Processing RAM chips

[jason_recliner]

The best method will depends on the volume you process.

I know at least one of our well respected members just throws kilograms of entire memory sticks into chloride leach, then processes the clean chips separately after they have fallen off. Whereas I have much smaller volume so am a manual chip remover.

In any case, make sure you can foresee your entire plan before starting.

 

[maynman1751]

There are also some gold traces found on memory boards. Are they worth to be processed (separated from gold fingers and black chips) via AP, for example?

In the past I have removed the fingers manually and then soaked the ram sticks in 'clean' AP to remove the chips as well as the smd's. I then pour off the AP to recover the chips and smd's. Then, with a spray bottle, spray the boards into a separate container to remove any gold that will come off. After that filter the AP to get any gold flakes that may be there. This needs followed with an HCl wash to remove tin. It takes time for a small yield but it doesn't cost anything but time. I just sit outside on a nice Sunday afternoon and enjoy the day doing this. It's up to you if you think that it's worth it! :?:

 

[kjavanb123]

Hi all

I used wet ashing (20 ml of sulfric acid on a hot plate) and one chip from a RAM stick and I could see the following;


Sample RAM stick with BGA chips


After wet ashing,


A closer look at above; it is very small and seems like a copper piece in the middle and bonding wire copper.


Silvery dots I believe from BGA balls


The lot is 1.5 kg RAM sticks just like picture, and after a 12-hour leach in hcl, I ended up with 399 grams of chips, 17 grams of SMD capacitors and resistors, and bare board with gold fingers.

I leached bare boards with dilute nitric acid, filtered and smelted the filter paper and all gold foils with lead, followed by cupeling the lead dore, it resulted in 0.240 gram silver bead, which I dissolved in nitric and got brown powder.


It seems lead which was used had silver contamination, and after converting silver chloride into metal bead weighed 0.120 grams

That concludes my yield from bare RAM sticks was 0.12g.

Processed SMDs using 9:1 borax feldsspar and silver as collector and got 0.056 gram of Palladium.

Processing ICs using lead oxide and 3:1:1 soda borax silica followed by cupeling the lead only yielded 0.06 grams of silver-gold.

I am remelting the slags with 1:1:1/4 borax:soda ash: feldespar, I used 19.29 grams silver powder and after 2 curicble melting silver beads weighed 24.06 grams

I dissolved those beads in nitric acid and got green solution and grayish residue.

Will be testing those further.

 

[kjavanb123]

This morning I noticed there was a chunk of lead that didnt cupel yesterday so I cupeled it and got the following bead which is silver and gold, I assume silver from those solder balls of chips.


That bead weighed 1.72 grams.

I dissolved it in nitric acid and silver dissolved and brown gold powder remained.


Then I used wheel balance lead pieces to cupel the powder, but noticed it has zinc as it formed a layer on the surface of molten lead, so I had to melt with borax and pour in cone mold and cupeled that new bead which resulted in nothing!

It is amazing I tried cupeling with palladium silver even rhodium and it works perfectly, but for gold powder failed twice.

Anyway I melted the silver into beads that weighs 0.87 grams

So that means from 1.5 kg memory RAMs got 0.85 grams and another 0.120 grams from plated gold on RAM stick.