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Application limits of Ta and Ta‐2.5% W for sulfur acid handling
Author(s) -
Renner M.,
Andersson K.,
MichalskiVollmer D.
Publication year - 1998
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/(sici)1521-4176(199812)49:12<877::aid-maco877>3.0.co;2-q
Subject(s) - chemistry , sulfuric acid , nitration , nuclear chemistry , inorganic chemistry , organic chemistry
Long term corrosion test with welded coupons were carried out to determine the application limits of Ta and Ta‐2.5% W in sulfuric acid (H 2 SO 4 ). The program included the following two fields of investigation: • Determination of corrosion behavior in 90 through 100% H 2 SO 4 at temperatures up to 200°C. •Determination of corrosion behavior in 96 wt % H 2 SO 4 comparing recovered nitration‐spent acid and technical grade between 150 and 230°C. Mainly immersion tests were performed. A comparison of Ta and Ta‐2.5 % W showed that in technical H 2 SO 4 the alloy performed better than the metal. Regardless of which material was considered, the higher the H 2 SO 4 concentration, the lower the temperature necessary to achieve acceptable corrosion behavior. In technical H 2 SO 4 , the following application limits were revealed: Ta: 96 wt %/200°C – 97 wt %/150°C Ta‐2.5% W: 96 wt %/210°C – 97.5 wt %/175°C. Above 97.5 wt % the corrosion resistance decreased rapidly. The recovered nitration‐spent acid led to remarkably lower corrosion rates due to small amounts of nitric acid. In these types of acidcontaining oxidizing compounds. 230°C seemed to be satisfactory, provided the wall of the heat exchanger was sufficiently thick.