Non-Chemical BGA RAM chips, metal concentrates refining.

[Shark]

I don’t like using bleach on anything. Especially anything thicker than finger foils. The situation here is one of the reasons why.

I would go with hot hydrochloric since you don’t want to use nitric or sulfuric. Do not boil in a plain jar. Lab beaker, boiling flask or, at a minimum a glass coffee pot with a Corningware pan as a catch pan. Put your material in your beaker, cover with twice the volume of HCl and bring to a low boil. Hold it there until it changes color. Once it stops reacting change the HCl and heat it up again until it stops reacting. Repeat until very little to no color change. Decant the remaining liquid leaving the left over solids in the beaker. This you will use AR on. Or HCl/Cl only if you can not access a nitrate. Here is why bleach is less useful, it takes a LOT of it to dissolve base metals. Bleach also neutralizes HCl. Two strike rule for me. Now if you need extra bleach you most likely will also need extra HCl as well. Make additions with this in mind. Finish off as usual, denox, drop lead, filter until clear (sediment clear) and drop.

When you work out side well known methods things become more complicated. So, if it doesn’t seem to work right…. It can be a shot in the dark as what to try next. For example, any residues from the IC bodies can have the ability to absorb some of your gold. Properly incinerated removes that ability. At times some remaining base metals have the ability to kick start a nitric reaction, even after being neutralized with sulfamic.

 

[DJPGold]

I don’t like using bleach on anything. Especially anything thicker than finger foils. The situation here is one of the reasons why.

I would go with hot hydrochloric since you don’t want to use nitric or sulfuric. Do not boil in a plain jar. Lab beaker, boiling flask or, at a minimum a glass coffee pot with a Corningware pan as a catch pan. Put your material in your beaker, cover with twice the volume of HCl and bring to a low boil. Hold it there until it changes color. Once it stops reacting change the HCl and heat it up again until it stops reacting. Repeat until very little to no color change. Decant the remaining liquid leaving the left over solids in the beaker. This you will use AR on. Or HCl/Cl only if you can not access a nitrate. Here is why bleach is less useful, it takes a LOT of it to dissolve base metals. Bleach also neutralizes HCl. Two strike rule for me. Now if you need extra bleach you most likely will also need extra HCl as well. Make additions with this in mind. Finish off as usual, denox, drop lead, filter until clear (sediment clear) and drop.

When you work out side well known methods things become more complicated. So, if it doesn’t seem to work right…. It can be a shot in the dark as what to try next. For example, any residues from the IC bodies can have the ability to absorb some of your gold. Properly incinerated removes that ability. At times some remaining base metals have the ability to kick start a nitric reaction, even after being neutralized with sulfamic.

Thanks heaps mate. Struggling to find a hot plate safe dish locally so might grab a corningware dish off eBay.
In regards to the bleach taking a long time to dissolve base metals, wouldn’t the base metals be gone after the HCl or are you talking about other base metals that will still be around after HCl washing, that will also go into solution with the gold?
Is it the carbon the supposedly absorbs the gold? That sounds familiar.
I feel at this point I should mention I have some memory issues and have to re-read information multiple times, over weeks in order to actually remember it and then because of the issues I always doubt that what I’ve remembered is correct. I’ll be writing these steps down as a method sheet for processing these BGAs so just wanna get accurate notes etc