From: JOHN L STRAUGHN <john.straughn**At_Symbol_Here**WISC.EDU>
Subject: Re: [DCHAS-L] A very different question on perchlorates.
Date: Tue, 7 Jun 2016 19:56:51 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: CO2PR06MB585AF34E0CCD54CC994E3E1835D0**At_Symbol_Here**

It's known that pure perchloric acid (not the wimpy 70% aqueous that we usually have), a liquid and very strong acid, will explosively decompose to chlorine, hydrogen chloride, oxygen and water at fairly low temperature, ~80 degC. Anhydrous salts of perchlorate are relatively stable to high temperatures, but what really sets them off, motivates that is, is being able to acquire electrons from organic and reducing compounds or elements. Being in strong acidic mixtures really helps this. Actual Martian soil will have neither of these. Being in neutral to alkaline dry mixture at a low perchlorate salt fraction should be very safe.

The perchlorate on Mars is from chloride ion being oxidized by oxygen atoms that come from water, with UV sunlight  driving the process.

From: DCHAS-L Discussion List <dchas-l**At_Symbol_Here**> on behalf of Yanchisin, Mark <mark**At_Symbol_Here**EHS.UFL.EDU>
Sent: Tuesday, June 7, 2016 12:07:38 PM
Subject: [DCHAS-L] A very different question on perchlorates.

Here is a very different question for the group.


One of our UF researchers at NASA is using dry samples of perchlorates under UV lights to simulate the perchlorates found in Mars soils by the remote sampling devices on the rovers. 


He is concerned about flammability or explosions of the pure reagent grade perchlorate compounds.  The “soils” mixture in the growth chamber will simulate the Mars atmosphere.  It will be under UV irradiation at temperatures between -80 to +20 oC.  The growth chamber is kept at a low pressure (7 mbar) versus Earth sea level pressure (1015 mbar), and it  will be under a nearly pure CO2 atmosphere. 


Any thoughts on if the low pressure and low oxygen atmosphere render the experiments safe?  Any other thoughts?


As always- a grateful thank you any replies.   



Mark Yanchisin

Coordinator for Clinical and Laboratory Safety Programs

Environmental Health and Safety

University of Florida

POB  112190 Bldg 179 Newell Dr.

Gainesville, Fl  32611-2190

O- 352-392-1591

F- 352-392-3647



“Just because you are in compliance doesn’t mean you are out of danger.”  Mike Rowe “Deadliest  Catch”




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