Working with AR

[margsu]

Hi everybody. This is my first try to dissolve basemetals with gold. I made AR as 1 part HNO3 60% and 4 part HCL 33% . At the moment seems that HCL will and before HNO3 and reaction will continue with HNO3 only. I think that If I take one part 60% HNO3 then I must take at least 6 part HCL 33%.

After trying AR solution I must wash powder. Can I wash it with HNO3 or I must use hot HCL only? In my country is HNO3 cheap as HCL.






I edited the title "Playing with AR" because it is not something that should be "played" with; we have some younger members of this forum and I don't want to have them with the mis-impression that this highly corrosive mixture is something meant for play! Lead by example! and thanks for your understanding, Lou

 

[qst42know]

If you can get HNO3. You should make things easy on yourself and dissolve the base metals first with 50/50 HNO3 and water before you use AR.

Solutions free of base metals are much nicer to work with.

 

[goldenchild]

First of all I want to say that you're lucky that you can get nitric for the same price as HCL in your country and I hate you(just kidding). You can use either acid to do your washes as long as your absolutely sure the other acid isnt present or you will lose gold. I would say nitric is better for your washes because it will also get rid of silver if present. But like qst42know said, dont use AR right away unless you have 18k(solid) gold or higher. Im guessing most of us on the forum do HNO3, AR, AR, HCL to refine all of our beautiful buttons and ingots.

 

[Harold_V]

First of all I want to say that you're lucky that you can get nitric for the same price as HCL in your country and I hate you(just kidding). You can use either acid to do your washes as long as your absolutely sure the other acid isnt present or you will lose gold. I would say nitric is better for your washes because it will also get rid of silver if present. But like qst42know said, dont use AR right away unless you have 18k(solid) gold or higher. Im guessing most of us on the forum do HNO3, AR, AR, HCL to refine all of our beautiful buttons and ingots.

There's a hole in your theory about nitric ridding gold of silver. If gold has been precipitated, any silver that may be present would be as silver chloride, which is not soluble in nitric.

I always recommend AGAINST using nitric for washing precipitated gold. You can achieve perfectly acceptable results by washing with HCl, and not risk losing any of the values. A follow-up wash with ammonium hydroxide will remove traces of silver chloride, should they be present.

Harold

 

[WIZZARD]

What do you get if you use ammonium hydroxide with silver chloride?, and it dries out? My thinking is, if you do this a lot and accumulates? Are there any circumstances that ammonium hydroxide will place gold ions in solution? Like if one adjusts pH with ammonium hydroxide and you go to far...........how to recover the gold?

WIZZARD

 

[butcher]

AgCl + NH4OH --> AgOH + NH4Cl
silver chloride and ammonium hydroxide gives silver hydroxide and ammonium chloride.

and I suspect there is also a possibility for other combinations of silver oxide and ammonia compounds and chlorides. depending on the reaction details I am guessing here.

anytime you have an ammonia compound and a silver compound,
DO NOT DRY IT, alway's acidify it with HCl to remove silver, and make it safer to dry, why take a chance with these dangers.

it takes a heck of a lot of ammonium hydroxide to dissolve silver chloride, I have heard something like 1 part silver chloride dissolves in 1000 parts ammonium hydroxide, these figures may be off base somewhat,the Idea here is it takes a whole bunch.

maybe a chemist will chime in here, or GSP will share more wisdom of his silver knowledge, well if we look in his book the information is probably there .

 

[machiavelli976]

AgCl+2NH4OH=> [Ag(NH3)2]Cl+ 2H2O

 

[margsu]

I am sorry about this title. I must apology and thaks Lou. At the moment I dryed some AR. I don´t use any SMB or other percipants. I get a dark green mud. At the moment I washed this mud with muriatic and nitric. At the bottom is a lot of brown seddiment. Is that gold or may be there is palladium or some othel platinum group metals. I used 30% nitric and 60% nitric.

 

[butcher]

you dried aqua regia I take this as you evaporated to salts. if so you should have the metals that was in the aqua regia, you said green mud, then you said you washed with aqua regia, and are left with brown mud. did you test your wash solution for values?
the brown mud can be gold but if there were base metals they can still be there, in this mud,it is very hard to wash powder crystals, they lockup all the metals in solution, this is why removing base metals first is so important, washing may help but it is no cure for a polluted powder. what I would do would depend on how much base metals are there, if alot of base metals I would dry incenerate and then use nitric to remove base metals and then redisolve the powders in aqua regia and denox, dilute check for silver chloride and use precipitantto get the gold.
if there were not much base metals I would not incenerate and just bring it back up in aqua regia and denox , dilute remove any silver chloride and precipitate gold, then if you suspect enough platinum group (for small amount add to your stock pot) concentrate solution and use ammonium chloride for platinum and few crystals of sodium chlorate (stock pot is usually best).

 

[margsu]

why to dissolve this brown mud in AR? If there is no reaction with nitric then there must be only gold. I don't think that in computer have platinum. I don't have SMB so I can only dry my solution.

 

[butcher]

the brown mud after nitric is gold or valuble metal.
and will be a fairly high purity but will not be pure.
you have gone this far why not finish the job and get pure gold?
there will still be base metals amout depends on if nitric was used up or not, even if it was not there are still metals it did not get, also there can be other impuritys depending on the input materials.
you have recovered gold now to make it more pure refine it in either aqua regia or HCl acid and bleach, following all the steps nessary I will not give them all now we have done that so many times.
if you have sulfuric acid you can make ferrous sulfate with Dilute sulfuric acid and Iron, there are also posts on this. if you can not find posts or run into problem ask for info.

 

[philddreamer]

When I was ready for my first batch of AR, I put together these steps for me to follow, so I wouldn't get lost during the process. Butcher took the time to explain to me the procedure, as he probably has explained it to dozens more before & after me. He also pointed out to read the posts, Hoke's & wacht lazersteve's videos...
I didn't get hurt & I had excellent results. So, I want to share a copy of these steps & hopefully it will be of help for those who read it.