Abstract
Sulfuric acid is one of the most complicated corrosives for passive alloys to handle. It gradually changes from the highly reducing character of dilute solutions to the strongly oxidizing character of concentrated solutions. It becomes even more complicated when other variables, such as temperature, pressure and impurities, are involved. The usefulness of many alloys in sulfuric acid is restricted to some specific conditions, such as low concentration, high concentrations, or low temperatures.
The corrosion of zirconium in sulfuric acid solutions is rather straightforward. It resists attack by sulfuric acid at all concentrations up to 70% and at temperatures to boiling and above. In 70 to 80% sulfuric acid, the resistance of zirconium depends strongly on temperature. In higher concentrations, the corrosion rate of zirconium increases rapidly with increasing concentration.
Certainly, the performance of zirconium in sulfuric acid solutions is affected not just by concentration and temperature, but also by many other factors. When these factors are properly addressed, zirconium can perform well in many sulfuric acid solutions. This paper discusses metallurgical, environmental, mechanical, design, fabrication, operational and maintenance issues that affect the performance of zirconium in sulfuric acid solutions. Examples will be given of the applications of zirconium in sulfuric acid service.
