Depopulated board in oil

[kurtak]

Most of this thread has been about depopulating RAM

IMO - there is only "one" way to do this --- put the RAM in a 5 gallon bucket (1/3 - 1/2 full) cover the RAM with HCl - give it about one hour for the HCl to react with the tin - pick the bucket up by the handle & twist/rotate the bucket back & forth - this gets fresh acid between RAM sticks that are touching each other - repeat bucket twisting/rotation about every 20 minute - 1/2 hour until it becomes evident chips & SMDs have come loose from board --- decant HCl & use same bucket twist rotate to do 3 or 4 water washes - separate boards from components (can be done with screening - or by hand)

Why HCl instead of some kind of heating :?:

Because with heat you have not eliminated the solder (tin) --- so - before you can move on to the recovery of your gold you still have to (at some point) do a HCl leach to remove the tin - other wise the tin is going to follow through the rest of your recovery processes

Therefore - IMO - get rid of the tin to start with &/or in THE FIRST PLACE

Just did about 40 pounds of RAM this way (& have been doing it this way for years)

Trust me --- I have tried ALL other methods will NEVER do it any other way then the way I just discribed

And it works on both the older types of RAM (older type chips) & on the newer BGA type RAM (chips)

Its the fastest - AND - it gets rid of the tin right out the gate

And - don't forget - the FINE black powder from dissolving the tin away contains "gold" (and antimony) as well - so let that fine black powder from you HCl decant & the water washes settle out for processing as well

Kurt

 

[Williamjf77]

The hcl is what I ended up doing. I don’t have to build anything and it’s practical.

Now I just have to figure out the pyrolysis and incineration.
I had bad experience the first time, I used my blacksmith forge, it’s rectangle with opening on both ends and a Venturi burner.

It started out good with my vessel sealed with some holes in the top, I put water in it threw it in the forge and the gases started burning but then it just blasted nasty smoke. I don’t know if it’s because the setup I have is tuned to burn neutral or slightly rich?

Or maybe not enough time for the gases to mix, either way next I think I’ll try rerouting the gas out of the crucible into the back of the forge.

Anyway it’s great how a dumb idea can generate good discussion

 

[Shark]

I like the conversation side as well. Sometimes other ideas arise that have nothing to do with the original question. I have never done 40lb of memory. Most of mine has been in the 4 to 5 pound range, but I like to think "what if", trying to be somewhat prepared, just in case. The idea I had for the oven was based on a much larger but similar machine from a video from a Chinese manufacturer, where they were doing whole boards. In the back ground you could see the parts dropping out as well as hear the capacitors popping. I enjoy studying different types of machines, and have since I was a kid.

I like the idea of the black dust having gold trapped in it. Every little bit counts. I have been doing my hydrochloric washes after recovering the chips. The thought was to use less chemicals. I may be loosing a tiny bit of gold right there. Next time I will try it Kurt's way and see how it works out as I know the acid will have plenty of use left afterwards.

 

[Williamjf77]

And then with the hcl method you have gallons of stannous test solution

 

[Shark]

Here is a new batch of waste going into the stock pot. I hate the sound of those air pumps bubbling away so I used these, they are much quieter, but occasionally one gets finicky about the depth. I added the same solution from a larger bucket yesterday, today it was very dark and had a fair bit of material cemented out.

It is hard to see, but I drilled a small hole in the bottom so the solution would run down the copper bars and out the bottom. It increase's circulation in the bucket as well as retains the solution in the confined area a bit longer. Most of all, it is very hard to hear from 8 or 10 feet away, has less splatter due to the cover and I can actually hear myself when I am talking to me. Even so I keep this smaller bucket inside a five gallon bucket to help reduce splatter as well. The drop on top is from a spray bottle is water.

 

[kurtak]

Williamjf77

I am having a problem with my computer right now so can't copy/paste links (my touch screen is working but my touch pad/mouse is not working)

concerning pyrolysis/incineration --- go to "Build your own Equipment" - scroll down about 2/3 & look for thread title "Pyrolysis reactor" by kjavanb123 - it's a very good discussion on methods for pyrolysis/incineration as well as info on milling smelting etc.

Kurt

 

[Williamjf77]

Those are great threads. This is what I have

That’s the back and the front is wide open.
I’m thinking to use the forge as the after burner and making a chamber that attaches to the forge. I know the forge can melt steel so it’s hot enough for an after burner while the incinerator doesn’t need to be that hot. I’m just not sure if an after burner will work without a blower

 

[g_axelsson]

Two important factors for an afterburner, oxygen excess and dwell time.

I think 4metals have discussed that a couple of years ago.

Göran

 

[Williamjf77]

Actually I just did a test and it worked pretty good as is, as long as I didn’t put too many in at once. I think the way the flame bounces off the floor and then pushes everything to the top kind of lets the gas dwell. Now I need a way to load and add air as needed.

The flow of air from small hole in back to open in front with the force of the flame and air from the burner going perpendicular seems to mix the gases and burn pretty good. Takes about 2 minutes per load of about 50 grams of north bridge tops.

I was really hoping I could use this because I don’t blacksmith much anymore, too much work but satisfying on a bad day to smash hot metal.