Mass balances and reaction heats to evaluate the vanadium extraction from spent catalysts of sulfuric acid production process

Abstract

Obtaining sulfuric acid by the contact method requires the use of catalysts with more than 4 % vanadium, which leave service once spent, requiring storage. On the other hand, the mill scale is generated during the hot rolling process, constituting approximately 2 % of the processed steel. The appropriate combination of these two industrial wastes can be exploited for the extraction of vanadium from the catalysts by the aluminothermic method. The results of the processing of these wastes can be evaluated by means of mass balances and the determination of the heats of the redox reactions involved. This analysis is the main objective of this work. As a result it is obtained that the mixtures of mill scale - catalyst can be processed in proportions from 1 / 0,25 to 1 / 1,5, obtaining alloys with vanadium and silicon contents between 0,6 and 2,69 % and silicon 8,9 and 23,12%, respectively. By means of determination of the reaction heats of the mixtures it was obtained that the amount of heat generated per mass unit exceeds the 550 cal / g barrier, for all the evaluated mixtures.