Preparation for refinement

[Alexander_Hun]

Hello!

After more than a year, I am refining gold again, I am attaching a few photos of what the raw material is like. I have never processed such a large batch before, it was a lot of work. They were all military connectors, a small percentage of them were new, unfortunately I didn't soak the rest in hydrochloric acid so that they would come off on the soldering iron, which is unfortunately the reason for this dark color.
Is it possible that the tin stuck to the gold-plated pins in the hydrochloric acid? Many pins are partly silver, but I tried it in nitric acid and the gold plating on it is flawless..
Is it worth cleaning them somehow before refining?

The whole thing weighs 2507 grams, I'm very curious about the final result

(I'm using a translator, sorry if there are mistakes)

 

[Alondro]

If you soaked them in HCl for a long while, there's no chance tin could be left if it's typical solder. If it was only a short soak, especially at a low temperature, then some tin could still be present.

However, you say these are high-grade military scrap, so the solder could be tin-silver alloy, which would not dissolve very well in HCl.

 

[Alexander_Hun]

If you soaked them in HCl for a long while, there's no chance tin could be left if it's typical solder. If it was only a short soak, especially at a low temperature, then some tin could still be present.

However, you say these are high-grade military scrap, so the solder could be tin-silver alloy, which would not dissolve very well in HCl.

Hello!

These pins, together with the connector, were soaked in hydrochloric acid, where they are tight in the plastic, some of them have a shiny metal color.
I wouldn't dare say silver, it's quite an old material, silver wasn't used much then.

 

[Yggdrasil]

Hello!

These pins, together with the connector, were soaked in hydrochloric acid, where they are tight in the plastic, some of them have a shiny metal color.
I wouldn't dare say silver, it's quite an old material, silver wasn't used much then.

I believe Silver and it's solders has been used since before digital electronics, so it can easily be Silver.

 

[Alexander_Hun]

I believe Silver and it's solders has been used since before digital electronics, so it can easily be Silver.

Hello!

Be that as it may, they did not regret the quality in the industrial or military line. In fact, in terms of gilding, they gilded things that I can't understand, here in the picture you can see that whole screws, but even the screw nut was gilded at the end, the washer was also gilded..... They were crazy

 

[Martijn]

Hello!

Be that as it may, they did not regret the quality in the industrial or military line. In fact, in terms of gilding, they gilded things that I can't understand, here in the picture you can see that whole screws, but even the screw nut was gilded at the end, the washer was also gilded..... They were crazy

It's another quality assurance. Screws not corroding means overall better performance, easy change out of components and longer life all toghether, because there is no rust working its way into other parts of a device.

Some parts are still made that way.

Not consumer devices, that needs periodic replacement for several reasons.

Edited for spelling

 

[kurtak]

I am attaching a few photos of what the raw material is like.

Nice looking pins

They were all military connectors,

Good chance (or not) that those are in the 3 grams per pound type (instead of the normal consumer type that only run 1.5 grams per pound)

These pins, together with the connector, were soaked in hydrochloric acid,

Then you have removed the VAST majority of the tin - any remaining "traces" of tin will likely come out in the rest of the refining process

particularly - if you use the CuCl2 (AP) to recover the foils the trace tin will be eliminated - if you use nitric to dissolve base metals to recover foils - most if not all trace "stannic" tin created by the nitric will wash out when you wash the chem out of the foils

IMO - what I see in the pics - you are ready for the next steps in the refining process

Kurt

 

[Alexander_Hun]

Hi, in 2022, 600 grams became 7.7 grams of this type, but it is mixed. Or it includes something that is very good, probably adding significantly to the final amount.
But I have an older post here, where, if I remember correctly, 600 grams became 21 grams, these military things are tricky, in the end you will find out how much.

 

[kurtak]

However, you say these are high-grade military scrap, so the solder could be tin-silver alloy, which would not dissolve very well in HCl.

That kind of depends on the percentage of silver in the solder alloy doesn't it

At 6% or less silver it should be little to no problem

up to 8% = somewhat problem

over 8% becomes more of problem

Most solders with silver used in electronics are 6% or less

There are of course exception to the rule

Based on the pics I don't see any indication of silver - at least not significant enough to be concerned about

Kurt

 

[kurtak]

Hi, in 2022, 600 grams became 7.7 grams of this type, but it is mixed. Or it includes something that is very good, probably adding significantly to the final amount.
But I have an older post here, where, if I remember correctly, 600 grams became 21 grams, these military things are tricky, in the end you will find out how much.

WOW that is REALY GOOD recovery

The best I have ever seen is 5 grams per pound (or 11 grams per kilo) those came from microwave telecom gear (not microwave ovens)

GSP (Gold Silver Pro) once talked about pins with insane high recover - don't remember numbers he posted but it was insane high - so they are out there

Please do post your results when you are done

Kurt

 

[Alexander_Hun]

WOW that is REALY GOOD recovery

The best I have ever seen is 5 grams per pound (or 11 grams per kilo) those came from microwave telecom gear (not microwave ovens)

GSP (Gold Silver Pro) once talked about pins with insane high recover - don't remember numbers he posted but it was insane high - so they are out there

Please do post your results when you are done

Kurt

Hi, I'll post pictures when I'm done with it, this is my own record so far:

link

 

[kurtak]

Hi, I'll post pictures when I'm done with it, this is my own record so far:

link

Awesome - can't wait for the results

And thanks for the link

Somehow I missed that thread when you posted it

Kurt

 

[nickvc]

The best e scrap I ever refined ran around 70 grams a kilo if I remember correctly it was many years ago , I never knew where it came from or it’s application but it was like refining gold clad material , I believe it was over kovar so I’m guessing military application on something that had to work come what may.

 

[Alexander_Hun]

The best e scrap I ever refined ran around 70 grams a kilo if I remember correctly it was many years ago , I never knew where it came from or it’s application but it was like refining gold clad material , I believe it was over kovar so I’m guessing military application on something that had to work come what may.

Hello!

That's very nice!! Here we are, and where you can still find the military things produced by the former Soviet Union. Gold-plated things are very good, there is a lot of gold in them. In general, the military stuff is good, but the Russian stuff is crazy.... Unfortunately, my country also belonged there until 1990, although it wouldn't have been that way.....

 

[nickvc]

A large amount of Soviet era electronics were very heavily plated and even had platinum and palladium in them in decent amounts again it just had to work , cost was not that important, look for telecom gear and early computer parts, again I have treated some of this stuff and the foils were incredible and solid.
The material I treated was from the uk I believe we had it twice and it was crazily heavily plated.

 

[Martijn]

Here we are, and where you can still find the military things produced by the former Soviet Union.

There seems to be a large junkyard of old sovjet machines growing in eastern europe, supposedly.

 

[Alexander_Hun]

There seems to be a large junkyard of old sovjet machines growing in eastern europe, supposedly.

I'm in the middle of Europe Unfortunately, there are fewer and fewer such ingredients here

 

[Thomas M Joseph]

Military plating by class in microinches of plating thickness. 1 microinch = 0.0254 microns. So the range of gold may be from gold flash to gold plated to gold filled depending on application. Corrosion resistance(thin) to friction wear(thick). The screw things look very good, the other stuff is a mixed bag. Hope this helps you to evaluate your material.

Class 00	20 µin
Class 0	30 µin
Class 1	50 µin
Class 2	100 µin
Class 3	200 µin
Class 4	300 µin
Class 5	500 µin
Class 6	1500 µin

 

[Alexander_Hun]

Military plating by class in microinches of plating thickness. 1 microinch = 0.0254 microns. So the range of gold may be from gold flash to gold plated to gold filled depending on application. Corrosion resistance(thin) to friction wear(thick). The screw things look very good, the other stuff is a mixed bag. Hope this helps you to evaluate your material.

Class 00	20 µin
Class 0	30 µin
Class 1	50 µin
Class 2	100 µin
Class 3	200 µin
Class 4	300 µin
Class 5	500 µin
Class 6	1500 µin

Hello!

Thanks, the rest are better too, only a bit dirty after the hydrochloric acid, the screwy things are new and they weigh a lot. For me, the main thing is many small parts with a large surface area.

I am attaching a picture, the others look like this when they are new and do not need to be put in hydrochloric acid

 

[Alexander_Hun]

I have a question, I am now switching from urea to sulfamic acid. They say that when using sulfamic acid, a little sulfuric acid is produced, which is good because the lead precipitates. My question is, after adding sulfamic acid, should I filter the solution again before adding SMB? Thanks!