Terminal ends?

[pimpneightez]

I have a bunch of terminal ends from copper wiring. They are plated with some kind of silver metal. I assume they will fall into two categories tinned and silver plated. When I get to the reclaimation stage can I process them all together or will it be advantagous to seperate out the tinned terminals? Seems like it would be way too time consuming to test every little terminal for silver content. I also have a boat load of plated copper and brass things That I have been saving for a long time. Mostly from electrical type scrap. Could these items be plated with anything else besides tin and silver? I.E lead? Is there an easier way to tell the type of plating other than proper testing?

 

[Geo]

a simple fix would be to place one in 32% hcl acid (just enough to cover the plated part) stand a peice in a beaker and add the hcl and then let it sit for a couple of hours and see what happens.

 

[pimpneightez]

I am assuming if its tinned the HCL will react with the tin making it oxidize. If its Silver plate the HCL will have no affect. Through my powers of interpretation If I take all the items that I have with the unknown plating and start them in a HCL bath I would be able to tell wich ones are tinned and wich ones are silver. As long as I have only those two types of plated items. The tinned plating should go into solution leaving only the base metals behind. Am I going in the right direction with my assumptions?

 

[Smack]

How many pounds do you have?

 

[Geo]

exactly, tin will dissolve and silver wont.

 

[pimpneightez]

I have about 50 pounds of assorted high voltage electrical contactors,terminal blocks,terminal ends,relay parts.pretty much anything that had a silver type plating on them. Pretty much nothing is the same. Just an assorted mess of electrical parts.

 

[pimpneightez]

Just did a few parts in 37% HCL. For a hot sec I saw a cloudy milk color.a rust type color to clear and some light smoking.

 

[Geo]

if you have any solids in the bottom of your vessel, it could be a couple of different things. some solder is silver/tin mix and the silver will settle as a dark powder when the tin is dissolved. silver will not dissolve in hcl alone so what ever is making the white precipitation isnt silver.

 

[pimpneightez]

It's been about two hours and most off the pieces are still silver. All but the smallest terminal end wich looks tarnished.there is some small black sand type sediment on the bottom. It still has some light smoking. What would this be? I'll have before and after pics this weekend.

 

[pimpneightez]

Well it looks like 80% of the tested material is silver plate. One small contactor was tinned HCL showed brass underneath. One large terminal basically just dulled. Now looks a lead color. What can that be?

 

[Geo]

the dull color could be the tin or maybe a little antimony plating back onto the copper.

 

[pimpneightez]

Intresting, Are you pointing towards the solder on the contactor. Are you saying the antimony would migrate Through the HCL re-plating the exposed copper? I know tin is similar to antimony. Anyway this method worked perfect. Can this be used to retrieve gold foils?

 

[Geo]

the process of removing gold foils with hcl acid is called AP (acid peroxide). the gold will not plate back to the copper but some metals will for a short time. during the AP process if an excess of peroxide is use in the solution a very small amount of gold may dissolve because of all the free oxygen in solution and when this occurs the gold will plate back out as black powder on the copper and will fall to the bottom of the vessel.

and the reference to the tin or antimony in my other post its not the same as the original plating but more of a cementing effect thats still described as plating.