Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Stainless steel pot ok?
gnitseretni
Hazard to Others
***




Posts: 280
Registered: 5-1-2007
Location: Medellin
Member Is Offline

Mood: No Mood

[*] posted on 27-8-2007 at 15:45
Stainless steel pot ok?


Could one use stainless steel pots to distill nitric acid? So far I've been doing it the brainfever way but i'd like to try vacuum distillation to get a purer product because my NA is always yellow.

I found stainless steel pots at the walmart that have a glass lid with a SS rim around it. I already got me two of those pots. I broke the glass and laid the rim on a flat piece of metal and poured aluminum in it and now i have an aluminum lid :-) I drilled a hole in it for my condenser. I wrapped the gasket, that fits around the rim, with teflon tape.

I wanted to just do it without asking here if using SS pots was a good idea, but... i'd feel better if someone who distilled NA before using SS pots told me that its ok to do so and that the NA vapors won't react with my SS pot or whatever and form sensitive peroxides around the lid or something like that :D

So all i need to know is if SS pots will withstand two or three distillations without giving unwanted side reactions or something like that.
View user's profile View All Posts By User
Xenoid
National Hazard
****




Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline

Mood: Comfortably Numb

[*] posted on 27-8-2007 at 16:53


Iron and chromium tend to be passivated by nitric acid, so I guess SS will be OK, although I haven't tried them for this purpose yet, let us know how you get on!

What I don't understand is why you smashed the glass lids, They normally have a knob with a hole drilled through, if it wasn't big enough, enlarge it with a glass drill.

Check where the pots originate. I have found that modern SS originating in China and especially India is total crap! I had some thin SS pots that I had some NaCl and KCl solutions in, they started to leak after about 48 hours. Numerous pinholes formed, I think they were formed from tiny specks of steel wire embedded in the SS during the brushing/polishing process. Check your pots are thick and free of imperfections!

Regards, Xenoid
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 27-8-2007 at 18:11


Halides are real tough on ferrous alloys, stainless steel or not. Oxidising mixtures are often OK, although elevated temperatures can be an issue.

Be aware that there are many types of "stainless steel", you're talking about a large family of alloys. So if someone reports success or problems when using stainless steel, unless they specify the allow class you may have entirely different results than they did.

But you are right, much of the consumer goods coming from Asia are lowest cost, which generally means as cheap of materials as can be had. For SS this means alloys that barely fall under the definition of stainless steel, with segregation of alloy constituents being common.
View user's profile View All Posts By User
MadHatter
International Hazard
*****




Posts: 1329
Registered: 9-7-2004
Location: Maine
Member Is Offline

Mood: Enjoying retirement

[*] posted on 27-8-2007 at 18:33
Stainless Steel


I wouldn't use stainless steel with any acid. As for BrainFever's method, you may
have to lower the temperature on the hotplate for a clearer product.




From opening of NCIS New Orleans - It goes a BOOM ! BOOM ! BOOM ! MUHAHAHAHAHAHAHA !
View user's profile View All Posts By User
gnitseretni
Hazard to Others
***




Posts: 280
Registered: 5-1-2007
Location: Medellin
Member Is Offline

Mood: No Mood

[*] posted on 27-8-2007 at 18:50


Quote:
Originally posted by Xenoid
What I don't understand is why you smashed the glass lids, They normally have a knob with a hole drilled through, if it wasn't big enough, enlarge it with a glass drill.


Yeah it had a knob. The hole was 1/4" in diameter. Not big enough. Now don't laugh but i didn't know they had drills specifically for glass. ** embarrassed **. Where do you get those anyway cuz i've never seen them in stores i think, else i would've known they existed. But hey, let me know where i can get em so i know for next time. Woulda been nice if i could've kept the glass in there so i can see what's going on.

The pots were "made in Pakistan". Guess i got the cheap stuff? They're pretty thin, but at least no imperfections.
View user's profile View All Posts By User
Xenoid
National Hazard
****




Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline

Mood: Comfortably Numb

[*] posted on 27-8-2007 at 19:28


Quote:
Originally posted by gnitseretni
Yeah it had a knob. The hole was 1/4" in diameter. Not big enough. Now don't laugh but i didn't know they had drills specifically for glass. ** embarrassed **. Where do you get those anyway cuz i've never seen them in stores i think, else i would've known they existed. But hey, let me know where i can get em so i know for next time. Woulda been nice if i could've kept the glass in there so i can see what's going on.


They are available in hardware stores (in the ceramic tile sections) or a specialist floor tile shop or maybe from a glazing shop. Admittedly they are pretty expensive, being diamond coated and all. They need to be cooled with water, this can be done by making a little "pond" using plasticene or putty around the area you are drilling. Google glass drilling, you'll get the idea.

Edit:
Thinking about it, you could probably enlarge the 1/4" hole by using some coarse "wet & dry" emery paper, wrapped around a partly slotted wooden dowel, fitted in a drill. I use this "technique" with ordinary "sand paper" for metal, plastic and wood, quite often. Depends a bit how big a hole you want.

Regards, Xenoid

[Edited on 27-8-2007 by Xenoid]
View user's profile View All Posts By User
Twospoons
International Hazard
*****




Posts: 1265
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline

Mood: A trace of hope...

[*] posted on 27-8-2007 at 19:28


Search on ebay for " diamond core drill". These can be used on glass - with plenty of water for cooling / lubrication. You can get almost any size from 3mm to over 150mm.



Helicopter: "helico" -> spiral, "pter" -> with wings
View user's profile View All Posts By User
DerAlte
National Hazard
****




Posts: 779
Registered: 14-5-2007
Location: Erehwon
Member Is Offline

Mood: Disgusted

[*] posted on 27-8-2007 at 21:25


Try an ordinary masonry drill from a hardware store, they cut concrete. Using Tungsten carbide. Der Alte
View user's profile View All Posts By User
evil_lurker
National Hazard
****




Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
Member Is Offline

Mood: On the wagon again.

[*] posted on 27-8-2007 at 21:59


Or buy break down and buy a nice borosilicate flask with a ground joint... a 3L flask is only around $60 new and by the time you try and afro-engineer something you'll be out just the same amount of money once you figure in your materials and time wasted.

Let me tell you that hot nitric acid is NOT something to be played around with, and I think boiling nitric would eat thru 316SS like a knife thru hot butter.

[Edited on 28-8-2007 by evil_lurker]




Not all chemicals are bad. Without chemicals such as hydrogen and oxygen, for example, there would be no way to make water, a vital ingredient in beer.
View user's profile View All Posts By User
undead_alchemist
Hazard to Others
***




Posts: 189
Registered: 12-1-2007
Location: Vancouver, Canada
Member Is Offline

Mood: Tired, Cleaning up corporate messes at work!

[*] posted on 28-8-2007 at 00:25


Consumer SS from Asia is crap.
Its true, you really don't know what else is in it.

I was doing some tests with some SS scrub pads as packing, and they rusted in no time.
View user's profile View All Posts By User
scientistfromdarkness
Harmless
*




Posts: 25
Registered: 26-6-2006
Member Is Offline

Mood: schlenk

[*] posted on 31-8-2007 at 04:22


Aluminum pot is the best for nitric acid distillation. Nitric acid does not attack aluminum at all.
View user's profile View All Posts By User
Xenoid
National Hazard
****




Posts: 775
Registered: 14-6-2007
Location: Springs Junction, New Zealand
Member Is Offline

Mood: Comfortably Numb

[*] posted on 31-8-2007 at 05:06


Quote:
Originally posted by scientistfromdarkness
Aluminum pot is the best for nitric acid distillation. Nitric acid does not attack aluminum at all.


Nitric acid, dilute or concentrated acts so slowly that nitric acid is said to have "no action on aluminium". Indeed aluminium containers are, or at least were, used for transporting nitric acid.
By "distill nitric acid" I assumed he meant distill from nitrate and sulphuric acid.
I haven't done a nitric acid distillation yet, but I would think the concentrated sulphuric acid added to the nitrate would react "rather badly" with aluminium.

Regards, Xenoid
View user's profile View All Posts By User
12AX7
Post Harlot
*****




Posts: 4803
Registered: 8-3-2005
Location: oscillating
Member Is Offline

Mood: informative

[*] posted on 31-8-2007 at 08:05


I've had nitric and sulfuric acids in contact with aluminum before. Any water present will cause hydrogen, NO2 and bad pitting, but roughly anhydrous seems to be okay.

Tim




Seven Transistor Labs LLC http://seventransistorlabs.com/
Electronic Design, from Concept to Layout.
Need engineering assistance? Drop me a message!
View user's profile Visit user's homepage View All Posts By User This user has MSN Messenger
gnitseretni
Hazard to Others
***




Posts: 280
Registered: 5-1-2007
Location: Medellin
Member Is Offline

Mood: No Mood

[*] posted on 31-8-2007 at 15:21


i've actually been trying to cast aluminum pots before resorting to SS pots. But i failed every time so i had to find something else. Doesn't mean i'm giving up on trying to cast aluminum pots though.

I also got me a 1 gallon glas pot and a glass drill and i managed to drill a hole in the lid. All i need now is a gasket for the glass pot and time and i could start distilling using the glass pot and a SS pot with an aluminum lid.
View user's profile View All Posts By User
gnitseretni
Hazard to Others
***




Posts: 280
Registered: 5-1-2007
Location: Medellin
Member Is Offline

Mood: No Mood

[*] posted on 2-9-2007 at 14:38


when i first started this thread i had two SS pots but used one for yet another unsuccessful attempt to cast an aluminum pot, so i got a glass pot and managed to drill a hole in the lid and used teflon tape as my gasket. I took my glass and SS pot, hooked up all the pumps for the water aspirator and condenser and started distilling. I used the SS pot to collect the HNO3 and was heating the glass pot containing the KNO3/H2SO4 mixture. I didn't drill a hole for the thermometer so i just put it in the waterbath. I heated the mix all the way to 90C (yeah, heated a glass pot to 90C :o) but never really saw alot of vapor. I know that HNO3 boils at 83C but how can you tell? I was expecting it to bubble alot and that it would get real foggy inside the glass pot because of all the vapor, but it didn't.

Anyways, i thought everything was going well but then i noticed that the potassium sulfate was slowly disappearing. This is when i stopped distilling. I took the aluminum lid of the SS pot and found out where the sulfate had gone :mad: I also noticed that my acid wasn't fuming. I weighed 10 mls of it and it only weighed 11.38 grams.

Wouldn't know how but maybe some water got into my acid through the vacuum hose. That would explain why it is so dilute. But how the hell the sulfate got in there i have no idea!!

I know the pics are crappy but it was the best i could do.

EDIT: how do you attach more than one pic?

[Edited on 2-9-2007 by gnitseretni]

Picture 001.jpg - 30kB
View user's profile View All Posts By User
froot
Hazard to Others
***




Posts: 347
Registered: 23-10-2003
Location: South Africa
Member Is Offline

Mood: refluxed

[*] posted on 2-9-2007 at 23:00


I heard that cast iron is safe to use with nitric acid?

If you can use glass appauratus, do so, it eliminates all variables associated with poor quality steel. Drilling glass is a very delicate process. You can use a tungsten tipped masonary drill but you must use a rigid pedestal drill with a very slow speed setting, and constant light pressure. The glass you are drilling must be emersed in water.




We salute the improvement of the human genome by honoring those who remove themselves from it.
Of necessity, this honor is generally bestowed posthumously. - www.darwinawards.com
View user's profile View All Posts By User
chucknorris
Hazard to Self
**




Posts: 57
Registered: 13-4-2012
Member Is Offline

Mood: No Mood

[*] posted on 13-4-2012 at 18:27


Ok I have some processes where glass cannot be used, for ex KOH NaOH fluorine compounds etc. harsh stuff that will eat through glass like nothing.

I thought of making stainless distilling pot and column. Could a normal stainless pots available at dairy stores be used or are they unusable for these processes?
View user's profile View All Posts By User

  Go To Top