"The rate of dissolution of polycrystalline beryllium was studied in hydrofluoric, hydrochloric and sulfuric acids. Two samples of beryllium containing different amounts of beryllium oxide were used. The experiments were performed at temperatures ranging from 20 to 50°C, and at various acid concentrations. The kinetics of these heterogeneous processes conformed to a reaction order of approximately one in all the cases. Since the conditions of the surface were complex during dissolution, these might complicate the reaction. This might be due to the oxide layer, which is present as impurity.
The difference effect was determined at various acid concentrations at 25°C using a beryllium-platinum cell. The difference effect in the initial stages was directly proportional to the galvanic current. At higher current densities, the difference effect declined slightly from a linear relationship. A very strong positive difference effect was observed for beryllium dissolving anodically in hydrofluoric acid. The value of the proportionality constant K was higher than 6.97.
The two beryllium samples differed markedly in their behavior in hydrochloric acid, exhibiting the negative and the positive difference effect. The beryllium reacted with hydrochloric acid forming chunks which were visible to the unaided eye.
In sulfuric acid, a positive difference effect was observed with the values of K well below 6.97.
The apparent valence of beryllium ions going into solution during anodic dissolution was calculated. This resulted in ionic charges of extremely high and low values. It was thus concluded that the normal valence of beryllium ions does not change under these conditions"--Abstract, pages ii-iii.
Straumanis, Martin E., 1898-1973
Larson, Andrew H.
Johnson, James W., 1930-2002
Webb, William H.
Materials Science and Engineering
M.S. in Metallurgical Engineering
U. S. Atomic Energy Commission
Missouri School of Mines and Metallurgy
xiii, 188 pages
© 1962 Daniel Santhamurthi Gnanamuthu, All rights reserved.
Thesis - Open Access
Beryllium -- Dissolution -- Testing
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Gnanamuthu, Daniel Santhamurthi, "A study of the chemical kinetics, activation energy and difference effect on beryllium dissolving in mineral acids" (1962). Masters Theses. 2722.