Graphite and Graphite-like Materials from Black Shale and Magmatic Ores: Raman Spectroscopy Data

Graphite and graphite-like materials widely are present at black shale and magmatic ores. The nature of these carbon materials (CM) is multifarious. In what cause connects a mineralization with carbon. The great numbers of parameters, namely, the temperature, the pressure, the shear stress, the catalytic species, the host-rock lithology, the time and etc., have an influence on the graphitization process. Accumulations of gold and platinum group elements in black graphite shale and extraction of these metals from rocks depend in considerable degree from structural properties of CM. Raman spectroscopy has wide applied for various carbon modifications, including nano-structuring materials. The first and second-order Raman spectrum have been correlated with changes in the structure of graphite. There is a linear relationship between temperature and Raman R2 and R1 parameters (derived from the area and intensity of the defect band (D) relative to the ordered graphite band (G), respectively). The purpose of the present study is to characterize the rocks and CM from carbon-rich rocks of gold-ore deposits of the black-shale formation and magmatic ores using micro-Raman spectroscopy technique (Horiba Jobin Ivon LabRam spectrometer). Exciting was performed with 325 nm line of He-Cd laser. The graphite and graphite-like samples from many ore deposits of Russia and Kazahstan are investigations. R1 and R2 ratio indicate variable degree of organisation CM in the samples. The results show different spectral variations of CM with metamorphic grade: the well-ordered graphite from magmatic rocks, more - ordered and the disordered less graphitized CM from black-shale ores. For the first time in the world practice the Raman spectroscopy technique has been applied to determine the temperature of graphitizing for CM at gold-ore deposits of the black-shale formation. The temperatures obtained on carboniferous substance for the gold deposits range from 405°С to 280°С. Temperature of CM formation from Pt-low sulphide ores of the Talnakh deposit ranges from 4700C to 6500C. It has been shown that the carbon-rich phases from black-shale and magmatic rocks have various degrees of graphitization and different carbon forms.