EM - Escola de Minas
URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6
Notícias
A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.
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Resultados da Pesquisa
Item Concentration of oxidized Brazilian zinc ore by flotation : comparative study between anionic and cationic routes.(2022) Ferreira, Pedro Henrique Tófani; Lima, Rosa Malena FernandesIn this work, a mineralogical characterization by X-ray diffractometry and thermogravimetric analysis of a new Brazilian zinc ore sample was performed. The mineralogical semi-quantification, conducted by normative calculation of the identified minerals, using their theoretical chemical formulas and the contents determined in the chemical analyses was as follows: smithsonite (20.3%), goethite (49.6%), kaolinite (12%), quartz (6.2%), cerussite (3.0%), chlorite (4.0%), dolomite (0.5%) and others (4.4%). Subsequently, bench flotation tests were executed, using sodium oleate (anionic route) and amine (cationic route) as smithsonite collectors. Sodium silicate was used as a depressant of the gangue minerals in both routes tested. These studies showed that the anionic route (30.1% Zn in concentrate and 83% Zn recovery) performed better than the cationic route (17.5% Zn in concentrate and 46.3% Zn recovery). Considering the mineralogical composition of the concentrates obtained in the best flotation results, associated with physicochemical studies published in the literature with the identified minerals, it was evidenced that the difference in performance between the tested routes is due to the influence of ions from the dissolution of carbonates present in the ore on the surface properties of the main gangue minerals (goethite and silicates), especially for the cationic route.Item Proposal for an environmentally sustainable beneficiation route for the amphibolitic Itabirite from the Quadrilátero Ferrífero - Brazil.(2020) Gonçalves, Gizele Maria Campos; Lima, Rosa Malena FernandesThe high world demand for iron ores opposed to the rapid exhaustion of high-grade deposits from the main producing regions around the world has motivated the search and/or improvement of beneficiation routes, which enable the economic use of iron formations previously considered marginal ores, which have the potential to considerably increase mineable reserves due to their large volume. In this study, a sample of amphibolitic itabirite from the eastern region of the Quadrilátero Ferrífero, minas Gerais, Brazil was characterized, aiming at its use in the industrial pelletizing circuit. The main physical characteristics of this ore are moisture = 10% and specific weight = 3710 kg/m3 . The ore has a high grade of loss on ignition—LOI (6.7%) and P (0.14%). Through X-ray diffractometry (XRD), optical microscopy and scanning electron microscope—SEM, the ore was found to consist of 64.5% goethite (amphibolitic, alveolar, massive and earthy); 6.8% hematite (martitic, granular and lamellar) and 0.9% magnetite. The main gangue mineral is quartz (25.5%). Based on the results of concentration tests (magnetic and flotation) performed with the studied sample, the magnetic concentration route of deslimed sample followed by the addition of slimes in magnetic concentrate can be incorporated into the pelletizing process.Item Toward the influence of iron oxide morphology on the grinding and filtration processes and on the cold crushing strength (CCS) of heat-treated iron ore pellets.(2020) Graça, Leonardo Martins; Silva, Gilberto Henrique Tavares Álvares da; Machado, Marcos Meyer; Silva, Josué Bortolini Sette da; Ávila, Carlos Fernando; Cipriano, Ricardo Augusto Scholz; Lagoeiro, Leonardo EvangelistaThe present study demonstrates the effect of the different morphological types on the cold crushing strength (CCS) of heat-treated iron ore pellets. Blends with different iron ore oxides morphologies were subjected to grinding, filtering and pot grate tests on industrial scale trials. Results of grinding tests showed the hematite-goethite aggregates the most influent one on energy consumption. The martitichematite content was straightly related to the final moisture and filtration productivity. The hematitegoethite aggregates, therefore the goethite content, influences CCS, being the lower the goethite content, the higher the values of CCS.Item Bench-scale calcination and sintering of a goethite iron ore sample.(2016) Silva, Mônica Suede Santos; Lima, Margarida Márcia Fernandes; Graça, Leonardo Martins; Lima, Rosa Malena FernandesThis work presents the results of bench calcination and sintering studies conducted on an iron ore sample from Iron Quadrangle, Brazil with high goethite content. The natural samples and the products of calcination and sinteringwere characterised by inductively coupled plasma optical emission spectroscopy (OES/ICP), X-ray spectrometry and gravimetric methods. Optical microscopy, X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) were used to identify the phases in the studied samples. Density, specific surface area, specific pore volume and pore diameter were determined through gas pycnometry. All of the natural sinter feed samples had a Fe grade N64% and a very high phosphorus grade (~0.17%). After calcination, a 3.1–3.4% increase was observed in the Fe grade compared to that of the natural sinter feed samples. The average Fe grade of the sintered samples was 59.1%. The identified phases with XRD in the raw materials were hematite and goethite. In the calcined samples, only hematite was identified because of the thermal decomposition of goethite. The density, specific surface area, specific pore volume and pore diameter of the calcined samples increased compared to those of the natural sinter feed samples. Hematite, brownmillerite, anorthite, and gehlenite were identified in the sintered samples. The sites for phosphorus occurrence were calcium silicates and apatite. The sintered samples exhibited specific surface areas lower than those of the calcined samples. This result was ascribed to the destruction of the pore structure by the sintering process.No relationship between the proportions of nucleate, intermediate and agglomerate particles used inmixture of sinter testswith the results of microtumbler was identified.