Sciencemadness Discussion Board

Nitric + sulfuric waste

Mildronate - 9-5-2010 at 05:40

Can i use Nitric + sulfuric waste for something?

hissingnoise - 9-5-2010 at 06:06

Nitric + sulphuric waste?

Mildronate - 9-5-2010 at 06:15

Unusable acid mixture that i got after nitration.

hissingnoise - 9-5-2010 at 06:26

It's likely that it contains but little HNO3; the bulk will be diluted H2SO4.
When you're satisfied that it contains no residual nitrate, you could try distilling the HNO3 off but it too, will be dilute.
It's probably better to reconcentrate the acid by boiling, while staying upwind of any HNO3 fumes given off.


Mildronate - 9-5-2010 at 06:46

I will try it :)

kilowatt - 9-5-2010 at 12:20

Depending on the amount you could react it with excess copper oxide to get a mixed copper nitrate/sulfate slurry. This is a suitable stock for thermal decomposition to yield NO2 + O2 at <300°C and SO3 at 650°C. Other base reactions that would produce a mixed nitrate/sulfate product may be useful if you have a use for the salts in that it form.

The WiZard is In - 9-5-2010 at 13:27

Quote: Originally posted by Mildronate  
Unusable acid mixture that i got after nitration.



Mixed acid used for gun cotton nitroglycerin and such is regenerated
by adding enough acid to bring it up to strength. Or it is "regained".

There is extensive literature.

kilowatt - 9-5-2010 at 17:36

Wouldn't that just mean that the total amount of liquid goes up and up? There must be some boiling at some time to concentrate it, either that or they must sell some.

grndpndr - 9-5-2010 at 17:58

FWIW youd assume some method to remove excess H20 would have to be part of the process.Literature

kclo4 - 9-5-2010 at 20:45

Quote: Originally posted by The WiZard is In  
Quote: Originally posted by Mildronate  
Unusable acid mixture that i got after nitration.



Mixed acid used for gun cotton nitroglycerin and such is regenerated
by adding enough acid to bring it up to strength. Or it is "regained".

There is extensive literature.



I was under the impression that they used very pure and very concentration nitric acid to produce nitrocellulose, with out H2SO4 -- and that the nitric acid was regenerated. The more I think about it, the less sense it makes, but I swear I read something similiar to that.

Chainhit222 - 9-5-2010 at 23:24

IIRC during the production of RDX (according to The Chemistry and Technology of Explosives) they recycle 60% of the anhydrous nitric acid used in the nitration. I believe this means they need to re concentrate it, but I am not sure.

http://img535.imageshack.us/img535/3184/hexamine.jpg
(exerpt from the book)

I glanced over the processes listed, and it seems they mostly have 50-60% conc left over HNO3

Not to mention, look at the reactions for hexamine

main reactions:
(CH2)6N4 + 4HNO3 -> (CH2-N-NO2)3 + 3CH2O + NH4NO3
and
(CH2)6N4 + 4HNO3 -> (CH2-N-NO2)3 + 6H2O + 3CO2 + N2

and that book also writes the following side reactions:
(CH2)6N4 + H2O -> 4NH3 + 6CH2O
2CH2O+2HNO3-> 2HCOOH + H2O + NO + NO2

So it seems you have a whole mess of waste reactants.

I need to look up nitrocellulose later, I don't have the volume on hand, but according to wikipedia
3HNO3+ C6H10O5 → C6H7(NO2)3O5 + 3H2O
so you got water aswell

[Edited on 10-5-2010 by Chainhit222]

Contrabasso - 10-5-2010 at 13:48

Unless you have fully read and understood Urbanski on waste recovery do not go there.

From most production methods the nitric is 1/3 used (some more so) and 2/3 waste. The problem comes with the miscellaneous fragments from nitration, some of which are more stable than others. These can make acid recovery more or (usually) less possible with safety.

If you have to ask you should do lots of learning before you play.

The WiZard is In - 10-5-2010 at 16:18

Quote: Originally posted by Contrabasso  
Unless you have fully read and understood Urbanski on waste recovery do not go there.

From most production methods the nitric is 1/3 used (some more so) and 2/3 waste. The problem comes with the miscellaneous fragments from nitration, some of which are more stable than others. These can make acid recovery more or (usually) less possible with safety.

If you have to ask you should do lots of learning before you play.



Yes and let me correct what I had previously posted. Mixed acid
form the production of TNT is recycled especially that used in the
DNT to TNT stage. Urbanski (1:349) gives the waste acids composition as —

1.5 % HNO3
92.0 H2SO4
4.0 H2O
2.5 NO2

Oleum is used remove surplus water.

Remaing mixed acid used for NG and cellulose nitrate has the
nitric acid removed 0 the sulphuric acid concentrated.

Mildronate - 11-5-2010 at 08:21

I dont have oleum

The WiZard is In - 13-5-2010 at 12:02

Quote: Originally posted by Mildronate  
I dont have oleum



What is used up is the nitric acid, most of sulphuric acid remains
assuming you are not nitrating a liquid.. boil what left that
should boil off the nitric acid... boil in your fume cupboard or
out of doors until white fumes arise and then stop.

The French had a complicated process to recover H2SO4 form
the mixed acid used to make nitroglycerin, I would posit steam
was used to remove any remaining NG.

http://tinyurl.com/25jgdts
http://tinyurl.com/2beqgfs
http://tinyurl.com/27qg3ce
&c., &c., &c.

SAFETY IN TNT MANUFACTURE

The manufacture of TNT is one of the safest operations in the
explosive industry. Nevertheless, any negligence about safety
regulations may have disastrous consequences. Because the
manufacturing process is regarded as safe, the fact must not be
overlooked that less experienced personnel may disregard the
regulations.

The spent acid from trinitration has also been the cause of several
disasters, although it had been considered safe to handle. The
most noteworthy example of this occurred in the Reinsdorf
factory in Germany in 1935. The hot spent acid flowed down to
open iron tanks, where, as the liquid cooled, a mixture of di and
tri nitrotoluenes rose to the surface. It was skimmed off from
time to time and transferred to a washing tank, where it was
washed with water. On skimming, a rubber glove and a shelf left
on the brim of the tank with some cotton wool on it, fell into the
tank. The reaction between the spent acid and the rubber and
cotton wool initiated violent decomposition and fire. An attempt
to extinguish the flames failed, and soon the nitro compounds on
the surface of the spent acid exploded. The explo¬sion and fire
spread over several nearby tanks, then to the nitro compounds in
the washing tank. As a result the whole plant for the recovery of
nitro compounds was destroyed. In addition to this the explosion
tore away the roofs of some nearby buildings, among them drier
buildings located at a distance of about 660 m. Parts of the tank
thrown off by the explosion into one of the driers detonated the
TNT present, and in another they caused the ignition of the load.
Similar explosions or fires spread over further buildings of the
TNT factory. Moreover, a neighbouring nitroglycerine plant also
exploded. This disastrous explosion cost 82 human lives and in
addition 104 people were seriously and 700 were lightly injured.

Accidents caused by spontaneous explosion of finished TNT are
also known. Some of them could be ascribed to the presence of
traces of trinitrocresol salts. Others were presumably caused by
products of decomposition of trinitrotoluene under the influence of
sunlight or alkaline compounds used for deacidification of the TNT.
Still others were due to the high sensitiveness of molten TNT to
impact. This is why the drying of TNT should be regarded as a
very dangerous operation.

Descriptions of several explosions that took place in French
factories, may be very instructive. As an example, the explosion
in the St. Chamas TNT factory in 1936 which caused the death of
53 people. Investigations showed that the explo¬sion occurred
after about 2000 kg of TNT in a drying tank had caught fire. The
TNT in question was that recovered from the spent acid from
trinitration ("plastic TNT"). It is known that such a product
contains various impurities, among them the isomers of a
trinitrotoluene, nitrocresols etc. .......This must have led to the
formation of typical decomposition products of TNT brought about
by reaction with alkalis. It is highly probable that these
compounds were the first to ignite, whereupon the flames spread
over the whole drier.

Urbanski 1:391-2

It has been a long time since someone blew themselves up
following my advice — please do not spoil my record.

Mildronate - 13-5-2010 at 12:11

its good idea to boil out all water an nitric

Contrabasso - 13-5-2010 at 13:31

It's a better idea to read the best literature thoroughly before you start.

If your chosen nitration leaves assorted fragments behind these will need to be removed from the spent acids before you analyse them and reconcentrate them for the next run.

Urbanski's writings on RDX give several residual organic components that you don't want in the product but can't easily separate from the acids safely.

maxidastier - 13-2-2011 at 11:45

Has anyone some literature on how to recover waste acids after preparation of especially ETN, RDX, NC, NG, NQ and NU? Apart from Urbanski.
Is anyone using a working method or are you all really wasting your acids?