Spectrophotometric study of the corrosion behaviour of chromium in molten alkali carbonates

The corrosion of chromium species in molten (Li/K)(2)CO3 and (Li/Na/K)(2)CO3 are investigated by spectrophotometry, A strong charge-transfer absorption band is observed in the ultraviolet region with lambda(max) = 372 nm, and the molar absorptivity of CrO42- in molten (Li/K)(2)CO3 is calculated. The corrosion rates are investigated by means of increasing the concentration of CrO42- in the melts. Under an air atmosphere, the corrosion rate is slower in molten (Li/K)(2)CO3 than in molten (Li/Na/K)(2)CO3 and Cr2O3 corrodes more easily in molten (Li/K)2CO3 than Cr. With an atmosphere of CO2 = 1 atm, there is no increase in the CrO42- concentration in the solution phase during a period of 5 h. (C) 1998 Elsevier Science S.A.