Graphite impurities

The product obtained is white calcium cyanamide whereas the product obtained from limestone and coal contains carbonaceous (graphite) impurities. None of these processes has been commercially exploited. 

Cyanamide pigments are produced from industrial-grade calcium cyanamide which is first dissolved. Sulfide and phosphide impurities are precipitated as iron or lead salts [5.127]—[5.132] or oxidized [5.133] [5.135] and filtered off together with graphite impurities. The pure calcium cyanamide is reacted in an aqueous medium with soluble lead or zinc salts or with a slurry of lead oxide or zinc oxide [5.127], [5.129], [5.133], [5.136]—[5.138]. The pigments are filtered, washed, dried, and ground. Zinc cyanamide [5.139] and pure lead cyanamide are not explosive. An explosion reported during the production of lead cyanamide was caused by contamination with small amounts of acid or nitrates [5.140],... 

Figure 1. Connectivities and principle bonding properties of carbon. From top to bottom connectivity, chemical bonding representation, distribution of n electrons, hybridization symbol, bond length, orientation of the n bonds relative to the carbon skeleton. The spectra represent polarization-dependent carbon 1 s XAS data for sp2 and sp3 carbons. The angles denote the orientation of the E vector of the incident light relative to the surface normal of the oriented sample. The assignment of the spectral regions is given and was deduced from the angular dependence of the intensities of each feature. The graphite impurity in the CVD diamond film is less than 0.1 monolayers.

By detonation A mixture of explosives with a negative oxygen balance is detonated inside a closed container. Due to the prevailing conditions, the resulting soot contains a large portion of nanoscopic diamond particles. These are purified by treatment with concentrated mineral acids that remove both metallic and graphitic impurities. 

The electrochemical procedure to build up the DNA biosensor included four main steps electrochemical conditioning of the electrode surface in order to oxidize the graphite impurities and to obtain a more hydrophilic surface to avoid DNA immobilization, calf thymus dsDNA immobilization, interaction with the sample solution, and electrode surface interrogation. 

The reactivity uncertainties due to systematic biases were not included in Table 4.2-8. A systematic bias is defined as a known effect, which affects reactivity, but which was not, for various practical reasons, included in analytical calculations. As noted earlier, the systematic biases due to added fissile loading and neglect of graphite impurities have already been taken into account in the expected nominal reactivity requirements. 

Several papers recently addressed the importance of studying the relationship existing between the basic macroscopic electrochemical properties of boron-doped diamond electrodes and their characterization at the microscopic level, in order to understand which factors influence the electrochemical reactivity [4, 5]. It was found that the boron doping level in the diamond and the presence of graphitic impurities play a major role in the basic... 

Graphitic impurities. In semiconducting diamond electrodes, the concentration of carbon parasitic phase is very low and cannot be detected with the 514.5-nm excitation. However, using a 632.8-nm excitation line, which is more sensitive to these phases [13], it was found that the concentration of this parasitic phase decreases as... 

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