Application of IR/SEM and Other Modern Instruments for Mineral Identification

Due to the limitations of resolution and magnification for the traditional optical microscope, qualitative analysis for fine particles is inaccurate and quantitative analysis of minerals contains errors, which makes it impossible to obtain accurate nano to micron grade mineral morphology and structure characteristics. With the development of oil and gas exploration and geological prospecting, all minerals in rocks and pores, and trace element information are required. Thus, integrating the Fourier Infrared Spectrometer, X-ray Diffractometer, Raman Spectrometer, and Scanning Electron Microscope, to obtain a mineral identification method on the basis of large-scale instruments, as described here, is essential for current geological work. The Fourier infrared spectral range is 7500-370 cm^-1, and is ideally suited for rapid and accurate qualitative analysis of minerals of more than 30% content in solid, liquid, or gas samples. It is mainly used for organic matter analysis, and then for some inorganic compounds with polar bond and metal oxide. The minerals which have greater concentration than 15% in the sample can be accurately analyzed quantitatively by X-ray Diffractometer. Nowadays, it is mainly used for qualitative analysis of all kinds of crystal mineral, also for analysis of carbonate minerals that without hydrated. The Raman Spectrometer spectral range is 200-1000 nm and the horizontal and vertical spatial resolutions are 0.5 μm and 2 μm, which can be utilized to obtain the temperature, pressure and fluid composition in the process of diagenesis based on the inclusion study. At present, it is mainly used for fluid inclusion composition test, then for qualitative analysis of liquid, powder and solid samples that have polarizability molecular. The resolution of the scanning electron microscope is up to 1 nm, which is suitable to clearly observe the morphology of nano-micron grade mineral characteristics and structure characteristics. It is mainly used for any non magnetic nano-micron grade of solid mineral morphology observation and related relations. This method of rock mineral identification through large-scale instruments is a significant improvement over traditional methods by being able to identify different varieties of minerals at the micro and nano level. It can also provide comprehensive, precise rock mineral content and mineral composition, accurate diagenetic mineral microstructure and structure characteristics. The overlapping instrument functions and mutual verification can ensure the reliability of test results. Compared with the traditional optical microscope identification method, modern large-scale instruments reveal the information on mineral symbiosis, reaction, evolution, the formation of the rock, sedimentary/diagenetic environment, which provide accurate, comprehensive qualitative/quantity, fabric characteristics and diagenesis minerals information in order to complete geological work.