rgwebb6 Posted March 28, 2014 Report Share Posted March 28, 2014 What is the accepted method of disposing of unused dichromate solution once your violin is stained? I think it can be saved and used again, but I have some that I mixed with a quart of water instead of a cup and I have something from years ago that I think is dichromate but I'm not sure. I would like to get rid of the weak and unknown solutions safely. Quote Link to post Share on other sites
Violadamore Posted March 28, 2014 Report Share Posted March 28, 2014 Proceed to at least 12 miles offshore, use what you've got to wash down your teak (wearing gloves, etc., of course), then flush it all thoroughly overboard with a salt water hose. Legally, "international waters" is the open season potty of the world. Have a nice day! [Well, that settles that topic ] If that's not satisfactory, take it to your local hazmat disposal where you already take batteries, old cans of Raid, fluorescent bulbs, and the like. Quote Link to post Share on other sites
La Folia Posted March 28, 2014 Report Share Posted March 28, 2014 The way to handle it is to reduce it and precipitate it. But the general public needs to have it disposed of professionally. Quote Link to post Share on other sites
rgwebb6 Posted March 28, 2014 Author Report Share Posted March 28, 2014 I think I'll go with the hazmat idea. If I had a boat........ nah, too much time involved. Quote Link to post Share on other sites
Guest Posted March 28, 2014 Report Share Posted March 28, 2014 I've taken P.Dichromate and Nitric Acid to our local HazMat disposal site and they said they incinerate these types of hazardous material. I would think most communities these days have places to dispose of harmful chemicals. Quote Link to post Share on other sites
captainhook Posted March 28, 2014 Report Share Posted March 28, 2014 Incinerating nitric acid would not be smart. It would either simply vaporize into the atmosphere or create even less desirable products. Much better would be to dilute it with lots of water and fertilize your lawn with it. In my working life our waste dichromate went down the drain, but if I ever need to dispose of a small amount it will be poured in a discrete location. Quote Link to post Share on other sites
Julian Cossmann Cooke Posted March 28, 2014 Report Share Posted March 28, 2014 This is the second recent thread that has addressed the issue of safe disposal of the byproducts of our trade. I sense an opportunity for further education on this topic through, perhaps, a VSA convention presentation/discussion. Violadamore, I nominate you as an MNer with bona fides in this area. Tentative title: The Greening of Violin Making and Maintenance... Quote Link to post Share on other sites
MikeC Posted March 29, 2014 Report Share Posted March 29, 2014 isn't p.dichromate highly toxic and carcinogenic? Quote Link to post Share on other sites
nathan slobodkin Posted March 29, 2014 Report Share Posted March 29, 2014 isn't p.dichromate highly toxic and carcinogenic? You bet! In the words of Rene Morel (I swear he really said it) "What 's the matter are you afraid to die?" Quote Link to post Share on other sites
Jim Bress Posted March 29, 2014 Report Share Posted March 29, 2014 isn't p.dichromate highly toxic and carcinogenic? The portion of dichromate composed of hexavalent chromium (Cr(VI)) can cause cancer in the lungs from inhalation, and cancer in the intestines and duodenum from ingestion. The "safe" health threshold (reference dose) was set back in 1998 and is currently in review by the EPA. Quote Link to post Share on other sites
La Folia Posted March 29, 2014 Report Share Posted March 29, 2014 The portion of dichromate composed of hexavalent chromium (Cr(VI)) ... ...which would be all of it. Chromate and dichromate are hexavalent. However, it can be easily reduced, so it's no longer hexavalent. Quote Link to post Share on other sites
Johnmasters Posted March 29, 2014 Report Share Posted March 29, 2014 ...which would be all of it. Chromate and dichromate are hexavalent. However, it can be easily reduced, so it's no longer hexavalent. What reducing agent please? A copper compound? Quote Link to post Share on other sites
fiddlecollector Posted March 29, 2014 Report Share Posted March 29, 2014 Just use some sodium metabisulphite (used in brewing), then treat with caustic soda. Will produce green chromium hydroxide which is relatively safe and insoluble(used as a pigment). Quote Link to post Share on other sites
Jim Bress Posted March 29, 2014 Report Share Posted March 29, 2014 ...which would be all of it. Chromate and dichromate are hexavalent. However, it can be easily reduced, so it's no longer hexavalent. Not knowing how the solution was used I was allowing for the possibility that the dichromate could be partially reduced to trivalent chromium (Cr(III)) which is much less toxic. Also I'm a biologist not a chemist, so I'm comfortable talking about the health effects (part of my job) but not redox reactions. Quote Link to post Share on other sites
nathan slobodkin Posted March 31, 2014 Report Share Posted March 31, 2014 Jim and fiddle collector In all seriousness. Obviously the dry chemical must be treated with a great deal of respect but if one washes the solution off your hands and don't boil it or create a vapor are you likely to have it enter your system? Like wise if one uses it with tannic acid as a mordant and let it dry with light exposure then seal it with shellac ( standard neck treatment)is it still dangerous? Quote Link to post Share on other sites
Jim Bress Posted March 31, 2014 Report Share Posted March 31, 2014 Sorry Nathan (and everyone else) I wasn't trying to sound like an alarmist. Yes the chemical is safe to use with proper safety and handling procedures. Can Cr(VI) cause cancer? Definitely, but when we're talking cancer it is from chronic lifetime exposures. Something to consider is that dermal contact exposure does not necessarily end when you wash your hands if the chemical is absorbed into the dermal layers. So I would recommend wearing gloves. Again, occasional contact is no big deal, but daily contact might be a problem. My best advice is to keep an MSDS sheet for every chemical you use, and follow the safety procedures for handling that chemical. Here is the MSDS for potassium dichromate. Rereading the above, I think I still sound like an alarmist. I guess it's just my direct writing style. -Jim Potassium dichromate MSDS.pdf Quote Link to post Share on other sites
Jim Bress Posted March 31, 2014 Report Share Posted March 31, 2014 Jim and fiddle collector Like wise if one uses it with tannic acid as a mordant and let it dry with light exposure then seal it with shellac ( standard neck treatment)is it still dangerous? Probably not, but I really don't know. Quote Link to post Share on other sites
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