# Purity of gold after inquartation and nitric digestion



## croakersoaker (Sep 28, 2011)

Hi I new here and am very interestedin refining karat gold. I was just curious about the purity of the gold after dissolving the base metals in nitric and water. Is it pure enough to melt and sent to the refinery? Also can it be stored in this state till I am ready to learn the next step of aqua Regia. I want to take it slow but I want to get started as well. Also after cementing out the silver with copper can it be reused again in this state for the next inquartation. Thanks in advance for replies and I am very much enjoying reading here.


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## Anonymous (Sep 28, 2011)

If you are going to send it to a refiner,you might as well send it in jewelry form,unless you plan on recovering the palladium and silver because some refiners will not pay you for that.
But if you do process with nitric to recover the other PM's,and you are going to sell the remainder to a refinery,then yes you can simply melt it,and ship it,however,we do have some good reputable buyers on our forum.You may want to ask one of them if they are interested in what you have.Here are 2 catagories to check out.This first one should help you with any questions you may have concerning selling what you have http://goldrefiningforum.com/phpBB3/viewforum.php?f=72
And this one will help you find someone.http://goldrefiningforum.com/phpBB3/viewforum.php?f=84
If you need any advice on a specific buyer,just ask publically on this thread,plenty of us will chime in to help.


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## nickvc (Sep 29, 2011)

Mic has given you some good ideas to look over and I'd follow up on the links. However the reason most members refine is to be sure of exactly what gold they have as assays especially in the US are fairly expensive and the gold is rarely exactly as is marked due to the marking rules there. The gold from a good well mixed inquartation should run at around 95-98% pure and if well rinsed you should be able to store this which if you intend to refine it is better than melting it, the silver recovered from the cementation can be re used after rinsing but it can have platinum group metals in the mix if you had any in your inquartation to start with, that's where things become more complicated and I suggest you download, read and study C.M.Hoke available as a free download of several members signature lines. Palladium is one of them. Make sure you read the safety section and use the search function top right of your screen for further information on topics that you may not fully understand and if you can't find answers post a question here, you will be answered but we like to see you have done your part and done the necessary reading to help yourself.


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## Lou (Oct 4, 2011)

995 is the very best. At this point it's melted and off it goes to Wohlwill.


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## goldsilverpro (Oct 4, 2011)

A few years ago, some company in Italy (I believe) was selling a gold refining unit based on copper inquartation. They leached with several applications of fresh nitric acid and claimed a normal 9995 purity and a possible 9999 after further applications, if I remember right. I may have some old info on it. I'll look for it when I get back home.


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## gurudatta (Oct 4, 2011)

in inquaratation , you are making pallets of karat gold and copper and treated it in conc nitric acid.which will dissolve copper and other base metals and leaves brown colour gold powder.but check the particle size becouse masking of silver will lowers your gold purity if your base metals not dissolve completely in nitric acid.so you make pallets in the flat thin form like rolled strip metal which gets larger surface area and fine thickness for treatment of nitric acid.that will reduce your nitric acid consumption also.and will not have to treat it for aqua regia process.but for getting 9999 purity you must go through the aqua regia process.


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## HAuCl4 (Oct 5, 2011)

If you inquart once with silver, digest the fine shot in nitric acid, wash and dry, inquart again with zinc, digest the fine shot with sulfuric acid, wash and dry, melt , you'll get better than 9995 and approach 9999 if you superheat the melt to 2000 C for 15 minutes in a clean zirconia crucible. :shock: 

You can get 9995 or very near by fluxing the once inquarted gold too. Search for the flux mix by 4 metals. 8)


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## Lou (Oct 5, 2011)

That's a great way to evaporate your gold.


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## HAuCl4 (Oct 5, 2011)

Yes it is, but it evaporates the silver first. :shock:


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## gurudatta (Oct 6, 2011)

hi,haucl4
as u told about inquartation,your process is so time consuming and also will effects cost consumption.better way to get .9999 purity is to rerefine that brown sponge using aquaregia with taking care of goldloss in process.


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## HAuCl4 (Oct 6, 2011)

gurudatta said:


> hi,haucl4
> as u told about inquartation,your process is so time consuming and also will effects cost consumption.better way to get .9999 purity is to rerefine that brown sponge using aquaregia with taking care of goldloss in process.


You are of course not exactly correct. A trained monkey can do my process and lose little gold while being taped with a video camera, and it doesn't take substantially longer, and additionally all chemicals can be recycled at very low cost...by the same monkey. An AR process requires a higher primate to do the refining carefully to avoid losing gold. :lol: 

One thing I will say though: 4metals inquartation+fluxing to get 9995 is MUCH better and faster, and a barely trained monkey can still do it. 8) 



4metals said:


> I got the method 2 years ago from a sterling refiner processing 30,000 ounce batches, we scaled down to 1000 ounces a day because *we melt 350 ounces of karat gold scrap in with the 1000 ounces of silver (essentially inquarting) and digest the alloy in 50% nitric. The gold doesn't react and is filtered out and cleaned up in another nitric dissolve and melted with a borax, soda ash, manganese dioxide flux which scavenges any remaining silver and produces a 999.5 fine bar consistantly.* The silver is processes as described and comes out 9999+ every time. The gold assay comes from a JM assay and the silver I assay with a Volhard titration in house because we sell the silver ourselves. We take care not to include any bars of gold with PGM's in the process because it will effect the gold purity, as it too will not dissolve completely. There is some on line literature about the method but it is sketchy and I go by the procedure I've outlined above. As with any process, familiarity will allow you to know when the drop is done just like you can look at a gold precip and know by looking that you've gassed enough. (of course I always have the guys check with stannous just in case) Recovery from the acid is complete and accountability is excellent. Just watch the pH, if the solution is stable at 1.5 when you start adding the reducing solution, and the reducing solution has been reduced to 4, you're OK. We make 55 gallon batches of reducing agent so it's on tap when we need it, it has never gone bad. One more thing, the digestion gets hot, which I'm sure you know, so heavy walled 316 stainless tanks hold up the best. Polypro is fine for the mixing and storing the sodium formate solution. Once you see the sponge this drops, you'll be hooked.


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