Analytical Method to Monitor Industrial Pickling Baths Initially Constituted by HF, HNO<sub>3</sub>
- 1 LGC UMR CNRS 5503, Université de Toulouse III-Paul Sabatier, Toulouse, France
- 2 LGC UMR CNRS 5503, Université de Toulouse III-Paul Sabatier, Toulouse, France
- 3 LGC UMR CNRS 5503, Université de Toulouse III-Paul Sabatier, Toulouse, France
- 4 Airbus, Campus 2-Building B23-Module 04-Room 0411, 1 Rond-Point Maurice Bellonte, Blagnac, France
- 5 LGC UMR CNRS 5503, Université de Toulouse III-Paul Sabatier, Toulouse, France
Abstract
The present study couple s the acid/basis titration and the ICP analysis in order to monitor the concentrations of nitric and hydrofluoric acids, and presents into baths used to pickle alloys of titanium or stainless steel, largely employed in the aeronautic industry. The pickling of the alloys release s various metallic cations able to react with HF in order to lead to metal-fluoride complexes and free H + , the last being able to react with the basis. In this study , it w as determined: the most significant correlations providing the number of the protons released by the complexation of the metallic cation by the fluoride. The proposed method based on: 1 ) these correlations ; 2 ) the titration pH = f(V KOH ) curves ; and 3 ) the content of metallic cations determined by ICP, enables the monitoring of the content of HNO 3 and HF into the pickling bath. Assuming that one bath was used for one type of alloy (alloys of Titanium for example, or alloys of stainless steel), then the proposed method appears providing reliable concentration values of both acids as well as metallic cations.
- Bahadori, A. (2015) Essentials of Coating, Painting, and Lining for the Oil, Gas and Petrochemical Industries. In: Surface Preparation for Coating, Painting, and Lining, Chapter 1, Elsevier, Amsterdam, 1-105.
- Kladnig, W.F. (2008) New Development of Acid Regeneration in Steel Pickling Plants. Journal of Iron and Steel Research International, 15, 1-6. https://doi.org/10.1016/S1006-706X(08)60134-X
- Sutter, E.M.M. and Goetz-Grandmont, G.J. (1990) The Behavior of Titanium in Nitric-Hydrofluoric Acid Solutions. Corrosion Science, 30, 461-476. https://doi.org/10.1016/0010-938X(90)90051-6
- Say, W.C. and Tsai, Y.Y. (2004) Surface Characterization of Cast Ti-6Al-4V in Hydrofluoric-Nitric Pickling Solutions. Surface and Coatings Technology, 176, 337-343. https://doi.org/10.1016/S0257-8972(03)00747-3
- Schneiker, T. and Forsberg, K. (2014) Process Chemistry and Acid Management in Titanium Pickling Processes. Conference on Titanium Europe, Sorrento, 19-21 May 2014.
- Steinert, M., Acker, J., Oswald, S. and Wetzig, K. (2007) Study on the Mechanism of Silicon Etching in HNO3-Rich HF/HNO3 Mixtures. The Journal of Physical Chemistry C, 111, 2133-2140. https://doi.org/10.1021/jp066348j
- Tongwen, X. and Weihua, Y. (2003) Industrial Recovery of Mixed Acid (HF + HNO3) from the Titanium Spent Leaching Solutions by Diffusion Dialysis with a New Series of Anion Exchange Membranes. Journal of Membrane Science, 220, 89-95. https://doi.org/10.1016/S0376-7388(03)00218-7
- Cros, C. and Bares, P. (2012) Procédé de régénération d’une solution de décapage ou d’usinage chimique de titane. French Patent, EP2438210A1.
- Hermoso, J., Dufour, J., Gálvez, J.L., Negro, C. and López-Mateos, F. (2005) Nickel Hydroxide Recovery from Stainless Steel Pickling Liquors by Selective Precipitation. Industrial & Engineering Chemistry Research, 44, 5750-5756. https://doi.org/10.1021/ie050422n
- Gálvez, J.L., Dufour, J., Negro, C. and López-Mateos (2006) Fluoride Speciation in Stainless Steel Pickling Liquor. ISIJ International, 46, 281-286. https://doi.org/10.2355/isijinternational.46.281
- Gumin, K., Kwangchil, L., Haesung, P., Jinho, L., Youngjean, J., Kyoungsik, K., Boongho, S. and Hyoungkuk, P. (2010) Quantitative Analysis of Mixed Hydrofluoric and Nitric Acids using Raman Spectroscopy with Partial Least Squares Regression. Talanta, 81, 1413-1417. https://doi.org/10.1016/j.talanta.2010.02.045