TO5 case transistors gold plated

[NobleMetalsRecovery]

I have a 1/2 pound of TO5 case transistors with the gold rim and gold tab showing. The inside of the bottom round plate (with the 3 legs) is gold plated. The problem I have is that the cases are filled with a white thermal grease.

It may have silver. Anyone know how to check for silver and how to best recover it from the grease?

 

[Harold_V]

I have serious doubts about the grease being conductive. I expect it would be a dielectric instead.

If you can open the cases, regardless of the method, incineration would be very well suited to eliminating any fluids involved. they need not be opened completely, just enough to permit air to enter for complete combustion. You might consider running them through a set of rolls, assuming you have them at your disposal. Otherwise, a solid hit on the side with a hammer might prove effective.

Harold

 

[NobleMetalsRecovery]

Yes, I agree, it would short out the transistor.

Look what I found on Wikipedia. A potential health risk, and a very serious one at that: beryllium oxide

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Thermal greases use one or more different thermally conductive substances:

* Ceramic-based thermal grease has generally good thermal conductivity and is usually composed of a ceramic powder suspended in a liquid or gelatinous silicone compound, which may be described as 'silicone paste' or 'silicone thermal compound'. The most commonly used ceramics and their thermal conductivities (in units of W/(m ·K)) are:[1] beryllium oxide (218), aluminium nitride (170), aluminum oxide (39), zinc oxide (21), and silicon dioxide (1). Thermal grease is usually white in colour since these ceramics are all white in powder form.

 

[Harold_V]

Yes, I agree, it would short out the transistor.

Look what I found on Wikipedia. A potential health risk, and a very serious one at that: beryllium oxide

That is certainly something of concern. Having worked in the machining industry for the bulk of my life, I am acquainted with beryllium due to its use with copper, resulting in a precipitation hardening alloy that is a non-sparking material. It is also used extensively in making springs of all sorts. Dangerous stuff! There are restrictions on how much contact one can have when working with beryllium. It would be best avoided-----but some research on the fluid in question may be in order. It may not be beryllium.

Harold

 

[solar_plasma]

Still having 30 pieces of those TO-3, each weighs 20g, and I wonder, if they are worth to process. I am sure, I can do this safely, now, but if there is not enough gold to recover, I will save them and maybe sell them later on.

The plating seems quite heavy and I read on the forum, that a good part of the value will be found in the Au-Si solder. On the other side the base is made of thick massive copper...a lot acid needed. Has anyone any idea, what they would yield? I have searched for TO-3 a long time now on the forum.

The number is GFT 4112/30.

 

[Lou]

We usually run those as a melt lot. Pretty good IIRC.

Lou