Methods of processing this

[johnny309]

Need to process the following resistors in the word document you have the data sheet:
1.ceramic substrate alumina ceramics
2.Ag-Pd layer
3.carbon
4.legs for the resistor made of copper
5.solder Sn-Pb
6.resin that would withstand heat

As I found from here....http://www.substech.com/dokuwiki/doku.php?id=alumina_ceramics........ the ceramic substrate wouldn't be atacked by acids.

So,my question is .....how to process them?

Cuppelation seems the best way,followed by nitric.......but I'm taking in cosideration grinding them and let them slowly dissolve in AP.

Too much metals involved...Cu,Sn-Pb alloy,Ag-Pd alloy.

 

[patnor1011]

How many of them do you have?

 

[johnny309]

They are different in size,yealds could not be determined by weight,so is not the point.
On the other hand,harvesting included trimmed legs and new resistors from the box with the terminals still intact.And it's a problem with different years of productions.
A "skittles" so to speak.
The amount I dont think matters and for the time been I'm still harvesting.
Let's say is in a range of 10' of pounds.

 

[butcher]

Johnny I assume you are positive these are resistors and they do contain silver and palladium.

They look like capacitor packages to me, and I cannot make out the numbers and letters from the photo to see if I can recognize them.

The document was also in a language I do not understand.
I think I would separate the copper legs, grind them to powder dissolve in nitric acid and cement with copper buss bar.

But before doing the Whole lot I think I would dissolve just a few and then test for silver and Palladium, just to make sure I was not wasting acids. On these devices

Other members may have a better suggestion

 

[johnny309]

Tks Butcher'
The reason is(the language of the document) is the resistors in question was produced only in Romania.......
Ag-Pd is often used in this in a procentage 80/20(on this layer....meaning part 2,not the whole product) .
The main problem I have processing directly with nitric is the large ammount of copper terminals(by weight) and the solder(Sn-Pb).
For this I searching options here.

P.S. :in the document is a description of layers......I translate this in english in my first post ....point 1 to 6.....from the word document.

 

[butcher]

Sorry I did not see the lead and tin in your product, you are very correct they would give you trouble with the nitric solution, I am glad you caught that.

well after separating the bulk of copper mechanically, crush and roast them, this will help oxidize the base metals, after cool boil in HCL the silver will not dissolve, if palladium did it will cement from solution on copper, tin will be dissolved, I would then decant solution, then rinse out lead salts with boiling hot water, when no more lead is removed (letting hot water rinse cool in another jar will precipitate the lead from the water when cooled)and then these powders neutralize them with sodium hydroxide wash out salt water formed and then again incinerate powders, then you can proceed to nitric acid and cement on copper.

I do not mess with palladium much so another member may have a better method to deal with these.

 

[patnor1011]

I disagree with your reply. Amount is important if you want to choose economical and proper procedure.

 

[johnny309]

Sorry Patnor.....let's come up with 2 scenarios:
1. big weight( I don't what this would be)....the proper procedure.
2. little weight...couple of pounds....again asking for steps.

Combining them(this 2 procedures) for the goal,and the chemicals in hand it's up to economy costs involved,because nitric cost,you are allowed to burn stuff,etc....

 

[tlcarrig]

Sorry but they look like capacitors to me. I agree with butcher. 5 years Air Force electronic technician. 30 years office machine repair technician. Just MHO.

 

[johnny309]

Let's take down in the fabrication procedure of this:

A substrate of alumina ceramic,to the left and right is place 2 pads of Ag-Pd alloy(80/20)...and between those 2 pads is a layer of graphite who make the resistor.The terminals(Cu+solder) are soldered to the pads using Sn-Pb solder and the entire assembly is imerssed in a heat resistent resin.The value of the resistor was trimed to the desire value using LASER(ajusting the width of the carbon pelicula between 2 pads).
The benefits of this type of resistor was that it had low tolerance(1%) ,good temperature stability and the elimination of the inductive effect.
Is the ancient one of the modern days cip rezistors(SMD).

Thank you Butcher and aslo thank you Pesco(http://goldrefiningforum.com/phpBB3/viewtopic.php?f=34&t=10838).....just combining them and lerning "on the hard way"......
And many tks to this forum......and the men that keep running: Noxx,Steve,GSP,Harold,Partnor,lou,Oz,Freechemist,Arthur,Manuel,Telcu...Thank you all and I'll try to give something back....