Trash to stash!
- Thread starter Acidrain
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Thank you for the detailed process description.
You could've just asked lol...
I covered the filters and crucible with HCL, put the beaker on the hot plate and once warm, started adding nitric acid slowly. I maintained a rolling reaction until finished. Then I let the solution cool to outside temp (quite cold here this time of year) and settled overnight. In the morning I decanted most of the solution into another beaker, then plopped the "filter pulp cake" into a buchner funnel and vaccuumed the liquid through a #1 watman filter, rinsed well with clear water, changed filters and vaccuum filtered the solution that was decanted.
To drop gold, I put filtered solution in a 1L beaker and back on the hot plate, just under simmering, placed a copper plate in the beaker and added a half tsp sulfamic acid, stirring the solution back and forth with the copper plate. Once the solution was a nice clean brown, I did a stannous chloride test to confirm all gold dropped. Then I force cooled solution in an ice water bath, removed copper plate, covered the beaker and let settle overnight.
Then I decanted most of the solution, added fresh cold HCL to soak, decanted, water washed the powder, then an HCL simmer, then more water washed, then simmered a few times in water, then cold water wash until neutral PH reading. I then collected gold powder and melted into a button.
I didn't have time to write all that when I posted pics....I always enjoyed recoveries from as you call it junk especially when I’d been fairly happy with previous results , it frequently took some time and the resulting values were frequently very small , I guess we all like that something for nothing feeling.
kurtak
Well-known member
When you are cementing gold (or other PMs) with copper there is no need to use sulfamic acid
The primary reason we use sulfamic is to de-Nox a solution (get rid of any "free" nitric in the solution which prevents precipitation with chemical precipitants)
When cementing (precipitating) gold (or other PMs) with copper you don't need to worry about the free nitric because the free nitric goes to work at dissolving the copper which in turn uses the free nitric up - so there is no need to "de-Nox" with sulfamic
In other words - copper not only uses up any free nitric (by dissolving copper) but also cements out (precipitates) the gold --- so no need for sulfamic to get rid of free nitric as the copper automatically uses the free nitric up
Kurt
haveagojoe
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Would sulfuric be appropriate? The other reason sulfamic is used is that it converts into sulfuric which preciptates any lead as lead sulfate; I would imagine that if no free nitric is present then the sulfamic would not convert to sulfuric, but I would think that a small addition of sulfuric itself could be beneficial? Although in this case I would guess that any lead in used filters would probably already be as lead sulfate...
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Hey Kurt,
The reason I use sulfamic acid in this scenario is not to "denox" so to speak. I use it in a method Orvi taught me where we use the combined action of sulfamic acid and copper to drop gold. The goal here is speed. There is quite a bit of unused nitric in solution and the reaction is run hot, just under simmering and if you put just the copper into the solution it reacts violently and erupts out the top of the beaker (learned that the hard way). The sulfamic acid is used in a small amount just to kill enough of it that red fumes are not produced and the foaming is kept minimal. Gold is forced out of solution very fast over the course of about 15 minutes vs cementing valuables cold overnight with air circulation to stir the solution. The way he taught me is absolutely my #1 favorite recovery method and I use it exclusively now because of how fast it is while using a minimal amount of nitric acid. I can have recovery finished in around 5 hours this way from start to dry powder in the beaker.
I wish I knew how to share a link with you to his process, it's quite fantastic and works exactly as he describes.
haveagojoe
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If you have the post, at the top of it in the grey bar there is an icon with 3 circles linked together, clicking that will give you the url for the post which you can copy-paste.
@kurtak , @haveagojoe ... here is the post.
Post in thread '~15lbs of gold plated pins.' https://goldrefiningforum.com/threads/15lbs-of-gold-plated-pins.34142/post-373811
Post in thread '~15lbs of gold plated pins.' https://goldrefiningforum.com/threads/15lbs-of-gold-plated-pins.34142/post-373811
Last edited:
haveagojoe
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Yikes! That's pretty wild. Thanks for linking. Not sure I have the confidence to try it just yet though!
It's pretty advanced and you really have to stay on top of it. It's the most amazing, beautiful and fun reaction though and super fast.
@orvi is amazing! I had to upscale to 5L beakers to make it worthwhile.
Thanks for teaching me how to share a link!
That is not what Kurt said.
Read it again.
haveagojoe
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I know. Kurt was saying about the use of sulfamic for denoxing. I was saying what about dealing with the lead.
Maybe when precipitating with copper we don't need to worry about lead?
A drop or two with Sulfuric never hurts. But it has to be done and filtered before any dropping of values.
For the cementing process the Nitric is beneficial.
This is a reliable method, I use it myself.
only my precipitant is iron sulfate.
I would also like to add that precipitation with copper powder requires skill and this method is for more experienced refiners.
in my understanding, you need to learn how to work efficiently and easily using classical methods before moving to a higher level.
haveagojoe
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Yes of course I do, but I don't see the harm in learning about the different methods and trying to understand new processes when they are posted. It helps me to get a clearer picture of how the elements are interacting and how they behave. I can see this is an advanced method, and I am very aware that there is no substitute for practical experience; certainly for now I stick to HCl-bleach and SMB and I do everything cold. I am a hobbyist, I don't have a fume hood and I don't have access to enough material to practice a lot, I just want to learn as much as I can so that one day when I have a chance I will not be clueless.
Anyway this one is not about copper powder, Acidrain used a copper plate. I am interested in cementing with copper as it's something I can use in my process as an alternative to SMB, but I would use it cold- I don't think I will be trying Orvi and Acidrain's turbo method any time soon!
this method is the ORVI method, a preliminary step to precipitation using all copper.
it is convenient for dirty solutions, in which there are different raw materials.
for example:
it is difficult to calculate the exact amount of nitric acid when you dissolve transistors with metal caps, from different manufacturers.
and also in the glass there are pins from connectors and ceramic microcircuits + gold-plated gears from watches.
and the like.
copper simply helps to denoxify the solution..... well
and precipitate faster.
it is convenient for dirty solutions, in which there are different raw materials.
for example:
it is difficult to calculate the exact amount of nitric acid when you dissolve transistors with metal caps, from different manufacturers.
and also in the glass there are pins from connectors and ceramic microcircuits + gold-plated gears from watches.
and the like.
copper simply helps to denoxify the solution..... well
and precipitate faster.
kurtak
Well-known member
Thank you for posting the link & I read that post from orvi when he first posted it
Side note; - orvi is "one" of my favorite members - he & I have had MANY privet discussions
I do not have time to post a real reply right now - but - I can tell you that with copper cementation you simply do not need to use the sulfamic - it doesn't hurt to use it - it just is not needed
For what it is worth - for the last 10 years copper cementation is just about the only way I ever drop my gold (like 95% of the time) & I have turned out MANY troy ounces 999 gold with copper cementation --- I am currently sitting on 5 ozt 999 gold from copper cementation & recently sold 4 ozt 999 gold from copper cementation
Will post more if/when I get more time
Kurt
