White crystals all around aqua regia

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sayf

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I did my first gold recovery from trimmed clean ram fingers 2 days ago
But i think i failed
I directly put the fingers in aqua regia made od 800 ml hcl and 300 ml nitric acid, i know thats too much nitric but i was confused, any ways the fingers wear clear and every thing seemed fine and the color of the solution was dark greenI then filtered the solution to get rid of any wood and remenants and started adding urea to neutralize the nitric, i noticed a white thick layer on top of the solution after adding last spoon of urea, is it due to excess urea? Giving that urea was added gradually untill reaction with nitric was stopped
Then i added about 8 grams of smb to the solution because i was expecting about 4 grams of gold
and i directly noticed a white thick layer at the bottom of the flask and to be honest i dont know if it was precipitated before or after or during the smb addition
, i left the solution and came back after 24 hours
I noticed like white big crystals all around the solution and white powder at the bottom of the flask
i did the following moved the liquid into another flask and started heating it with adding some hcl to the solution, every thing dissolved and white crystals has disappeared and solution went dark green again, i used smb to precipitate again, same thing has happened, white crystals has formed all around the solution and white powder at the bottom of the flask, i did several study in this forum but mistakes still happens
can u answer these question pls
what the mistakes i have done?
What are these white crystals that spread all around the solution and why they appeared?
What is the precipitated white powder at the bottom and why it appeared?
how to fix such a problem to get my gold ?
Thanks every one
 

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Martijn

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One big mistake you made: Not taking your time to study, and not asking questions here or proposing your intended steps before you attempted a process that would be strongly discouraged here.

Number 2: using urea. Don't use urea unless you understand the chemistry behind it. And why and when to use it.

Urea does not neutralize free nitric!

I read it can even be dangerous and create explosive compounds. Remember a recent big explosion... Because of this i have never tried it.

Don't take risks you dont understand.
Don't exeriment with things, use proven methods.
Don't try to take shortcuts.

This is a classical example of what NOT TO DO.
So many things to correct here..

Wood on RAM fingers??
Dare i ask for pictures?
Please stop this madness and go study.

Homework for you:
How do i start and where do i learn these skills:
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=49&t=28521
Welcome to newbies:
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=33&t=796

Be safe. Stop and save your life.
Martijn.
 

Martijn

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Anyone please comment on if he created dangerous or explosive compounds that need immediate attention and how to dispose of said compounds.

How to get your gold back, will become clear after you have read the 'dealing with waste' thread.
 

Martijn

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https://www.google.com/url?sa=t&source=web&rct=j&url=https://en.m.wikipedia.org/wiki/Urea_nitrate&ved=2ahUKEwjilMyoi4nsAhVNwKQKHSsPBiAQFjAAegQIAhAB&usg=AOvVaw0u1sNpoPZOEtOMha04o7vt
I do believe you have created a very serious problem.
Get help and move your experiment to a safe area away from people and animals.... :shock: :shock:
 

sayf

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Man u scared the hell out of me, are you serious about explosions and i read alot and lot of people say that urea is used to neutralize nitric, as i saw many videos about that
 

Martijn

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No I am serious. I dont know howmuch urea you have used but read the wiki link. It explains how its made.
As long as its wet, I think you'll be oke.
I will read some more and get back when i have some info.
 

sayf

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Ok ill get rid of it in a safe far place
But tell me please what to use to neutralize nitric acid if its not urea?!!
 

kurtak

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Martijn said:
Wood on RAM fingers??
Dare i ask for pictures?

Martijn.

Martijn - it's likely a translator issue --- sayf is from Jordan - so when he typed board (as in circuit board) in his native language - then translated his native language to English the translator saw board as wood

Kurt
 

nickvc

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It’s best not to over use the nitric in the first place in honesty but if you do we recommend using sulphamic acid which will convert the nitric to sulphuric, problems can arise if you use too much sulphamic as the sulphuric acid you make will eat your filter papers.
The reason we worry over urea is that it is a main component of gunpowder :shock:
 

sayf

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Is thereany thing dangerous in that solution?
Do i have to worry about it being therd at my roof?
 

sayf

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nickvc said:
It’s best not to over use the nitric in the first place in honesty but if you do we recommend using sulphamic acid which will convert the nitric to sulphuric, problems can arise if you use too much sulphamic as the sulphuric acid you make will eat your filter papers.
The reason we worry over urea is that it is a main component of gunpowder :shock:
How to know when i need to stop adding sulphamic acid to the solution?
 

Martijn

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I did not consider the google translation from boards to wood... :roll: sorry... got carried away in my amazement.

So. How to proceed? Just filter cold and keep the filter wet I assume. How to dispose of this solution and the filtered solids without making it someone elses problem?

Can it be treated as waste by raising Ph?

Or can it be converted to a less dangerous compound, say fertilizer (UAN solution)? After getting the poisonous metal salts out.

Cementing the filtered solution with copper to retrieve the gold as usual?

I would like to know. Just for the sake of knowledge and safety. And I can not find much info on it, for obvious reasons i think.

Martijn.
 

Martijn

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[/quote]
How to know when i need to stop adding sulphamic acid to the solution?
[/quote]

First i would ask i it ok to add sulfamic acid to this mix of compounds. Or do i create a bigger mess by doing so?

Second i would say in the future, when trying something on a very small scale to get acquianted with the process, like test tube scale and after asking us if your on the right path before attempting anything....
Learn how far a little nitric will go. Like in a covered, but not closed off beaker on slight heat. A 50 degree celsius temperature warm water bath will doo fine. Take your time, observe and take notes of added quantities and the effect.
Add milliliters at a time in a beaker. Drops from a pipet in a test tube.
Adding more is easy. Getting it out harder and unnecessary.
Then you don't need to fight the symptoms of problems of which you can easily prevent the cause.
 

kurtak

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Martijn said:
Anyone please comment on if he created dangerous or explosive compounds that need immediate attention and how to dispose of said compounds.

Martijn

First of all - yes you are correct in that combining urea with nitric will create the explosive compound of urea nitrate - which is somewhat more sensitive (more explosive) then ammonium nitrate

However - both of these compounds are "commonly" used as fertilizers as they are a common source for providing nitrates to soil

So although yes they are an explosive compound - the reason they are also a common fertilize is because as an explosive they are relatively stable & are classed as a "secondary" explosive (as opposed to a "primary" explosive)

In other words they are not "self igniting" meaning they wont ignite under their own pressure/force/energy/shock/ --- in order to "set off" the explosive reaction of urea/ammonium nitrate you need to provide it with a "greater" source of pressure/force/energy/shock --- in other words it takes a primary explosive to set off the more stable secondary explosive

Examples of a primary explosive that can/will set off a secondary explosive - an electrical spark or other high energy spark (such as a match spark or welding spark etc.) or the ignition of a more sensitive (primary) explosive compound

Primary explosives are VERY unstable & can/will be set off with very little pressure/force/energy/shock

Examples of (common used) primary explosives are mercury fulminate or silver fulminate --- silver fulminate is MUCH more sensitive then mercury fulminate --- silver fulminate is so sensitive that it will self ignite under the pressure of it's own weight as it precipitates from solution & will do so when wet

Mercury fulminate is one of the (many) primary explosives used to set off secondary explosives such as used in the primers for bullets &/or blasting caps --- in a bullet prime it is the pressure of the firing pin striking the the primer that sets off the mercury fulminate (primary explosive) which in turn sets off the gun powder (secondary explosive) --- in other words gun powder it's self will not ignite under the pressure of a firing pin striking it - the gun powder requires the primary explosive to set off the secondary explosive

Like wise - urea nitrate is a secondary explosive & therefore relatively stable explosive which is not going to self ignite - which is why in turn it is used - in large quantities - as a nitrate source of fertilizer - you can throw 50 pound bags of urea nitrate around all day long & they wont blow up on you --- on the other hand - stick a blasting cap in a 50 pound bag of urea nitrate & touch the blasting cap off & that 50 pound bag of urea nitrate will blow a 6 - 7 - 8 foot diameter tree stump out of the ground --- how do I know that ? --- because that is how we got rid of BIG tree stumps when I worked in the woods building logging roads

The bottom line here being that IF (big if) what sayf created here is actually urea nitrate - its not going to just blow up in his face because all he really did was make a (urea) nitrate fertilizer

The problem(s)/question(s) I see here are - because he also added SMB - did the SMB also precipitate some &/or all of his gold - in which case the gold is going to be tied up in the urea nitrate --- &/or did the SMB create some other chemical compound other then urea nitrate (butcher can likely help with that)

In other words we need a stannous test on the solution to see where the gold is - as well as someone like butcher to tell us how the SMB may have or not effected what actually precipitate --- in other words did the SMB stay in solution & only urea nitrate precipitated - or did the SMB create a compound other then urea nitrate ????

Kurt
 

kurtak

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sayf

because you have also added SMB to your solution the "first" thing we need to know is where your gold is

in other words - your gold could still be in your solution - or the gold may have precipitated along with the urea nitrate that precipitated

So the very first thing you need to do is a test on the solution with some stannous chloride to see if the gold is still in the solution

Do you know what stannous chlorides is? --- &/or do you know how to make & use it ?

Bottom line - don't get excited & just start adding more chemicals to the mess you have already made - set it all to the side & wait for other members to provide questions/answers

We can solve most problems - but you need to wait for other members to chime in with both questions & answers to get to the bottom of the problem --- other wise you can end up creating more problems

The first problem we need to solve is --- where is your gold - that means you need to do a stannous test - if you don't know how to do that --- then that is the first/next thing we need to teach you - before moving on to anything else

Kurt
 

sayf

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kurtak said:
sayf

because you have also added SMB to your solution the "first" thing we need to know is where your gold is

in other words - your gold could still be in your solution - or the gold may have precipitated along with the urea nitrate that precipitated

So the very first thing you need to do is a test on the solution with some stannous chloride to see if the gold is still in the solution
Thanks kurt yes i know how to make stannous chloride i already did test the solution and no gold inside it so it has precipitated, right?

Do you know what stannous chlorides is? --- &/or do you know how to make & use it ?

Bottom line - don't get excited & just start adding more chemicals to the mess you have already made - set it all to the side & wait for other members to provide questions/answers

We can solve most problems - but you need to wait for other members to chime in with both questions & answers to get to the bottom of the problem --- other wise you can end up creating more problems

The first problem we need to solve is --- where is your gold - that means you need to do a stannous test - if you don't know how to do that --- then that is the first/next thing we need to teach you - before moving on to anything else

Kurt
 

butcher

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While I do not think that you have to worry about your solution going through the roof tonight.

I do believe using urea in most of our processes is basically useless, and can be possibly dangerous.

We may have a solution of a substance or salts involved in different operations or different conditions throughout our different recovery and refining processes all the way through to the waste treatment and disposal processes, where we may perform other operations on these substances, some possible including changing the pH, heating, and possibly including incineration of the salts, filters, or residues in some later recovery processes...

We are not dealing with pure salts or compounds, metals and other chemicals are involved which can change the playing field or what compounds are made and their dangers involved.

We also make changes to the chemistry, pH. temperature, additions of certain metals, or other salts and compounds of metals can also make many different reactions, possibly making the dangers more pronounced under certain conditions than a pure substance may be under other conditions.



I will not recommend using urea with aqua regia, yes it can help to eliminate NOx gases from a solution of nitric acid or NOx gases from aqua regia, although it will not remove excess nitric acid from the solution but convert free nitric to nitrate salts.

Salts of nitrates which can be reacidified back into solution again as free nitric acid when acidified.

Urea will form white salts of urea nitrate from the free nitric acid in solution, urea nitrate is basically insoluble in HNO3, but soluble in water or can become soluble acidic solutions of aqua regia in the right conditions, basically leaving you with a nitrate salt in solution which with an added acid such as HCl could be converted back to aqua regia much the same as adding other nitrate salts to HCl where we make poor mans aqua regia.

We also have to remember when dealing with our chemistry we may be dealing with several other compounds or salts of metals and of different acids really a toxic and dangerous batch of soup for any nonchemist to be playing around with. so we must be careful if not even a bit over-cautious, for even the best chemist can have a chemical explosion or some other accident in his lab.

So yes, I may tend to try and scare you into being more cautious, I am not a chemist and do not know or understand all of the details myself...

-------------------------------------------------------------------------------------
These are some notes I collected from researching urea Nitrate:

Urea nitrate is explosive when left in a dry state. Wetting reduces the possibility of an explosion but may explode under prolonged exposure to heat or fire, even when wet.

It reacts with strong oxidizers such as perchlorates and hypochlorites. With hypochlorites it forms a compound nitrogen trichloride which explodes spontaneously in the air (J. Am. Chem. Soc. 63:3530-32).

Organic nitrates may explode when shocked, exposed to heat or flame, or by spontaneous chemical reaction. It must be stored in a cool, ventilated place, away from acute fire hazards and easily oxidized materials. Also reacts violently with Al; BP; cyanides; esters; PN2H; P; NaCN; SnCl2; sodium hypophosphite; thiocyanates.
Dangerous disaster hazard due to fire and explosion hazard. On decomposition, they emit toxic fumes. They are powerful oxidizing agents which may cause violent reaction with reducing materials. Nitrates should be protected carefully in storage. (SAX and Lewis, 1987) p.664.

Decomposition is catalyzed by the presence of heavy metals such as lead or iron in trace amounts [Bretherick, 1995, pg. 201].

Produces toxic oxides of nitrogen during combustion. Decomposed with explosive evolution of gas during the evaporation of an alkaline solution. [Bretherick, 1995, p. 201].

Urea nitrate is insoluble in nitric acid, it can make insoluble salts of nitric acid.
Urea nitrate is soluble in water.


Normally classified as an oxidizing agent. The pure salt is not classed as an explosive because it is difficult to detonate. Spark, flame, or friction normally do not cause detonation, However, a variety of substances, such as chloride and oil, are known to sensitize the material.
---

As it becomes more acidic, stability can decrease of these substances, the acid in solution is a significant source of or a contributing factor to solution decomposition.

Contaminated with organic materials is more easily detonated.

Inorganic contaminants also sensitize nitrate and include chlorides and some metals, such as chromium, copper, cobalt, and nickel. These contaminants reduce the energy required to initiate a critical nitrate decomposition reaction.

Chlorides react synergistically with some metals to further reduce energies needed to initiate thermal decomposition.

Studies show synergistic catalysis with chloride generally requires a metal capable of forming metal chloro- complexes of reasonable stability in two oxidation states differing by one electron unit, and at the same time are capable of forming chloro-complexes of moderate stability in these states. Chromium was considered a special case because oxo complexes were believed to be involved. Metals that react synergistically with chlorides to further reduce thermal decomposition reaction temperatures include chromium, copper, silver, nickel, iron, palladium, gold, cerium, and cobalt.

----------------------------------------------------------------------------------------------------..........

I agree with Kurt 100% and his very informative and detailed post.
You need to determine where the gold is or is not.
if the gold is in the solution you could cement it out with copper.
If the gold is in the salts you could dissolve the salts away from the gold.
 

kurtak

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Being as how creating explosive compounds - unintentionally - when refining PMs has come up in this thread I would like to post a reminder of one such case in which you can create a VERY dangerous explosive during refining

In this tread I talked about silver fulminate being a VERY pressure sensitive primary explosive

There is a situation in which silver fulminate can be created in a particular silver refining situation

that situation is when you have dissolved silver with nitric acid AND the silver nitrate solution also has Pd dissolved in the silver nitrate - and - so you decide you are first going to drop the Pd from the silver nitrate with DMG - which fine as "one" way to do it

The problem comes in how you decide to prepare your DMG to make the Pd drop from your silver nitrate solution

There are basically 3 ways to dissolve your DMG (1) by boiling in water - the hardest way to do it (2) use some NaOH to dissolve the DMG (3) use some alcohol (&/or ethanol) to dissolve the DMG

preparing Dmg with (any kind of) alcohol is the method of concern here

Adding alcohol (of any kind) to silver nitrate is how you make silver fulminate

Read more :arrow: precipitating pd from an ar solution wth copper

Palladium Explosion

&/or you can search my posts using "fulminate" to read more of what I have posted about this

Kurt
 

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