Copper powder

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EMRE

Well-known member
Supporting Member
Joined
Apr 17, 2014
Messages
63
Hello all,

I was wondering if anyone has ever used copper powder instead of sheets for cementing pms from wasted AR Solutions? Pros and cons?

Thanks
Emre
 
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=58&t=26245&p=278393&hilit=copper+powder+cementing#p278393


http://goldrefiningforum.com/phpBB3/viewtopic.php?f=50&t=24565&p=259903&hilit=copper+powder+cementing#p259821
 
A few years ago (2014) I was having a problem cementing PGMs (Pd) using solid copper (instead of zinc) from solutions that where "dirty" (the reason for using copper instead of zinc)

4metals got me on the right path by suggesting using copper powder instead of solid copper

here is the thread that discusses the "problem" with solid copper & the resulting solution to the problem using copper powder

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=21218&hilit=cementing

Its a very good discussion about cementing

Kurt
 
I used the aforementioned cu powder for the cementation of pgms from stone removal aqua regia. I think I used a 5 lb batch on about 200 gallons of liquor. Ended up with copper bar that was about 10% pgm content, a good amount of silver and balance copper.

I carefully applied powder to surface of liquid so that it formed a uniform thin layer expecting it to sink as individual particles. I then mixed and tested with stannous. When I achieved a negative stannous, I added the same amount I had added to get to that point and let it sit. It worked wonderfully.

I do now prefer to add cu powder in a glass container, let it settle, then add to waste without filtering. When a good sized chunk of powder made it thru, it was not uncommon to see it actually melt in to the polypropylene barrel some....so I assume I lost some due to adhesion to the barrel wall.

One note, if you have killed off excess nitric with sulfamic, you may see silver sulfide in the melt, so use scrap iron in the crucible to reduce it.

I cannot remember your location, but if you are processing a lot of stone removal lots, you are well ahead to find a consultant to help you get set up with an appropriate technique. It will pay for itself.


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