Prereduction of Manganese Briquettes Produced with Tailing Dam Materials from Urucum/Brazil

In Brazil, the waste disposal in tailing dams has been a significant problem. During the production of ferroalloy raw materials up to 50 % of the material extracted from the mines is placed in tailing dams due to its low particle size. The aim of this work is to evaluate the behaviour of briquettes made with tailing dam material from Urucum/Brazil in the prereduction zone of submerged arc furnaces during manganese ferroalloys production. To achieve the goals of the work, briquettes made with two different binders were tested in a similar environment to the pre-reduction zone, regarding heating rate and atmosphere composition. Furthermore, the briquettes were compared with lumps of the same material. Beside the prereduction tests, porosity and compressive strength of raw materials and products were also assessed. The results showed that the agglomerates had a better overall performance. The briquettes presented better CO reactivity, especially when molasses was used as binder. The compressive strength of the materials was sensitive to the presence of coke. Agglomerates made with bentonite as binder presented the higher compressive strength after prereduction. The briquettes also showed higher decrepitation than lumps.