Video discussion. Gold recovery from 14kg of CPU by using the lead bath method.

[Martijn]

SS cage works as long as its not fine mesh. Too fine of a mesh and the "pores" gets clogged by the solidified litharge.

This is the latest lead bath I did:

Great feed back and great video showing some mistakes and learning points! Those are the best imo letting people learn from your mistakes.

 

[Martijn]

@Owltech ;
How do you experience the lead fumes, if any? Are there a lot fumes or is it a negligible? Do you wear a mask?
Do you reduce the lead oxide back into metal after cupelling?

 

[Martijn]

I just saw you wear a mask in the video. So something to keep in mind when I start experimenting.
I was wondering if the button with silver and gold can be put in the silver cell after cupelling.

 

[Owltech]

@Owltech ;
How do you experience the lead fumes, if any? Are there a lot fumes or is it a negligible? Do you wear a mask?
Do you reduce the lead oxide back into metal after cupelling?

Lead fumes are a nasty thing, use common sence and a mask rated for welding fumes, change your clothes before and after work, wash yourself after work with plenty of soap, position yourself so the wind is at your back, don't exceed the needed temperature. A mobile weldig fume extractor should be more than enough to deal with the fumes from small batches like mine. I never experienced any health problems, but it's never too late. I drink 2 liters of milk every day, but thats because I'm loving it, some old folks say it helps for heavy metal poisoning.

Yes, reduction of litharge to lead easily done with a source of carbon

 

[offtrailhiker]

In a back yard, a respirator on a windy night!

 

[4metals]

(I read somewhere that they started adding silver to solders to inhibit the solubility of gold, which is the opposite of what I'm trying to achieve).

Many years ago I worked in a connector factory and learned one of the major reasons for failure of solder joints was the formation of gold stannate in the solder joint which was brittle and often suffered from stress fractures. The solder was tin lead. The solution was to switch to a silver based solder that did not form the brittle alloy as there was no tin in the solder. I think that is what the reference to gold solubility was about, not solubility as much as not forming brittle joints prone to stress cracking.

I like throwing the Silver in while stripping the gold as it is actually a refining step if the Silver you add is sterling Silver. Either way it is a good way to process these chips. On a large scale the lead would cause environmental and health issues though.

 

[Yggdrasil]

If one ramped up the exhaust system.
Could this be suitable for running chips directly?
Maybe just pyrolyzing?
The Carbon is useful for the Lead Oxides after all.

 

[4metals]

In the US the dangers of lead exposure seem to make its use guarded. However they never give assayers a hard time. And for years millions of cars, hundreds of millions of cars, burned leaded gasoline spraying the tetraethyl lead all over the roads.
Lead fume condenses out of the air quickly and is easily caught in a bag house or a welders fume hood.

 

[Yggdrasil]

In the US the dangers of lead exposure seem to make its use guarded. However they never give assayers a hard time. And for years millions of cars, hundreds of millions of cars, burned leaded gasoline spraying the tetraethyl lead all over the roads.
Lead fume condenses out of the air quickly and is easily caught in a bag house or a welders fume hood.

I was thinking on the VOCs from burning chips directly.
The Lead must be handled correctly of course, but that should not complicate things much.

 

[4metals]

VOC’s are easily handled with an afterburner with a 2 second dwell time. Lead may be harder to be permitted for. Lead recyclers get tons of grief.