Melt pins before nitric or not?

[Nickperl]

I learned, I assume from here and Hoke, to melt the pins I refine first before using the 50-50 nitric and water over medium heat. Am I under a wrong assumption? I melt them and drop into a large bucket with a stainless bowl at the bottom for forming larger (and faster) surface area of the material. Are there other reasons? I found Hoke mentions it on page 33 as "if necessary". It was asked in another forum why I melt the pins first and not just go straight to nitric? Thanks, Nick

 

[jimdoc]

I learned, I assume from here and Hoke, to melt the pins I refine first before using the 50-50 nitric and water over medium heat. Am I under a wrong assumption? I melt them and drop into a large bucket with a stainless bowl at the bottom for forming larger (and faster) surface area of the material. Are there other reasons? I found Hoke mentions it on page 33 as "if necessary". It was asked in another forum why I melt the pins first and not just go straight to nitric? Thanks, Nick

Hoke never worked on pins or any computer scrap.
Don't melt them. Study the forum.

 

[FrugalRefiner]

I agree with Jim.

Dave

 

[Nickperl]

Thanks.

 

[butcher]

Page 33 in Hoke's book is discussing high-grade yellow gold scrap without PGM's and excluding any low-grade material like electronic pins with solder, cheap jewelry or other low grade or problematic metals like tin or mercury...

 

[Martijn]

Welcome to the forum Nick.
You need to study a lot more.
Don't waste large amounts of nitric to base metal digestions. You'll only create more waste water to handle and dispose responsibly.
Study dealing with waste in the safety section.
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=47&t=1300

Nitric won't attack base metals if they are covered with gold.
If you melt pins, one way to go would be pouring it into anodes and electrorefining the copper and treating the anode slimes.
Study electro refining copper

Do the pins have solder on them? Then don't treat with nitric. It can create a difficult to handle substance called tin paste. Learn how to avoid that.

Another way can be the gold stripping sulfuric cell.
Dangerous process, it uses concentrated sulfuric acid.

Before you are going to use any acid on metals, start with small tests and dealing with waste or reuse of created solutions.

But study first. Learn safety precautions and read the MSDS of the acids you are going to use and of the fumes and metals in the solutions you will create.


A good place to learm from others is the help needed section.
https://goldrefiningforum.com/phpBB3/viewforum.php?f=49
Others have had the same problems with the same material. Read them and try to understand whats being discussed. You will see things different if you spend some time in studying.

Good luck, have fun and be safe.
Martijn.

 

[Nickperl]

Thanks, Martin, your answer was helpful. I always though I was doing just that, melting the gold plated contacts then dropping in water to make flake or small buttons to help the nitric attack it faster, rather than just tossing all the pins into a beaker and dissolve that way. Yes, I agree, reverse electroplate would be best, I just never pursued it. I now focus mostly on the hundreds of gold filled old fashioned eyeglasses I've collected over the years, and I do melt those first since there is so much stainless in them. Again, thanks.

 

[kurtak]

I always though I was doing just that, melting the gold plated contacts then dropping in water to make flake or small buttons to help the nitric attack it faster,

DO NOT DO THAT - doing that will cause the gold (which is VERY LITTLE compared to the amount of copper/brass) to alloy with the copper brass --- then when you dissolve the copper/brass SOME of the gold will be so fine it will not settle (stays in suspension) which can lead to losing gold

I suspect what you heard about melting & then pouring to shot (corn flake) was suggested as "one" way to deal with the so called "gold drops" sold on Ebay

The "gold drops" sold on Ebay are pins that have "already" been melted into large "blobs" &/or poured into bars

RE-melting those "gold drops" & pouring them to corn flake then dissolving them in nitric would be "one way" (but not the best way) to deal with the so called "gold drops"

If you are going to use nitric as the method to recover the gold from gold plated pins then do it WITHOUT melting them - just dissolve the pins "as they are" so you can recover the gold plating as "gold foils"

It is MUCH EASIER to recover/filter/wash the gold foils - then trying to recover/filter/wash the "ultra fine" gold "dust" created by melting the pins "before" treating with nitric

Kurt