Letter 31046

Titanium analysis wet-titration method

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Does anyone know of a procedure for the manual titration of titanium metal dissolved in a solution of hydrofluoric acid / Ferric Sulphate??

Nigel Gill, B.Sc MIMF AIEMA MRSC
Aerospace - Glasgow, South Lanarkshire, Scotland

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I don't know of any titration for dissolved titanium. You could do it colorimetrically by taking a small sample of bath, adding some (say 20 ml)1:1 sulfuric acid, and heating strongly, in a fume hood of course, to white fumes. This is to drive off the fluoride as HF. Now, let the mixture cool, add it to about 400 ml water in a 500 ml volumetric flask, let this cool, then make up to the mark with water. Now take out a 10 ml portion, and add 1 ml of 3% hydrogen peroxide. A yellow color will develop, the intensity of which is proportional to the concentration of titanium. By comparing with standards made up in a similar way, you can get to the answer.

This would be a lot of work to set up, but once you do the initial work, routine analyses shouldn't take too long.

Dave Wichern
- The Bronx, New York

January 19, 2009

Does anyone know of a manual titration for the determination of dissolved titanium generated from an etch tank?
I am not looking for Atomic Absorption, ICP etc.

Nigel Gill
Aerospace. - Glasgow, Scotland

January 23, 2009

Nigel,

Vogel's "Quantitative Inorganic Analysis" [link is to info about the book at Amazon] has three wet analysis methods, it may be worth trying to get hold of a copy and see if one of the methods fits your needs.

Brian Terry
Aerospace - Yeovil, Somerset, UK

January 25, 2009

I stay with Dave that there is no known titration for titanium, maybe there is an indirect method.

A colorimetric determination is still a good idea. Also you can use the density of the solution to analyse the titanium content.

Why do you want a time consumption titration method?

Antonio Poell
- Brilon, Germany, EU

January 29, 2009

The problem with cations like Al3+ and Ti4+ is that they are very easily hydrolysed.

If you're determined on titration, you might have luck adding a known excess of EDTA at a low pH, stirring for ten minutes, then raising the pH to 10 and back titrating to a pink Eriochrome T endpoint with a standardized Zn2+ or Mg2+ solution.

Take a look at Meites' Handbook of Analytical Chemistry [link is to info about book on Amazon].

Dave Wichern
- The Bronx, New York