All issues
Volume 34, Issue 5
Displaying 1-20 of 20 articles from this issue
- |<
- <
- 1
- >
- >|
-
Shohgo SUZUKI, Yukiko OKADA, Shoji HIRAI1985 Volume 34 Issue 5 Pages 217-223
Published: May 05, 1985
Released on J-STAGE: January 15, 2010
JOURNAL FREE ACCESSConcentrations of 54 elements in coal samples were determined by instrumental neutron activation analysis(INAA). Coal samples indigenous to Japan, Australia and U.S.A. (c.a. 501000 mg) were irradiated by neutrons for short time (5 min) and long time (5 h) in Musashi Institute of Technology Research Reactor (MITRR). Various methods of neutron irradiation and of gamma-ray spectrometry were used in order to improve the detection sensitivity. Samples were irradiated by three methods, namely, no-filter, cadmium-filter and boron-filter irradiations. Gamma-ray spectra of irradiated samples were collected by four methods, namely, spectrometry using a coaxial Ge(Li) detector, anticoincidence and coincidence counting spectrometries using a coaxial Ge(Li) detector and a well-type NaI(Tl) detector, and low energy photon spectrometry using a planer Ge detector (LEPS). Gamma-ray spectra obtained were analyzed by a peak-fitting procedure using a minicomputer system (GAMA system). Concentration of 35 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, As, Br, Rb, Sr, Zr, Mo, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy, Hf, Ta, W, Tb and U) were determined by the combination of no-filter irradiation and spectrometry using a coaxial Ge(Li) detector that is conventionaly widely used. Concentrations of other 19 elements were determined by other combinations of irradiation and spectrometry. Mercury concentration was determined by the combination of no-filter irradiation and anticoincidence counting spectrometry. Concentrations of 7 elements (Cu, Nd, Gd, Ho, Tm, Yb and Lu) were determined by the combination of no-filter irradiation and LEPS. Concentrations of 3 elements (In, Ga and Ag) were determined by the combination of cadmium-filter irradiation and spectrometry using a coaxial Ge(Li) detector. Concentrations of 5 elements (Pr, Cd, Au, Te and Sn) were determined by the combination of cadmium-filter irradiation and anticoincidence counting spectrometry. Selenium concentration was determined by the combination of cadmium-filter irradiation and coincidence counting spectrometry. Silicon concentration was determined by the combination of boron-filter irradiation and spectrometry using a coaxial Ge(Li) detector. Iodine concentration was determined by the combination of boron-filter irradiation and anticoincidence counting spectrometry.View full abstractDownload PDF (1050K) -
Kiyoshi SAITO, Misaburo MOROHASHI1985 Volume 34 Issue 5 Pages 223-228
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThis study has been achieved to establish the direct determination method of oxygen content of organic compounds in coal. The recommended procedure was as follows. The thermal decomposition of a known amount of sample is dealed with two stage system and evolved volatile matter is pyrolyzed completely in thermal decomposing zone heated to keep 1100 °C. Carbon dioxide in occured gas is reduced to CO in Pt·C zone of 900 °C. Produced gas is collected into Tedlar bag and then introduced to gas-meter by tubingpump and the sample gas is taken periodically by autosampler through this process to measure concentration of CO by gas chromatography. Experimental results showed that it was suitable to determine the calibration value with anthraquinone and anthracene. The observed value of anthracene was coincident to intercept of calibration curve with anthraquinone. The chip of silica tube was used as filler of thermal decomposing zone of 1100 °C. In the case of porcelain material with porosity, adsorption of CO gas was observed. And the correction about the oxygen of inorganic compounds in ash could be disregarded. The observed values of oxygen content of organic compounds in coal by this method are good coincident to the calculated values based on the difference subtracted the analytical values of elements and ash from 100(%). The precision of analytical value is good and the coefficient of variation is 2 %. The time required of each analysis by this method is 20 minutes.View full abstractDownload PDF (1175K) -
Noriko FUDAGAWA, Akira KAWASE1985 Volume 34 Issue 5 Pages 228-233
Published: May 05, 1985
Released on J-STAGE: May 25, 2010
JOURNAL FREE ACCESSConditions for determination of cadmium in coal were investigated by atomic absorption spectrometry using a boat-shape tungsten furnace. For concentrating and separating cadmium from the coexisting components cadmium dithizonate-m-xylene solution and the 0.05 mol/l perchloric acid solution were examined. Ashing and atomizing temperatures, sheath gas composition, distribution of the cadmium atoms in the furnace were examined. Similar characteristics were obtained for the determination of cadmium in perchloric acid solution and the chelate m-xylene solution, except that a reduction of the peak time and FWHM(full width at half maximum) was observed for the latter solution. When the atomization temperature is near 2300 °C, the change in the magnitude of absorbance is small in terms of the temperature. The influence of hydrogen contained in the sheath gas was complicated: Change in the thermal conductivity with increasing hydrogen content, resulted decrease of the atomization temperature but the integrated absorbance did not change so much. The concentration of cadmium atoms decreased linearily in the vertical direction of the furnace, while absorbance in the horizontal direction was almost constant. Cadmium in coal was determined by the methods (1) solvent extraction, (2) back-extraction with perchloric acid, (3) on-boat standard addition method.View full abstractDownload PDF (917K) -
Kozo KIYA, Kiyoshi MASHIMO, Tohru WAINAI1985 Volume 34 Issue 5 Pages 233-238
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThe chain length of alkyl groups bonded to aromatic rings, free straight-chain alkanes and straight-chain fatty acids in the pyridine extracts of coals having various carbon contents were studied. The pyridine extract of coal was divided into the hexane solubles (γ2 fraction) and the material insoluble in hexane but soluble in chloroform (γ2 fraction). The γ2 fraction was hydrogenated with tetralin and the resulting product was named γ2' fraction. Alkanes in γ1 and γ2' were separated by liquid chromatography on a column of neutral alumina using hexane or cyclohexane. From the gas chromatograms of γ2' fraction, straight-chain alkanes detected in various coal samples were in the following ranges of carbon number: Alberta (C 87.37);C16-C29, Kentucky(83.3 %) ; C14-C28, Akabira(80.4 %); C17-C35, Taiheiyo(74.5 %) ; C15-C30, Nakayama lignite (69.0 %); C17-C34, Joban lignite(67.7 %); C15-C35. The gas chromatograms of alkanes in γ1 fractions of Alberta, Kentucky, Akabira, and Taiheiyo coals showed the presence of long straight-chain alkanes. Although no straight-chain alkane was confirmed in the γ1 fractions of two lignites, ester wax was found in the fraction of Joban lignite. Long straight-chain alkanes produced by the hydrogenolysis of γ2 fractions were presumably generated by the scission of straight-chain alkyl groups or alkyl groups bound by ether linkages to aromatic rings. On the other hand, straight-chain alkanes found in γ1 fraction were regarded as free saturated compounds contained in coals. Accordingly, straight-chain alkanes derived from the hydrogenolysis of γ2 fractions and those in γ1 fractions could be distinguished clearly. The origin of the free straight-chain alkanes in Taiheiyo coal and the aliphatic structure of Joban lignite were also discussed in relation to the presence of and the straight-chain fatty acids in these samples.View full abstractDownload PDF (916K) -
Yutaka BAN, Takuo SUGAWARA, Keiichi FURUYA, Yoh-ichi GOHSHI1985 Volume 34 Issue 5 Pages 238-242
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThree different types of analytical methods on sulfur in coal have been compared: (1) state analysis of sulfur using high resolution x-ray fluorescence spectrometry (XRF) for the determination of total sulfur, S2- and S6+, (2) chemical analysis using Eschka method and incineration at 815±10°C, which determined total sulfur, combustible and noncombustible sulfur, and (3) form analysis based on ASTM in which total sulfur (combustion-IR method), sulfatic, pyritic, and organic sulfur were determined. Eight types of pulverized coal dried in a silica gel desiccator were analyzed. The results of total sulfur were in good agreement in the three methods. Between the values of S2- and combustible sulfur as major components of sulfur in coal, a good correlation was observed. The quantity of sulfate sulfur was, however, 8 % of those of S6+ and noncombustible sulfur, due to incomplete extraction and/or inclusion partially in organic sulfur fraction.View full abstractDownload PDF (833K) -
Junichi SHIDA, Mamoru ITOH, Tateaki OGATA, Hitoshi KAMADA1985 Volume 34 Issue 5 Pages 243-247
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSCharacterization of manganese in coal was studied by electron spin resonance(ESR) spectrometry, atomic absorption spectrometry(AAS) and a leaching method. A total of 33 samples of coal from Japan, China, South Africa, Australia and the U.S.A. were pulverized to pass a 60-mesh screen. Several kinds of coal were fractionated with heavy fluid. ESR spectra of manganese(II) and free radical were measured. The total manganese content was determined by AAS. The powdered samples were immersed in a 1 M hydrochloric acid solution and were irradiated with ultrasonic waves at 2025°C to investigate the leaching behavior of manganese in coal. The characterization of manganese in coal was considered as follows: The linear relationships were observed between manganese and ash contents, and between manganese and free radical contents in fractionated coal. The results suggested that most of manganese existed, not in organic substances from plants but mainly in mineral substances such as rock and soil present in coal. The content of manganese in coal was not correlated with the signal intensity of manganese(II). Manganese was leached more rapidly from coal with a high intensity of manganese(II) signal. Coal treated with hydrochloric acid did not show the hyperfine structure of manganese(II). These results indicate that manganese in coal is of various oxidation states such as +2, +4, etc.View full abstractDownload PDF (744K) -
Tateaki OGATA, Kiyoshi MIZUKI, Tamaki SAITO, Junichi SHIDA, Hitoshi KA ...1985 Volume 34 Issue 5 Pages 248-252
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSElectron spin resonance (ESR) spectra of various coal samples were measured. ESR parameters obtained from ESR spectra were g-value, line-width (ΔHmsl), micro wave power of saturation curve and spin concentration for free radical, and first signal intensity of hyperfine structure for manganese(II). A classification of the coal samples was performed by a pattern recognition method. Non-linear map(NLM) calculated with the five ESR parameters indicated that coal could be characterized with ESR parameters. A practical classification of coal was carried out by K-nearest neighbor (KNN) and linear-learning machine(LLM) methods. The percentage of accurate classification of the LLM calculated by one-out-leave procedure was 77 % for 8 classes (Miike, Taiheiyo, other Japanese, China, South Africa, Australia-I, Australia-II, and America). The use of the LLM technique gave superior results to the KNN method(K= 1 and 3). Therefore, these results indicated that the properties of coal could be estimated by using the ESR spectrometry and the pattern recognition method.View full abstractDownload PDF (881K) -
Hiroki HARAGUCHI, Masao KUROSAWA, Yasuo IWATA1985 Volume 34 Issue 5 Pages 252-257
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSSimultaneous multielement analysis of coal and fly ash samples has been investigated by inductively coupled plasma atomic emission spectrometry(ICP-AES). The coal and fly ash samples were digested with an acid mixture of HNO3-HF-HClO4 in Teflon beakers at 250°C, and finally dissolved with HCl. The acid concentrations of the analysis solutions were ca. 1.3 M for HClO4, and ca. 0.6 M for HCl. The recovery test in digestion procedure, the influences of acids used and the correction of spectral interferences with major elements in the ICP-AES measurements were also examined to evaluate accuracy and precision in analysis. The standard reference materials of coal (SRM 1632 and 1632a) and coal fly ash (SRM 1633 and 1633a) issued from National Bureau of Standards, and some real samples of coal and fly ash were analysed, and 21 elements at the major, minor, and trace levels could be determined simultaneously. The condensation factors of compositional elements from coal to fly ash were evaluated to obtain some information about the origins of coals, fly ash production conditions in furnaces, environmental impacts, and so forth.View full abstractDownload PDF (924K) -
Yoshihiro MIYAJIMA, Tadashi KIKUCHI, Keiichi FURUYA1985 Volume 34 Issue 5 Pages 258-264
Published: May 05, 1985
Released on J-STAGE: May 07, 2010
JOURNAL FREE ACCESSIn order to characterize coal fly ash, a shaking separation method and a supersonic separation method with meshes were applied for the particle size separation as a preliminary treatment. The supersonical method showed its effectiveness with a good reproducibility in separation of submicron particles adhered on the surface of larger particles by electrostatic force. The size separated fractions were subjected to density separation using mixtures of CCl4, CH2Br2 and CH2I2. The rate of higher density fractions(>2.4 g/cm3) increased with the decrease of their particle size in 5149 μm range. Scanning electron microscopy-energy dispersive X-ray analysis and high resolution X-ray fluorescence spectrometry were applied for the elemental composition and morphology analysis, and the state analysis of sulfur, respectively. The enrichment of Fe, Ca, Ti, Mg and S in smaller size and higher density fractions, was observed. And the decrease of the ratio of cenosphere particles in the smaller size range than 44μm in 2.42.8 g/cm3 was suggested by the comparison of estimated density from its components. Submicron sized precipitated crystalline particle on a larger particle was proved to be consisted of sulfur(VI) and calcium.View full abstractDownload PDF (1723K) -
Yutaka BAN, Ikuo WATANABE, Keiichi FURUYA, Hidetsuru MATSUSHITA, Yohic ...1985 Volume 34 Issue 5 Pages 264-268
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThree analytical methods on sulfur in coal fly ash have been compared: (1) state analysis of sulfur using high resolution x-ray fluorescence spectrometry(XRF) by which total sulfur, S2- and S6+ were determined, (2) chemical analysis using Eschka method and incineration at 815±10°C, by which total sulfur, combustible and noncombustible sulfur were determined, and (3) ion chromatography which determined sulfate ion in leaching solution. Eight types of pulverized coal were burnt in a laminar flow and a turbulent flow test furnace, and their fly ash were collected at a cyclone and a following bagfilter. In case of total sulfur analyses, the XRF results were in good agreement with those by chemical method. The quantity of S6+ and noncombustible sulfur showed a fairly good correlation. The relationship between the quantities of S6+ and sulfate ion in leaching solution depends on the difference of furnace types and collecting devices. No correlation between S2- and combustible sulfur were observed. The difference of the quantity of S6+ and noncombustible sulfur suggested the possibility of sulfur loss during the incineration process. The quantity of leachable sulfate in bagfilter fly ash was less than that of S6+, and therefore nonleachable S6+ was suggested to be in bagfilter fly ash.View full abstractDownload PDF (694K) -
Masami ICHIKUNI, Makoto TSURUMI1985 Volume 34 Issue 5 Pages 268-271
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSChemical characterization of coal ash was made by simple leaching experiments. Coal ash suspended in dilute hydrochloric acid was ultrasonicated for 30 min. After filtration, dissolved Na, K, Mg, Ca, Sr, Al, and Fe were determined by atomic absorption spectrophotometry. Leached amounts of Na, K, Mg, Sr, and Fe can be expressed as a function of those of Ca and Al: a[Ca] +b[Al], where the coefficients a and b are constants for a given element. Leached amounts of the above 5 elements, calculated with the coefficients determined by the least squares method, were in good agreement with the observed values. This suggests that the coal ash is composed of water-soluble phase and aluminosilicate phase. The coefficients describe partition of a particular element between the phases. The proposed method was proved to be useful to the characterization of minor elements in coal ash, and possibly in any environmental solid samples.View full abstractDownload PDF (599K) -
Kazuo SATO, Masahiro SAKATA1985 Volume 34 Issue 5 Pages 271-275
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThis paper describes a simple and rapid method for the determination of 15 elements (aluminium, barium, beryllium, calcium, chromium, copper, iron, magnesium, manganese, nickel, silicon, strontium, titanium, vanadium, and zinc) in coal ashes. To check the recoveries of the elements of interest, three fly ash samples including NBS standard sample(No. 1633a) were analyzed. Analytical procedures proposed are as follows; 0.2 g of coal ash is digested at 110 °C for an hour in a Teflon-lined bomb with a mixture of 2 ml of hydrofluoric acid and 2 ml of nitric acid. After cooling, 25 ml of 4 w/v% boric acid is added to the solution, and is heated again at 100 °C for an hour. Then, the solution is filtered and diluted to 50 ml. This solution is analysed for 14 elements except silicon by ICP-AES and for silicon, the solution is further diluted to 20- fold. The coal ashes could be decomposed with hydrofluoric and nitric acid without the aid of hydrochloric or perchloric acid. If more than 0.5 g of sample was digested, hexafluorosilicic acid dissolved in the solution was transformed to silica gel when boric acid was added, and elements in the solution were incorporated into the gel. So the amount of the sample is desirble to be 0.2 g. When the sample was digested at 140 °C for more than 2 hours, poor recovery was obtained for aluminium, calcium and magnesium, because fluorides of these elements in the solution would become hard to dissolve by aging even if the solution was heated after boric acid was added. Fifteen elements could be determined without any spectral interferences, while lead could not be determined because of the stray light due to boron added to the solution, and of the line overlap due to aluminium and iron, which are major constituents of coal ash.View full abstractDownload PDF (866K) -
Masayoshi SADAKATA1985 Volume 34 Issue 5 Pages 276-282
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThe purpose of this study is to examine the behavior of mercury in the pulverized coal combustion system. For this purpose, the applicability of the gold-amalgam method of analysis combined with an atomic absorbtion analyzer which has been broadly used for the analysis of atmospheric mercury was examined by using a methane gas combustor and the small size coal combustor. As the result, it was found that SOx coexisting with mercury in the flue gas plays as an interferential species for the analysis of vapour mercury. Consequently, an analysis of vapour mercury by the gold-amalgam method became possible by removing SOx in the high temperature gas region of the sampling system. This improved method of analysis was tested in the flue gas of the experimental pulverized coal combustion furnace which was designed to be able to simulate the combustion condition of an industrial power plant boiler. It was shown that the conversion of mercury in the raw coal to the vapour gas in the flue gas of 400 °C was around 70 %. The usefulenss of this improved method was verified as the mercury in the vapour phase plus that in the fly ash was balanced with that in raw coal.View full abstractDownload PDF (1077K) -
Senya IMAMICHI, Takanori KODAMA, Fujio MORISHITA, Tsugio KOJIMA1985 Volume 34 Issue 5 Pages 282-289
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSA systematic analytical method of azaarenes in coal-derived oil was investigated. The basic nitrogen-containing substances extracted with 6 M hydrochloric acid were fractionated sequentially by using gel permeation chromatography(GPC) with TSK G1000 HXL gel and thin layer chromatography(TLC) on an alumina plate. Thus, ten TLC fractions were obtained from the last GPC fraction. TLC separation affords some qualitative information on the intramolecular environment around nitrogen atoms. Azaarenes in these fractions were characterized by using gas chromatography (GC) and gas chromatography/mass spectrometry, in which an OV-101-coated and a PEG 20M-coated capillary columns were used. Aromatic amines were differentiated from azaarenes by acylation with trifluoroacetic anhydride. The retention index (I) of an azaarene was found to be able to be calculated on the basis of incremental contributions of each structural constituent. The change in I resulted from insertion of Ni(II) ion containing post-column reactor divides azaarenes into three groups : (a) the compounds whose nitrogen atom is completely shielded by adjacent substituents or rings, e. g. 2-methyl- and 2, 6-dimethylquinoline, (b) the compounds whose nitrogen atom is partly shielded by an adjacent substituent or a ring, e. g. quinoline and 4-methylquinoline and (c) the compounds whose nitrogen atom is not shielded at all and which can form a Ni(II) complex easily, e. g. isoquinoline. Some attempts were made to predict molecular structures of components unidentified because of unavailability of authentic standards based on informations from TLC and the postcolumn reactor and comparison of the observed I value with the calculated values, in addition to mass spectra.View full abstractDownload PDF (999K) -
Osamu NITOH, Toshiaki KABE, Yaeko KABE1985 Volume 34 Issue 5 Pages 289-295
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSFor the analysis of mechanism of hydrogenation and cracking of coal, the liquefaction of Taiheiyo coal using tritium labeled gaseous hydrogen and tritium labeled tetralin with small amounts of carbon-14 labeled naphthalene has been studied. Taiheiyo coal(25 g) was thermally decomposed in tetralin or naphthalene solvent(75 g) at 400440 °C under the initial hydrogen pressure of 5.9 MPa for 30 min with Ni-Mo-Al2O3 catalyst(05 g). The reaction mixture in an autoclave was separated by filtration, distillation and solvent extraction. Produced gas, oils and the solvent were analyzed by gas chromatography. The tritium and carbon-14 contents of separated reaction products were measured with a liquid scintilation counter to study the hydrogen transfer mechanism. The distribution of reaction products and the amount of hydrogen transfer from gas or solvent to the products were also determined. In hydrogen donor solvent such as tetralin, the coal liquefaction yield was independent from the catalyst, but the catalyst was effective in hydrocracking of preasphaltene and asphaltene. In naphthalene solvent, the coal liquefaction reaction hardly occured in the absence of the catalyst, because hydrogen transfer from both the solvent and gaseous hydrogen was scarce. Tritium distribution in the reaction products showed that complicated hydrogen exchange reactions between gaseous hydrogen, coal liquids and solvent came out by the presence of coal liquids and catalyst. The very small amounts of carbon-14 transferred to the liquefaction products showed that carbon exchange or transfer between solvent and coal did not take place.View full abstractDownload PDF (1076K) -
Analysis of saturate fractionTakashi KATOH, Yae KATOH, Koji OUCHI1985 Volume 34 Issue 5 Pages 295-302
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSIn order to elucidate the chemical structure of coal, Shinyubari coal was hydrogenated under mild condition with Adkins catalyst repeatedly. Hexane soluble part of the product (52 wt% of d.a.f. coal) was washed with base and acid, then fractionated into compound types with alumina chromatography. In this report the saturate fraction was analysed in detail. The saturate fraction was fractionated into three fractions with urea and thiourea ; urea adducts (35 wt%), thiourea adducts (12 wt%) and non adducts (52 wt%). Nonadducts was separated into 24 fractions (Fr. 1 to Fr. 24) by silica chromatography. Fr. 2 and Fr. 3 were further separated with silica chromatography into six subfractions respectively. These total 36 fractions were all analysed by gas chromatography and gas chromatography mass spectrometry in detail. In urea adducts, n-alkanes of C12 to C31 occupied 93 wt% and iso-, anteiso-alkanes, long-straight chain alkyl cyclohexanes are contained in a small amount. There were about 100 peaks in the gas chromatogram of thiourea adducts. n-Alkyl(C6 to C20) cyclohexane, tricyclic alkanes, cyclohexanes with branched alkyl chain and C15C20 isoprenoids were dominant components in the thiourea adduct. Urea and thiourea nonadducts contained a enormous number of compounds and peak identification was very hard. In these fraction the homologous series of long alkyl benzenes, steranes and terpanes were the characteristic compounds.View full abstractDownload PDF (811K) -
Kichinosuke HIROKAWA1985 Volume 34 Issue 5 Pages 303-305
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThe surfaces of coal and coal fly ashes were analyzed by X-ray photoelectron spectroscopy. The quantification was performed by Ebel-Hirokawa's method, which was not necessary to prepare reference sample groups. Further, to elements which may be present as oxide form in fly ashes such as Al, Si and Fe, the relative sensitivity factor method could be applied. On the surface of fly ashes, sulfur in SO42- type which was easily dissolved in water with Ca2+ and Na+ could be found. On the surface of coals, sulfer in oxides type and thiophene type, nitrogen in pyrrole and pyridine types were found, respectively. Sulfer in these types and nitrogen in pyridine type were easily leached in water.View full abstractDownload PDF (363K) -
Mitsuyuki SOMA, Keiko MIYASAKA, Masataka NISHIKAWA, Yoshiaki KUZUHARA1985 Volume 34 Issue 5 Pages 305-308
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSIn order to have an insight into the acid digestion methods for the elemental analysis of coal fly ash, the extent of dissolution of some major and trace elements from the fly ash samples treated by various acids (based on hydrochloric, nitric and sulphuric acid), and the accompanied changes in the surface elemental composition and in the surface morphology of the ash particles were investigated. The amount extracted as determined by ICP emission spectrometry ranged from several % to 80 % depending on elements, but, for the most elements, the efficiency of the extraction varied with the acid only within a factor of two. Characteristic etching patterns were observed on the individual particles by scanning electron microscopy, while ESCA measurements revealed that most elements except Si, Al and Ti were almost completely dissolved from the surface layers of the ash particles. An important part of the dissolution of elements, especially trace elements, is considered to take place without giving clear etching patterns, which is consistent with the reported mechanism of the accumulation of trace elements onto coal fly ash particles.View full abstractDownload PDF (688K) -
Ikuo WATANABE, Kiyoshi TANABE, Keiichi FURUYA, Hidetsuru MATSUSHITA1985 Volume 34 Issue 5 Pages T45-T50
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSFor the estimation of the leachability of elements and anions from coal fly ashes(FA), twenty-five elements and six anions, which were extracted from FA into redistilled water in an ultrasonic bath, were analyzed by inductively coupled plasma emission spectrometry and ion chromatography, respectively. Three kinds of pulverized coal were burnt in two experimental furnaces with laminar flow and turbulent flow, respectively, and fly ash samples were taken from a cyclone(CFA) and a bagfilter (BFA) in each furnace. Calcium and sulfate ion concentrations were highest in the solutions, and Al, K, Mg, Na, Si, Sr, F- and Cl- followed after these. BFA contained more soluble compounds than CFA. Ca, Cu, Na, F-, Cl- and SO42- in BFA were remarkably extracted in the solution. Positive correlation between extraction and pH 612 was observed in Al(only for CFA), Ba(BFA), Cr(CFA) and negative correlation in Mn, Mg, Co, V, Ni, Zn, Cd and P(CFA). The differences of equivalent between the sum of Na, K, Mg, Ca, Sr and Ba and the sum of F-, Cl- and SO42- were propotional to the pH of the solution of CFA, which suggests that the balance of these ions controlled the pH. On the other hand, no obvious relationship was observed in the case of BFA. Unburned carbon in FA affected to the collection of Ca, Na, Cl- and SO42- as soluble forms.View full abstractDownload PDF (921K) -
Osamu WATANUKI, Akio MATSUBARA, Keiichi BETSUMORI1985 Volume 34 Issue 5 Pages T51-T55
Published: May 05, 1985
Released on J-STAGE: May 29, 2009
JOURNAL FREE ACCESSThe accuracy of a thermogravimetric analysis (TGA) for the determination of moisture, volatiles, fixed-carbon and ash in coal was investigated. The method consists of the following 4 sequential steps: (1) preparation: Load a 50 mg sample of constant humidity base coal to a thermobalance and purge high-purity nitrogen into a furnace. (2) moisture determination: Heat the sample up to 107 °C in a nitrogen atmospher and hold it at the temperature for 10 min. (3) volatiles determination: Increase furnace temperature up to 900 °C and hold at the temperature for 7 min. (4) fixed-carbon determination: Decrease furnace temperature to 815 °C and switch furnace environment from nitrogen to high-purity oxygen. After each procedure, the weight losses of each component were measured as percentages to the total sample weight. In regard to moisture, fixed-carbon and ash contents, the results by the TGA method were in good agreement with those of JIS method. For the volatiles, however, TGA showed a little lower values than those by JIS method.View full abstractDownload PDF (655K)
- |<
- <
- 1
- >
- >|