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Subject: Re: [DCHAS-L] reactive mixture
Date: Thursday, June 29, 2017 at 12:20:24 PM
Author: "Chainani, Edward Torres" <echaina2**At_Symbol_Here**ILLINOIS.EDU> 		Next by Date:
Subject: Re: [DCHAS-L] reactive mixture
Date: Thu, 29 Jun 2017 16:39:58 +0000
Author: William Banner

(Note: This post is 8 years old and may contain outdated information.)

From: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] reactive mixture
Date: Thu, 29 Jun 2017 12:26:40 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 15cf4ad09cc-7fac-5a1c**At_Symbol_Here**webprd-a67.mail.aol.com
In-Reply-To


Interesting.  That's the alternate for "bombing" which consists of 35% hydrogen peroxide and HCN which is, as I understand it, used for both diamond cleaning and getting the last of the mold refuse off of a gold casting.  The hospitals in NYC all have cyanide kits on hand because every couple of years a Hasid from the Diamond District is schlept to an ER in extremis.  


Someone really ought to take a Chemist's-eye look at this industry and develop some safer ways to do things. We already know there are better ways of polishing than to use high silica Tripoli that the traditional houses still use.  We need a new way to make casts also, since jeweler's investment mold compound comes as a powder that is usually 60 to 80% respirable and nano silica in the form of cristobalite.  

The blood associated with diamonds isn't just in Africa, it's right here, too.

If your school teaches a small metals/jewelry class, take a look.  They won't be bombing, but they will be using what they call "investment plaster" which is the high silica flour product and it is likely to be all over the place.  They need a fume hood for handling this.   And rouge and Tripoli might still be used and should be replaced with the a selection of the various grades of 3M Scotchbrite polishing wheels that don't need an abrasive.

And don't be fooled by the buffing wheel cabinets that provide "ventilation."   Open the cabinet and look at that filter.  It's usually an AC filter that captures 100% of crumbs and flies.  

Monona Rossol, M.S., M.F.A., Industrial Hygienist
President:  Arts, Crafts & Theater Safety, Inc.
Safety Officer: Local USA829, IATSE
181 Thompson St., #23
New York, NY 10012     212-777-0062
actsnyc**At_Symbol_Here**cs.com   www.artscraftstheatersafety.org

 


-----Original Message-----
From: Ellen M. Sweet <ems325**At_Symbol_Here**CORNELL.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Thu, Jun 29, 2017 11:39 am
Subject: [DCHAS-L] reactive mixture

Hi everyone,
We have a question from a colleague:
 
I have a researcher who is proposing to reflux a mixture of hot nitric 70%)/ perchloric (70%) and sulfuric acids (95%+) in a 1:2:1 mixture for removal of contamination from diamond surfaces. I was wondering if any of you have experience with a similar process? I'm concerned as there is limited information available for this method (published research data) and the available safety data does not recommend mixing sulfuric and perchloric acids not to mention heating such a mixture. We do have a perchloric acid hood available to the researcher, but I'm looking for a more defined, successfully executed process that can be used as reference in terms of apparatus, parameters such as time, temperature, volumes etc. Any feedback on overall safety considerations are also welcomed J
 
Ellen Sweet
Laboratory Ventilation Specialist
Department of Environmental Health and Safety, Cornell University
American Chemical Society, Division of Chemical Health and Safety
315-730-8896
 
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--- For more information about the DCHAS-L e-mail list, contact the Divisional secretary at secretary**At_Symbol_Here**dchas.org Follow us on Twitter **At_Symbol_Here**acsdchas

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