.
Separate steps for each element.Romix - 12-9-2022 at 19:20
Received the pump, I think hose will go directly on a pump's outlet with blue lid.. Don't need no adapters, very good news.
