... A lot of dumb stuff is being told about chemicals.
Yup. But take care not to do so as well. Check facts with more than
orchid archives. Lots of people knowing lots of stuff, but in
essence, it’s back fence gossip. Check with actual researched or
verifiable source before assuming chemical facts on Orchid are indeed
such…
As I said, you can speed up the action of nitric acid by heating it
up in a pan with a lid. You are not supposed to take the lid off!
Heating Nitric, or for that matter, other strong acids, needs more
than a lid. Just as steam comes out from under the lid of a cooking
pot, acid fumes too can escape from a boiling or very hot pot of
acid. Ventillation is critical. And nitric fumes are nasty indeed.
Who in her right mind would do such a thing? Once the solution is
boiling, put it outside, keep away from it and let it cool. Pretty
harmless, in my opinion.
Using the term “pretty harmless” in reference to boiling acids in
general, is just setting yourself up to make assumptions and careless
mistakes. It’s never harmless. Only one small slip or mistake away
from dangerous, even when handled properly. The key is careful
meticulous procedure and an attitude of care. Referring to the stuff
as harmless, even if in fact it “CAN” be harmless, is setting
yourself up for a greater chance of error.
As for the second point, many years ago there was a discussion
going on between goldsmiths about the health hazards of pickle. I
looked up at couple of articles at that time and, if memory serves
me well, I found out that fumes of sodium bisulphate form sulphuric
acid in the lungs
Sodium bisulphate is a salt of sulphuric acid. It doesn’t easily or
substantially break down to gasseous fumes on normal hot pickle use.
There can be a little, but not much. What does happen is that with
any boiling liquid, some of the liquid escapes as tiny aerosol
droplets along with the steam from boiling. The droplets are still
sodium bisulphate, and in the lungs, which means simply mixing with
fluid, it becomes more dilute sodium bisulphate. This does not mean
it’s harmless there. Only that it remains an acid salt of sulphuric
acid, rather than the straight acid itself. This is perhaps a minor
point, since the chemical actions of sodium bisulphate are not
tremendously different from the acid itself, only less potent, and
importantly for pickle use, it does not actually emit acid gas fumes,
as sulphuric acid can do. That is actually the main factor that makes
it markedly safer to use as a pickle than plain sulphuric acid. The
easy fix is both to keep your pickle covered, and to operate it at
below boling temps. That pretty much controls most of the fume
issues with sodium bisulphate pickle. There will be some trace fumes
even so, and some people find themselves sensative to it. For them,
use it cold, or switch to something like citric acid. But compare the
smell of sodium bisulphate pickle, even hot, to that of even cold
sulphuric acid pickle, and you can quickly smell and feel the drastic
reduction in fumes from the sodium bisulphate pickle.
about Sparex pickle which many people use warm, but of which I am
certain that it is downright carcinogenic for the reason stated
above, although this is still not recognised in the msds
What, pray tell, leads you to think acid fumes, such as from sodium
bisulphate, are carcinogenic? Sulphuric acid burns. It’s pretty
nasty stuff, especially to organic materials (concentrated sulphuric,
spilled on a wood table top, can sometimes even cause it to ignite,
it’s that aggressive an oxidizing agent). but just because something
is toxic or nasty or caustic or acidic does not equate in any way to
being carcinogenic. I’m not saying it’s somehow safer, but lets keep
the risks seperate. Nothing I can find on either sodium bisulphate or
even sulphuric acid itself suggests any sort of carcinogenic
activity. Materials that are carcinogenic are not just ordinary run
of the mill things that cause cell damage, etc. They have to be able
to cause quite specific types of damage that change a cells function
and genetics perhaps, rather than kill it. Acids are pretty good at
killing cells, not just tweaking them a bit to become cancerous down
the road… So then. Carcinogenicity of sodium bisulphate or
sulphuric acid? References please. Not just back fence gossip
suspicions from the Orchid archives.
Peter Rowe