Hi all,
I had to proceed few kilos of RAM (mainly SDRAM, also some DDR and even old EDO and FPM sticks). By advice of a friend (he doesn't read forums ) I decided to treat them with diluted nitric. From 6 kg. sticks I collected 490 gr. very close cut fingers. Put them in diluted 1:1 nitric. Every 2 hours stirred them and let them sit overnight. At the morning most of the foils were on the bottom of the beaker. No air, no bubbler, just simple nitric. I'd say that it's much easier and faster than AP process.
But when I trimmed the fingers, I noticed some of the modules had a row of gold-plated holes just above the fingers:
As seen, the foils are gone, but most of the holes are untouched. Also there were few Dummy modules for RDRAM sockets with gold holes:
So I decided to try to take this gold too. I mixed a small quantity of AR (20 gr. HCl + 5 gr HNO3), which I intended to use later for the foils. Before foils, I put the proper pieces in AR for a minute (only few pieces at a time, because the AR was too little). It took me maybe half an hour extra. But it worth it, as the yield was 2.9 gr.
Meanwhile, since I was threatinig "the holes", AR little by little began to became classical orange. I expected a greenish, as I thought the holes are too copper with gold plate. Unfortunately I forgot to take a picture. Maybe the holes are with thicker plate, or without a copper (only gold)? Anyway, when I put the foils, AR became little greenish.
So, if you have access to nitric, I belive treatment with diluted nitric is a better process than AP. Also processing the holes above the fingers adds some more yield. I think 2.9 gr. from 490 gr. fingers is good
P.S. Now I'm beginning to collect chips and MLCCs
Regards, Miro.
I had to proceed few kilos of RAM (mainly SDRAM, also some DDR and even old EDO and FPM sticks). By advice of a friend (he doesn't read forums ) I decided to treat them with diluted nitric. From 6 kg. sticks I collected 490 gr. very close cut fingers. Put them in diluted 1:1 nitric. Every 2 hours stirred them and let them sit overnight. At the morning most of the foils were on the bottom of the beaker. No air, no bubbler, just simple nitric. I'd say that it's much easier and faster than AP process.
But when I trimmed the fingers, I noticed some of the modules had a row of gold-plated holes just above the fingers:
As seen, the foils are gone, but most of the holes are untouched. Also there were few Dummy modules for RDRAM sockets with gold holes:
So I decided to try to take this gold too. I mixed a small quantity of AR (20 gr. HCl + 5 gr HNO3), which I intended to use later for the foils. Before foils, I put the proper pieces in AR for a minute (only few pieces at a time, because the AR was too little). It took me maybe half an hour extra. But it worth it, as the yield was 2.9 gr.
Meanwhile, since I was threatinig "the holes", AR little by little began to became classical orange. I expected a greenish, as I thought the holes are too copper with gold plate. Unfortunately I forgot to take a picture. Maybe the holes are with thicker plate, or without a copper (only gold)? Anyway, when I put the foils, AR became little greenish.
So, if you have access to nitric, I belive treatment with diluted nitric is a better process than AP. Also processing the holes above the fingers adds some more yield. I think 2.9 gr. from 490 gr. fingers is good
P.S. Now I'm beginning to collect chips and MLCCs
Regards, Miro.