From: Richard Sullivan (richsul@earthlink.net)
Date: 02/20/03-02:22:39 PM Z
Gordon,
I had figured that this subject had been dropped. But.... again:
I was correcting primarily an email post forwarded here that was quoted
again in my recent post that one could safely cap up aqua regia. It is
again quoted in the following paragraph.
This is the point of contention:
> > >Aqua regia is a stable mixture of acids that will not spontaneously
explode
> > >at normal temperatures, though a small amount of pressure will build
up in
> > >its container until any air present is saturated with the acid
vapours. It
> > >should, of course be kept in a glass or plastic container with screw cap,
> > >which is capable of withstanding the small build-up of pressure that
> > >occurs. [Liam Lawless]
As noted by the AIHA this is simply wrong and if this advice was followed
it could cause serious harm by maiming, blinding or even killing someone.
There was a long discussion following my original critique of the article
in PF in which others alluded to the safety of aqua regia. I do not have a
copy of PF #3 on hand but I have been told there is a picture of Liam in
what appears to be a kitchen.
As for doing a paper on aqua regia I can post it here simply: don't, unless
you have professional training and equipment to deal with it. If you have
to learn how to do this from a paper on the Internet you don't have the
skills or equipment to deal with it. It used to be that you could basically
write any set of instructions such as how to make bombs and be legally
immune. No longer. Things are wacky now.
One error in the paper write could in fact be a cause for liability. Had
the paper stated that aqua regia could be capped as was posted here, and
the bottle had exploded as cited in the American Hygene Association and
maimed someone, liability issue could arise.
As for general safety issues concerning alt photo I have two papers that I
will donate. One is called Platinum Green and the other is called Gum Green
both of which deal with both safety and environmental issues.
The liability issues are different for me than for most here due to the
fact that I am associated with a professional business. The waters are
quite muddy in this area. Under commercial liability laws, much hinges on
the target market. My business aims at the professionally trained
photographer. My 25 years of experience in dealing on a day to day
consulting basis with this market tells me that this is not the market that
should be dealing with aqua regia. You work in a university environment and
may be immune from liability for that reason.
In 1990 I was surrounded by plain clothes DEA agents with drawn weapons,
handcuffed and thrown to the ground in the parking lot outside my work
place in full view of co-workers! This because I bought a Tri-beam Ohaus
scale and 3 >>empty<< Cubitainers at Tri-Ess Sciences which was under
surveillance and they tailed me back to LA City Hall where I worked. This
was for a high school class in photography of which I was helping a friend
set up a darkroom for! Not that anyone is going to do this to you or me
over this issue but I want to point out that there are all kinds of issues
concerning chemistry today that go beyond what was traditionally the case.
Your post required a response but I had no intention of discussing the
issue again. I accept the censoring of posts on aqua regia under protest.
Making topics off limits for the comfort of those whose posts are being
criticized seems a bit odd, but if it brings peace to the List, so be it.
--Dick Sullivan
At 09:29 AM 2/20/2003 -0600, you wrote:
>I received a lot of private email concerning Dick Sullivan's recent
>posting entitled "Kitchen brewed gold chloride! Not!" (Feb 10 2003)
>about the safety of working with Aqua Regia. A copy of his posting is at
>the end of this message.
>
>This stems from an article entitled "Make your own Gold Trichloride"
>written by Liam Lawless, published in the World Journal of Post-factory
>Photography in May 1999 (page 30). In this article Liam Lawless
>summarizes a method in which gold trichloride is produced from "scrap
>gold".
>
>As others have noted Liam did not suggest doing this procedure in the
>kitchen or darkroom. His procedure also avoids the problems associated
>with storing Aqua regia by neutralizing the aqua regia solution at the end
>of the procedure.
>
>I considered how other publications associated with alternative
>photographic processes dealt with issue of working with hazardous
>chemicals.
>
>I did a "review" of many of the alt-photo web sites, those written as a
>public service and commercial web sites, as well as a number of books.
>Almost all of these give some sort of warning that many of the
>chemicals used are hazardous and that people should assume everything is
>hazardous unless they know otherwise.
>
>None of the sites I visisted provided any specific information on how to
>deal with the potential hazards. Most sites didn't even identify which
>materials were hazardous and which were not.
>
>Liam's article, like most other alt-photo information currently available
>assumes the worker is aware of the hazards involved.
>
>On the alt-photo list its assumed that everyone knows how to handle the
>potentially dangerous chemicals. When we post a message about salted
>paper we don't describe the hazards and necessary precautions to be taken
>when working with silver nitrate. The same for dichromates in gum
>printing and so on.
>
>A lot of the people working in this field come into it with some sort of
>training that informs them of the appropriate laboratory/chemical
>practices. As alt-photo becomes more popular, this is becoming less and
>less common.
>
>The lay-person starting to work with alt-photo can usually find plenty of
>information about the hazards, but little information on how to work
>safely in this field.
>
>What I would like to see is an effort to properly document the potential
>risks of each process, the basics of the chemistry involved (why there is
>a safety risk) and the appropriate steps that should be taken to minimize
>the risks.
>
>If people are genuinely concerned about providing indepth safety
>information, perhaps list members could collaborate on producing
>documentation on the proper safe darkroom/lab practices for each process.
>I would be happy to post these on the alt-photo archive site.
>
>Since the use of Aqua Regia is such a concern, perhaps we could start with
>this process. At this point anyone going through the archive looking for
>information on aqua regia and gold chloride will get the left with the
>impression that some people think its dangerous and some people think its
>not.
>
>I would like to ask the people who have worked with aqua regia and gold
>chloride to collaborate on a document that clearly outlines the hazards,
>and the appropriate precautions. If people are unable to agree I would
>like to get dissenting opionions, and post these.
>
>I will post one or more documents on the alt-photo archive site.
>
>If people are unwilling to do this then I would insist that the issue of
>Aqua Regia safety should no longer be discussed on this list.
>
>Thanks
>
>Gord Holtslander
>List Manager
>
>On Mon, 10 Feb 2003, Richard Sullivan wrote:
>
> > Subject: Kitchen brewed gold chloride! Not!
>
> >
> > Several years ago there was a brouhaha here over an article in Post Factory
> > No 3 on making gold chloride in your kitchen or darkroom.
> >
> > The issue at hand was safety. I believe some correction were made in No 4
> > but the problem still exists as many here might read No. 3 without the
> > benefit of the corrections in No 4. It is highly doubtful that anyone would
> > try this trick at home but someone just might as the article proposes just
> > such a project.
> >
> > Several had said here that aqua regia would not explode in closed
> > containers. Wrong!
> >
> > Liam Lawless, author of the article, said the following June of 1999 on the
> > list via another members repost or forward.
> >
> > Liam says:
> >
> > >We have perhaps been remiss in implying that this process can be carried
> > > >out indoors, which it definitely should not without the proper
> equipment,
> > > >etc., but the only other point that gives me real cause for concern
> is your
> > > >assertion that stored aqua regia could explode.
> >
> > Not only my assertion but that of the American Industrial Hygene
> Association!
> >
> > >I have, therefore, spoken
> > > >to a chemist about this today (whose name I shall not give as he has
> > > >nothing to do with this debate, but who has some interesting views on
> > > >safety and responsibility that I hope he will one day share), and
> the gist
> > > >of what he told me is as follows.
> > > >
> > >Aqua regia is a stable mixture of acids that will not spontaneously
> explode
> > > >at normal temperatures, though a small amount of pressure will build
> up in
> > > >its container until any air present is saturated with the acid
> vapours. It
> > > >should, of course be kept in a glass or plastic container with screw
> cap,
> > > >which is capable of withstanding the small build-up of pressure that
> > > >occurs. And the general rule for acids is that they should be stored
> in a
> > > >cool, dark place; heat increases the pressure, and light may cause
> > > >photolysis that in turn causes decomposition and the liberation of
> gases.
> > > >It is also important that the container is clean, to avoid contaminants
> > > >that could catalyse decomposition.
> >
> > This is patently wrong and compounds the error in PF No 3.
> >
> > To add to the warnings I have found the following at:
> >
> > http://www2.umdnj.edu/eohssweb/aiha/accidents/explosion.htm#Two
> >
> > Do a page search on "aqua regia" as the pertinent part is about 80% down
> > the page. It is from the American Industrial Hygene Association on the New
> > Jersey Medical and Dental College site. It highlights two cases of aqua
> > regia explosions. These were not just caps blowing off but violent
> > explosions shattering the glass bottles with enough force to break other
> > nearby bottles. Had someone been in the room and been the subject of flying
> > glass and hot aqua regia spray it could have been very messy.
> >
> > The text follows:
> >
> > >Two Explosions Involving Aqua Regia (top)
> > >Key Learning Points
> > >1. Use a reagent that is milder than aqua regia for cleaning glassware if
> > >it will suffice.
> >
> >
> >
> > >2. Do not take aqua regia out of the fume hood in which it was prepared,
> > >and do not store it there either; make only what you need and destroy the
> > >residue. Aqua regia can be destroyed by cautious and careful dilution with
> > >water - talk to your supervisor or your safety office for a detailed
> > >procedure. If necessary, the solution can then be neutralized and disposed
> > >of in the approved manner.
> >
> >
> >
> > >3. Never put aqua regia in a closed container or near flammables.
> >
> >
> >
> > >There have been explosions involving aqua regia ( a mixture of
> > >hydrochloric acid and nitric acid) reported at two universities. Both of
> > >the incidents took place in chemistry laboratories.
> >
> >
> >
> > >In the first incident, a graduate student was using aqua regia for the
> > >cleaning of NMR tubes. When he was finished, he placed the residues (about
> > >50-60 ml) in a 4 litre waste bottle, capped it tightly and placed it in a
> > >flammable storage cabinet. Approximately one hour after the bottle was
> > >placed in the cabinet, it burst, breaking an adjacent bottle of pyridine.
> > >Luckily, the pyridine did not ignite and other nearby bottles containing
> > >flammable solvents did not become involved. The pyridine leaked onto the
> > >floor, where it dissolved floor tiles and created a lingering bad smell.
> > >The second incident occurred in a fume hood in a synthetic chemistry
> > >laboratory. A tightly closed waste bottle containing used aqua regia
> > >exploded, most probably due to pressure buildup inside the bottle.
> > >Since the sash was not completely closed the broken waste bottle was not
> > >contained. Broken glass as well as some liquid acid waste were thrown out
> > >of the hood. Since nobody was near the hood at that moment, there were no
> > >injuries. Moreover, a nearby bottle of mercury nitrate waste was also
> > >broken as well as the secondary container, so that a small spill (less
> > >than 1 liter) of liquid acid and solid mercury nitrate occurred inside the
> > >hood.
> >
> >
> >
> > >What is aqua regia?
> > >Aqua regia has been used by chemists for centuries, especially as a medium
> > >for dissolving noble metals but also for other purposes. It is a mixture
> > >of concentrated hydrochloric and nitric acid which forms a powerful
> > >oxidizing medium. Mixing an oxidizer with organic materials may result in
> > >a highly exothermic reaction. Even without other materials present, a
> > >chemical reaction occurs slowly and brown fumes of NO2 can be observed (in
> > >freshman chemistry terms, nitric acid is reduced and hydrochloric acid is
> > >oxidized). The activity as a dissolving agent decreases slowly and so, by
> > >definition, the solution is unstable - it should be used "freshly
> prepared".
> >
> >
> >
> > >Rules for using aqua regia
> > >Aqua regia is often used as a substitute for chromic sulfuric acid
> > >cleaning solutions. However, aqua regia is also corrosive and strongly
> > >oxidizing. It is essential for some purposes but should not be used for
> > >routine cleaning of glassware. If a milder reagent will suffice avoid
> > >using aqua regia. Alternatives include ultrasonic baths, alconox or
> > >similar detergents, Pierce RBS-35 (available from VWR) or similar
> > >detergents or biodegradable surfactants.
> >
> >
> >
> > >Be aware that sufficient pressure can build up in a short amount of time
> > >to burst the container, even from a very small volume of aqua regia.
> >
> >
> >
> > >If it is decided that aqua regia is needed, wear protective clothing
> > >(goggles, gloves, coat) and work in a clean well-ventilated fume hood.
> > >Keep the sash down when reactions are in progress.
> >
> >
> >
> > >Never take aqua regia out of the hood.
> >
> >
> >
> > >Prepare it, use it, and destroy any excess in the hood in which it was
> > >prepared.
> >
> >
> >
> > >
> > >Only prepare the amount of aqua regia you need for immediate use. Never
> > >store it and never put it in a closed vessel, since evolved gases will
> > >cause a pressure build-up and possible explosion.
> >
> >
> >
> > >Aqua regia is a strong oxidizer. It is incompatible with organic solvents,
> > >flammables and any reducing agents.
> >
> > --Dick Sullivan
> >
> >
> >
>
>---------------------------------------------------------
>Gordon J. Holtslander Dept. of Biology
>holtsg@duke.usask.ca 112 Science Place
>http://duke.usask.ca/~holtsg University of Saskatchewan
>Tel (306) 966-4433 Saskatoon, Saskatchewan
>Fax (306) 966-4461 Canada S7N 5E2
>---------------------------------------------------------
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