Rota de processo para aproveitamento de rochas itabiríticas estéreis da Mina de Conceição

Abstract

The improvement of materials with low grade is used more and more in the mineral industries. The CVRD in the 90s it began the concentration of the itabirite with the grade close 45% of iron in the Timbopeba Mine (Mariana, MG), producing 1,8 million tons a year (Mty) of pellet feed. Practicing mass recoveries close of 50%. The investigated material is disposed now as sterile of ferrous formation of Conceição's mine, located in Itabira, Minas Gerais. The current generation of this material is of the order of 3Mty, reaching superior landings 20Mty starting from 2013, adding superior deposit to 300 million tons (Mt). The use of this material, if just considered the sterile, it can generate about 150Mt of pellet feed, being considered 50% of mass recovery. This use would increase the global recovery of Conceição's Mine, of the next ten years, of 47 for 58%. Accomplished it together with CVRD approaches the mineralogical characterization, iron ore concentration and use of technology of simulation of mineral process, aiming at the definition of more appropriate process route to the use of this sterile of ferrous formation. The study understood the chemical and size characterization; mineralogical characterization; rehearsals in bench scale for gravity and magnetic separation, grinding, dislam, flotation and use of tools of simulation of processes. The results shows the best of processing by flotation, preceded of grinding and deslam, generating concentrated inside of specifications of pellet feed of direct reduction, with tenor of SiO2 smaller than 0,80%, for all of the studied samples. Studies were developed being used technology of simulation of mineral processes seeking different objectives for each stage improvement. For the grinding circuit, the evaluation of routes was aimed at. The deslam studies sought the dimensioning and definition of operational parameters. The objective, for the flotation, went to define a preliminary mass balance.