Re: CALCIUM FLUORIDE SLUDGE USE

[Harriet Ige <hige@u.washington.edu>]

I have not confirmed this but I heard that ammonium hydroxide can be used
to neutralize hydroflouric acid without creating a precipitant.  You would
need to control the pH more closely to minimize formation of ammonia gas.  



On Tue, 25 Feb 1997, William C. Simon wrote:

> Richard Illig (717) 327-3568 wrote:
> > 
> >     THIS DID NOT SEND THE FIRST TIME, LETS TRY AGAIN
> >     RIC
> > 
> >     ---------------------------------------------------------------
> > 
> > Subject: Calcium Fluoride Sludge Use
> > Date: Fri, 7 Feb 1997 06:41:00 EST
> > From: "Richard Illig (717) 327-3568" <ILLIG.RICHARD@a1.pader.gov>
> > To: Remote Addressee <p2tech@great-lakes.net>
> > 
> >     FROM: R. Illig
> > 
> >     RE: Calcium Fluoride Sludge  and
> >         Hydrofluoric Acid for Etching Glass
> > 
> >     E-MAIL: illig.richard@a1.dep.state.pa.us
> > 
> > 
> >     One and All,
> > 
> >     1)  I too would be very interested in alternate uses, or users,
> >     for calcium fluoride sludge...pending full analysis of the sludge
> >     of course.  I have a site visit coming up next week and that is
> >     one of the waste streams needing addressed.
> > 
> >     I request that anyone answering the earlier request for
> >     information on CaF copy me and/or post the response to the list.
> > 
> > 
> >     2)  About a month ago, I requested information on any known
> >     methods for etching glass that would avoid the use of hydrofluoric
> >     acid (a better means for eliminating generation of the calcium
> >     fluoride sludge).  Unfortunately, the best, and only, response I
> >     received was not applicable, and involved the use of abrasive
> >     material.  I'm rather sure a chemical etching process would be
> >     needed (the inside of a glass (light) bulb is the object needing
> >     etched).
> > 
> >     Assumming I'm stuck with the hydrofluoric acid for etching, my
> >     next thought was to study the waste treatment system.  A
> >     significant drop in the molecular weight of the sludge MAY be
> >     possible by looking for replacements for the calcium source.
> >     Sodium, potassium, or other lighter elements that have similar
> >     chemical properties may allow for substitution of the calcium
> >     material.  Am I dreaming (about dead chickens) or does this seem
> >     like a worthy P2 method for attacking the problem?
> > 
> >     Any takers??
> > 
> >     As usual, thank you for any consideration.
> > 
> >     Ric
>                 ----------------
> P2-techies:
> 
> Calcium fluoride (CaF2) MAY be able to be recycled back to the HF
> production process.  HF is made from fluorspar, which is CaF2.  However,
> the potential for recycling is dependent on water content and, of
> course, economics.
> 
> I am not aware of anyone doing this now, but I have heard of
> facililities considering it as part of a project that regenerates KOH
> from neutralized fluoride-containing waste water.
> 
> Contact your HF acid source or Chemtech, Allied, or Dupont to discuss
> the feasibility.  
> 
> Also, please let us know if you succeed!
> 
> 				Bill Simon
> 
> -- 
> ***********************************************************************
> *  William (Bill) C. Simon                     wcsimon@jol.mobil.com  *
> *  Environmental Advisor                                              *
> *  Mobil Oil Corporation                                              *
> *  P.O. Box 874                               Phone: +1.815.423.7749  *
> *  Joliet, Illinois  60434                      Fax: +1.815.423.7726  *
> ***********************************************************************
> 
>