I need Aqua Regia knowledge!!

[BenSon]

Thanks guys i got it now

 

~Scott

[Josefin]

I have old Aqua regia, don´t excatly know how long it´s been stored, but a guess is for several years. Now I have to neutralize it, beacause the chemicalwaste-firm dont take Aqua regia. But I´m not sure how to do it properly. Any suggestions? I have several amount of KOH -pellets, can I use them?

[John Cuthber]

First; be very careful with this. Aqua Regia decomposes in solution to produce chlorine among other things. There have been explosions in the past caused by storing the stuff in closed bottles. The stuff generates gas which bursts the bottle- nasty.

Secondly I think mixing it with water to dilute it before you do anything else is probably a wise move. Thirdly KOH will react fairly violently with water, nevermind that acid.

I'd buy washing soda instead (and be carefull about all the foaming when you mix them).

 

Take the stuff outside.

Open it very carefully.

Pour the acid into a few times its volume of cold water in a big plastic bucket then add washing soda slowly while stiring it with a stick.

Gloves are pretty much a neccessity here. A face mask and apron aren't a bad idea.

If you have any reason to believe that the bottle is pressurised then you might want to leave this to the hazmat experts.

[frosch45]

Might be a good idea too to wait until it is a little bit windy outside too, that way the gasses won't just sit there.

[YT2095]

forget the fizzing in the sodium carbonate (washing soda), that can present it`s own dangers, go to a garden center and get a small bag of garden lime, you can pour it directly into that as a solid.

it`s used industrially to neutralise all sorts of acids, it`s a better choice

if you`r worried about over pressure, you can bury it the bag as well, of use a long metal rod through the bag touching the bottle and hit the end with a hammer, the bottle breaks inside the lime and is neutralised instantly.

it`s also far more environmentally friendly than the sodium analog.

[John Cuthber]

For a given sample of acid, calcium carbonate generates exactly as much fizz as sodium carbonate.

[YT2095]

I agree, If garden lime was calcium carbonate

[frosch45]

woh, Wait a second.

 

Define lime.... there are many kinds. Do you mean magnesium carbonate or calcium oxide or what? I have heard of hydrated lime, high calcium lime, dolomitic lime.

 

I thought Quicklime, the product of calcination of limestone, consisted of the oxides of calcium and magnesium.... right?

[YT2095]

it was defined, I said Garden Lime and that can only be one thing, Calcium Hydroxide (slaked lime).

[frosch45]

thats what I thought you meant because it had to be a strong base, but where I live, garden lime can be more than just CaOH

[YT2095]

there Are other garden products that resemble the lime, and some are also called Chalks, but to sell something as "Garden lime" that isn`t calcium hydroxide is breaking the law as false advertising, certainly in the UK it is.

[frosch45]

here we go, I personally went to check it out

 

at the garden center closest to my house, for example, they sell Espoma Garden Lime

 

you can look up the msds yourself if you don't believe me, but it is made up of the carbonates of calcium and magnesium, not CaOH

[John Cuthber]

YT2095,

The box of "arthur J Borwn's " garden lime that I have is labeled as containing "screened limestone"

It fizzes with acids.

Shouldn't you have checked what garden lime is before assuming I was wrong?

Why would someone choose to use a more dangerous and more expensive material when crushed rock would do?

[kevinalm]

In the US, all "lime" for agricultural/garden use is calcium carbonate. (powdered limestone). To get CaOH you would have to specifically get "slacked lime", which isn't very commonly available. Kind of a lift = elevator language thing going on I think.

[YT2095]

we sell 25Kg bags of the stuff in the shop (as well as other fertilisers) it`s called Garden Lime, and it has no carbonates in it and will not "fizz" with acid, it`s CaOH.

 

in fact I use this stuff myself every autumn in conjunction with wood/plant ash and ammonium nitrate to make KNO3 en mass for next years Tomato and Chilli feed.

 

this should clear things up: http://www.sdfern.com/lime.htm

 

seems there are 4 types, and since I mentioned it doesn`t fizz, it Can only be the CaOH sort can`t it

[John Cuthber]

"seems there are 4 types"

So there's a 3 in 4 chance that the advice you offered the guy with the spare acid is wrong.

By the time he found out it fizzed it would be a little late.

[YT2095]

there`s a 2 in 4 chance (you didn`t read the article) that it would proceed in the way You advised, and chance the same it would proceed in a better way.

but ALL leave more environmentally friendly product.

[John Cuthber]

"there`s a 2 in 4 chance (you didn`t read the article) that it would proceed in the way You advised, and chance the same it would proceed in a better way.

but ALL leave more environmentally friendly product.

"

Pardon?

Anyway I think the environmental impact of one bucket of mixed nitrate/ chloride is trivial whether it's the Na or Ca salt.

The foaming is only a problem if you don't expect it.

[daniel limbert]

aqua regia should be freshly prepaired

[harryformiller]

I will like to know if I have agua regia and I evaporate it and then condence the vapors will I keep on having agua regia

[hermanntrude]

i will like to know why anyone would want to further concentrate aqua regia. it's one of the most corrosive substances known to man already. why try to make it more concentrated? that's insane

[nitric]

well, i can think off the top of my head that they would be trying to dissolve iridium, any way i would not want to even encounter almost pure nitrosyl chloride

[lukers]

after the gold has dissolved in the agua regia, what is the process to recover the gold? In lamemens terms.(names of acid, acids in amounts) ty

 

most of these post are years old.. is there anyone out there

[Genesis]

Guys, sorry to bring this topic up again but i really need some help

If i understand right... to make a Agua regia i need ==== Cloridric acid + Nitric acid=====

 

- ratio: cloridric 3:1 Nitric is that right? or the other way around?

 

-if i have 100 grams of gold, how much agua regia i should need ? Ratio ?

 

Thank u guys so much... i really apriciate it... and sorry my english i m brazilian... not good english over here...

[elementcollector1]

Guys, sorry to bring this topic up again but i really need some help

If i understand right... to make a Agua regia i need ==== Cloridric acid + Nitric acid=====

 

- ratio: cloridric 3:1 Nitric is that right? or the other way around?

 

-if i have 100 grams of gold, how much agua regia i should need ? Ratio ?

 

Thank u guys so much... i really apriciate it... and sorry my english i m brazilian... not good english over here...

 

The ratio is 1:3 (nitric : hydrochloric), respectively.

Your chemical equation, taken straight from Wikipedia: Au (s) + 3 NO−

3(aq) + 6 H⁺(aq) → Au³⁺(aq) + 3 NO₂(g) + 3 H₂O (l) andAu³⁺(aq) + 4 Cl⁻(aq) → AuCl−

4 (aq).

Condensing all that down into this reaction:3 HNO₃ + 4 HCl + Au -> 3 H₂O + 3 NO₂ + HAuCl₄ Using this handy-dandy website (http://theodoregray.com/PeriodicTable/MSP/BalanceReactions), we can now conclude that for every 100g of gold, you will need 96 grams of nitric acid (or 136 mL at max concentration) and 75 grams of HCl (or 236 mL at 31.75% concentration). That would make for about 372 mL of strong aqua regia for every 100g of gold.I hope that helped, and remember: Aqua regia is nasty stuff! Use as many safety precautions and protections as you can, nothing short of gloves, goggles, labcoat, and it would help immensely to have a fume hood (or just do this outside).

Edited October 12, 2012 by elementcollector1