STP830

    Effects of Impurities in Sulfuric Acid on the Corrosion Resistance of Zirconium

    Published: Jan 1984


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    Abstract

    Zirconium is one of the few metals that resists attack by sulfuric acid (H2SO4) up to 75% concentration. It is being frequently used to handle the acid in the difficult concentration range of 40 to 60%. However, due to environmental concerns, the dumping and the storage of H2SO4 wastes have become a problem. Contaminated H2SO4 is involved in many processes. The purpose of this investigation is a more precise characterization on the effects of impurities on the corrosion resistance of zirconium.

    Corrosion behavior of zirconium alloys in H2SO4 with common detrimental impurities, that is, Fe+3, Cu+2, Cl, NO3, and seawater, has been investigated. It has been found that Zr 702 and Zr 704 can tolerate a larger amount of impurities than Zr 705. Welds of zirconium alloys are susceptible to local corrosion in contaminated H2SO4. However, the local corrosion of welds can be easily avoided by a proper that treatment. For our corrosion tests, the heat treatment was performed at 760°C for 15 min.

    The performance of passivated Zr 702 and Zr 705 under a simulated upset condition, for example boiling 74% H2SO4, has been studied. It has been found that Zr 702 can withstand the upset conditions without significant attack up to 20 min, but Zr 705 will corrode immediately and rapidly.

    Keywords:

    zirconium, zirconium alloys, sulfuric acid, contaminated sulfuric acid, corrosion, upset condition, industrial applications


    Author Information:

    Yau, T-L
    Corrosion group head, Metallurgical Research and Development, Teledyne Wah Chang Albany, Albany, Ore.


    Paper ID: STP32524S

    Committee/Subcommittee: B10.02

    DOI: 10.1520/STP32524S


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