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Pinto Jr. L.A.B.,PROPEMM IFES | Vieira E.A.,PROPEMM IFES | Tenorio J.A.S.,University of Sao Paulo | Peixoto R.A.F.,Federal University of Ouro Preto | de Oliveira J.R.,PROPEMM IFES
Revista Escola de Minas | Year: 2011

This study focuses on the technical feasibility of the utilization of waste from the cutting of granite to adjust the chemical composition of slag from steelworks LD, targeting the addition of clinker Portland cement. For this, chemical characterization of the waste, its mixture and fusion was performed, obtaining a CaO/SiO2 relationship of around 0.9 to 1.2 for the steelworks slag. We selected samples of the waste, mixed, melted and cooled in water and in the oven. Samples cooled in water, after examining with X-ray difractrograms, had been predominantly amorphous. For samples cooled in the furnace, which had vitreous, there was the presence of mineralogical phases Akermanita and Gehlenita, which is considered as the ideal stage for the mineral water activity of the slag. The adjustment of the chemical composition of the slag from steel works by the addition of waste granite was efficient, transforming the waste into a product that is the same as blast furnace slag and can be used in the manufacture of cement. Source

In this work were evaluated the titanium and carbon effects on the hot ductility of medium carbon steels. In order to achieve this, used were the thermomechanical simulator Gleeble® 3500, for the hot tensile tests, and Scanning Electron Microscope (SEM) to analyze the aspect of the fracture. Microstructure analysis was done by an optical microscope. Five types of steel were studied. Two of them contained 0.02% of titanium and the others contained only residual amounts of this element. The results indicated that the Ti/N ratio between 3 and 5 regards lower loss of ductility at temperatures between 700°C and 800°C and at these temperatures the fractures are non-ductile. Steels containing titanium also show lower austenitic grain size at temperatures near to the austenite to ferrite transformation (Ar3). Moreover, the low ductility temperature was found to be inversely proportional to the equivalent carbon content. Source

de Aguiar F.N.,PROPEMM IFES | Grillo F.F.,PROPEMM IFES | Tenorio J.A.S.,University of Sao Paulo
Revista Escola de Minas | Year: 2012

The objective of this paper is to present an analysis of the use of residual marble mixtures in the pig iron desulfurization process. The study involved the use of: marble waste, fluorspar, lime, and hot metal. Four mixtures were made and added to a liquid hot metal - with known chemical composition - at a temperature of 1450°C. The mass of each element was calculated from its chemical analysis and compared with an industrial mixture. All of the four mixtures used in the experiments were stirred by a mechanical stirrer. Samples were collected by vacuum sampling for times of 5, 10, 15, 20, and 30 minutes, and analysis was performed to check sulfur variation in the bath with time. The results were analyzed and they verified that it was possible to use marble waste as a desulfurizer. Source

de Aguiar F.N.,Engineering Metalurgica e de Materiais | de Oliveira E.B.,Engineering Metalurgica e de Materiais | Vieira E.A.,PROPEMM IFES | Tenorio J.A.S.,University of Sao Paulo | de Oliveira J.R.,PROPEMM IFES
Revista Escola de Minas | Year: 2012

This paper involves the characterization of marble waste, steelmaking fine sludge and aluminum dross, to ascertain the technical feasibility of using these in the desulfurization and dephosphorization of hot metal. The characterization of these residues was done taking into consideration: Chemical analysis, particle size, X-ray diffraction results and scanning electron microscopy (SEM) with Energy Dispersive Spectrometry (EDS) data analyses. The steelmaking fine sludge has a FeO content of 84.90%, the marble waste lodged content of 61.5% CaO and 33.9% MgO, and aluminum dross 36.5% of Al metal and 62% of Al2O3. The particle size of marble waste had of the average grain size equal to 42.8 μm, in aluminum dross the average size was 101.8 μm and steelmaking fine sludge showed around 54.7% of its grain size between 0.15 and 0.075 mm. These results indicate the feasibility of using these materials in the desulfurization and dephosphorization of hot metal. Source

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