Electrical contacts
- Thread starter Reggy
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Ok opened a couple of these up found these inside, look Au/plated definitely not magnetic
do not remember what kind of board they came off. There was a copper coil in there as well. They have 8 pins
You are confusing berylium copper and beryllium bronze.
bronze contains tin.
and it's really evil when you dissolve it with acid.
but if you dissolve the entire lever, then everything will go into solution, leaving a golden button.
kurtak
Well-known member
That is not quite true - though most common bronzes contain tin & there are several tin containing types of bronze (alloys) but not all bronze contains tin - what makes bronze (a copper alloy) bronze different from brass (also a copper alloy) is the physical characteristics of the copper alloy - characteristics such as tinsel strength, hardness, wear etc. etc.
Example; - bronze is generally harder then brass
So they can alloy copper with various different elements to produce copper alloys with bronze like characteristics that are classed as bronze but contain no tin
Beryllium bronze is one such bronze that has no tin in the copper alloy
https://www.buckcopper.com/news/wha...nickel, chromium, titanium and other elements.
I believe aluminum bronze is another bronze that has no tin
I believe (but could be wrong) that the evil you are talking about here when dissolving the common tin bronzes with nitric is the nasty meta-stannic acid (white tin paste) that is a real pain in the butt to filter out of the solution as some of it does not like to settle well - & the ultra fine stannic tin particles (at least some) tend to go through filters & if you have a lot of it the ultra fine particles plug the filters making it near impossible to filter even with vacuum
You may be talking about phosphor bronze - which is a bronze alloyed with tin & is a bronze commonly found in electronics
Kurt
I believe he means the Beryllium.
Proffshuggarn
I know it’s out there, somewhere..
kurtak
Well-known member
Sorry for the delay in getting back to you on these relays - those are exactly the relays I thought you were talking about --- I processed two & a half 1 gallon ice cream buckets full of those this last summer
IMO - for the amount of work involved to process those relays to recover the gold from the points in them I consider them LOW yield - only got about 1.5 grams gold
The points in those relays are not solid gold they just look like they are (when you look at them with a 10X jewelers loop still mounted to the reed/bus bar) they do however have a gold "cap" on them that is thicker then plating - about the thickness of gold filled (maybe "a bit" thicker)
After dissolving them in nitric the gold cap you get in the bottom of your beaker is only about one tenth the thickness of the actual point (which is VERY tiny to start with)
Also - I am not sure what the rest of the actual point is made of - but when you first put them in the nitric a black ink starts to ooze out & tiny little fibers start to expand out of them - it takes awhile in the nitric but both the black ink goes away (first) & then the tiny fibers dissolve away --- "maybe" some kind of carbon fiber ???
Per the bold print - the reeds (or bus bars) are absolutely beryllium copper (or beryllium bronze) so IF (the BIG IF) you are going to process those you want to nip the points from the reeds as close to the point as possible to minimize the amount of beryllium you are putting into solution --- you need a "small" - "sharp" nippers
That certainly works but trust me if you try that with a gallon or 2 ice cream buckets full of them you will have a very sore/stiff hand
I found that smacking them with a hammer works better - it cracks the outer shell like an egg shell & the shell then peels right off
Kurt
kurtak
Well-known member
That could be but he talked about tin then said --------
which is why I said -------
Kurt
I meant tin, perhaps I did not process modern relays with bronze to which beryllium is added.
In any case, on forums and on YouTube, in the segment of the former USSR, I have not heard or read about the difficulties with beryllium in solution.
Tin is a problem, everyone knows that.
however, with such small relays, manually, this is work for the sake of work....
In any case, on forums and on YouTube, in the segment of the former USSR, I have not heard or read about the difficulties with beryllium in solution.
Tin is a problem, everyone knows that.
however, with such small relays, manually, this is work for the sake of work....
I do not think there are difficulties, just exceedingly toxic.
https://www.ddr-rft-elektronik.de/fundgrube-fuer-bastler/ddr-rft-relais-0370-001-00024-sa-23-auni-5/What is that wonderful “thing” with the German “coil”?
/Dennis
I know about its toxicity.
But it poses the greatest danger to people involved in its mechanical processing.
Turners, milling operators, machine operators.
The paradox is that by cutting the relays mechanically, you are at greater risk than by throwing them into the solution.
After all, no one would think of breathing acid vapors.
And in that “fox tail” from nitric acid, the danger of berylium is much less than other dioxides....
Yep, I just assumed they were beryllium-containing and go out of my way to cut off as much of it as possible.
I suppose they just looked solid, since I did my test dissolve of the little gold contacts in HCl. It did make a slightly greenish solution. Hmmm... a black nitrate... it might be one of the initial less stable hydrates of nickel nitrate, which then changes forms and dissolves. That would make sense since the chloride hexahydrate of nickel is pale green.
If it's nickel, even a tiny plating, then the contacts should be at least weakly magnetic. I'll check! (after test) Well, a few of them were magnetic, and some of the larger button types were as well. But most of the tiny contacts had zero magnetic attraction, even to the strongest magnet I have.
So it can't be pure nickel on most, at least. Maybe nickel chromium alloy? Chromium nitrate is very dark-colored. What the fibers are, I have no idea. I didn't watch the initial test too closely, just let it react for a couple days.
Golddigger76
Well-known member
I just processed some relays exactly like these and got a nice amount of gold but I didn't weigh the recovery gold before I combined it with the first refined gold from 3 other projects that I was working on and refined them for a second time together.
Interesting. That might be why mine looked so solid, as that alloy wouldn't react at all in HCl.
When I do the full batch, nitric acid will be the way to go, in that case.
