Grapehene and Crystalline quality Any opinions and thoughts on this news?
Bob
Canada Carbon's Miller has high crystalline quality
2014-02-04 08:17 ET - News Release
Mr. R. Bruce Duncan reports
CANADA CARBON REPORTS HIGH ORDER CRYSTALLINITY OF ITS MILLER GRAPHITE BY RAMAN SPECTROSCOPY, AS WELL AS DISPERSION AND EXFOLIATION TO GRAPHENE
Canada Carbon Inc. has provided the results of the first in a series of laboratory characterization tests being conducted by Evans Analytical Group (EAG) on its Miller high-purity hydrothermal graphite. The crystallinity results reported herein were obtained using Raman spectroscopy, which definitively determines the degree of crystallinity of certain materials, including graphite. The EAG laboratory report summarizes the results, as follows: "The Raman spectrum was that of a single crystal of graphite. The crystalline quality of the graphite was better than any other industrial graphite sample we at EAG have analyzed to date."
Bench-scale tests to examine the dispersion behaviour of the Miller graphite were conducted by Dr. Karol Putyera at EAG Liverpool, N.Y., laboratory. When this sample was immersed in a common industrial chemical, carbon disulphide (CS2), it partially exfoliated. Dr. Putyera remarked, "In combination with the exceptional high purity and highly crystalline nature of the Miller graphite, this dispersion behaviour could lead to solution-based processing of this material for producing graphene, which opens up a wide range of potential applications."
Other characterization procedures, including X-ray diffraction spectroscopy (XRD), to provide greater insight into the crystalline nature of the Miller graphite, and scanning electron microscopy (SEM), to provide visual images of the crystals, are currently being conducted. The results of those procedures are expected shortly, and will be reported when received.
The company also reports that management, accompanied by technical and legal advisers, recently met in Ottawa with a number of federal government officials from various agencies, to ensure that the company is in full compliance with import/export controls, licensing, and documentation required by domestic and international law with respect to production and shipments of nuclear and military grade graphite. The company further advises that additional meetings with federal government officials are planned.
About the Raman spectroscopic results
Raman spectroscopy is the collection of light in elastically scattered by a material or compound. When a light of known wavelength strikes a material, the light is shifted according to the chemical functionalities of the material. The intensity of this shifted light depends on both molecular structure and macrostructure. As a result of these phenomena, the collection of the shifted light gives a Raman spectrum that can provide direct information regarding the molecular vibrations of the compound or material. The company can then interpret this information to determine chemical structure, organization, and in some cases, non-covalent intermolecular interactions. The Raman spectrum of graphite is very well characterized, which permits clear interpretations of the Raman spectra of graphite test materials, based on the component peak intensities and positions of the spectral features.
A sample of the Miller high-purity graphite was submitted to a LabRam J-Y spectrometer. An Ar-plus ion laser (514.5-nanometre wavelength) with an 1,800 gr/mm grating were used for the measurements. The Raman spectra were collected in the backscattering geometry (180 degrees) under an Olympus BX40 microscope. The key spectral features collected were the G-band (1579 cm-1) and D-band (1350 cm-1), where the G-band is theoretically the only permitted band arising from a single crystal of graphite, and the D-band is a measure of the disorder within the crystal. The sharp, high-intensity, narrow-shouldered G-band peak strongly suggests that the sample is a single crystal of graphite. The proportionally very small D-band peak indicates extremely low disorder in that crystal, and may be due to minor mechanical damage experienced by the crystal during earlier processing. The complete Raman report, which includes the Raman spectrum of high-quality industrial graphite for comparative purposes, can be viewed at the the company's website.
About the exfoliative behaviour of the graphite
Currently, most producers intent on separating natural graphite into individual sheets (graphene) or low-multiple sheet graphene use variations on Hummer's method, which involves some very harsh chemicals that can oxidize the graphene sheets. Those defects can be partially repaired by chemical reduction, yielding reduced graphene oxide. The quality of the graphene produced by this method is not only variable, it can be quite poor when compared with graphene produced by synthetic methods. Synthetic graphene, although often of very high quality, is much more expensive to produce.
The last step in the exfoliation of graphene from natural graphite by Hummer's method (the actual separation of the individual graphene layers) is by immersion in a polar solvent, in combination with sonication (high-frequency vibrations induced by ultrasound emitters). Dr. Karol Putyera, working at EAG, dispersed a sample of the high-purity Miller graphite in the non-polar solvent carbon disulphide, and without sonication, the sample partially exfoliated.
R. Bruce Duncan, chief executive officer and director of Canada Carbon, remarked: "Our Miller hydrothermal graphite has once again exceeded our most optimistic expectations. Following our earlier metallurgical testing at SGS Lakefield, which yielded graphite as pure as could be determined by their analytical method (please refer to the press release dated July 23, 2013, 'Canada Carbon achieves 100 per cent graphitic carbon on second purification test on Miller graphite sample'), a sample of that same material was shown to be of nuclear-grade purity by GD-MS (please refer to press release dated Oct. 15, 2013). Then, we were able to show that brief thermal upgrading could remove more than 90 per cent of the already very low contaminant burden (please refer to press release dated Dec. 12, 2013). And now, we have clear scientific evidence of the high order crystallinity of our Miller hydrothermal graphite. Moreover, the simple process to exfoliate the graphite to graphene, in combination with its highly crystalline nature and high purity, will also allow us to produce top-quality graphene materials. This will give us access to yet another high-value market."
Mr. Duncan further states: "We hope to soon receive our bulk sampling permit, which will allow us to significantly expand our test work program. Because we have numerous veins exposed at surface, we can not only systematically determine the characteristics of the individual graphite occurrences, we can easily extract substantial amounts from each one. With that information, we can proceed with our planning to develop a mine on the Miller property. It is Canada Carbon's goal to commercialize its Miller project, with speed to market the top priority for our highly differentiated graphite."
A full update of current exploration results at Miller (trenching and drilling) is to be released soon after reception of analytical results from Activation Laboratories of Ancaster, Ont.
Remi Charbonneau, PhD, PGeo, No. 290 (an associate of Inlandsis Consultants senc) is an independent qualified person under National Instrument 43-101, and has reviewed and approved the technical information provided in this news release.
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