Classificação e concentração a seco do minério de ferro: estudo comparativo aos contextos geológicos de Carajás e Quadrilátero Ferrífero

Abstract

Iron ore beneficiation is a strategic stage of the mineral production chain, directly influencing product quality, operational costs, and compliance with environmental requirements. Increasing restrictions on water use, combined with the demand for higher energy efficiency and reduced environmental impacts, have driven the development and application of dry classification, concentration, and pre-concentration technologies. In this context, this study aims to analyze and compare conventional particle size classification methods with innovative dry concentration and pre-concentration technologies for iron ore, considering the geological and mineralogical characteristics of the Carajás deposits, in the state of Pará, and the Quadrilátero Ferrífero region, in Minas Gerais, Brazil. The methodology was based on a technical and scientific literature review, including classical mineral processing textbooks, academic papers, institutional reports, and technical documentation from equipment manufacturers. In addition, a qualitative comparative analysis was conducted involving six beneficiation methods: vibrating screens, fixed screens, and rotary screens, representing conventional particle size classification methods; high-intensity roll magnetic separators and triboelectric separators, applied to dry mineral concentration; and sensor-based sorting systems (ore sorting), used in the pre-concentration stage. The comparison considered criteria such as particle size range, operational efficiency, energy consumption, economic feasibility, mineral selectivity, technological maturity, and environmental impact. The results indicate that conventional particle size classification methods exhibit high operational robustness and broad adaptability, making them particularly suitable for scenarios characterized by greater mineralogical heterogeneity, such as the Quadrilátero Ferrífero. Conversely, innovative dry concentration and pre-concentration technologies demonstrated superior performance in more homogeneous geological contexts with high iron grades, such as the Carajás ores, enabling significant grade improvement, mass reduction in subsequent stages, and minimization of water consumption. It is concluded that there is no universally superior technology for dry iron ore beneficiation. The selection of the most appropriate method must be based on the compatibility between ore mineralogical characteristics, production objectives, and the operational and economic conditions of the plant. The current trend points toward the adoption of hybrid processing routes that integrate conventional methods with innovative technologies to enhance operational efficiency and meet modern mining sustainability requirements.