ORALS

Samarco’s iron ore concentration process consists, basically, of the following steps: crushing, screening, grinding, desliming, coarse flotation, fine flotation, regrinding and columns flotation. After the mill, an ultrafine material rich in iron is generated and, after the desliming step, this material is discarded in actually disposed in a pit. The main idea of ​​this study is to develop a new co-product to be used as a raw material in steelmaking processes. The challenges were the low levels of iron and high levels of silica and alumina, incompatible with the products offered on the market, and the granulometry of the ultrafine material (70% of mass passing through 10 micrometers). To make the product more attractive to the market, it was necessary to develop a magnetic concentration process for the ultrafine ore, increasing its iron content with adequate mass recovery. The iron content in the concentration product is inversely proportional to the mass recovery and the amount of material to be disposed of in suitable structures. After the concentration stage, the ultrafine material passes through a dewatering stage in thickener and press filter route, resulting in an ultrafine pellet feed with ideal humidity for agglomeration in discs, intensive mixers or extruders. The agglomerates can be heat-treated in a travelling grate furnace or be produced with a cold bonded binder, to acquire physical strength for handling and transport to customers. There will be an increase in the overall metallic yield of the process and a significant reduction in the area required for waste disposal, increasing sustainability and reducing business risks.