Dusts produced and collected along the Electric Are Furnace (EAF) steelmaking line cause strong pollution problems unless appropriately treated. In 1996 the Italian Agency for Environmental Protection (ANPA) has initiated a study of the environmental impact of the industrial sector of steel by EAF. Within the framework of this study the University of Pome "La Sapienza" is developing a hydrometallurgical process consisting in dusts leaching by sulphuric acid followed by SX-EW steps in order to obtain pure electrolytic zinc. The aim of this work is to study the leaching step in order to highlight the dust dissolution mechanism related to zinc ferrite. In fact until now just few paper directly referring on dust leaching kinetics are reported in literature. The effect of both temperature in the range of 303 to 343 K and H2SO4 concentration over the 0.1-2 M range, on the rate of reaction for the three elements was investigated. The rate constant describing thp Zn dissolution was found by using stochastic model that fit very well the experimental extraction data. The kinetic model for Fe is the surface reaction model and for Mn is the shrinking core model with diffusion through an inert product layer. The apparent activation energy in the case of Fe and Mn are also reported.
A Kinetic Study on EAF Dust Leaching / Lupi, Carla; Pilone, Daniela; Cavallini, Mauro; P. P., Milella. - STAMPA. - (1997), pp. 27-33. (Intervento presentato al convegno 1st National Congress on the Valorisation and Recycling of Industrial Wastes tenutosi a L'Aquila nel JUL 07-10, 1997).