a b s t r a c t A slurry nebulisation technique was applied for elemental analysis of bituminous coals SARM 18, SARM 19 and four coals from three different seams in Witbank, South Africa, by inductively coupled plasma optical emission spectroscopy (ICP-OES). Major elements (Al, Ca, Fe, Mg, S, Si and Ti) and trace elements (Ba, Cr, Mn, Ni, Sr, V, Zn and Zr) in coal were determined. Various slurry preparations were evaluated using two dispersants (glycerol and Triton X-100) and by varying the concentration of dispersants, between 0.1% and 1.0% (v/v). The effect of initially solubilising the ground coal in N,N-dimethylformamide (DMF) was investigated by varying the volume of DMF added. The effect of wet grinding with DMF was investigated. Wet grinding with DMF was shown to drastically reduce particle sizes (50.0% < 0.28 lm and 90.0% < 6.17 lm) as compared to dry grinding (50.0% < 5.25 lm and 90.0% < 11.1 lm). The reduced particle sizes and increased transport efficiency of the coal slurries led to improved analytical recoveries of elements in the reference coal, SARM 18. The best analytical recoveries for all elements were achieved using 0.1% Triton X-100 with 10.0% DMF. Results obtained by ICP-OES after wet grinding of the coal with DMF, using 0.1% Triton X-100, also gave excellent recoveries (Al, 100%; Ca, 103%; Cr, 106%; Fe, 102%; Mg, 100%; Mn, 104%; Ni, 109%; Si, 102%; Ti, 95.0%; and V, 108%). The results obtained with 10.0% DMF and 0.1% Triton X-100 were in agreement with certified values for all selected elements according to paired t-test at the 95.0% confidence level. Selected elements (Al, Ca, Fe, Mg, Mn, Si, Ti and V) were also analysed with X-ray fluorescence for comparison with results obtained from ICP-OES. Analysis by ICP-OES of microwave digested coal was also carried out. It is suggested that the DMF slurry technique could be used for routine analysis of bituminous coals.

No description available.

Submitted to: School of Mining Engineering, Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, South Africa September 2015 / Most coal seams in the Waterberg Coalfield contain medium to high levels of phosphorus in coal. Thermal coal, which has a lower value than metallurgical coal, is produced from these coal seams. Metallurgical coal used as feed for char production has especially stringent phosphorous content specifications. Phosphorous levels vary both laterally and vertically through the coal succession of the Vryheid Formation. If the coal horizons with elevated phosphorus could be identified and selectively removed, significant amounts coal could be saved and utilized as metallurgical coal through the life of the mine. Different mining horizons with regards to their phosphorus content have to be determined to increase the amount of char plant feed coal. Bench definitions and their techno-economic applications are therefore the main purpose of the current investigation. Bench 11 is currently the only source utilized for char plant feed coal. The char plant is therefore entirely dependent on coal supply from Bench 11. This poses a risk on the continual production of char at Grootegeluk Mine. It was determined that this bench is not suitable for char plant feed coal in certain areas of the resource. A high phosphorus coal horizon was identified in the upper portion of the bench. If this coal is removed separately, the phosphorus content of the coal in the remaining portion of the bench would be suitable for char plant feed coal. This alternative step is dependent on the phosphorus distribution in the resource and may therefore not always be effective. No changes to the other bench definitions could be established that would increase the amount of potential char plant feed coal. Three further aspects were investigated: The potential to reduce phosphorus in coal by means of coal beneficiation was determined. Results showed that phosphorus levels in coal cannot be lowered sufficiently by means of coal beneficiation. Secondly, the suitability of using different coal analyses to improve the estimation of phosphorus in coal was investigated. Results showed that phosphorus prediction and analyses cannot be enhanced nor replaced by other coal analyses. Lastly, the importance of Zone 1 as a source of low phosphorous coal was investigated. Zone 1 is currently not part of the mine plan, but if mined, it could be used as a source for blending; thereby increasing the amount of char plant feed coal from the reserves. In certain portions of the resource, utilizing Zone 1 may be the only feasible way of securing the continual supply of low phosphorus content coal. Analytical exploration borehole data of phosphorus in coal is limited in certain areas of the resource. Due to the variability of phosphorus in the coal horizons, more borehole data is required to increase the estimation accuracy of phosphorus in the coal. Based on such data, mining horizons might be changed in future to secure more char plant feed coal.

The sensible heat losses in the flue gases was exceeding the best economical operating ranges of the Boiler No. 6. This was done to study the adverse effect on the flue dust carryover in the furnace. / Master of Science

In this investigation, approximately 500 pounds of germaniferous coal was sampled and split into size and specific gravity fractions. The specific gravity fractions were analyzed for ash, volatile matter, fixed carbon, and germanium. Richer fractions of the coal were further treated by solvent extraction, and on the basis of these tests, extraction tests of varying times were conducted. In addition, a sample of the coal was tested by froth flotation and the effects of flotation on germanium concentration were noted. Size and specific gravity separations have given products that contain two to three times as much germanium as the feed. Solvent extraction with suitable solvents was able to give products that contained as high as 250 times the germanium content of the feed. Froth flotation produced concentrations of the germanium that were only one and a half times greater than obtained in feed. The greatest concentration made by burning the coal was 50 to 1 when comparing the germanium in the ash to the germanium in the sample. / Master of Science

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Bibliography: leaves 294-308. / by Howard D. Franklin. / Ph.D.

Abstract not available

M.Ing. / Eskom's power stations receive their main supply of coal from mines next to the power stations. The coal supply contracts only specify maximum allowable variations of some coal quality parameters. The quality of the supplied coal can, however, vary greatly within a few hours. The boilers in the power plant are optimized for a certain quality of coal, while the supplied coal is burnt as it is received from the mine. The variations in the coal quality can, therefore, have a negative impact on both the life expectancy and maintenance costs of the power plant as well as the controllability of the boiler. The effects of short term variations in the coal qualities can be reduced by segregating the supplied coal into separate stockpiles according to coal quality parameters such as ash content and volatile matter, and then blending different portions from these stockpiles to a preferred coal quality before the coal goes to the boilers. A self organising feature map neural network was proposed in this research, to determine how to separate the supply coal, according to measured coal quality data. Furthermore, linear programming was proposed to determine the proportions to be taken from each stockpile in order to achieve a more consistent blended coal again. The segregating and blending systems are described in this thesis; and they were tested by means of a simulation based on measured coal quality data from a power station. It was shown that it is possible to successfully segregate coal from a single supply and then blend the different stockpiles to render coal with less short term variations in its quality parameters. The blending process uses stockpile size as its main driver to optimize the selection of the proportions, such that the most coal is taken from the largest stockpile, while the resultant coal quality remains within the specified constraints.

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The middle eocene to early oligocene Bowmans and Lochiel coal deposits of the northern St. Vincent Basin, South Australia have been studied to elucidate their depositional environments. These coals occur within predominantly fluvio-lacustrine transgressive system tract sequences that formed during the initial phase of basin infill. The aforementioned facies are unevenly distributed and their stratigraphic succession highlights evolutionary changes in local palaeoenvironments. Within individual seams the transition from subaquatic to topogenous forest swamps and ultimately ombrogenous conditions is most common. However, over the coal sequence as a whole, conditions evolved from exclusively terrestrial through mixed terrestrial and subaquatic to open water. Also detected were multiple rapid reversals of the water table, especially higher in the sequence, and cyclic patterns reflecting a brief basal subaquatic phase prior to the onset of sustained terrestrial conditions. These patterns suggest a fluctuating, although progressively rising, water table and a balance between accommodation and accumulation. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280880 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007

Title page, table of contents and abstract only. The complete thesis in print form is available from the University of Adelaide Library. / The middle eocene to early oligocene Bowmans and Lochiel coal deposits of the northern St. Vincent Basin, South Australia have been studied to elucidate their depositional environments. These coals occur within predominantly fluvio-lacustrine transgressive system tract sequences that formed during the initial phase of basin infill. The aforementioned facies are unevenly distributed and their stratigraphic succession highlights evolutionary changes in local palaeoenvironments. Within individual seams the transition from subaquatic to topogenous forest swamps and ultimately ombrogenous conditions is most common. However, over the coal sequence as a whole, conditions evolved from exclusively terrestrial through mixed terrestrial and subaquatic to open water. Also detected were multiple rapid reversals of the water table, especially higher in the sequence, and cyclic patterns reflecting a brief basal subaquatic phase prior to the onset of sustained terrestrial conditions. These patterns suggest a fluctuating, although progressively rising, water table and a balance between accommodation and accumulation. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1280880 / Thesis (Ph.D.) -- University of Adelaide, School of Earth and Environmental Sciences, 2007