aqua regia processing in SNF...

Mary Tang mtang at stanford.edu
Sun Mar 11 14:54:28 PDT 2012


Hi all --

Jim is absolutely right, this stuff needs to be respected.  The mixture 
creates a "superacid" whose pKa is more acidic than pure sulfuric acid.  
Aqua Regia was once used widely in the semiconductor industry (and just 
about any where else that chemical brute force was used), but has been 
phased out due to safety reasons.  It's also highly discouraged for use 
in university labs, because there are almost always safer alternatives 
for most of the applications for which it is generally used (for 
example, KI for etching gold.)

Please refer to:  
http://www.aiha.org/insideaiha/volunteergroups/labHandScommittee/Pages/IncidentsExplosions.aspx

Therefore, for the CCB, some homework (i.e., demonstration of due 
diligence) will be required.  Basically, we'd want to see:

1.  Your process flow showing how and why it would be used.
2.  An overview of possible alternatives to aqua regia and why or why 
not they would work for your process.
3.  A detailed procedure on how this process would be done, especially 
safety measures to be taken.   This should include the volumes and what 
order your chemicals are to be mixed and how you will dispose of waste, 
how the area will be isolated from other labmembers, a description of 
the labware you will use, how long your process is, secondary 
containment for your chemical vessels.  And I'm with Mahnaz, why the 
water?  I'm no expert, but it strikes me as being rather dangerous to 
add water...   Make sure to read the MSDS -- it's not the same as HCl 
and Nitric -- it is air reactive, strongly oxidizing, water reactive, 
self-heats, and decomposes into toxic gases, according to a couple I've 
just pulled up...

I honestly have never worked with aqua regia, so personally can't 
contribute much on its safe use.   If you want to use it, we'd have to 
have a good rationale and clearly defined procedures for its use.  I 
expect that we would draw tight boundaries around how, when, and who can 
use it in the lab.

Mary

On 3/11/2012 9:14 AM, Mahnaz Mansourpour wrote:
>
> Hi all,
>
> Jim thanks for information.
> Just to be sure, specmat, have not okay the process yet.
> Robert , please attend the next CCB meeting, Thursday at 2:30.
> i hope I have the time correct?
>
> mahnaz
> On 3/10/2012 12:30 PM, Jim McVittie wrote:
>> Robert,
>>
>> Be very careful in using aqua regia. It can suddenly "spitted" acid 
>> out of a beaker. Mixing HCl and NHO3 forms a new stronger acid.  As a 
>> gradate student, I use to mix a gal of it up at a time for doing 
>> super cleaning of quartz ware. Over the years better methods were 
>> found for cleaning quartz. It was also used for cleaning Si before 
>> the advent of the RCA clean.   Jim
>>
>> ----- Original Message -----
>> From: "Mahnaz Mansourpour"<mahnaz at stanford.edu>
>> To: "Robert Huang"<roberth at quswami.com>, 
>> "Mahnaz"<mahnaz at stanford.edu>, Specmat at snf.stanford.edu, "maurice 
>> stevens"<maurice at stanford.edu>, "Uli Thumser"<uli at snf.stanford.edu>
>> Sent: Friday, March 9, 2012 2:08:04 PM
>> Subject: Re: aqua regia processing in SNF...
>>
>>
>> Hi Robert,
>>
>> Mixing HCL and NHO3 is ok but why mix it with water?
>> I am not sure how will react?
>> Please give me more information.
>>
>> mahnaz
>> On 3/9/2012 11:16 AM, Robert Huang wrote:
>>
>>
>>
>>
>> Hi Mahnaz,
>>
>>
>>
>> So of course HCl and HNO3 are already approved chemicals in SNF. I 
>> assume it is then OK to mix them up in an aqua regia solution (3 
>> parts HCL, 1 part nitric, and 2 parts water) for use at wbgeneral 
>> (our intent is at room temperature) as long as we follow the usual 
>> guidelines including proper labeling, correct?
>>
>>
>>
>> Regards,
>>
>>
>>
>>
>> Robert Huang
>>
>> Director, Process and Device Technology
>>
>> QuSwami, Inc.
>>
>> 455 Mission Bay Blvd. South
>>
>> Building 3, Suite 125
>>
>> San Francisco, CA 94158
>>
>> W: (415) 834-9910
>>
>> M: (408) 854-0450
>>
>> F: (415) 834-9975
>>
>> Email: roberth at quswami.com
>>
>>
>>
>> **********************Privacy and Confidentiality 
>> Notice**********************
>>
>> The information contained in this communication is proprietary, 
>> confidential, copyright, trade secret of QuSwami, Inc. It is intended 
>> solely for the use of the individual or entity to whom it is 
>> addressed and others authorized to receive it. If you are not the 
>> intended recipient, you are hereby notified that any disclosure, 
>> copying, distribution or taking any action in reliance to the 
>> contents of this information is strictly prohibited.
>>
>> ****************************************************************************** 
>>
>>
>>
>>
>>
>>
>> From: Robert Huang
>> Sent: Thursday, March 08, 2012 1:05 PM
>> To: 'Mahnaz Mansourpour'
>> Subject: aqua regia processing in SNF...
>>
>>
>>
>> Hi Mahnaz,
>>
>>
>>
>> Is aqua regia (combination of HCl and HNO3) already an approved 
>> chemical in SNF? If so, what are the procedures including where it 
>> can be used?
>>
>>
>>
>> Regards,
>>
>>
>>
>> Robert Huang
>>
>> Director, Process and Device Technology
>>
>> QuSwami, Inc.
>>
>> 455 Mission Bay Blvd. South
>>
>> Building 3, Suite 125
>>
>> San Francisco, CA 94158
>>
>> W: (415) 834-9910
>>
>> M: (408) 854-0450
>>
>> F: (415) 834-9975
>>
>> Email: roberth at quswami.com
>>
>>
>>
>> **********************Privacy and Confidentiality 
>> Notice**********************
>>
>> The information contained in this communication is proprietary, 
>> confidential, copyright, trade secret of QuSwami, Inc. It is intended 
>> solely for the use of the individual or entity to whom it is 
>> addressed and others authorized to receive it. If you are not the 
>> intended recipient, you are hereby notified that any disclosure, 
>> copying, distribution or taking any action in reliance to the 
>> contents of this information is strictly prohibited.
>>
>> ****************************************************************************** 
>>
>>




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