[TheForge] Re: Finding Nitric

[Mike Spencer]

Bruce wrote:

> And another caveat: The waste from nitric acid remains dangerous.
> Remember that nitrates are used in explosives.  So you should be
> real careful how you dispose of this stuff, or a waste container may
> explode on you.  I've seen it happen.

I'd be interested in hearing the details of that.  What did they do,
put a quart or more of concentrated nitric acid into a drum of mixed
paint, thinner and industrial solvent waste?

If you've been etching iron or copper in small quantities [1] of
nitric acid, the waste is just fertilizer, slightly contaminated with
iron or copper.  Dilute it 20:1 with water, neutralize it with a
little baking soda and put it on your flower bed.  Even after etching
stainless, the amount of chromium or nickel salts in a small quantity
of acid is going to be negligible.

BTW, the big deal about "adding acid to water slowly" is specifically
about concentrated sulfuric acid. [2] The hydration of concentrated
sulfuric is highly exothermic.  If you add water to that acid, you get
very rapid heating, vigorous spatter, possibly boiling that shoots the
contents of your vessel up in your face.  That's also why a spill of
concentrated sulfuric is so bad: not only does it eat your clothes and
(wooden) bench or floor, it rapidly sucks the water out of your skin
and flesh, turning it quickly to greasy mush.  Ikk.

I would add to Bruce's advice for handling concentrated acids that you
buy an eye-wash bottle of the sort used in industrial settings and
fill it with clean water. [3] Assuming that none of us is working with
big tanks of acid where a major spill is a possibility, your first
concern after a minor accident is to ensure that any acid that has
gotten into your eyes is washed out.  You do not want to use your
quench tub water for this. You want the eyewash bottle to be in a
place where you can get it while in a panic with both eyes shut.

I also keep a quart or two of sodium bicarbonate dissolved in water
handy when using concentrated acid.  Not for eye wash but to
neutralize any other spills before they get smeared around or eat
something. 

While I'm pontificating, I might mention that lye -- either sodium
hydroxide or potassium hydroxide -- should be treated with the same
caution as concentrated sulfuric acid.  If you get a bit of lye
(crystal or solution in water) on your skin, it feels slimy.  That's
because strong lye quickly attacks the fats in you skin and begins
to soaponify them.  If, when working with lye crystals, you raise even
a smallish cloud of lye dust into the air and get that dust into your
eyes, you're in for a nasty time.  The process of dissolving lye in
water is also exothermic -- heats the mix. Once again, an eye wash
bottle on hand is a good idea and, for lye, possibly some diluted
vinegar as well.

Jeff wrote:

> ...my wife runs Barking Crow Soap so we use lots of lye (NaOH) which
> we get in 50 lb bags at a local chemical supply house.

What do you do, when handling large quantities of lye, to avoid
problems with dust -- in eyes, inhaling, sticking to clothes or
whatever?

Time to get off my soapbox.  For myself, I'm less alarmist about this
stuff than Bruce but it doesn't hurt to go overboard on safety
precautions.  I've never witnessed a serious chemical injury but I've
seen a couple of very scary near misses.


- Mike


[1] A teaspoonful? A half pint? Several gallons is not a "small
    quantity" by my standards.

[2] There are other acids that behave in a similar way but we're not
    likely to encounter them. Concentrated chloro-sulfnonic acid is
    one.

[3] And, unless you buy a pre-packaged, sealed kit containing sterile
    water or sterile opthalmic sloution, rinse out the bottle and
    change the water every once in a while.  Various infectious
    microorganisms can grow in (apparently) clean water after a few
    weeks or months in a warm place.  You don't want to flush them
    onto your already injured eye tissues.

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^