finishing.com -- The Home Page of the Finishing Industry

-----

NOx Emissions from Titanium NDT Etching?

Part of the NDT flaw detection process for Titanium alloy jet turbine components requires a Macro-Etching process to examine anomalies at low magnification.

The etching process is Nitric Acid based at 500 g/litre at maximum 35C. My question is: under these conditions I have been told (by Scrubber Manufacturer) that one can expect NOx emissions in excess of 100 ppm.

I'm sorry but I am having trouble believing that NOx fumes even exist since HNO3 at 35C and Ti are very compatible. Am I missing something?

Robert Burns
designer - Montreal, Quebec, Canada
March 27, 2009

It is not NO or NO2 that your scrubber manufacture is talking about it is actually nitric acid fume- HNO3. Nitric acid at that temperature and concentration has a high enough vapor pressure to emit a considerable amount of nitric acid fume. It doesn't matter what kind of parts or how many you process- it is just concentration and temperature related. Nitric acid fume requires a multiple-stage wet scrubber.

Jon Barrows, MSF, EHSSC
Kansas City
April 22, 2009

No dead threads! If this page isn't already on the Hotline your Q, A, or Comment will move it there.

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: