# Inquartation.



## sri steve (Nov 20, 2014)

Hi, I need some advice on inquartation; I am in a new world of dental alloys and wish to know the values needed for inquarting a clean mix of Pd and Au laboratory waste, this is castings waste and will contain small amounts of other precious metals.

The laboratory where I have obtained my waste keeps none precious metalwork separated from precious so less chance of contamination.

The waste itself is in shot and thins form but do I still mix with clean silver? At 10 to 1 mix? Or would nitric take into solution without inquarting, I look forward to your replies, Steve.


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## Lou (Nov 20, 2014)

Is there a lot of silver in the alloy? You may not need to inquart.


L


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## sri steve (Nov 20, 2014)

Hi Lou, thanks for your reply, its very much appreciated, the following is brake down on the metals used, Pd 79.5%, Cu 4.9%, Sn 4.9%, Ga 4.2%, In 4.0%, Zn 2.0%. but there is a small amount of Au as all the precious metals are collected into one pot.

There could be very small amount of Ag from the other alloys used, the noble alloys used the highest level of Ag is contained in the lowest noble at 44.0%, over here in the UK the common noble alloys are 90,60,40 these numbers refer to Au content the rest of the mix is made up from Pd, Ag, Cu, Zn except the 90 the content is Au 89.5%, Pt 5.3%, Pd 1.6%, Ag 1.2%.

So do you think it would be best to inquart and at high level of Ag 10 to 1 mix? 
Thanks Steve.


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## etack (Nov 20, 2014)

With no real Ag content you shouldn't need to inquart at all. You inquart to raise the Ag content so it can be removed with nitric, and in turn this lowers the Ag content so that you can put it into AR. 

With the numbers you stated I would just use AR and go from there.

Also "inQUART" means to "quarter" you are looking for 75% Ag or metal reactive in nitric 25-30% of metal that is not reactive to nitric acid: Au, Pt.

(there is some room for discussion on the exact amount)

Eric


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## Lou (Nov 20, 2014)

Given the low silver content, this material would go straight into aqua regia.


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## sri steve (Nov 20, 2014)

Cheers guys for the information, I will take small sample of waste and experiment with it, Steve.


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## Harold_V (Nov 20, 2014)

In a sense, the material is already "inquarted", considering the fact that palladium will dissolve in nitric. Assuming it is a homogeneous blend, you may discover that you can dissolve the base metals, silver and palladium, along with traces of platinum, simply by a dilute nitric digest, leaving behind the gold, along with some of the platinum. 

Because the gold content was much higher in dental alloys when I was refining, I inquarted routinely. However, the ten to one ratio you speak of is not even close to the required ratio. As a rule of thumb, I considered the alloy to be 60% gold, and inquarted accordingly, shooting for an overall gold content of 25% after inquartation. You may not be dead on, but it will usually process adequately. 

Harold


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## g_axelsson (Nov 20, 2014)

If I remember correctly, the 10:1 ratio is for dissolving platinum with only nitric.

Since it isn't 1/4 gold I don't think it would be called inquarting any longer...
... it should be called intention! :mrgreen: 

Göran


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## nickvc (Nov 20, 2014)

I wish you luck because refining PGMs isn't easy unless you really know your chemistry.
This sounds like a put down but believe me it's not, extracting the gold, if present, should be easy but separating the Pd from the Pt will test your resolve and your knowledge, I hope you know what your doing because there are few who really understand the chemistry or have the equipment needed to be successful.
My opinion, just recover the gold for later refining and extract the PGMs by cementation, melt assay and sell..easy and in the UK cheap and fairly quick.


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## 4metals (Nov 20, 2014)

I agree that the assay you provided will go nicely into aqua regia but filtration may be a bear because of the tin.

You could consider a nitric dissolve and settle and decant the insolubles to avoid filter issues then you can cement on copper, very fine copper powder will serve you well in that process. 

That will give you your best shot at having the palladium without base metals to get in the way. Then you can use aqua regia, filter out the silver chloride and use ammonium chloride, (filter out any ammoniumchloroplatinate that forms) and sodium chlorate to get your relatively clean Pd salt. 

When you collect enough insolubles from the first nitric dissolve you can go for the gold with aqua regia.


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## sri steve (Nov 21, 2014)

Hi guys, did a small experiment today, I put small amount of waste into AR, instant reaction and the solution turned blood red, time to digest about 1 hour.

I then let it cool, the colour of the solution is now very dark red and you cannot see through it, now filtering time, very little trash very small amount of silver chloride and couple of spots of white particulate which I believe to be Sn.

After filtering the solution is still very dark and not transparent at this point I used my S02 bubbler to see if their was any Au content, no precipitation it just lighted the solution to still dark red but transparent, solution now very clear.

Any tips on what to do next, try and precipitate Pd or Pt first?.

Thanks Steve.


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## kurtak (Nov 21, 2014)

sri steve said:


> I used my S02 bubbler to see if their was any Au content, no precipitation it just lighted the solution to still dark red but transparent, solution now very clear.
> 
> 
> Thanks Steve.



Did you give it plenty of time for settling - very fine &/or small amount of gold can take a fair amount of time to settle (a day or more) & you may not even be able to really see it (as fine particles in suspension or precipitate settled on the bottom) in the darker solution

I ask because the fact that you had a change in transparency suggest you had a reaction that dropped something out

Kurt


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## g_axelsson (Nov 21, 2014)

You didn't mention denoxing the solution before trying to precipitate gold, did you do it?

Göran


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## 4metals (Nov 21, 2014)

To recover the Pd you need to add the saturated ammonium chloride first so any Pt will come down. if it does come down, filter the solution and add sodium chlorate to drop the Pd salt. For small batches you can drop the Pd with DMG.

It is important to have de-Noxed the solution. Without having removed excess nitric the gold will not settle out. Some refiners get rid of excess Nitric by bubbling SO2 in the solution, this drops the gold which immediately re-dissolves until the nitric is gone and then the gold will drop and remain out of solution. Rather wasteful of SO2 but it is often done. If there was no gold in there to begin with, there will be nothing to consume the excess nitric. 

What did your stannous chloride tell you?


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## sri steve (Nov 21, 2014)

Sorry guys forget to mention I de-Noxed the solution with sulfamic.

Kurt I will check solution tomorrow to see if anything as precipitated?

Thanks Steve.


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## sri steve (Nov 22, 2014)

Hi guys just an update on things, today after leaving the solution to settle overnight to see if anything had precipitated, result: nothing, the solution is very clear, I warmed and stirred the solution on my stirring hotplate to dissipate the S02 gas.

The solution as down darkened, I believe this down to the dissipation of the S02 gas, I will now leave it overnight to cool and settle, tomorrow I will do a stannous test and spot test the solution with DMG and hopefully have some Pd particulate.

As this was only experiment with a very small amount of scrap if the results are good, then I will be able to do the rest of the scrap.

I know the rest of the scrap I have does contain Au, I hope for a successful result.

Harold as given me advice on being very cautious and selective with this kind of scrap, so I am following this advice to the letter, thank you Harold.
I will post my results and if anybody see where they can advise me, feel free to do so, I’m here to learn and gain, thanks Steve.


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## Anonymous (Nov 25, 2014)

Ahh a fellow Yorkshireman!

Hi Steve nice to meet you.

Jon


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## sri steve (Nov 26, 2014)

Hi Jon: God who'd a thought that somebody who only lives 30 minuets away would meet on a forum based in the US, well hard at it tomorrow as I have a few days off work.

I am processing some laboratory waste (dental) which contains Au, Pd, Pt, mainly, the process I have planed if successful, I should end up with clean Pd, Pt, the Au I will recover and reprocess this later to refine it.

you will have to let me know what kind of refining you are into? Steve.


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## Harold_V (Nov 26, 2014)

sri steve said:


> on a forum based in the US,


The reality is this forum is not based in the US, although it is in North America. 

Noxx, the owner and our leader, is Canadian. 

As a point of interest, he was just a young lad of 17 when the forum was founded. 

Harold


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## g_axelsson (Nov 26, 2014)

Harold_V said:


> sri steve said:
> 
> 
> > on a forum based in the US,
> ...


Too young to know what he was doing was impossible, so he just went along and did it.
... and look where we are today, over 30.000 registered users worldwide. :shock: 
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=60&t=1215&p=10172

Göran

Edit : corrected the link to point at the first post of the thread, not to my post. Makes more sense.


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## sri steve (Nov 27, 2014)

I'm sorry if I've upset anybody with the reference of this forum being in the US, I didn't know Mr Noxx was Canadian.

Göran I don't understand the link?


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## g_axelsson (Nov 27, 2014)

Just looking back to when I joined the forum. We had just broke the 1000 member line. Now we are 30.000 members here.

8) 

Göran


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