# Ceramic E proms



## ilikesilver (Jun 8, 2013)

so i was doing some sorting today, and finally got around to sorting out all my eproms. I took out all the plastic type black styles/from what i understand there is nothing in them? i sorted out the three types of ceramic style, large with silver showing in the windows, large with gold showing in the windows, and then large and small with no windows at all. pain to break open i know that. I did manage to break open one of the ceramics with NO window showing. this is what i found. You can see the wires running through the underlayment of the top piece and then the glass eye completely surrounded in gold. ive searched the forum but i dont see anyone running these? is that correct. tim


----------



## Geo (Jun 8, 2013)

they have been discussed at length. its best to break them in the middle and avoid exposing all the extra base metal.


----------



## ilikesilver (Jun 8, 2013)

Geo, do the black plastic ones contain any values? im going to run the gold ones in AP, but can i do the same with the silver ones? tim


----------



## Geo (Jun 8, 2013)

you have to be more specific. i have boards with the DIP chips that are thicker than the others. i was getting small copper coils in my incinerated chips and tracked it to these thicker chips. theres only a few on the whole board but it really interferes with the cleaning of the ash and AR afterwards. if anyone wants to see the chips im talking about, just let me know and ill try and post some pictures of them. someone may know what im talking about.
there are thicker quads and the yields are about the same as the thinner ones PER PIECE and not by weight. the yields depend more on the number of legs as one leg represents one bonding wire.
i process them all the same.the silver ones are a alloy of palladium and silver.the bonding wires can still be gold.


----------



## g_axelsson (Jun 8, 2013)

Geo said:


> you have to be more specific. i have boards with the DIP chips that are thicker than the others. i was getting small copper coils in my incinerated chips and tracked it to these thicker chips. theres only a few on the whole board but it really interferes with the cleaning of the ash and AR afterwards. if anyone wants to see the chips im talking about, just let me know and ill try and post some pictures of them. someone may know what im talking about.
> there are thicker quads and the yields are about the same as the thinner ones PER PIECE and not by weight. the yields depend more on the number of legs as one leg represents one bonding wire.
> i process them all the same.the silver ones are a alloy of palladium and silver.the bonding wires can still be gold.


It sounds to me that your copper wire coils comes from magnetic components used on the network connector. It is a couple of small transformers inside those components, 2-4 of them.
I can't see any reason why they should contain any precious metals at all. It is probably safe to sort them out before processing them.

This is an example of what I'm talking about, the larger black "chip" between the ethernet connector and the flat pack.






Göran


----------



## ovidiuanghel (Jun 10, 2013)

I have refine this type of eproms and its a pain when filter the solution
Here are some photos


----------



## Geo (Jun 10, 2013)

the white material you see is glass. its the middle layer between the two ceramic pieces. in AR, this glass layer comes apart. this is why i said its better to break them in the middle where important part is. it will not stop this from happening but it will not be that sever. the PM's will dissolve before the glass comes apart.


----------



## ovidiuanghel (Jun 10, 2013)

Three days i filter this solution and i sweared i never process this eproms ever again.


----------



## g_axelsson (Jun 10, 2013)

Pretreat them in nitric acid. The glass will turn into the grey sludge and you can wash it off, the gold is still with the ceramics. Then take it to AR. Very nice and clean scrap to work with but a bit messy to crack open and remove all the pins.

Göran


----------



## machiavelli976 (Jul 30, 2013)

If the pins of the Eprom-s are silver-tin brazed , the white sludge could also contain metastanic acid , in fact hydrated SnO2.

It is the result of pre treating in nitric acid. It may dissolve in AR but will exhaust some of the HCl .


----------



## g_axelsson (Jul 30, 2013)

machiavelli976 said:


> If the pins of the Eprom-s are silver-tin brazed , the white sludge could also contain metastanic acid , in fact hydrated SnO2.
> 
> It is the result of pre treating in nitric acid. It may dissolve in AR but will exhaust some of the HCl .


If you look at the picture before acid treatment, there were no pins left. The only thing that is brazed is the chip inside the capsule, the legs are only held by the glass layer and can be removed when you break the chip open.
In other words, there is no tin so there can't be any metastannic acid.

Older types of eprom with side brazed legs could be another story, but then you wouldn't have that glass layer either.

Göran


----------



## machiavelli976 (Jul 30, 2013)

g_axelsson said:


> machiavelli976 said:
> 
> 
> > If the pins of the Eprom-s are silver-tin brazed , the white sludge could also contain metastanic acid , in fact hydrated SnO2.
> ...



Yes you're right. I did break some ceramic IC's and the glass layer is there. The legs are not side brazed and are kept aligned in the glass. The picture above is not very sharp to me and I have supposed the previous removal of the pins mechanically or thermally .

Thanks!


----------

