From: NEAL LANGERMAN <neal**At_Symbol_Here**CHEMICAL-SAFETY.COM>
Subject: Re: [DCHAS-L] Clarification: [DCHAS-L] HF working surface decontamination solution - recommended concentration or alternate?
Date: Tue, 14 Aug 2018 13:02:30 -0700
Reply-To: neal**At_Symbol_Here**CHEMICAL-SAFETY.COM
Message-ID: 034701d43409$bc3866f0$34a934d0$**At_Symbol_Here**chemical-safety.com
In-Reply-To


Rachel

 

Your question is a bit confusing. The surfaces you describe are non-porous and will not allow ions to penetrate. Aqueous F- sources of concern HF, NH4F2-, CF3COOH, etc, are completely miscible and soluble in water. As such, standard equipment washing methods, such as soaking in Alconox and thorough rinsing with tap water followed by DI will remove all F-. The proposed Ca binding step will create an insoluble CaF2, which will cling to surfaces by adsorption forces and will be more difficult to remove.

 

Can you provide a rationale for wanting to do the Ca step? I do not see the chemistry and am curious.

 

Thx

 

 

 

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From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Layman, Rachel
Sent: Tuesday, August 14, 2018 12:06 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] Clarification: [DCHAS-L] HF working surface decontamination solution - recommended concentration or alternate?

 

Hello, thank you for replies so far.  However,  I am not interested in skin or other personal exposure or medical responses.  We have those in place and they include calcium gluconate and other emergency practices.

 

We are solely interested in identifying the best work practice to recommend to lab personnel to clean tongs, utensils or other working surfaces before storing these reusable items after their use with HF.  Our initial understanding was that a calcium hydroxide solution would be satisfactory; however, we realized providing the concentration would be more useful to lab personnel. We have not yet been able to locate such information.

 

Thank you for any input in advance.

 

Rachel

 

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of David C. Finster
Sent: Tuesday, August 14, 2018 2:30 PM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] HF working surface decontamination solution - recommended concentration or alternate?

 

I am puzzled.   My understanding is that HF, and other ionizable/ionized forms of fluoride, if exposed to the skin should be treated with calcium gluconate.  ("Calgonate" is a preparation of calcium gluconate.)  However, these treatments would neither be effective nor necessary if the fluorine-containing compound is covalently-bound F.  Thus, I don't know what a "fluorinated acid spill" might be or whether calcium carbonate (which is not calcium gluconate/"Calgonate") would be effective.   (An example of a fluorinated acid might be TFA, trifluoroacetic acid; these F atoms are not ionizable.)

 

When once researching medical events about fluoride exposures I came across anecdotes of medical ER folks using calcium gluconate on an exposure that was clearly a covalently-bonded fluorine compound.  (I can't find this now.)  The treatment was ineffective, as expected.  But, the patient was not suffering from "fluoride exposure", either.)

 

I would welcome other insights that clarify my understanding.

 

Dave

 

 

David C. Finster
Professor, Department of Chemistry
Wittenberg University
937-327-6441

https://www.wittenberg.edu/academics/chemistry/facultystaff/finster2.html

 

 

From: ACS Division of Chemical Health and Safety [mailto:DCHAS-L**At_Symbol_Here**PRINCETON.EDU] On Behalf Of Sara J
Sent: Tuesday, August 14, 2018 11:32 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: Re: [DCHAS-L] HF working surface decontamination solution - recommended concentration or alternate?

 

Calgonate also has a lot of info. on HF safety and has spill kits and gels available. At my company we keep calcium carbonate on hand for any fluorinated acid spills, but we do not handle HF. 

 

http://www.calgonate.com/safety_info.php

 

Sara Johnson, Ph.D.

 

Inorganic Chemist

The Shepherd Chemical Company

Norwood, OH 45212

sjohnson**At_Symbol_Here**shepchem.com

Cell: (810)730-8963

Office: (513) 731-1110

 

On Tue, Aug 14, 2018 at 11:21 AM, Paul Weller <wellerp**At_Symbol_Here**elon.edu> wrote:

Honeywell has a neutralization guide

https://www.honeywell-hfacid.com/literature/

 

Paul Weller

 

Paul Weller

Senior Science Laboratory Manager-Chemistry
Elon University

2625 Campus Box

Elon, NC 27244

Phone  336.278.6225

Location MCMI 302

wellerp**At_Symbol_Here**elon.edu

From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Layman, Rachel
Sent: Tuesday, August 14, 2018 10:50 AM
To: DCHAS-L**At_Symbol_Here**PRINCETON.EDU
Subject: [DCHAS-L] HF working surface decontamination solution - recommended concentration or alternate?

 

Hello,

 

Does anyone know what percent solution of calcium hydroxide would be appropriate for decontamination of working surfaces where HF has been used, or small spill of HF known?

 

Or is there a better solution anyone can recommend?

 

Thanks,

 

Rachel

 

Rachel M. Layman, MS, CHMM, CHO

University Chemical Hygiene Officer

Environmental Health and Safety

Virginia Tech

575 Beamer Way

(540) 231-3427

 

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