THE CORROSION AND EROSION OF NICKEL BY MOLTEN CAUSTIC SODA AND SODIUM URANATE SUSPENSIONS UNDER DYNAMIC CONDITIONS

摘要

Compared with that measured under static conditions, the corrosion rate of nickel in molten caustic soda under dynamic conditions is approximately 10 times as great. The addition of sodium uranate increases this further by a factor of 3 at SCO C, although at 500 the uranate has no effect.nThe operation of thermosyphon loops containing molten caustic soda has revealed some of the difficulties and limitations of the system. Under an inert gas atmosphere at temperatures above 600°C, mass transfer of nickel causes complete obstruction of the flow in a few weeks, while at 500, blocking occurs after about 200 days. In these cases the mass transfer depositis a higher oxide of nickel whose composition uis complex, but approximates to Ni2°3.nUnder a hydrogen atmosphere loops are slower to plug than those operated under an inert atmosphere at the same temperatures, and here the deposit is found to be pure nickel.