New here

[TeamGold]

Hello all im new here and im still trying to figuer out this forum so i might post a few wrong places and so on lol
I do have a few questions and its mostly to the leaders of this forum and i dont know if its important to you but for me as a none english member it is very important because not everything can be translated correctly and a chemical as Urea dont exist in Danish or can not be translated, so maybe you can use a international formula for those chemicals, and maybe you already have lol and i just havent found them yet here and if so dont think more about this here and i will find it some day lol.
Im not a chemist and only do this here as a hobby but im having fun with it and that is the main plan for me with this.

 

[jason_recliner]

Hello TeamGold

Welcome to the forum.

Firstly, your language is a non-issue. Yes, the forum is based in English, but there are people from all over the world who don't have correct and proper English as a first language. Plenty of Americans, for example.

The formula for urea is CN(NH₂)₂. But apparently it's not necessary. The general consensus is that sulfamic acid, H₃NSO₃, is a better choice. I'm not 100 % clear on why, they both eliminate excess nitric, but sulfamic does it better. Personally, for all my very many mistakes, I have still never needed to use either of them. If you add your nitric slowly, neither will you.

 

[FrugalRefiner]

TeamGold, welcome to the forum. For chemical names that don't translate well for you, try the Glossary of Common Terms. We also have some threads geared toward helping new members get acquainted here. Take a look at the Tips for Navigating and Posting on the Forum thread. You'll find a lot of helpful links there, especially lazersteve's Guided Tour.

Dave

 

[TeamGold]

Thanks for the info and yes im not English and the translations for some of the chemicals is very wierd and give no direct names i can use but i will look them up on those places, i have not used Urea yet but that was just an example and maybe i can find a name for it here after looking at those forums. So far all im douing is collecting folie and all im using is the AP methode for that and that is a good beginner way to recover bouth gold and silver, and yes im saving the solutions for later if i want to try to get the other metals out, and i might do so later when i have more used solution.

 

[MarcoP]

Hi TeamGold and welcome to the forum! Urea in Danish: https://da.m.wikipedia.org/wiki/Urinstof

I've recently learned, and hope I'm right here, that urea get rid of NO₂ gas in solution, not the free nitric. Sulfamic acid, instead, get rid of free nitric and this is what we need.

Marco

 

[Anonymous]

Marco - unless my chemistry is completely wrong Urea does actually neutralise Nitric acid.

Urea plus Nitric Acid = Urea Nitrate.

(NH2)2CO (aq) + HNO3 (aq) → (NH2)2COHNO3 (s)

Jon

 

[FrugalRefiner]

Jon, take a look at Lou's posts in these threads:

Little Problem
Recovering precious metals from polishing sweeps
urea

I tend to trust Lou's chemistry.

Dave

 

[Anonymous]

Okie doki no harm no foul. Hopefully Lou will clarify Dave.

 

[g_axelsson]

This is an interesting question, I'm no chemist myself so I feel a bit at lost here.

According to the wikipedia article https://en.wikipedia.org/wiki/Urea_nitrate the reaction is correct that Jon is giving and would produce a solid precipitate. (Urea nitrate is slightly to quite soluble in water, haven't found any numbers there)
I have also found several patent texts supporting this reaction, for example https://www.google.com/patents/US3141039 says

In the past, urea nitrate has been prepared by reaction of urea with nitric acid in aqueous solution. Such a method has a disadvantage in that urea nitrate is soluble in Water to a substantial extent and it is difficult to separate urea nitrate from water-soluble impurities.

This would leave nitrate ions in solution that could form new nitric acid and possibly aqua regia, complicating precipitation of gold.
Maybe urea and nitric acid only reacts in specific conditions.

On the other hand the usage of urea has been a very common knowledge but I haven't been able to trace it's origin. I couldn't find any references in Hoke for example.

I found this thread that I suggest we can make part of the library.
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=48&t=13102#p131441

Göran

 

[Anonymous]

Good thread hunting Goran.

So if I read correctly the answer is actually a combination of what Lou said and what I said.

Freechemist confirms Lou's points totally and then goes on to say that:

"With nitric acid urea reacts as a weak base, forming the salt urea nitrate, which apparently can be crystallized easily:

(H2N)2CO + HNO3 ==> (H2N)2COH(+) + NO3(-)"

 

[solar_plasma]

When I meet a word that is not included in the dictionairy, then I try to find the english word in the english wikipedia and once found I shift to the german or danish wikipedia page.

This works very well for chemicals, methods and technical terms.