Pretreating Steel Scrap to Speed Oxidation.
Khalafalla-SE; Payne-SL; Reimers-GW
NTIS: PB 190 027 :20 pages
The extremely sluggish oxidation of steel scrap was appreciably accelerated when the charge was pretreated in aqueous solutions of sodium metavanadate or sodium molybdate. The degree of oxidation acceleration was inversely correlated with the melting point of the promoter oxide possessing the highest valency. The magnitude of oxidation enhancement exhibited a systematic inverse dependence on the duration of pickling processes; mere dipping of the oxidizable charge in the vanadate bath was most effective. In general, the rate of steel scrap oxidation increased with increasing concentration of the pickling reagent. The results are explained on the basis of the hydrolytic decomposition of the pickling agent with subsequent slow interaction with the metal surface, coupled with the tendency of vanadium to form polyanions in alkaline media. The data not only served to elucidate the mechanism by which catastrophic oxidation takes place but also showed that the accelerating species need not be alloyed with oxidizable metal; surface impregnation by minute amounts of the accelerating species can still produce catastrophic effects.
IH; Report of Investigation;
NTIS Accession No.
NTIS: PB 190 027