Per: beatriz fausta gandra (usiminas), Larissa Rodrigues de Carvalho Rocha (usiminas), Mauro Vivaldino Fernandes (usiminas)
Abstract:
Reducing gas' chemical composition affects significantly its diffusivity through the bed and the ability to reduce the metallic burden. Moreover, the economic and environmental scenario demands increasingly productivity of blast furnaces, with low fuel rate and lower CO2 emissions. Therefore, companies have pursued a high coal injection rate and, in cases of favorable policy, intensify the natural gas use. In these cases, the amount of material reduced via H2 as compared to CO is increased. In the present paper, the results of softening and melting (S&M) of two types of NPO, one kind of pellet and industrial sinter are presented, using as reductant gas with different content of H2 (0% to 12% ). It was found that, for the NPO, there is no definite trend. Although higher hydrogen content could favor the reduction, this did not reflect in better bed permeability. In the pellet case, there was a slight tendency of improvement in the evaluated parameters when the gas richest in hydrogen was used. However, its performance in S&M was less than expected, since it presented high resistance to permeability associated with low reducibility until the softening. For sinter, was identified a clear improvement in reduction and bed permeability aspects.