Caracterização de rejeito da barragem da mina de ferro de Gongo Soco, MG, com foco na definição de rota de processo para recuperação de barragens

Abstract

During a process of ore processing by mineral concentration, part of the processed mass becomes product (concentrate) and another part becomes waste, which is then deposited in dams. However, with increased production in companies, waste generation tends to increase and if not properly managed, it may generate environmental liabilities. Considering this scenario, a study with the tailings dam of the Gongo Soco Mine was proposed, with the objective of defining a process route for the treatment of this iron ore tailings, based on the chemical-mineralogical-microstructural characterization of the dam samples and bench tests of solid-liquid separation and concentration. For the mineral characterization, granulochemical, optical microscopy, X-ray diffractometry and even QEMSCAN (automatic scanning electron microscopy with energy-dispersive X-ray microanalysis) tests were carried out to verify the mineralogical composition of the samples. A strong presence of compact hematite was observed along with a high liberation degree, favorable to processing by magnetic concentration. The results of the bench tests agreed with this application, since both the quality (chemical and physical) and the mass of the product generated were satisfactory. Therefore, the product from the treated waste would be a fine sinter feed, with 62.65% Fe, 7.00% SiO2 and maximum humidity at 10.70%, having 75.0% mass recovery and 87.05% metallurgical recovery, being considered a protoproduct. This concentrate has great relevance because it could be used in blending with other products, thus maximizing the use of resources. As a conclusion, this waste can be utilized following the proposed process route.