# Inquartation necessary?



## creading (Aug 7, 2009)

If you want to recover gold from an 20 carat gold/silver item, can't you just dissolve it in AR (where silver is insoluble), filter and precipitate with SMB. If there is contamination in the first process, it could be subjected to repurification. This way you don't need to have silver for the inquartation, and you recover the silver on the filter from the AR.

Prospector


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## kelly (Aug 7, 2009)

Someone hasn't done their homework. The whole reason behind inquartation and parting is to reduce the gold content so that the AR can disolve the gold. If the silver content is too high, silver chloride will form on the outside preventing access to the gold by the AR. You could literally boil 20 Karat gold in AR for days with no joy. Too much silver and your gold ends up too fine to easily work with, too little silver and your gold won't disolve, ergo the target of 25% gold and 75% silver. Steve has and excellent video on this by the way. Search the forums for inquartation or inquarting and you'll find some informative and entertaining posts. Really, one thing I've learned from this forum is inquarting karat jewelry is better than sliced bread. By the way, Carat is for gems (weight) and Karat (%) is for PM's.
K


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## 4metals (Aug 7, 2009)

If you know the silver assay of the 20 karat material and it's less than 7.5% you can dissolve directly and recover the silver from the AR. But in most cases where you do not have a cumulative assay, inquarting is a safe bet and it often saves time.


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## Harold_V (Aug 7, 2009)

Yes, it is possible to process without inquartation, but there's one thing you need to know. 

When silver content exceeds a given limit, while it is converted to silver chloride, it doesn't do so freely. Instead, as the base metals and gold are dissolved, the silver forms a hard shell around the remaining alloy, eventually stopping the acid from reaching the metals intended to be dissolved. The shell takes on a strange greeen/gray appearance and is impervious. Once that happens, you can boil the remaining values in AR endlessly, with no results. I experienced this phenomenon on more than one occasion, resulting in re-melting the metal in question in order to achieve my goal. My conclusion? It's faster and easier to inquart. YMMV.

Inquartation is a system by which you are guaranteed that you can process the values. By no means is it a requirement. However, for those with little to no experience, it's an excellent way to process, insuring success. 

Any of the gold alloys that contain no silver are readily dissolved directly in AR. White gold would be an example. Blue another. The problem is, if you dissolve all of the base metals along with the values, the resulting gold will most assuredly be of questionable quality, due to drag down of unwanted elements. While they can be washed from the precipitated gold, some remain. It is for that reason a second refining tends to raise quality----very little contamination is present, thus little is dragged down.  

If you have little to no experience in refining, I highly recommend you use inquartation until you become familiar with refining. Once you have a firm understanding, you may wish to experiment with direct dissolution. 

Personally, and keep in mind, I refined daily when I ran my refining business, I chose to inquart, and did so to the end. I processed both silver and gold daily, so it was easy for me to use silver, which had to be dissolved in acid, anyway. I benefited by inquartation, where those that do not prefer to process silver may not. 

Harold


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## 4metals (Aug 8, 2009)

Anyone who wants to refine jewelery scrap will be well served by learning to fire assay karat gold. A small lab area will yield big returns for a jewelery refining operation, allow you to blend lots to enable direct AR refining by keeping the silver levels down when possible. And letting you know if the only option is to inquart. (like 18 karat lots which have high silver in the alloy) You will also benefit from the ability to value melted alloy which you may be asked to buy. 

The assay furnace can do double duty as a cupellation furnace and to melt your fine gold. 

Plus the skills you learn in assaying will further enhance your refining ability.


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## Oz (Aug 8, 2009)

Inquartation is hard for many to grasp. They wonder why on earth would someone that is trying to purify gold wish to melt it with silver. 

The way I explained this to a non-refining friend of mine was to ask him to envision the individual molecules of elements as cubes in a stack. By adding enough cubes of silver compared to gold it becomes very unlikely that there would be a cube of silver completely surrounded by cubes of gold. In this way virtually all the silver can be removed from the gold with nitric. You just posed the opposite question.

Beyond that even if your proposal would succeed you would still be left with silver chloride. There are very few karat gold alloys that do not contain silver. Silver chloride solids require far more labor to reduce to metal and refine than the silver nitrate solutions do. 

Many karat golds also contain platinum group metals as part of the alloy. Making a chloride of your silver eliminates the great advantage you have of your silver acting as a carrier of your PGM values separating them from your gold. 

At the end of the day you are far better served if you can assay as has been suggested. However if you lack that desire or ability it is hard to beat the advantages of inquartation.


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## g_axelsson (Aug 8, 2009)

This is a fact about silver in AR that I haven't heard for a long time on the forum.

I've read before on this forum that silver chloride is soluble to a certain grade in concentrated AR. I don't know how much but enough to be detectable.
If you dissolve silver containing gold in concentrated AR you could precipitate the most of the silver by diluting the solution afterwards before filtering. In diluted acid the silver chloride will precipitate as a solid. So by using concentrated AR and diluting it with water before filtering out the silver chloride you could probably handle higher amount of silver than if you start with diluted silver.

I don't have any experience of inquartation myself so I would follow the experts advice and do it. It adds some extra steps to the process but it minimizes the risks of complications.

/Göran


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## Oz (Aug 8, 2009)

You can indeed have silver go into AR to a limited degree. Dilution does eliminate most of it. As to how much, it is enough that I bother saving it. It is also worth noting that lead will do the same thing and is easily eliminated with a little sulfuric acid precipitating it as a sulfate.

I guess I can see where some may view the melting with silver process as “extra steps” but for me it is far less hassle than silver chloride. 

The PGM carrying capacity of silver is one of my primary reasons as well. If I think of it I will take a picture of 2 small batches of cement silver tomorrow showing the difference in color between cement silver run once and some run several times in inquartation that has picked up PGM.

How is it Irons used to say? Everything but the squeal.


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## Harold_V (Aug 8, 2009)

Oz said:


> I guess I can see where some may view the melting with silver process as “extra steps” but for me it is far less hassle than silver chloride.


That's right! 
What everyone is conveniently overlooking is the fact that the silver chloride that comes from the dissolution of gold that has not been inquarted is loaded with dissolved values that are not easily separated from the chloride. Tell me how much work you eliminate by not inquarting if you consider that issue. 

If you ran like the "big boys", that may not be important, but it's rare that anyone processing at the hobby level will ever benefit by the process. All it does is shift where time is spent, but it will be spent if one expects to recover all values. 

Harold


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## 4metals (Aug 8, 2009)

In defense of the "big boys" it should be mentioned that all jobs are settled on assay not by physical refining. That being said the losses from individual lots do not exceed the economy of scale. The gold left in the chlorides from AR digestion is recovered after the chloride is reduced and melted. The small amounts of PGM's are recovered from the treatment residues as low grade sweeps. 

There are a good number of hobby refiners on this forum, and for them I believe inquartation is, hands down, the best option. But there are a surprising number of questions from guys who want to refine larger lots to process for their jewelery scrap businesses. For them, learning both sides of the aisle would be of great benefit as many are seeking to run before they can walk. 

It is my hope that from this forum we can help both types of members to fine tune their operations into the most efficient (both in recovery and in labor) shop possible.

Concerning silver chloride in the aqua regia, while it is mostly insoluble there is some that remains in the acid. Fortunately the solubility is directly related to the temperature of the solution. Many of us have filtered a warm acid solution only to come back the next day to see the jug bottom coated with a fine thin layer of silver chloride. To prevent this the aqua regia can be diluted and chilled with ice before filtration, this will cause the lions share of the remaining chloride to be caught by the filtration.


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## Oz (Aug 8, 2009)

Well as promised here is that picture. The container on the left is cemented silver that did not come from inquartation, the one on the right has been used for inquartation several times (I actually need to remove the PGM build-up).

Both of these were cemented on copper and dried in separate containers at the same time. Using AR for dissolution these PGMs are often a contaminate in gold buttons. It is a shame to make a .98 gold button instead of .999+ especially if the contaminates are PGM.


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## 4metals (Aug 8, 2009)

Oz,
Do you have any idea what the concentration of the platinum group metals is in the cemented silver? How do you recover the PGM's from the silver? 

I have never had issues with gold being less than .9995 due to PGM's usually the major contaminates are silver and copper even when single drop aqua regia produces .9997 the culprits are usually copper and silver. One place I set up had lead issues often but sulfuric cured that.
The main issue with the PGM's in aqua regia is collecting them in the low concentrations they are in in the spent acid. Usually resins collect them but monitoring that requires an increase in technology requiring at least an AA. They remain in the acid and can be collected with a copper bar acting to displace the metals but on a large scale it's impractical.


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## Oz (Aug 8, 2009)

As to the PGM content, no I do not know the concentration. I am not set up yet for very fine mass determinations nor the exacting quantitative filtering needed to give you an accurate number (but I’m almost there). 

I remove the PGMs by dissolving the contaminated cement silver in nitric and decanting or filtering to reclaim any gold that may be present and some of the PGMs. I then take the nitric filtrate and add HCl until no more silver chloride is formed. I filter or decant once more and am left with an AR filtrate containing PGMs that can be processed by normal means (after making the AR a chloride I do practice dilution and sulfuric for scavenging any remaining silver or lead before proceeding to reclaim the PGMs). Harold is correct in that silver chloride traps significant values as it forms, but this is of little concern for me as I reduce the silver chloride to elemental and continue using it for inquartation. 

It does not surprise me that you never had problems with PGM contaminating your gold as you were dealing with large lots that you would separate based on the alloys and choose the appropriate process for each based on assay. Doing smaller lots I do not have that luxury and it is easier for me to let the silver do a lot of the work for me.


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## goldsilverpro (Aug 8, 2009)

I didn't usually inquart or evaporate down or use urea or incinerate. I used dedicated plastic buckets to drop the gold in and never had problems losing gold in the scratches

I dissolved everything I could (all the Ag, Cu, etc., in 10K, or less) with very hot 50/50 nitric. I then rinsed the residue a bit and used aqua regia, with a bare minimum of nitric. After dissolving the gold, I diluted the AR at room temp, with 3 times its volume of tap water and added a little sulfuric, especially when I had class rings. I let it settle fairly well, siphoned or decanted off the tops, filtered the tops completely and then the residue on the same filter. I rinsed the residue several times with hot water and then added a warm solution of sodium sulfite to drop the gold. I filtered and rinsed the gold with hot tap water (about 5 times). All done in the same filter, I then leached with ammonia, rinsed 5 more times, leached with about 25% nitric, rinsed 5 times, and rinsed twice with hot distilled water. All this rinsing and leaching took about 30 minutes - good gold powder filters fast. I always had vacuum filters, of various sizes, but I preferred a fairly big plastic funnel sitting in a hole in a piece of plywood over a bucket. I had about 10 of these going all the time.

The residue was treated separately - I sometimes removed the AgCl with ammonia and inquarted the gold chunks left over, when I got a bunch of them. Usually, about 96-97%, or more, of the gold dissolved in the AR - sometimes, all of it.

In general, the lower karat gold has a larger percentage of silver than the higher karats. I got rid of it in the 10K (the worst) with the nitric. Most of the 14K, 18K, and 22K breaks down completely in the AR.

I never had trouble with silver. It was always copper. If any was present, I usually could remove it in the melt. It's a guess, but I think I only had to re-refine about 1 out of every 20 batches.

The best heating source I've ever had was a 6' gas restaurant grill. You could keep it hot on one end and warm on the other, with a whole range of temps in between. You could cushion it with a cloth made from the material used for furnace gloves. We used to use asbestos cloth.

With 10, 4 liter beakers, I could do several hundred oz/day.


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## 4metals (Aug 13, 2009)

Oz got me to thinking and I had 3 days to kill at a clients place so I set up an experiment to see if recoveries were comparable for PGM's using the inquarting method ala OZ and the classic waste precipitation using copper on aqua regia refining. I wanted to see if PGM recovery was more effective one way or the other. 

What I had them do was process a 1000 ounce karat lot in aqua regia the standard way, process the chlorides (karo syrup) and segregate the waste so I could do the copper precipitation of PGM's and collect the residues, which I melted into a copper bar and had assayed by ICP. 

The second 1000 oz lot 1 split up into 10 lots of equal sized bars, inquarted with 150 ounces of fine silver and digested in 50% nitric, cemented the silver and inquarted the next lot, and the next until the 150 ounces had inquarted all 10 bars and also collected about another 100 ounces of silver from the karat bars. The accumulated semi refined gold was then aqua regia refined to make fine gold for sale. The silver was melted, and an assay was run for Pt and Pd on the bars. What a pain running Pt/Pd on silver by ICP. 


The recovery was equally good from both methods, considering the gold assay was lower and the silver higher on the inquarted lot it makes sense the PGM's would be lower in a less valuable lot.
here's the data on excel

I'm torn as to how to clean up the silver in a production environment so I can't say as I'd be inquarting on a large scale until I can work that out. 

Comments?


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## Harold_V (Aug 14, 2009)

If the platinum metals aren't excessive, they are recovered nicely from the slimes from the silver cell. 

Too high of a concentration of the platinum metals and gold in the anode can lead to isolation of the silver, resulting in a depletion of silver in the electrolyte. 

Harold


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## goldsilverpro (Aug 14, 2009)

4metals,

Excellent post!!


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## 4metals (Aug 14, 2009)

If it were only platinum in a silver cell it would be easy, it's the palladium, when it builds up in the cell it contaminates the silver. Quite a bit of the platinum alloy I see today is platinum / palladium (95/5) no where's near as much Platinum / irridium (90/10) as in the past. 

The test I ran shows it's a viable way to collect the PGM's using an inquarting technique but the recovery from the silver may be an issue. (I'm talking on the small scale refining level where analytical instrumentation is limited.)


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## Harold_V (Aug 16, 2009)

I don't recall every having a problem with palladium co-depositing with the silver. I did experience a slight buildup in solution, however. 

My method of making my next batch of electrolyte was to dissolve crystal that was removed from the previous batch. That allowed chemical testing of the resulting solution to determine the presence of copper or other elements. On rare occasion I'd have to re-run a batch of crystals, which were simply placed back in the basket with an anode on top. They refine perfectly well without melting and pouring an anode. The few times I re-ran was because of copper inclusion.

I do not recall ever having any palladium show up in solution when making my electrolyte. I'm of the opinion that as long as the concentration level is kept reasonable (in the anode), it isn't a problem. I rarely used any of my cement silver a second time for inquartation, in order to avoid a buildup. I processed a respectable amount of dental gold, so that was important. 

Overall, I'd suggest that for the small refiner, it's an excellent way to handle not only palladium, but platinum as well. 

Harold


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## saadat68 (Dec 29, 2018)

Hi
Can we dissolve 14, 18 or ... Karat yellow gold directly in AR without any gold loss? Yes I Know inquartation is a must in these situations but I just want to know what happen?
Does silver chloride cause to loss some gold or we can dissolve all of golds finally with just more work and more time?

Thanks


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## anachronism (Dec 29, 2018)

saadat68 said:


> Hi
> Can we dissolve 14, 18 or ... Karat yellow gold directly in AR without any gold loss? Yes I Know inquartation is a must in these situations but I just want to know what happen?
> Does silver chloride cause to loss some gold or we can dissolve all of golds finally with just more work and more time?
> 
> Thanks



Excuses me for asking however do you actually understand what you've written here or is there some loss in translation going on? 

"In the body of this thread and many other threads the answers to your questions lie."

You must be reading these 9 year old threads before re opening them I guess and in many cases your questions have been answered already.


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## saadat68 (Dec 30, 2018)

anachronism 
Thanks for your comment and I am sorry for my bad English

I read this topic before, I just try to post in a related topic

I ask my question otherwise in this topic

https://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=19777&p=292071#p292071


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## Geo (Dec 30, 2018)

Inquartation in recommended but not absolutely necessary. 14K and higher will dissolve in AR but will eventually come to a point where silver chloride will stop the dissolution. Prodding or other mechanical agitation will dislodge the crust of AgCl letting the acid under the crust. If the action stops completely, decant the solution from the remaining solids and dry the solids. Drying will cause the AgCl to break and fall off. Return the solids back to the solution and continue the dissolution. You may have to repeat this several times to fully dissolve the gold. Loss of gold will be minimal depending on attention to detail and expertise of the refiner.


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## saadat68 (Jan 1, 2019)

Thank you Geo
Got it


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