Gold filled filtrate

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Williamjf77

Well-known member
Joined
Oct 30, 2018
Messages
138
Hello all , after spending the last while reading up and getting myself a safer better set up for refining, I processed some gold filled, not a lot about 300g.

Did dilute hot nitric baths til all base metals dissolved.

Now a lot of the foils broke up to some small flakes which I’m catching in a filter but the sludge in the bottom of the filter is pretty nasty. First it was a grayish dark blue, then pretty black and then started to go purple.( I only have a pretty small Büchner funnel that I have good paper for that will catch everything)

What is the best way to retrieve the foil flakes ?


I was thinking refine the clean part as normal and just accept the rest will be very dirty and need more refining.

Or incinerate the filters with the flakes then treat with Hcl
before AR?
 
It's hard to vacuum filter the residue that is left over from some gold filled components. Especially when stainless or tin might be involved. Gravity filtering is best situated for these situations.
This might give you some ideas.
https://www.youtube.com/watch?v=BmZgunOWiSo&t=210s
 
I ended up processing the clean stuff after I dusted off all the loose foils from all my dried filters into the beaker.

Then took all the rest of filters and sludge and put in dilute AR solution, I’ll probably process that tomorrow.

The gravity filtering makes sense. Although I’m probably chasing a very small amount.
 
A bulk of the gold is in the foils, but the fine stuff adds up really quickly.

It helps to use ripped up filter paper on top of your filter paper. You are fighting with metastannic acid.



Sent from my iPhone using Tapatalk
 
I often add used filter papers to mine near the end of the process. It helps to stop the fine particles from going through the filter as well as improve the filtering where tin is involved. Leave the filters long enough for them break down into the fibers and add them to your filtering funnel.
 
The tin is really a pain.

On another note, after dissolving the clean gold for a second time, the orange AR was crystal clear when hot, then I rinsed the sides down of the flask and ran it through a filter, it wasn’t hot but warm, and after the solution was cloudy. And didn’t get better with another pass through so I precipitated and redissolved. I haven’t checked yet to see if it is clear or not.

The first time I didn’t use distilled water, would that cloud up the gold solution?
 
Silver would be my first guess. I dilute my solution 2 to 3 times with water. If I have 100ml of gold solution I add 200ml to 300ml of water. This will cause the silver to form silver chloride and then it can be filtered out. Before filtering add a few ml of sulfuric acid (battery acid will work) and it will cause lead to drop out. After both treatments then filter. This will leave you a pretty clean gold chloride if filtered until it is crystal clear.
 
Williamjf77 said:
On another note, after dissolving the clean gold for a second time, the orange AR was crystal clear when hot, then I rinsed the sides down of the flask and ran it through a filter, it wasn’t hot but warm, and after the solution was cloudy. And didn’t get better with another pass through so I precipitated and redissolved. I haven’t checked yet to see if it is clear or not.
Click to expand...
Interesting. You had a clear solution before filtration, but cloudy after. So what did we possibly add? Rinsing down a flask might add contaminants on the inner walls of the flask (unlikely), or from the rinse solution (possible). You ran it through a filter. Now we have possible contamination from the funnel, the filter papers, or the container into which you filtered. I don't have the answer, but those are possibilities to look at.

I'll be interested to hear how your new solution looks.

The first time I didn’t use distilled water, would that cloud up the gold solution?
Click to expand...
That depends on your water. As I mentioned above, your rinse solution might have something that's caused your problem.

Dave
 
FrugalRefiner said:
Interesting. You had a clear solution before filtration, but cloudy after. So what did we possibly add? Rinsing down a flask might add contaminants on the inner walls of the flask (unlikely), or from the rinse solution (possible). You ran it through a filter. Now we have possible contamination from the funnel, the filter papers, or the container into which you filtered. I don't have the answer, but those are possibilities to look at.

I'll be interested to hear how your new solution looks.
Click to expand...

I wonder if he used home brew nitric. If you make your nitric by super saturating the water sodium nitrate and then adding H2S04 to the broth a lot of crystals will fall out of solution. The cooler it gets the more falls until the solution is at room temp. But even if you put the nitric in the freezer it would never drop everything out. Then when you refine with this nitric the same thing happens in the heating and cooling phases. That would explain the crystal clear when hot but cloudy when cool. The precipitate wouldn't hurt anything though even if you left it there while dropping gold out. But it's really easy to filter.
 
A couple of questions first...

Was there any white gold in the mix?
How much heat did your use to dissolve the material?
When you started to dissolve your gold filled, did you have silver looking flakes that did not want to dissolve?
When you added the water, did your solution turn cloudy, looking like you added milk to it?
When filtering, did the filter stop up almost immediately with very fine off white particles?
 
Shark said:
A couple of questions first...

Was there any white gold in the mix?
How much heat did your use to dissolve the material?
When you started to dissolve your gold filled, did you have silver looking flakes that did not want to dissolve?
When you added the water, did your solution turn cloudy, looking like you added milk to it?
When filtering, did the filter stop up almost immediately with very fine off white particles?
Click to expand...

As far as heat it wasn’t rolling boil but at least 100c
Yes there was white gold and silvery flakes that didn’t dissolve

Yes when I add water the solution turns cloudy

And when filtering it actually filters pretty good and fast.

And no the nitric wasn’t made it was purchased ACS grade
 
Also I have been trying to do my refined drop from very concentrated solutions to get bigger particle size.

When I just filtered the new solution still pretty concentrated it was clear and ambient temp, about 50f.

I started adding water in the funnel and I can clearly see a separation like clear golden orange on bottom and milky yellow on top where distilled water was added. I wish I got a picture.

So next I diluted it by @50% and stirred it and I’m letting it settle. It’s taking a while.

When I precipitated this the water on top was pretty clear

I think frugalrefiner might be on to something with the filter itself, I have a Some brand new glass cone funnels I’ll try to run it through after it settles.
 
Always filter after letting it settle. Otherwise it’s a nightmarish wait.

There are exceptions, but for the most part it’s solid advice.


Sent from my iPhone using Tapatalk
 
I am not sure what those flakes are, but they only dissolve, for me anyway, at high heat. On medium heat, I can actually filter them out pretty easy. If they dissolve and I add water it looks like milk in an glass of orange juice. And filtering is a total nightmare. Usually 4 to 5 passes through the same #1 Whatman filter at a slow drip, even with vacuum assistance. I am just finishing up a batch of white gold fill that was the worst lot I have ever done, as well it was my first that was all white gold. The filter did not turn purple when exposed to light.
 
Yeah the shiny flakes were making me add too much nitric in the first treatment because in the dirty solution it looks like gold moving around in there but it doesn’t dissolve or it really dissolve slowly.

Do they rhodium plate white gold filled?
 
I assume that is what it is, but then assuming is never a good thing. Here is my thoughts on it.

It does not affect my stannous testing.
It will cement a black, heavy powder after dropping the gold.
It is my understanding that rhodium is not testable by stannous.
Palladium will give a reaction to stannous.
Platinum will react with stannous.
There are other metals it could be, but they are even further outside the normal usage range.

I have just moved the black powders I had into my collection jar and never thought to get a picture of them.

I have maybe 30 more filters put back that I have caught the foils in. Maybe one day I can work with them for more understanding. I have 1200 more grams of gold filled on the way so I may get a chance to look into it more next week.
 
Shark said:
It does not affect my stannous testing.
It will cement a black, heavy powder after dropping the gold.
It is my understanding that rhodium is not testable by stannous.
Click to expand...

Steve showed test results for rhodium using stannous. Unfortunately, when I searched for it just now, I find that his images have disappeared, probably related to his site being down. He mentions that he used heated stannous to get the result. I don't know if there are other posts that may still have images, or if someone else might provide more information.

Dave
 
Yeah, the picture is gone and there's only a link to Lazersteve's website.

The post about rhodium testing is here.
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=41&t=2007#p16869

The picture isn't on the wayback machine either.

Göran
 
g_axelsson said:
The picture isn't on the wayback machine either.
Click to expand...
And that's the downside to linking to images stored elsewhere. If the site disappears, so do the linked images. Images placed in a post as attachments will survive as long as the forum exists.

Dave
 

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