Efeito da distribuição granulométrica e da umidade na performance das prensas de rolos da Ferro+ Mineração

Abstract

The optimization of comminution through High Pressure Grinding Rolls (HPGR) is essential for operational efficiency in the particle size adjustment of itabirite ores. The use of HPGR has proven to be a promising alternative for particle size reduction; however, challenges such as material moisture and the presence of fines affect equipment performance. In this context, the evaluation and improvement of the comminution circuit are fundamental to ensuring operational continuity and maximizing the efficiency of both the presses and the processing plant. The objective of this study was to evaluate the performance of HPGR units in the industrial circuit and propose improvements in the processing of current and future ores, identifying factors that affect the efficiency of the presses and proposing operational adjustments that increase the generation of fine fractions (<1.00 mm), thereby optimizing the performance of the subsequent concentration circuit. The methodology involved detailed mapping of the industrial process, identification of critical stages, sampling and particle size analyses, as well as characterization of the processed material. The effects of moisture were also evaluated through photographic records and visual documentation. Industrial tests, blend formation, and in situ experiments made it possible to propose changes in the beneficiation route aimed at improving the efficiency of the presses. The results showed that the presence of fines (<2.00 mm) in the feed and high moisture content reduce comminution efficiency. In collaboration with the R&D team, a brainstorming session identified operational bottlenecks and optimization strategies. It was found that the screening stage preceding the presses (PNs-08) requires improvement, as the recirculation of fines as circulating load compromises the circuit’s performance. Moreover, the expected increase in ROM particle size from 2027 onwards will require additional improvements to prevent circuit overload. Excessive moisture was confirmed as a critical factor, reducing material adhesion to the rolls and the grinding efficiency. In summary, the study broadens the understanding of HPGR application on an industrial scale and provides technical support for operational and strategic decision-making, reinforcing the importance of integrating applied research and industrial practice as a key factor for the sustainability and competitiveness of the mining sector.