Per: Iara Patricia Vieira de Oliveira (gerdau usina ouro branco), leandro guilherme moreira (gerdau), edna monica da silva (gerdau), victor barbosa simões (gerdau)
Abstract:
With the low supply of high-grade hematite iron ores in the Quadrilátero Ferrífero region, it is becoming necessary to concentrate itabiritic iron ores to obtain a product with a higher iron content. However, when itabiritic iron ore is concentrated, there is a product with a particle size fraction < 0.150 mm ≥ 85%, called pellet feed, which compared to conventional sinter feed has lower SiO2 and Al2O3 contents. In this scenario, the use of high proportions of pellet feed to replace sinter feed in iron ore mixtures for sintering becomes a necessity, whether to reduce the volume of sinter slag and/or business strategy. Studies already carried out have shown that the increase in pellet feed in the iron ore mixture reduced the productivity of conventional sintering. Therefore, for this replacement to occur in greater proportions, above 65%, new process routes for preparing the mixture for sintering and equipment have been developed, in addition to improvements in operational procedures, to compensate for the loss of process productivity, improve the chemical composition, maintaining the physical and metallurgical characteristics of the sinter product. This work aims to present the results of the evaluation of the use of natural and pressed feed pellets in the sintering process, obtained through pilot scale tests. The results show pressed pellet feed as a way forward, together with HPS (Hybrid Pelletizing Sintering) and intensive mixer (IM) technologies, to recover the loss of process productivity and improve the chemical composition of the sinter without compromising its physical and metallurgical characteristics.
