# My gold is black and floats. No matter what I do



## Rreyes097 (Dec 22, 2022)

So I got about 2-3 grams of gold from my wastes. Well most of that came from wastes but my problem is that the gold keeps dropping totally different than what I'm used to. This gold is black and very fine. It floats and the liquid it sits in is also dark, almost black. It takes all night for it to settle and when I move it to decant the rinses it's a frustrating problem because I feel that the dark liquid is actually gold. Very fine particles. So I'm sure my coffee filters are letting it right thru. So I try my best to keep the larger particles. I've used dish soap and that seems to help only slightly and with that only larger particles. Somewhere I heard that this is happens when it comes from a dirty solution. So I went ahead and dissolved it. 
I figured it would for sure drop like normal. It did not.
So I thought I'd leave it for now and went ahead and dried it. It dried black which is also new to me.
Well I took that black gold and just mixed it with a little bit of gold I had dried already. Then I melted it to see what kind of karat quality I'd get out of this weird gold  of mine. Needless to say it didn't look great so I dissolved it again!

I dissolved it into this beautiful yellow/ orange color and I thought it would be very pure drop. Well it wasn't. It came out the same way. It took a lot of sulfamic acid to get the nitric out of the way. Like a lot. But that's because I was heavy handed when trying to make this gold button dissolve. There was quite a bit of settlement that did not dissolve and I took that as the impurities. Boy was I wrong. Anyone know what's going on?
Oh I used HCl and nitric well aqua regia to dissolve every time and sulfamic acid and smb. So I'm not sure what to do now. 
Those 2 pictures are from tonight.


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## Rreyes097 (Dec 22, 2022)

Oops I forgot I already posted this in the beginning of all this. Sorry


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## Yggdrasil (Dec 22, 2022)

Rreyes097 said:


> So I got about 2-3 grams of gold from my wastes. Well most of that came from wastes but my problem is that the gold keeps dropping totally different than what I'm used to. This gold is black and very fine. It floats and the liquid it sits in is also dark, almost black. It takes all night for it to settle and when I move it to decant the rinses it's a frustrating problem because I feel that the dark liquid is actually gold. Very fine particles. So I'm sure my coffee filters are letting it right thru. So I try my best to keep the larger particles. I've used dish soap and that seems to help only slightly and with that only larger particles. Somewhere I heard that this is happens when it comes from a dirty solution. So I went ahead and dissolved it.
> I figured it would for sure drop like normal. It did not.
> So I thought I'd leave it for now and went ahead and dried it. It dried black which is also new to me.
> Well I took that black gold and just mixed it with a little bit of gold I had dried already. Then I melted it to see what kind of karat quality I'd get out of this weird gold  of mine. Needless to say it didn't look great so I dissolved it again!
> ...


Why did you melt the powders??
You should just have added a few ml HCl then a few ml of Peroxide or a drop or two of bleach, ending up with not much more 10ml liquid.
Then cement it again, getting rid of what ever metal oxides you have in there.
Most likely Iron compounds of some kind. They can have some tantalising golden colours.


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## Martijn (Dec 22, 2022)

Did you try a gentle boil with a dash of H2SO4? 
It should clear it up and drop the fine suspended gold particles.


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## Shark (Dec 22, 2022)

Since it is from your waste, there is a possibility that it is not gold but another pgm. I seen this in my waste a lot before I knew how much rhodium and other pgm’s can be found in gold filled. 

I am with Martin though, hot sulfuric. Be very careful, that stuff is very unforgiving.


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## Rreyes097 (Dec 22, 2022)

Martijn said:


> Did you try a gentle boil with a dash of H2SO4?
> It should clear it up and drop the fine suspended gold particles.


So heat and add a drop or 2 of sulfuric acid?


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## Yggdrasil (Dec 22, 2022)

Rreyes097 said:


> So heat and add a drop or 2 of sulfuric acid?


Yes, the Sulfuric drops seems to clean the surface of the particles somehow.
What is important is a gentle low boil that will bring the particles to coalesce better.


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## Rreyes097 (Dec 22, 2022)

Thanks so much y'all! I'll try that right now.


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## Rreyes097 (Dec 22, 2022)

So just a drop or 2?


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## Yggdrasil (Dec 22, 2022)

Rreyes097 said:


> So just a drop or 2?


Depending on how much liquid you have yes.
A quarter a bottle cap or so for a Liter.
It is not an exact thing, a splash, 1-2ml or so.
The purpose is to dissolve/remove what ever layer is stopping the agglomeration of the particles.


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## Rreyes097 (Dec 22, 2022)

Yggdrasil said:


> Depending on how much liquid you have yes.
> A quarter a bottle cap or so for a Liter.
> It is not an exact thing, a splash, 1-2ml or so.
> The purpose is to dissolve/remove what ever layer is stopping the agglomeration of the particles.


So as soon as I put a few stops into solution, all floating particles dropped. So just right there helps tremendously. Thanks everyone! I appreciate it very very much.

About how long should I boil?


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## Yggdrasil (Dec 22, 2022)

Rreyes097 said:


> So as soon as I put a few stops into solution, all floating particles dropped. So just right there helps tremendously. Thanks everyone! I appreciate it very very much.
> 
> About how long should I boil?


Until it clears up a bit and then let it sink and siphon off what liquid you can.


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## Rreyes097 (Dec 23, 2022)

Well it's still black in color after I rinsed a few times and dried. I'm not sure what's it is going to look like when it's melted though.


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## Yggdrasil (Dec 23, 2022)

Rreyes097 said:


> Well it's still black in color after I rinsed a few times and dried. I'm not sure what's it is going to look like when it's melted though.


Just re dissolve it in minimum HCl and some bleach, just make sure it is always acidic.
And then if you have Copperas use that to precipitate it.


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## Golddigger76 (Dec 23, 2022)

I have had black gold that takes a week to settle a few times
After I dissolved it in aqua regia again and dropped it with smb it was normal cinnamon colored powders. 
Once I re-dissolved and cemented it out with copper and that worked very well too.
I have also had palladium from catalytic converters do the same thing, days to settle. 
A splash of hydrochloric acid and a little heat helps also.


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## Martijn (Dec 23, 2022)

Shark said:


> I am with Martin though, hot sulfuric. Be very careful, that stuff is very unforgiving.


Very dilute addittion of H2SO4 and only a couple of ml (10 -20) per liter of solution. That brings it to just over boiling point of water, but not much. A gentle simmer is needed. Not strong boiling!! 
Still warm sulphuric in solution but much less aggressive compared to concentrated 98% hot sulphuric. 
Look at it as dish soap in hot dish water. Cleans everything up nice and shiny.


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## Martijn (Dec 23, 2022)

Rreyes097 said:


> Well it's still black in color after I rinsed a few times and dried. I'm not sure what's it is going to look like when it's melted though.


Did you rinse it? A solution? Or is the black powder filtered out of solution? 

I meant: heat the black solution with 10 to 20 ml of concentrated HS2O4 for ten minutes and you should see it clear and settle to the bottom. 
I would not melt black powders. Wash them until light brown or dissolve again and wash again.


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## Rreyes097 (Dec 23, 2022)

Ok thanks. Yeah I dried it out.


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## Martijn (Dec 23, 2022)

I always get great results following harold's washing steps in cleaning gold. 








Getting pure gold (shining)


Hello, I would like to know what I must add/change to a standard AR process to get pure gold after melting it. Most of the gold buttons I get are not completly shining and seem to have a very thin layer of impurties. How can I correct that ? Thanks




goldrefiningforum.com


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## Christian333 (Dec 23, 2022)

Rreyes097 said:


> So I got about 2-3 grams of gold from my wastes. Well most of that came from wastes but my problem is that the gold keeps dropping totally different than what I'm used to. This gold is black and very fine. It floats and the liquid it sits in is also dark, almost black. It takes all night for it to settle and when I move it to decant the rinses it's a frustrating problem because I feel that the dark liquid is actually gold. Very fine particles. So I'm sure my coffee filters are letting it right thru. So I try my best to keep the larger particles. I've used dish soap and that seems to help only slightly and with that only larger particles. Somewhere I heard that this is happens when it comes from a dirty solution. So I went ahead and dissolved it.
> I figured it would for sure drop like normal. It did not.
> So I thought I'd leave it for now and went ahead and dried it. It dried black which is also new to me.
> Well I took that black gold and just mixed it with a little bit of gold I had dried already. Then I melted it to see what kind of karat quality I'd get out of this weird gold  of mine. Needless to say it didn't look great so I dissolved it again!
> ...


I did a side by side experiment with the same AR solution. One was cold/ambient and the other was hot 220F. The cold on the left after one hour vs the hot on the right.
SMB was used for this second refine experiment.

Janie


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## Martijn (Dec 24, 2022)

Christian333 said:


> I did a side by side experiment with the same AR solution. One was cold/ambient and the other was hot 220F. The cold on the left after one hour vs the hot on the right.
> SMB was used for this second refine experiment.
> 
> Janie


What was the experiment? 
Just dropping the gold or adding sulphuric in cold vs hot solution?


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## Christian333 (Dec 24, 2022)

Martijn said:


> What was the experiment?
> Just dropping the gold or adding sulphuric in cold vs hot solution?


Just dropping, hot was more finely divided particals, cold clumped.

Janie


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## Golddigger76 (Dec 24, 2022)

Was your smb applied as dry powder or mixed with water ?


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## Rreyes097 (Dec 24, 2022)

Christian333 said:


> I did a side by side experiment with the same AR solution. One was cold/ambient and the other was hot 220F. The cold on the left after one hour vs the hot on the right.
> SMB was used for this second refine experiment.
> 
> Janie


Nice so the issue for that was heat or no heat? Because I don't usually use heat when dropping gold. But thanks! I'll try and have things heated when I drop gold from now on.


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## Rreyes097 (Dec 24, 2022)

Golddigger76 said:


> Was your smb applied as dry powder or mixed with water ?


I apply my SMB in powder form. Is it best to dissolve it in water first?


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## Geo (Dec 25, 2022)

For a beginner, dissolve the SMB in water. Boiling the powder in water alone will settle the powder better. H2SO4 will help. After the drop, decant the solution to another vessel and heat the solution to 200° F for two hours and then remove from heat and allow to cool. Test the solution with stannous chloride. If negative, decant and evaporate and send it to the stock pot. Check for any extra dropped powder.


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## Christian333 (Dec 25, 2022)

Rreyes097 said:


> Nice so the issue for that was heat or no heat? Because I don't usually use heat when dropping gold. But thanks! I'll try and have things heated when I drop gold from now on.


The one I heated was worse than the cold one. 

Janie


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## cejohnsonsr1 (Dec 25, 2022)

Rreyes097 said:


> Nice so the issue for that was heat or no heat? Because I don't usually use heat when dropping gold. But thanks! I'll try and have things heated when I drop gold from now on.


Actually you need to be more concerned about keeping it cool. SMB produces an exothermic reaction.


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## Rreyes097 (Dec 26, 2022)

Should I have tried to cement with copper?


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## Yggdrasil (Dec 26, 2022)

Rreyes097 said:


> Should I have tried to cement with copper?


What did you cement with?


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## Rreyes097 (Dec 26, 2022)

Yggdrasil said:


> What did you cement with?


I didn't cement anything. I was just wondering if instead of dropping with SMB I could cement out my gold with copper and possibly change the black dirty water it keeps going back to. But Im just planning on following the instructions that someone posted a link to the thread for cleaning up the gold.


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## Yggdrasil (Dec 26, 2022)

Rreyes097 said:


> I didn't cement anything. I was just wondering if instead of dropping with SMB I could cement out my gold with copper and possibly change the black dirty water it keeps going back to. But Im just planning on following the instructions that someone posted a link to the thread for cleaning up the gold.


You can try.


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## Rreyes097 (Dec 27, 2022)

So I'm trying to follow that thread that Martijn posted on this thread. But I'm scared to do all that boiling. Because my hot plate won't boil since I have a catch jar or dish underneath it. And my other hot plate is a simple thing that you're supposed to cook food with so it gets really hot and has broken many glasses of mine. Do you really actually boil it? And that many times?! Don't they break glass too? I'm just hesitant.


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## Yggdrasil (Dec 27, 2022)

Rreyes097 said:


> So I'm trying to follow that thread that Martijn posted on this thread. But I'm scared to do all that boiling. Because my hot plate won't boil since I have a catch jar or dish underneath it. And my other hot plate is a simple thing that you're supposed to cook food with so it gets really hot and has broken many glasses of mine. Do you really actually boil it? And that many times?! Don't they break glass too? I'm just hesitant.


Then get some proper gear or some makeshift things.
I use a sheet of fiberglass between my catch basin and the hotplate and then one between the catch basin and the glassware.


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## Rreyes097 (Dec 27, 2022)

Yggdrasil said:


> Then get some proper gear or some makeshift things.
> I use a sheet of fiberglass between my catch basin and the hotplate and then one between the catch basin and the glassware.


Just get proper gear? Is that all I need to do? Hahaha. Trust me I'm trying.


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## Yggdrasil (Dec 27, 2022)

Rreyes097 said:


> Just get proper gear? Is that all I need to do? Hahaha. Trust me I'm trying.


Well I told you how I do it so I gave you more.


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## Shark (Dec 27, 2022)

Proper glass is #1 priority. They are fairly cheap when measuring cost versus the risk of loosing your gold. Been there done that, put a stop to it quick and never look back.

Try a layer of sand in your catch pan. Clean sand is key but be very careful of scratches as it can cause cracks where the scratches make the glass weak.

Even a glass coffee pot is better than jars and drinking glasses. 

Bring the heat up slower, most glass can be heated but not quickly. Boiling in plain glass is a disaster already beginning.


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## Yggdrasil (Dec 27, 2022)

Shark said:


> Proper glass is #1 priority. They are fairly cheap when measuring cost versus the risk of loosing your gold. Been there done that, put a stop to it quick and never look back.
> 
> Try a layer of sand in your catch pan. Clean sand is key but be very careful of scratches as it can cause cracks where the scratches make the glass weak.


That is why I use fiber glass mats.


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## Shark (Dec 27, 2022)

I have plenty of Corning ware these days and good glassware, so I seldom use anything in my catch pans these days. But I still tend to bring the heat up slowly out of habit. Never thought about using fiberglass, Interesting what others come up with when trying to solve problems.


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## kurtak (Dec 27, 2022)

Rreyes097 said:


> Well it's still black in color after I rinsed a few times and dried.


If this is coming from your waste it may not be gold - it *might* very well be PGMs - which is why it's black

Kurt


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## Rreyes097 (Dec 27, 2022)

kurtak said:


> If this is coming from your waste it may not be gold - it *might* very well be PGMs - which is why it's black
> 
> Kurt


Well I'm not sure how to deal with that then. I haven't dealt with that. How do separate the gold and the pgms


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## Martijn (Dec 27, 2022)

As i understand you've dissolved it several times and precipitated with smb. Did you test the solution and the waste with stannous for pgm's?
My best guess is just dirty gold that needs a good wash. Did you cool and filter a couple times through the same filter before dropping the gold?


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## Martijn (Dec 27, 2022)

Rreyes097 said:


> So I'm trying to follow that thread that Martijn posted on this thread. But I'm scared to do all that boiling. Because my hot plate won't boil since I have a catch jar or dish underneath it. And my other hot plate is a simple thing that you're supposed to cook food with so it gets really hot and has broken many glasses of mine. Do you really actually boil it? And that many times?! Don't they break glass too? I'm just hesitant.


I use an electric kitchen hotplate with a stainless steel pan filled with a layer of dry sand to keep the sand at a more or less constant temperature of 100 degrees C. That protects the flask or beaker against extreme heat. 
I cap off a small erlenmeyer with a glass cup to keep the vapours condensing back in. Tie a rolled up paper tissue round the neck to catch any accidental droplets on the outside. Keep the sand dry. And use pyrex or labglass beakers and flasks.


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## Rreyes097 (Dec 27, 2022)

Martijn said:


> As i understand you've dissolved it several times and precipitated with smb. Did you test the solution and the waste with stannous for pgm's?
> My best guess is just dirty gold that needs a good wash. Did you cool and filter a couple times through the same filter before dropping the gold?


No I used different filters almost every time with every filtration. This picture is of its current state it's no longer floaty anymore and have black water all around it, but it still has a black tint to it. I'm going to attempt to clean it further.


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## Rreyes097 (Dec 28, 2022)

Well I forgot to take a picture of it but after a few HCl boils and boiling water rinses. I was able to melt down and get somewhere around 22kt. Well that's what I sold it for. But it could've been better deal since the testing was limited to the scratch test. But thanks to all y'all. That thread about cleaning the gold. Helped out a lot.


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## orvi (Dec 28, 2022)

Rreyes097 said:


> No I used different filters almost every time with every filtration. This picture is of its current state it's no longer floaty anymore and have black water all around it, but it still has a black tint to it. I'm going to attempt to clean it further.


For gold drop - there are few crucial parameters needed to obtain nice precipitates.

1. concentration of Au - if your solution is diluted - there will always be light precipitate, if any (when too diluted, say under 0,3g/L). In these situations, it is very wise to use coagulating agent/flocculent. Microcrystaline cellulose works fine, special flocculents, gelatin or polymer based work nicely too. Or use Celite/bentonite to adsorb the microparticles and filter the solution. Then redissolve the gold from the filter cake, increasing Au concentration orders of magnitude.

2. clear solution - discussed many times here. If you have cloudy solution - most likely due to AgCl/PbCl2 or tin compounds, you will obtain light and small particles, which settle just slowly. This is typical black ppt, hard to work with, hard to decant as it always swirls from the bottom when pouring the barren liquid. You need to filter it crystal clear - if the filter paper is not making it, use mentioned adsorbents like microcrystalline cellulose, and preferrably Celite or bentonite.

3. pH during the drop - you want constantly low pH - it helps to prevent any precipitate forming, and also helps coagulate forming gold particles. That meaning if possible using sulfur dioxide gas - as it is acidic and does not require acid to liberate active reagent, like in the case of SMB or sulfite. Also, preferrably SMB over regular sodium sulfite - and not overdoing it with SMB/sulfite - as unnecessary sulfite will start to kill acid in the solution - to liberate now unnecessary SO2. Breaking the crucial AgCl2- anions to plain AgCl - drastically increasing the chance of liberation of AgCl cloudiness.

If you follow this, you start with strongly acidic, crystal clear solution and use preferrably SO2 gas (or at least topple with some few dozen mL of fresh HCL and continue with SMB) - there is little to zero possibility to obtain fine gold precipitates. Only parameter which is hard to adjust is the concentration. In the cases where you are dealing with large volumes of spent AR solutions with little gold (less than 1g/L), it is wise to cement the gold on copper sheet (after de-noxing) and bringing the whole pot with copper to the very slight boiling- this helps to coagulate the gold into bigger particles and kill all possible traces of nitric (seen by yellow/brownish gasses when beaker is covered - in case of this, vent the beaker from time to time). When doing this, try to minimize contact of air with solution - as it lead to undesirable dissolution of too much copper into the solution.

Also, some solutions containing high nickel or PGMs are hard to de-nox with sulfamic acid (NO and NO2 complexing to these metals). In these cases, use of copper as denoxing agent and also precipitant could be also great advantage.

PS: 22k is 91,6%. Even with the dirtiest gold I ever produced, I never gone below 95%. And this gold was obviously dirty and flocculent, floaty - due to conglomerates of tin oxohydroxides and silver chloride. So be careful when selling the other time. And after melting (regular torch melt on the silica dish glazed with borax), it is hard to get less than 97% (if the solution wasn´t totally milky from AgCl)  like, you need to put a lot of "effort" to produce button with less than 97% Au.
It pays off to re-refine gold


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## orvi (Dec 28, 2022)

Rreyes097 said:


> Well I'm not sure how to deal with that then. I haven't dealt with that. How do separate the gold and the pgms


Easily. Just as regular gold separation - with SMB, or ferrous sulfate. Redissolve the precipitate in AR or preferrably with HCl/ 10-30% H2O2 (no need of de-noxing afterwards) and only gold will drop after applying SMB or ferrous, PGMs will stay in solution. 

But be careful with assumptions when obtaining the black precipitate after copper cementation. Black precipitate could easily be just copper oxides flaking off the copper. Very similar look, but stannous test and also colour of the solution after black cement redissolution will tell you the truth  Happened many times to me, but XRF told the truth in 2 seconds  no PGMs or other PMs. Double checked with stannous to be surely sure  

Also good think about where the PGMs may enter your batch - as PGMs are much more scarce in e-scrap than gold. Aside of some special industrial PdAu plated pins, relay contacts and MLCCs and some jewellery white gold alloys, there are little to no common sources of Pd. Like 99% of the times when you do not expect PGMs, they wouldn´t be there  Or at least not in concentrations worth chasing....


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