# AR Method is Taking too much time



## Golden mermaid (Mar 21, 2022)

Hello, this is my first thread here. Even though I have searched in the forum i could not found someone with this problem. My purifications are taking way too much time, like 3-4 days.
Is this normal ?
I really don't know the concentration of the acids that I'm currently using, and that's a problem, to remediate that, first I pour the HCl, and then add half the NHO3 I pretend to use, from there on i just go adding 10-10% until every piece of gold os dissolved. That's when my problems begin; even though I add every drop of Nitric Acid, there is still gold in the crucible. Then I go above the amount I intend initially. But, the HCl probably have already evaporated at this point, and there's no reaction, at some point, I add more HCl. This takes almost a day. When I'm going to my 2nd day there's already 500ml of liquid. And I have to keep doing that until everything is dissolved. At the end I'm with almost 2L of liquid to deal with.

Please, could someone help me?!


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## Alondro (Mar 21, 2022)

Golden mermaid said:


> Hello, this is my first thread here. Even though I have searched in the forum i could not found someone with this problem. My purifications are taking way too much time, like 3-4 days.
> Is this normal ?
> I really don't know the concentration of the acids that I'm currently using, and that's a problem, to remediate that, first I pour the HCl, and then add half the NHO3 I pretend to use, from there on i just go adding 10-10% until every piece of gold os dissolved. That's when my problems begin; even though I add every drop of Nitric Acid, there is still gold in the crucible. Then I go above the amount I intend initially. But, the HCl probably have already evaporated at this point, and there's no reaction, at some point, I add more HCl. This takes almost a day. When I'm going to my 2nd day there's already 500ml of liquid. And I have to keep doing that until everything is dissolved. At the end I'm with almost 2L of liquid to deal with.
> 
> Please, could someone help me?!


If you don't know the concentrations, that's a HUGE problem. If it's too dilute, it really won't work, and the proportions will be so far off it's impossible to get it right. 

For proper AR, it really MUST be concentrated HCl and HNO3 that is confirmed. 

Does the HCl fume in moist air when exposed to it? If it doesn't, it's not a high concentration. Conc. nitric should fume too. You could test the nitric by putting a little of it onto some clean copper wire in a beaker. It should react immediately and very vigorously if it's fairly concentrated. If it only bubbles slowly, it's dilute. You won't get a measure of exact concentration, but you'll at least know if one of both acids is CLEARLY much too dilute to work.


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## Golden mermaid (Mar 21, 2022)

Alondro said:


> If you don't know the concentrations, that's a HUGE problem. If it's too dilute, it really won't work, and the proportions will be so far off it's impossible to get it right.
> 
> For proper AR, it really MUST be concentrated HCl and HNO3 that is confirmed.
> 
> Does the HCl fume in moist air when exposed to it? If it doesn't, it's not a high concentration. Conc. nitric should fume too.


Both of them fume, but I'm not sure that the concentrations are right to proper make AR. Here in my country is a little bit hard to buy buy this products, and when we find someone that is willing to sell, they hardly know the concentrations (I've already asked them). One time they told me that HCl is 37% and HNO3 is 53%.

But it's normal to take so long to dissolve the gold?


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## Alondro (Mar 21, 2022)

Golden mermaid said:


> Both of them fume, but I'm not sure that the concentrations are right to proper make AR. Here in my country is a little bit hard to buy buy this products, and when we find someone that is willing to sell, they hardly know the concentrations (I've already asked them). One time they told me that HCl is 37% and HNO3 is 53%.
> 
> But it's normal to take so long to dissolve the gold?


Well, if those are the concentrations, it should dissolve the gold. The other possibility is that you have so much gold, you need more acid to dissolve it all... which would be a GREAT problem to have!

Both acids fuming certainly should be concentrated enough to get it to work to some degree. Does your stannous chloride test show gold in solution? 

Have you tried gently heating it to coax the reaction along if it's slow to start? Is the gold alloyed with some other metal that might resist acids? A high amount of platinum would prevent easy dissolving in AR until it gets nearly to a boil, but then you'd likely have 'white gold', which would be pretty obvious.


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## justinhcase (Mar 21, 2022)

It always makes me chortle.
The gold has taken three hundred and sixty-five million years to get to you.
And you are still in a hurry.
It is not about how long it takes.
It is how long it takes for you to do a good job, you could cut corners and do a half effort.
But if you want to get it right, it takes as long as it takes.
Some will filter faster, some slower, it is more about dealing with the impurity not refining the gold.
I tell clients it should take me a week or so, good lot in four days to recover properly, if it is being stubborn and not filtering sometimes almost two weeks to slowly put it through gravity filters and wash them properly.


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## Golden mermaid (Mar 21, 2022)

Alondro said:


> Well, if those are the concentrations, it should dissolve the gold. The other possibility is that you have so much gold, you need more acid to dissolve it all... which would be a GREAT problem to have!
> 
> Both acids fuming certainly should be concentrated enough to get it to work to some degree. Does your stannous chloride test show gold in solution?
> 
> Have you tried gently heating it to coax the reaction along if it's slow to start? Is the gold alloyed with some other metal that might resist acids? A high amount of platinum would prevent easy dissolving in AR until it gets nearly to a boil, but then you'd likely have 'white gold', which would be pretty obvious.


Well, I take approximately 100g of 18k yellow gold per procedure. I'll try to look for an alternative supplier. 

About the heating, my reaction is only working when heated.

Thank you for your time.


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## justinhcase (Mar 21, 2022)

Golden mermaid said:


> Well, I take approximately 100g of 18k yellow gold per procedure. I'll try to look for an alternative supplier.
> 
> About the heating, my reaction is only working when heated.
> 
> Thank you for your time.


Are you inquarting first?
Or just trying to go straight into A.R,?


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## Golden mermaid (Mar 21, 2022)

justinhcase said:


> It always makes me chortle.
> The gold has taken three hundred and sixty-five million years to get to you.
> And you are still in a hurry.
> It is not about how long it takes.
> ...


Hahahaha. 
Well, I'm not actually in a hurry, just thought that was something else I was doing wrong. Like, there's a chance I could be heating too much the AR, and accelerating the HCl evaporation?! Or, if I should really be ready to such quantities of liquid?!


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## Golden mermaid (Mar 21, 2022)

justinhcase said:


> Are you inquarting first?
> Or just trying to go straight into A.R,?


Straight to AR


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## justinhcase (Mar 21, 2022)

Well, first, you should not try and never hurry when handling dangerous chemicals and valuable metals.
You will lose your health and your gold.
And I know you what to get your mittens on that gold just as soon as you possibly can.
But there are some very good reasons refiners refine in the manner we do.
It is not by chance that we have come to these methods, it is age-old experimentation and everyone thinking they know better and trying to cut corners.
If this had ever been true, I can assure you we would be using that shortcut, not hearing about people repeatedly going down that particular dead end road.
There is also the glaring problem with heating your liquids.
I take it you do not have a reflux condenser or proper reaction vessel?
Then you should not be heating your beakers very much, bumping and bubbling will spread value and metallic salts all over your work aria.
I would advise you start to inquart your material and preform a base metal leach before trying to put into A.R.
I hope that is of help.


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## Alondro (Mar 21, 2022)

Golden mermaid said:


> Well, I take approximately 100g of 18k yellow gold per procedure. I'll try to look for an alternative supplier.
> 
> About the heating, my reaction is only working when heated.
> 
> Thank you for your time.


Well that IS a pretty large amount of gold. You're looking at about 2 oz or a little more per 100g of 18k. Using 500 mls of total solution is not surprising. And if you have chunks of this material instead of thin foils, yes it will take time to dissolve it all. Definitely use a little heating if you want to move it along. But only GENTLE warming. Do not let it boil. That will splatter dangerously. I have a warming plate with the temps controlled so it won't overheat.

You'll also have silver (which will fall out of the solution as a white or gray-white powder of silver chloride which may slowly turn to silver oxide if your reaction takes place in strong direct light), and probably a bit of platinum, which likely also will drop out since you have a very concentrated solution of metal dissolved. If the solid powder after the metal is dissolved looks grey, then there's a decent amount of Pt-group metals in there too, along with silver chloride.


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## Golden mermaid (Mar 21, 2022)

justinhcase said:


> Well, first, you should not try and never hurry when handling dangerous chemicals and valuable metals.
> You will lose your health and your gold.
> And I know you what to get your mittens on that gold just as soon as you possibly can.
> But there are some very good reasons refiners refine in the manner we do.
> ...


Yes, I have a hood with an exhaust fan, and I always cover the beaker with a clock glass (I don't know how you refer to it)
Thank you, next time I'll try to inquart!


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## Golden mermaid (Mar 21, 2022)

Alondro said:


> Well that IS a pretty large amount of gold. You're looking at about 2 oz or a little more per 100g of 18k. Using 500 mls of total solution is not surprising. And if you have chunks of this material instead of thin foils, yes it will take time to dissolve it all. Definitely use a little heating if you want to move it along. But only GENTLE warming. Do not let it boil. That will splatter dangerously. I have a warming plate with the temps controlled so it won't overheat.
> 
> You'll also have silver (which will fall out of the solution as a white or gray-white powder of silver chloride which may slowly turn to silver oxide if your reaction takes place in strong direct light), and probably a bit of platinum, which likely also will drop out since you have a very concentrated solution of metal dissolved. If the solid powder after the metal is dissolved looks grey, then there's a decent amount of Pt-group metals in there too, along with silver chloride.


Thank you very much for your help!


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## justinhcase (Mar 21, 2022)

Golden mermaid said:


> Yes, I have a hood with an exhaust fan, and I always cover the beaker with a clock glass (I don't know how you refer to it)
> Thank you, next time I'll try to inquart!


Although some seem to find it economical to refine silver on its own, I do not.
But it does make a most wonderful solvent to wash your gold clean with.
Platinum group metals which by themself are acid hardened will now go to a nitric solution, leaving you a relatively pure sediment to put into AR.
I tend to run the base metal leach in the day and leave it overnight to finish, test the residual with a little acid in the morning to make sure there is no more reaction.
If there is a reaction, leach some more, if not put into solution.
Wash with lots of hot distilled water before AR.
You will be able to use a minimum of acid because of the reduced mass and ease of observation, should be in solution inside the hour.


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## justinhcase (Mar 21, 2022)

Golden mermaid said:


> Yes, I have a hood with an exhaust fan, and I always cover the beaker with a clock glass (I don't know how you refer to it)
> Thank you, next time I'll try to inquart!


And just to clarify.
A beaker and watch glass(I have a collection of saucers for my larger beakers) will keep a bit of your ejected value in if used on small lots, and you avoid too much bumping.
But extensive boiling or frothing will result in a nice little fountain of value coming out just at the space between poring spout.
I recommend a good round bottomed flanged reaction vessel and reflux condenser instead.


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## Golden mermaid (Mar 21, 2022)

justinhcase said:


> And just to clarify.
> A beaker and watch glass(I have a collection of saucers for my larger beakers) will keep a bit of your ejected value in if used on small lots, and you avoid too much bumping.
> But extensive boiling or frothing will result in a nice little fountain of value coming out just at the space between poring spout.
> I recommend a good round bottomed flanged reaction vessel and reflux condenser instead.


Those are some valuable tips! Thank you very much!


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## orvi (Mar 21, 2022)

If you are boiling 18k gold straight in AR, that will take quite a bit of time without inqartation. Ultrasonic cleaner could help a lot to disintegrate AgCl crust. But I will definitely go with inquartation. That would be cutting the dissolution time from days to hours 
You also get better separation of silver.


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## orvi (Mar 21, 2022)

Golden mermaid said:


> Both of them fume, but I'm not sure that the concentrations are right to proper make AR. Here in my country is a little bit hard to buy buy this products, and when we find someone that is willing to sell, they hardly know the concentrations (I've already asked them). One time they told me that HCl is 37% and HNO3 is 53%.
> 
> But it's normal to take so long to dissolve the gold?


Very simple way how to approximately tell how strong is the acid, is by measuring its density. Get a volumetric flask, measure say 100 mL of the acid and weigh it. From the volume and weight you calculate density, which will tell you how strong the acid is. Density tables are widely available on the internet for common acids like HCl or HNO3.
If you do not have volumetric flask, graduated cylinder is also usable, but with bigger error margin. Or you can use calibrated glass pipette. This is also quite accurate.

Also pay attention to temperature, as the density tables are always measured at defined temperature. Difference or 2-4°C make quite an error.


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## Golden mermaid (Mar 21, 2022)

orvi said:


> If you are boiling 18k gold straight in AR, that will take quite a bit of time without inqartation. Ultrasonic cleaner could help a lot to disintegrate AgCl crust. But I will definitely go with inquartation. That would be cutting the dissolution time from days to hours
> You also get better separation of silver.


Ow, I'll try using the ultrasonic cleaner in this batch. Next time, inquart! Hahaha


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## Golden mermaid (Mar 21, 2022)

orvi said:


> Very simple way how to approximately tell how strong is the acid, is by measuring its density. Get a volumetric flask, measure say 100 mL of the acid and weigh it. From the volume and weight you calculate density, which will tell you how strong the acid is. Density tables are widely available on the internet for common acids like HCl or HNO3.
> If you do not have volumetric flask, graduated cylinder is also usable, but with bigger error margin. Or you can use calibrated glass pipette. This is also quite accurate.
> 
> Also pay attention to temperature, as the density tables are always measured at defined temperature. Difference or 2-4°C make quite an error.


Oh yeah! O forgot about the volumetric mass  I'll try that too.


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## nickvc (Mar 22, 2022)

You should have little problem with dissolving 18 karat directly in AR but you will need good heat, I would suggest that after your first addition of nitric starts to slow add another amount of HCl before adding any more nitric if the reaction kicks off again you had depleted your HCl , adding more HCl causes no problems unlike adding too much nitric. In honesty you should be able to dissolve 100 grams of 18 k in one day at most.
inquartation is good when you have mixed white and yellow gold items as any PGMs will follow the silver into solution making recovery easier but most large refiners never use it as it slows down the gold refining where there main profit lies.


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## Golden mermaid (Mar 22, 2022)

nickvc said:


> You should have little problem with dissolving 18 karat directly in AR but you will need good heat, I would suggest that after your first addition of nitric starts to slow add another amount of HCl before adding any more nitric if the reaction kicks off again you had depleted your HCl , adding more HCl causes no problems unlike adding too much nitric. In honesty you should be able to dissolve 100 grams of 18 k in one day at most.
> inquartation is good when you have mixed white and yellow gold items as any PGMs will follow the silver into solution making recovery easier but most large refiners never use it as it slows down the gold refining where there main profit lies.


Wow, there are some useful tips you gave me. Never tried to inquart for the AR Method, just that when I used that more inefficient method with only Nitric. My main problem is the volume of liquid in the end, because I'm a little clumsy . And that's a problem when filtering the solution. To avoid this problem I even tried some desperate methods, like using NaCl to increase the Cl in the solution without adding more volume. But there was no meaning difference in the end.


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## nickvc (Mar 22, 2022)

Golden mermaid said:


> Wow, there are some useful tips you gave me. Never tried to inquart for the AR Method, just that when I used that more inefficient method with only Nitric. My main problem is the volume of liquid in the end, because I'm a little clumsy . And that's a problem when filtering the solution. To avoid this problem I even tried some desperate methods, like using NaCl to increase the Cl in the solution without adding more volume. But there was no meaning difference in the end.



You shouldn’t worry too much about the volume of acids as the value of the gold you are refining is high , perhaps you need larger beakers and a bigger filter head to handle it , and to repeat you need high heat when dissolving solid gold pieces which helps keep the volume down.


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## justinhcase (Mar 22, 2022)

nickvc said:


> You should have little problem with dissolving 18 karat directly in AR but you will need good heat, I would suggest that after your first addition of nitric starts to slow add another amount of HCl before adding any more nitric if the reaction kicks off again you had depleted your HCl , adding more HCl causes no problems unlike adding too much nitric. In honesty you should be able to dissolve 100 grams of 18 k in one day at most.
> inquartation is good when you have mixed white and yellow gold items as any PGMs will follow the silver into solution making recovery easier but most large refiners never use it as it slows down the gold refining where there main profit lies.


I tend to run all my karat gold through an inquatation.
I always have a very mixed bag so one reliable run for it all is very economical.
The silver would not be economical at all if I did not use it in inquartation.
The only time I ever put gold directly into AR is for diamond recoveries.
Some go into solution okay, but a lot will not, there is always a range of digestions.
Some require regular washing with ammonia to strip off the AgCl.
But I am not a large refiner.


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## nickvc (Mar 22, 2022)

Justin the big boys buy in scrap as bars or melt the scrap in house then assay them for gold for settlement and for silver so they can mix the bars to keep the silver content low, they can recover any PGMs later and will convert the silver chloride to metallic silver and put it into a cell to recover any gold traces unless they use the atomization process which negates any need for a silver assay, for the majority of members inquarting is advised as it negates the need for assays and any PGMs will report with the silver making recovery easier , for you inquarting makes perfect sense and is best practice for your circumstances.


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## justinhcase (Mar 22, 2022)

nickvc said:


> Justin the big boys buy in scrap as bars or melt the scrap in house then assay them for gold for settlement and for silver so they can mix the bars to keep the silver content low, they can recover any PGMs later and will convert the silver chloride to metallic silver and put it into a cell to recover any gold traces unless they use the atomization process which negates any need for a silver assay, for the majority of members inquarting is advised as it negates the need for assays and any PGMs will report with the silver making recovery easier , for you inquarting makes perfect sense and is best practice for your circumstances.


Yes, I do kind of love a good inquartation.
If you get it right from then on in, everything is easy.
Sometimes I cornflake and find I do not have an even alloy, so have to dry it and remelt until it is nice and uniform.
But the result is nice crumbly broken alloy that sits nicely at the bottom of your reaction vessel while you wash it.
Then, if you have washed it right, very little sediment to block filtering after your A.R. digestion.
Also, the refinement is easier as you have a cleaner recovery to work from.
But for the last two years I have had nothing to do all day but wait for clients to come in and refine, so I take the easiest rout to a product I am willing to send out and put my feet up as much as I can.


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## Golden mermaid (Mar 23, 2022)

justinhcase said:


> Yes, I do kind of love a good inquartation.
> If you get it right from then on in, everything is easy.
> Sometimes I cornflake and find I do not have an even alloy, so have to dry it and remelt until it is nice and uniform.
> But the result is nice crumbly broken alloy that sits nicely at the bottom of your reaction vessel while you wash it.
> ...


I didn't get the image, is that precipitade gold after inquart? So far I didn't inquart yet, I'll try it on my next batch, and report it in here my results.

Although, the ultrasonic cleaner tip was spot on! I mean, just a few hours after putting it back into the heating, all the remaining gold was dissolved by AR.


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## Yggdrasil (Mar 23, 2022)

That is gold after the Silver has dissolved. Yummi


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## justinhcase (Mar 23, 2022)

Golden mermaid said:


> I didn't get the image, is that precipitade gold after inquart? So far I didn't inquart yet, I'll try it on my next batch, and report it in here my results.
> 
> Although, the ultrasonic cleaner tip was spot on! I mean, just a few hours after putting it back into the heating, all the remaining gold was dissolved by AR.


Yes, that is a "Parted" Inquatation.
Just washing it off before putting into AR.
If you want to digest something, it is normally advised to remove as much of the base metals as possible before going to Chloride.
I personally find the longest distance between two points is the shortcut.
But small lots can be managed in a great may ways, and all roads do lead to Rome eventually.
The inefficiency and problems are amplified as you increase the lot size.
An impurity that was a pain when filtering a few hundred ml become a real problem when you get up to 10L.
Have fun, stay safe and good luck.


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## orvi (Mar 24, 2022)

justinhcase said:


> Yes, that is a "Parted" Inquatation.
> Just washing it off before putting into AR.
> If you want to digest something, it is normally advised to remove as much of the base metals as possible before going to Chloride.
> I personally find the longest distance between two points is the shortcut.
> ...


Very nicely said.


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## Golden mermaid (Mar 24, 2022)

Inquart really helped with my time! Thanks for everyone that helped me!


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