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Kinetics of the Dissolution of Tin and Aluminum in Basic Aqueous Solutions.

Palmer BR

NTIS: PB 293-926 :61 pages

10009489

The rate phenomena involved in the dissolution of aluminum and tin in basic solutions were identified to provide data concerning the suppression of aluminum dissolution in the detinning of scrap materials. In the case of aluminum, a surface reaction involving the removal of al(oh)3 from the anodic site is rate controlling. Rate is first order with respect to the activity of hydroxyl ion, and an enthalpy of activation with 17.1 Kcal/mole is observed. The rate of dissolution of tin was measured in the presence of oxygen, sodium nitrate, and sodium stannate; oxygen was found to be the most effective oxidant. The reaction of tin with oxygen was found to be controlled by the diffusion of this reactant to the metal surface. This mechanism was confirmed by development of a model for the transport of oxygen to the surface of the rotating tin sample utilized in this work. The highest rate of reaction in the tin system is observed when a temperature of 65 deg c is involved and when the sodium hydroxide concentration is maintained at values less than 1 molar.

19780101

CP; Final Contract Report;

1978

PB-293926

A05

OFR 27-79

RORC;

NTIS: PB 293-926

SD;

S.dak. School of Mines & Tech.