# Contacts left overs after AP and nitric



## Slochteren (May 26, 2015)

After processing +/- 400 small contacts, most from relais, this is left after precessing first with ap and then with nitric. Looks like Gold foils but are there relais used with gold plated contacts? There are also 2 or 3 complete contacts, i assume that is thunsten.


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## shmandi (May 26, 2015)

Many relays can have gold plated contacts. Also gold plated silver.


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## Slochteren (May 26, 2015)

A nice, a litle bit bonus gold.


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## Geo (May 26, 2015)

Some contacts have gold plating. Especially small micro-switches. Going from AP to nitric means you more than likely have some dissolved gold in your nitric acid. If you cemented the silver on copper, you have have gold in your silver. Always roast the points to red hot before the nitric acid bath.


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## Slochteren (May 26, 2015)

Ok, roasting the points to get rid of the hcl to prevent Ar in the nitric. Because it are contacts how about the CA in it?
I'm not that far but would the gold be left in the filter of a silver cell?


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## Geo (May 26, 2015)

The Cd will stay in the solution. The gold will be in the anode slimes from the silver parting cell.


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## richard2013 (May 26, 2015)

Hello all isn't it that Cd will dissolve in AP or HCL wash?


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## Geo (May 26, 2015)

It stays in the nitric acid after cementing the silver.


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## Slochteren (May 27, 2015)

After examining the cemented silver i notice there are also gold foils in it. Just ignore them and melt them with the silver and get it back wenn running it thru the silver cell or is there a way to get them out before melting?

Paul


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## Geo (May 27, 2015)

If you are going to run the silver through a parting cell, there's nothing else you need to do but make the anode bars and proceed. You may be able to digest the foils out of the silver with HCl/Cl but it will be contaminated with silver and it most likely isn't a great quantity to begin with. Considering there may already be some gold in the cemented silver, the foils wont matter all that much.


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## Geo (May 27, 2015)

This is some small contacts I did as an experiment on. The small button points is gold plated.


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## nickvc (May 27, 2015)

Much of the profit from refining comes from bonus metals that weren't expected or needed paying for, the skill is making sure you actually do recover them, hence stockpots and the use of silver cells, little bits add up over time and can be an unexpected bonus when eventually recovered 8)


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## Anonymous (May 27, 2015)

Slochteren said:


> Ok, roasting the points to get rid of the hcl to prevent Ar in the nitric. Because it are contacts how about the CA in it?
> I'm not that far but would the gold be left in the filter of a silver cell?



Why would you roast points that you know have Cadmium in them? 

I'm thinking safety here. If you have a full fume hood set up with the relevant scrub for Cadmium then I'll step away respectfully but if you don't I would suggest you rethink this method.

Regards

Jon


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## Geo (May 27, 2015)

Jon, I certainly respect your respect of all things toxic But if risks were never taken, all of the ewaste in the world would be sealed away never to see the light of day again. I have sweated off many pounds of contact points in the years I've been recovering and recycling and can tell you there's a right way and a wrong way. The right way is of coarse to wear your PPE's and keep your work space clean. Next is is to only heat the points enough for the solder to melt. If at any time you get it hot enough to smoke, it's too hot. Collect all solder beads. Never saw or grind contact points. Never hold the torch to sweat off points. Set the torch stationary and hold the buss with one hand and something (screwdriver) to push the point with. When the solder is hot enough to melt, the point will slide right off with no smoke. I heat the copper buss instead of the point to keep from melting the point. If you heat below the boiling point of Cd, there should be little inhalation danger but still always protect yourself just in case.


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## Anonymous (May 27, 2015)

Thanks Geo I appreciate the words and the sentiment behind them mate.

You know as well as I do that constant low exposure to NOX fumes is a cumulative effect. It's one of those things that builds up damage over time and messes things up later in life, whereas inhaling a couple of Cadmium webs isn't anywhere near as forgiving. If we can educate people on those lines then I'm a happy bunny mate.

Jon

edit for grammar and context


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