Newbie needs help...

[zorba]

Hi guys, this question has surely been brought up numeral times in this forum. Anyway, because i am a real noob in gold refining i will ask this question again... Can i get an exact recipe on how to make an 100% succesfull Aqua Regia? I´ve downloaded and read "Catfish´s AR recipe", but what im really unsure on is why it needs to be Nitrate Soda (NaNO3) and not nitric acid which is the main acid used to make AR (as i have understood). I know that this may be a stupid question for you guys but since i am a noob to this and even to Hooks book, i need an answer.
Thanks :!:

 

[SilverNitrate]

NaNO3 is used because it would be the source of nitrate needed to make the AR. Otherwise if you have concentrated nitric acid then use that along with 3 volumes of conc. hydrochloric acid and possilbly some added water for lessening the excaping gasses.

 

[butcher]

NaNO3 sodium nitrate, it is the NO3 - we are using, this nitrate when mixed with H+ hydrogen from an acid, becomes nitric acid.

lets look at this , Na is a positive metal sodium, a very reactive metal, the NO3 nitrate is negative, so when we take this metal salt NaNO3, and mix it with an acid lets say sulfuric acid H2SO4, two Hydrogen positive and SO4 sulfate negative, the equation would look like this:

2NaNO3 + H2SO4 --> 2HNO3 + Na2SO4

so here we took sodium nitrate (a salt of nitric acid), and sulfuric acid, and made nitric acid, and sodium sulfate (a salt of sulfuric acid)

the same principle applies if we take the nitrate salt and mix hydrochloric acid, we will have a nitric acid and hydrochloric acid in the mix, and of coarse we have also created some table salt NaCL in solution,

here the preportions will make a difference
as we could just end up with just nitric acid and table salt

NaNO3 + HCl --> HNO3 + NaCl

we are useing nitrate like NaNO3 as a work around because of price or availability of nitric acid, nitric would be better if price or availability was not an issue,
as with Aqua Regia, using only as much nitric acid (or NANO3), needed to get the gold dissolved,with hopefully using it up in the dissolution process, this is what oxidizes the gold, but it will need to be eliminated later by boiling to be able to precipitate the gold.

a common mistake for people is how much acid to use, and also the thinking if a little is good more should be better.

 

[zorba]

wow, thank u so much, i understand now. So it really dont make any difference if i use nitric acid or sodium nitrate, it is just a workaround because of the price and availability.
Thanks, I may ask many more question in the future and im glad that there is experts like u guys to answer!

 

[butcher]

nitric would be best, you will not have other salt byproducts.

also remember eliminate the base metals, before using aqua regia.

 

[aflacglobal]

http://www.youtube.com/watch?v=G8U7t_UDy8s

 

[zorba]

the same principle applies if we take the nitrate salt and mix hydrochloric acid, we will have a nitric acid and hydrochloric acid in the mix, and of coarse we have also created some table salt NaCL in solution,

I actually have nitrate salt, so will it all be just fine mixing the nitric salt with 3-4 ounces hydrochloric acid to acquire AR ? Or do i first need the nitric acid to be concentrated, which is better ?

 

[zorba]

Please, an answer...

 

[Irons]

Please, an answer...

It all depends what you are trying to dissolve. Sodium Nitrate and HCl work fine if you're trying to dissolve small particles of Gold. It is not as aggressive as the Nitric Acid Aqua Regia, so for heavy gold or Platinum, us the Nitric acid.

Only add small amounts of Sodium Nitrate at first, or it may boil over once it warms. You can always add more later. Keep some ice handy, so you can cool the reaction vessel if the reaction gets to look like it's going to boil over. Don't do this indoors. Be safe.

I like to keep a couple of jugs of bicarbonate solution handy in case of an acid spill. I was once splashed in the face with White fuming Nitric Acid, when a 500 ml bottle of it fell off a shelf and exploded on the bench right in front of me. If it wasn't for an emergency shower just a few feet away, I might not be here.

 

[zorba]

Please, an answer...

It all depends what you are trying to dissolve. Sodium Nitrate and HCl work fine if you're trying to dissolve small particles of Gold. It is not as aggressive as the Nitric Acid Aqua Regia, so for heavy gold or Platinum, us the Nitric acid.

Only add small amounts of Sodium Nitrate at first, or it may boil over once it warms. You can always add more later. Keep some ice handy, so you can cool the reaction vessel if the reaction gets to look like it's going to boil over. Don't do this indoors. Be safe.

I like to keep a couple of jugs of bicarbonate solution handy in case of an acid spill. I was once splashed in the face with White fuming Nitric Acid, when a 500 ml bottle of it fell off a shelf and exploded on the bench right in front of me. If it wasn't for an emergency shower just a few feet away, I might not be here.

Thanks for the answer, sounds good but i think i must go with the AP method. I have like, lets say tons of E-scrap filled with gold and as i have understood it will be better with AP rather then AR with e-scrap? What do you think?
P.S that HNO3 spill doesnt sound rather pleasent... I hope you did not get any remaining injuries?

 

[butcher]

remove base metal before disolving in any aqua regia, HCl/H202 acid peroxide works well for lowering the base metal content, can be reused, not as expensive as nitric is for most of us.

 

[leavemealone]

Keep some ice handy, so you can cool the reaction vessel if the reaction gets to look like it's going to boil over.

I have Cracked a lot of borosilicate glass that way irons.Now I always make sure I use 2000ml labware or larger,and small amounts of AR at time.

nitric would be best, you will not have other salt byproducts

So true butcher.

"True" Aqua regia is made using nitric acid,not sodium nitrate.Using sodium nitrate you will make,what we so lovingly call,poor mans AR.I,like many others on here,do not have access to inexpensive nitric.So we are forced to do one of 3 things......either make our own nitric,or use sodium nitrate,or use a process that doesn't call for a nitrate at all.I started several years ago only using AP and AC to digest.Then I went to true AR and realized quickly that the material I process does not have a high enough percentage of gold content to justify the high cost of nitric.Now years later I am much more experienced and I use poormans AR when I need to.I purchase sodium nitrate at a local Ace hardware for $4 for a 4lb bag.I also use copperas to percipitate instead of SMB.I also get that from Ace for $1 a pound.It takes a little over twice the weight of copperas versus SMB,but the savings makes it worth it.
Johnny