Oil agglomeration of weakly hydrophobic coals and coal/pyrite mixtures

Fine particle suspensions of various materials in water were agglomerated with heptane in a modified blender to determine the agglomeration characteristics of the solids. The materials included Upper Freeport coal, oxidized Upper Freeport coal, two batches of Illinois No. 6 coal, graphite, and iron pyrite. The response of these materials to oil agglomeration varied over a wide range and seemed to depend on their relative hydrophobicity. Treating the weakly hydrophobic materials with traces of sodium oleate greatly enhanced their response to oil agglomeration. The separation of mixtures of pyrite and various carbonaceous materials by selective agglomeration with heptane was also studied. While an excellent separation of graphite and pyrite was achieved, the separation of coal and pyrite proved elusive

Mounting Materials for Automated Image Analysis of Coals Using Backscattered Electron Imaging

In order to apply SEM-based automated image analysis (AIA) to the characterization of not only minerals in coal but to the coal itself, sample preparation methods need to be developed beyond common practice. A significant consideration is the degree of contrast achievable between the mount media chosen and the coal. Four low-atomic number materials (epoxy, polyethylene, polystyrene and carnauba wax) were compared for their potential as suitable mounting media for coal samples. Epoxy is satisfactory only for characterization of mineral particles since the contrast between epoxy and coal particles is negligible. Polyethylene or polystyrene have marginal application for use as mounting material for coal characterization due to limited contrast and sample preparation artifacts. Carnauba wax appears satisfactory as a mounting material since it provides good contrast with coal particles with minimal artifacts

Role of induction time and other properties in the recovery of coal from aqueous suspensions by agglomeration with heptane

The percent recovery of fine coal or graphite particles suspended in water by agglomeration with heptane was highly dependent on the measured induction time, i.e., the gas bubble to particle attachment time of the material. The induction time was found to correlate closely with the heat of immersion of the solids in water, another indicator of the hydrophobic/hydrophilic character of the material. For a series of coals and graphite, the agglomeration recovery decreased exponentially with increasing induction time. For the more oleophilic coal or graphite particles, an increase in salt (NaC1) concentration of the suspending medium caused an increase in agglomeration recovery and a decrease in induction time. For the less oleophilic coal or pyrite particles, an increase in salt concentration caused a decrease in agglomeration recovery apd an increase in induction time. Due to the opposing effects of salt concentration on the recoveries of a highly hydrophobic coal and pyrite, it was possible to improve the separation of these materials by an increase in salt concentration. On the other hand, because the recoveries of pyrite and a weakly oleophilic coal were affected similarly by an increase in salt concentration, it was not possible to improve the separation of these materials

Evaluation of the Removal of Organic Sulfur from Coal

As the removal of sulfur from coal prior to combustion acquires more importance in order to meet evermore stringent antipollution regulations, research on the development of methods for the cleaning of coal continues to expand. Reviews are available which describe the various methods for desulfurizing coal (1, 2, 3). The sulfur content in coal is usually a few per cent, but it can range from less than 0.5 per cent to as much as 8 per cent or more. Much of the sulfur is inorganic in nature, occurring in discrete mineral phases; the inorganic sulfur is mostly pyrite with small amounts of sulfates such as gypsum. Part of the sulfur in coal is termed organic sulfur, being intimately bound to the organic coal matrix. The chemical nature of this organic sulfur is not well established. During the desulfurization of coal, some of the coarse inorganic sulfur components can be removed

2014 iAREA campaign on aerosol in Spitsbergen – Part 2: Optical properties from Raman-lidar and in-situ observations at Ny-Ålesund

In this work multi wavelength Raman lidar data from Ny-Ålesund, Spitsbergen have been analysed for the spring 2014 Arctic haze season, as part of the iAREA campaign. Typical values and probability distributions for aerosol backscatter, extinction and depolarisation, the lidar ratio and the color ratio for 4 different altitude intervals within the troposphere are given. These quantities and their dependencies are analysed and the frequency of altitude-dependent observed aerosol events are given. A comparison with ground-based size distribution and chemical composition is performed. Hence the aim of this paper is to provide typical and statistically meaningful properties of Arctic aerosol, which may be used in climate models or to constrain the radiative forcing. We have found that the 2014 season was only moderately polluted with Arctic haze and that sea salt and sulphate were the most dominant aerosol species. Moreover the drying of an aerosol layer after cloud disintegration has been observed. Hardly any clear temporal evolution over the 4 week data set on Arctic haze is obvious with the exception of the extinction coefficient and the lidar ratio, which significantly decreased below 2 km altitude by end April. In altitudes between 2 and 5 km the haze season lasted longer and the aerosol properties were generally more homogeneous than closer to the surface. Above 5 km only few particles were found. The variability of the lidar ratio is discussed. It was found that knowledge of the aerosol’s size and shape does not determine the lidar ratio. Contrary to shape and lidar ratio, there is a clear correlation between size and backscatter: larger particles show a higher backscatter coefficient

The state-of-the-art determination of urinary nucleosides using chromatographic techniques “hyphenated” with advanced bioinformatic methods

Over the last decade metabolomics has gained increasing popularity and significance in life sciences. Together with genomics, transcriptomics and proteomics, metabolomics provides additional information on specific reactions occurring in humans, allowing us to understand some of the metabolic pathways in pathological processes. Abnormal levels of such metabolites as nucleosides in the urine of cancer patients (abnormal in relation to the levels observed in healthy volunteers) seem to be an original potential diagnostic marker of carcinogenesis. However, the expectations regarding the diagnostic value of nucleosides may only be justified once an appropriate analytical procedure has been applied for their determination. The achievement of good specificity, sensitivity and reproducibility of the analysis depends on the right choice of the phases (e.g. sample pretreatment procedure), the analytical technique and the bioinformatic approach. Improving the techniques and methods applied implies greater interest in exploration of reliable diagnostic markers. This review covers the last 11 years of determination of urinary nucleosides conducted with the use of high-performance liquid chromatography in conjunction with various types of detection, sample pretreatment methods as well as bioinformatic data processing procedures

Microcharacterization of coal components for beneficiation

Automated image analysis (AIA) of mineral association with the coal matrix was shown to be helpful in predicting froth flotation behavior of an Indiana No. 3 and Upper Freeport coal when the association was expressed in terms of the relative amount of particle surface covered by coal and mineral phases. AIA measurements of the amount and quality of material with more than 80% of the particle surface covered by coal were found to relate to the pyrite and ash reduction observed in froth collected after 1.5 minutes of flotation. Results accurately predicted more ash reduction by froth flotation for the Indian No. 3 coal than for the Upper Freeport coal. The association distribution derived from AIA also showed the changes in ash reduction as a function of cleaning severity. In another task, analysis of the repeatability of coal-mineral matter association results for a single pellet of coal indicated that characterization of 3000 particles should be adequate to provide {plus minus}16% relative repeatability for phases measured to be present at the 5% level. 3 refs., 3 figs., 4 tabs

Altered levels of nucleoside metabolite profiles in urogenital tract cancer measured by capillary electrophoresis

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