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Analysis of FeCl3, HCl and HNO3 in etch solution
August 24, 2009
I have an etch solution which consists of FeCl3, HCl and HNO3.
I need to analyze for the concentration of each constituent of this solution.
Can anyone help with analysis methods to accomplish this?
Chemical Engineer - Norway
I'd analyze for iron by AA, then do a titration for total chloride (AgNO3 to the dichromate ep), and follow with a total acidity titration. I'd calculate the HCl by subtracting out the chloride in the FeCl3 from the total chloride, then calculate the HNO3 by subtracting out the HCl from the total acidity.
James Totter, CEF
- Tallahassee, Florida
August 27, 2009
A cheaper alternative is to precipitate Fe as Fe(OH)3 and estimate gravimetrically as Fe2O3 and do the other calculations as given already.
Ramajayam
Subramanian Ramajayam
consultant - Bangalore, India
September 23, 2009
December 14, 2011
Hello We are actually trying this ideas at the lab, I would like to know if this method works for you and how do you make the pH adjustment for the chloride determination? If somebody can help me I will be really grateful.
regards,
Claudia
- Chihuahua, Mexico
Adjust the pH to between 7 and 10. Sodium bicarbonate or aqueous ammonia
[on
eBay or
Amazon] are good things to use.
You will need to filter out precipitated Fe(OH)3, then wash the precipitate with distilled water 2 - 3 times.
My preferred Fe method would be to add an excess of EDTA at low pH, adjust pH to 11 with aqueous ammonia, then back titrate to a pink Eriochrome Black T
[affil links] endpoint with a standard solution of Zn or Mn.
Dave Wichern
Consultant - The Bronx, New York
December 16, 2011
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