Influência do antracito adicionado à mistura de pelotização sobre ascaracterísticas físicas das pelotas queimadas

• Ano de defesa: 2016
• Autor(a) principal: Priscilla Messias Pereira da Silva
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Pelotização; Adição de antracito; Hematita especular; Pelotas; Física; Engenharia metalúrgica
• Link de acesso: http://hdl.handle.net/1843/BUBD-AC8GGB

The high demand of iron ore and pelletizing plants over the past few years have accelerated the depletion of high iron concentration deposits. Moreover, the consumer market has become more demanding for pellets of high quality, especially the physical ones. The specular hematite content plays an important role in the mechanical strength of ironore pellets. The higher the amount of specular hematite, the greater is the mechanical strength of the pellets. With the scarcity of this mineral type, it is necessary to develop processes which can help on producing at high levels, also keeping the qualities required by the consumer market. The dosage and size of the coal used as solid fuel, added to the mixture to be agglomerated in the balling discs, are factors which influence on the physical quality of the fired pellets. Its addition is beneficial to the productivity of the furnaces. On the other hand, its dosage can impact, in association with its size distribution, over the physical quality of the pellets. In this study, direct reduction pellets were produced in Grate Pot. They were evaluated in terms of physical quality, having as variables the mineralogical characteristics of iron ore and the dosage of solid fuel. To determine the influence of these factors on the physical quality of the fired pellets, different parameters were evaluated: (1) specular hematite content, (2) coal dosage and, (3) particle size of the coal. The variable responses were the tumble index (ISO 3271) and cold compression strength (ISO 4700). The study showed that the best physical quality scores were obtained for smaller coal dosages associated with higher levels of specular hematite. The particle size of coal was the factor of minor influence in relation to the physical quality. The study showed that the best indexes of physical quality were obtained with lower dosages of coal, associated with higher levels of specular hematite. The anthracite particle size was the factor presenting the lowest influence on the physical quality of the fired pellets.