Questions About My First Batch Of Nitric Acid

[viacin]

I'm making my first batch of nitric acid as I type this (it's cooling to room temp), and I believe I have a problem. My sodium nitrate did not disolve completely. Heres what I did:

1. I added 200ml of distilled water to a beaker, and brought it to a semi-boil.
2. while boiling, I added 170g of sodium nitrate, and stirred untill the solution was clear.
3. I then added another 164g (was aiming for 170, technical dificulties forced me to move on) of sodium nitrate (by now my solution was not boiling), and stired for about 20 minutes. 3/4's of the total 334g of sodium nitrate disolved, the other 1/4 refuses. I got a odd film on the top of the solution, and the undisolved sudium nitrate settled to the bottom as powder.
4. I decided to continue, and added 112ml of "amazing liquid fire" drain cleaner straight from the bottle. sulfuric content is unknown to me, but I was told it was 98% or so by members of the forum. (could anyone confirm?)
5. I stirred as I added. The solution turned a nice yellow, with the sodium nitrate still sitting at the bottom. I stirred for about two minutes.
6. I decided to let it sit to room temperature at this point, so I came in and checked the forum for possible answers. Someone mentioned that they stirred the solution after adding the sulfuric for about ten minutes, so I went back outside to stir. My solution at this point was clear, with the powder settled to the bottom.
7. I stirred for about ten minutes. The solution was still producing steam as I stirred. I washed down the sides of the beaker with a spray bottle, stirred a bit more, and came in. It is clear, no color at all. (I thought it would be yellow?)

Could my problem be that I did not allow the water to come to a complete boil before adding the sodium nitrate? Should I have brought it back to a boil before adding the second 164g? I was beginning to lose water (about a line thickness on my beakers 100ml graduated scale), so I decided to move on. Or am I even expierencing anything abnormal here?

 

[viacin]

An update: I let it sit for about a hour now in a salt/ice/water bath. It's so cold the condensation on my bowl is turning to frost

My solution is clear, and completely colorless. I have a large amount of white power in the bottom in a solid mass. I hope it is the salt, but I suspect it is mainly the undisolved sodium nitrate. Surely I did something wrong here, isn't nitric acid at these concentrations a yellow color?

When I first poured in my sulfuric acid, it turned yellow immediately, but after stirring it turned clear. I'm lost, any answers?

I think I will pour it off and give it a test with some base metal, see if I get a reaction.

EDIT! A Sudden Change: I went outside, and checked on it again. I now have three little solid mounds of a yellowish looking salt on the bottom. I poked at them a bit with a stir rod, they are pretty solid. And minutes later little particles began forming throughout the solution. Perhaps it is just now reaching -5c? It's been almost 2 hours in the bath.

 

[Redders]

I wish I could help. Please continue recounting this experiment.... I will have a go at this soon, myself.

What kind of product was the sodium nitrate that you procured.. (fertiliser? cake mix?)

good luck to you....

I hope that the 'gun players' pitch in on your thread.

 

[lazersteve]

Everything sounds fairly normal.

Relying on a normal beakers graduation marks is not the most accurate way to go. I use a graduated cylinder to measure my liquids. Perhaps you had too little water until you sprayed the beaker down.

My nitric varies from clear to yellowish depending on the sunlight exposure and other conditions. More often then not, it tends to be clear with a slight tint of yellow. If your sulfuric was colored thats most likely where you got the yellow from.

Using distilled water and boiled down battery acid or lab grade sulfuric acid is the best way to go for good clear nitric. Even then the color can lean towards pale yellow sometimes.

Keep the liquid on ice until no more precipitate forms.


Steve

 

[qst42know]

It takes a strong boil to get the nitrate into so little water. It may be of unknown concentration but should work well enough. I left one batch over night and the remaining salt was solid and very easy to separate from the nitric acid. All the color was grabbed by the remaining salt. The remaining acid was water clear and worked fine. Don't panic just yet.

 

[viacin]

I finished everything up just a few minutes ago. My final liquid was crystal clear, colorless, and smells like clorox. I still cannot get the smell out of my nose. uuhg. I doubled everything on steves cold process, but did not get double the nitric. I got aprox 150ml, measured by the beaker.

This is my thinking, the final 1/3 (111g) of sodium nitrate I put in did not disolve (I had a obvious layer on the bottom, under the salt), so this can only mean that I added 1/3 (40ml) too much sulfuric acid, since it had nothing to react with. What does this mean for my final solution?

A Few Notes:
I used a graduated cylinder to measure all liquids
I used a .1g scale to measure all weights
My water was distilled
My sulfuric acid was "amazing liquid fire" straight out of the bottle


Redders: My sodium nitrate was purchased off of ebay, it came in a ziplock bag. It could be sugar for all I know. It is supposed to be technical grade, in 1/2mm pellets. Here is a picture of the bag. http://www.bodyworkzsupply.com/chem004.jpg

For full details on this procedure, please read lazersteves cold nitric process, for I am only copying it. Here is a link: http://goldrefiningforum.com/phpBB3/viewtopic.php?p=2572#2572

 

[viacin]

I made another batch this morning. It's in ice now. Everything turned out perfect! I made sure it was fully boiling this time and all the sodium nitrate mixed in, after about 10-15 mins of stirring.

I did experience some strange things however, and was wondering if they are normal.

1. after adding the sulfuric acid, I stirred for about 10 minutes. 5 minutes into the stirring the yellow color began to fade and the liquid became cloudy with a white powder. This power slowly settled to the bottom. Is this normal?

2. after about 30 minutes all the cloud settled. My liquid was again crystal clear and colorless. The fine power that settled on the bottom formed a very hard, pure white crystallin mass with "christmas trees" standing up. I do not think this is the salt byproduct because it formed while the solution was still hot from the boiling and exothermic process. Also the salt has a yellowish tint to it, this is pure white. What could it be?

EDIT NOTE: The unknown substance is also impossible to remove from the bottom of my beaker without filling it with water and boiling for a few minutes. Eventually the bubbles break it up a bit and I can work at it with my stir rod.

Also, is there a post on disposal of the salt and whatnot from this process? There's gotta be something better than taking it to the landfill.

Here's a good laugh for you all. The first day it took me 6.5 hours from start to completion, working hard too. Today it took about 3 hours, and I sat around for about a hour of that just waiting for it to cool. Maybe next time I can get it down to something reasonable, like 30 minutes to a hour.

 

[qst42know]

I believe this is the remaining salt. If you wiki this its added to animal feeds, and occurs naturally in spring waters. I could be wrong but I don't see any issues in sending it to the land fill. It would be nice to have a use for it though.

http://www.jtbaker.com/msds/englishhtml/S5022.htm

 

[viacin]

ty for the info qst. I agree, I wish we could use this. But then again it would be another chemical I would have to store for long periods of time.

I think this unknown substance I'm getting is a salt, but I'm not so sure it is the salt produced from this reaction, because I get that when I chill everything down. This unknown salt appears after the sulfuric acid is fully disolved into the mix. I just wonder if I am the only one getting this.

Also, I have a big problem here. I am exactly doubling lazersteves formula, but I am only getting about 150-160ml of nitric. It should be 320ml. This is a serious problem (waste not, want not), and I must solve it.

It makes me wonder if I am not adding enough sulfuric acid, and this unknown "salt" I'm getting is actually sodium nitrate coming back out of the solution, if this is even possible? This would explain my missing nitric.

 

[qst42know]

Anything indicated on the label of the drain cleaner as to additives, buffers, etc.?

I had used a drain cleaner listed to have 12 buffers the yield seemed low but I hadn't measured it. I had contributed the low yield to too short of time on the ice. The salt was fine grained and did not solidify into large flakes. It was difficult to get the fluid from the salt.

When using concentrated battery sulfuric the salt begins forming fairly quickly while stirring and after a time did solidify into a coarse crystalline mass before I put it on ice. The yield seemed higher but again I didn't measure it.

In each case the nitric acid seemed to work well enough but they were not tested side by side.

 

[viacin]

no, the label lists nothing, not even sulfuric acid. The only way you can even tell it's in there is from the warnings. Nor can I find a MSDS on it, I have searched and searched.

I would agree with you qst, as this seems the most likely answer. But it seems to they are two different substanced. The unknown is pure white, hard as a rock when settled, and very fine. It also has little "chrismass trees" sprouting all over it reaching upward. The salt that forms after freezing is yellowish, somewhat easily crumbles, and is corse. The yellow salt is on top of the unknown substance.

 

[butcher]

the salt should be Na2SO4 (you can test it to see if it contains nitrate).
I save my chemical byproducts for other uses.why throw away good chemicals.

 

[qst42know]

the salt should be Na2SO4 (you can test it to see if it contains nitrate).
I save my chemical byproducts for other uses.why throw away good chemicals.

What do you use sodium sulfate for? What purpose have you found for the remains.

 

[Lou]

Sodium sulfate is a great drying agent (dessicant) for gases and in particular, organic compounds.

High capacity for water.

 

[qst42know]

I don't have anything I need to mummify however.

I have been doing some more reading and was wondering if one of the more chemically oriented members would explain this formula.

From the Wiki

"Sodium sulfate reacts with an equivalent amount of sulfuric acid to give an equilibrium concentration of the acid salt sodium bisulfate[5][6]:

Na2SO4(aq) + H2SO4(aq) ⇌ 2 NaHSO4(aq) "

Could this waste salt be converted to sodium bisulfite to drop gold?

 

[Platdigger]

That's "bisulfate" not "ite"

but hey! There are plenty of uses for that.
Randy

 

[qst42know]

OOPS. Slight chemical dyslexia.

One entry in the wiki may be of interest.

"Lately, sodium sulfate has been found effective in dissolving very finely electroplated micrometre gold that is found in gold electroplated hardware on electronic products such as pins, and other connectors and switches. It is safer and cheaper than other reagents used for gold recovery, with little concern for adverse reactions or health effects.[citation needed]"

Does anyone here know this process they are referring to? Or is this one of the unfounded false wiki entries?

 

[Platdigger]

Oh well, I am glad you brought that up.

Perhaps I won't have to buy any more sodium bisulfate!

 

[viacin]

I have read that before somewhere qst, but no idea where. I'll see if I can find it.

I just wonder what the extra salt could be. And, more importantly, why in the world I'm getting such a low ammount of nitric acid. From a non-chemisty expert's point of view (and I stress this), I would think it has something to do with the amount of sulfuric moles I'm putting in, since I'm getting exactly half, which is also what I would get if I followed steves cold process to "T" - 160ml.

 

[qst42know]

If the sulfuric in the drain cleaner is diluted you could try boiling it first. Water is driven off well below the boiling point of sulfuric. Your drain cleaner is the big unknown.