Search

In this paper a quantitative physical characterization of the chromite concentrated with refractory characteristic belonging to the deposit Merceditas is presented, using for it technicals of infrared and Mössbauer spectroscopies, X-ray difractometry, chemical and grain size analysis. It settles down that the concentrate is constituted by the phases mineralogical well-known as chromopicotite, antigorite and chlorite, being determined its respective cristalo-chemical formula. By means of the techniques of thermal analysis (DTA, TG and DTG) the thermal behavior of a mixture of chromite concentrated and aluminum is studied with the purpose to valuing the possibilities of the products of the reduction like component of saturating mixtures for the thermodifusives surfaces of chromium and silicon in steels. [ABSTRACT FROM AUTHOR]

In many ore deposits chromium is present as complex oxides known as chromospineless which show high chemical stability especially towards halides, affecting negatively its possible use as a chromium source in diffusive treatments. In this work, the aluminothermy reduction of one chromite concentrate from Merceditas deposit was studied and their products were characterized, with the objective of using it as raw material in chromizing. In order to make the grain size analysis, two samples were prepared. First the concentrate was crushed in a ball mill and later was screened in two sieve sets, with maximum openings of 100 and 200 µm . The mixture of the reduction products of the concentrate was characterized, using RX difractometry and infrared spectroscopy. It was corroborated that when using treatment D (55 mm; 4 h; 950 °C), the metallic aluminum peaks disappears; the relative intensity of chromopicotite diminished and the higher relative intensity of reflection peaks were occupied by chromium and ferrochromium. These results allow to anticipate that the resulting compound is suitable as chromium source in diffusive treatments. [ABSTRACT FROM AUTHOR]

In Cuba important chromium mineral reserves exist. Within the Cuban chromites deposits Merceditas for its levels and exploitation stands out. In this work the mineralogical characterization of chromite concentrated belonging to the deposit previously mentioned is presented and its possible use as carrying silicon and chromium source in diffusive process is valued. The determination of the chemical composition of the concentrate was carried out by means of the gravimetric and volumetric methods, whereas for the identification of its phases techniques of Infrared and Mössbauer Spectroscopies, and X-Rays diffraction were used. Additionally the statistical parameters of the grain sized distribution from a sifted process were determined. It is established from its chemical composition, that the concentrate is refractory and that the chromium, iron, aluminum, magnesium, silicon and calcium appear in different proportions. The chromium and silicon content in the concentrate and its relation are similar to the previous reports for the application from diffusive processes of simultaneous saturation with both elements, whereas the levels of aluminum and magnesium combined with oxygen guarantee the refractivity of mixtures. Also, it was corroborated that the mineralogical phases were chromopicotite, antigorite and chlorite and it was concluded that its main phase is the chromopicotite. Finally, it was established that it has an average diameter of 513 µm, obliquity of a 0.93 and a dispersion of 1.83. [ABSTRACT FROM AUTHOR]