Vanadium in coal

Alvarado, J., Leon, L.E., Lopez, F., Lima, C. Comparison of conventional and microwave wet acid digestion procedures for the determination of iron, nickel and vanadium in coal by electrothermal atomization atomic absorption spectrometry. J. Anal. At. Spectrom. 3, 135-138 (1988)... 

Catalytic Activity of Some Vanadium Peroxo Complexes Structural Properties of Vanadium Peroxo Complexes Vanadium in Mushrooms Vanadium in Coal... 

There is a good deal of information on the inorganic forms of several elements in many rocks, soils and coals, but much remains to be done on the organic associations of trace elements. For example copper, lead and zinc are associated with humic acids, probably through carboxyl or phenolic groups (Saxby, 1969 Nissenbaum and Swaine, 1976). Vanadium porphyrins occur in petroleum (Davis, 1967), but the form of vanadium in coal has not been established. In most shales and coals, trace elements probably occur partly inorganically and partly organically bound. 

I and liquid SRC II products and to probe the chemical and structural environment of vanadium in coal and coal liquefaction products.( ) Quantitative aspects of these studies were not considered. In the same vein, an extensive extraction (acidic methanol) and chromatographic procedure has been applied to Daw Mill coal (92 Kg) with the result that 17.8 mg of a mixture of gallium complexes of homologous porphyrins (C27-C32) has been isolated for the first time. Identification was based upon a combination of spectroscopic techniques.( )... 

Langmyhr, F.J., Adalen, U., (1980), Direct atomic absorption spectrometric determination of copper, nickel and vanadium in coal and petroleum coke, Anal. Chim. Acta, 115. 365-368. 

Type and use of coal Coal, 1,000 tons Vanadium in coal, tons Vanadium in fly ash, tons Control of fly ash, % Vanadium emitted to air, tons... 

The modern investigations of trace elements in coals were pioneered by Goldschmidt, who developed the technique of quantitative chemical analysis by optical emission spectroscopy and applied it to coal ash. In these earliest works, Goldschmidt (31) was concerned with the chemical combinations of the trace elements in coals. In addition to identifying trace elements in inorganic combinations with the minerals in coal, he postulated the presence of metal organic complexes and attributed the observed concentrations of vanadium, molybdenum, and nickel to the presence of such complexes in coal. 

Vanadium-Rich Coals in the Eastern Interior Region... 

Figure 10 graphically shows data for the columnar samples of coal bed 5 of Illinois and its correlative in Indiana and Kentucky. The thicknesses of the beds at the localities sampled and of the top (block 1), the adjacent blocks, and the bottom blocks are also shown. The sizes of the blocks of the central portions of the columns are not shown. Data for vanadium, chromium, and nickel from these sections of the bed are shown in Table II. Samples 1-12 contain normal amounts of vanadium samples 13-19 contain large amounts of vanadium in the top part. 

Mr. Zubovic. I feel that the relations shown by boron and gallium in their distribution in coal would be operative in these studies you mention. Depositional environment is important in that organic matter is needed in the near-source nonmarine rocks in order to entrap these elements as well as germanium and beryllium. The other elements, such as vanadium and chromium, should be found more uniformly distributed. 

Another test method for the determination of mercury in coal (ASTM D-6414) involves (method A) solubilizing of the mercury in the sample by heating the sample at a specified temperature in a mixture of nitric and hydrochloric acids. The acid solutions produced are transferred into a vessel in which the mercury is reduced to elemental mercury. The mercury vapor is determined by flameless cold-vapor atomic absorption spectroscopy. An alternative method (method B) involved solubilization of the mercury by heating the sample in a mixture of nitric acid and sulfuric acid with vanadium pentoxide. The acid solution is then transferred into a vessel in which the mercury is reduced to elemental mercury. The mercury content is determined by flameless cold-vapor atomic absorption spectroscopy. However, mercury and mercury salts can be volatilized at low temperatures, and precautions against inadvertent mercury loss should be taken when using this method. 

The less common elements in coal ash (e.g., beryllium, chromium, copper, manganese, nickel, lead, vanadium, zinc, and cadmium) can also be determined using atomic absorption (ASTM D-3683). In the test method, the ash is dissolved by mineral acids, and the individual elements determined by atomic absorption spectrometry. 

Coal contains several elements whose individual concentrations are generally less than 0.01%. These elements are commonly and collectively referred to as trace elements. These elements occur primarily as part of the mineral matter in coal. Hence, there is another standard test method for determination of major and minor elements in coal ash by ICP-atomic emission spectrometry, inductively coupled plasma mass spectrometry, and graphite furnace atomic absorption spectrometry (ASTM D-6357). The test methods pertain to the determination of antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, molybdenum, nickel, vanadium, and zinc (as well as other trace elements) in coal ash. 

Trace element data can shed some light on the source of this SO -episode oil-combustion emissions are enriched in vanadium and coal-combustion emissions, on the other hand, are enriched in selenium. 

In the United States, the largest concentration of atmospheric vanadium occurs over Eastern seaboard cities where residual fuels of high vanadium content from Venezuela are burned in utility boilers. Coal ash in the atmosphere also contains vanadium (36). Ambient air samples from New York and Boston contain as much as 600—1300 ng V/m3, whereas air samples from Los Angeles and Honolulu contained 1—12 ngV/m3. Adverse public health effects attributable to vanadium in the ambient air have not been determined. Increased emphasis by industry on controlling all plant emissions may have resulted in more internal reclamation and recycle of vanadium catalysts. An apparent drop in consumption of vanadium chemicals in the United States since 1974 may be attributed, in part, to such reclamation activities. 

Vanadium is widely distributed in nature, it forms up to 0.05% of the earth s crust and there are over 60 vanadium ores. Vanadium occurs widely in coal and certain petroleums, especially those from Venezuela (up to 1%), in the form of oxovanadium(rv) porphyrins. The major world producers of vanadium in recent years have been the United States, South Aftica, and Finland. 

Vanadium is known to exist in petroleum and shale deposits as a porphyrin complex. Many catalytic processes that take place in oil production or advanced coal conversion may be critically affected by the presence of trace amounts of vanadium. Also it is known that vanadium, in combination with S compounds, can cause problems in oil hydroprocessing. Investigation of the manner in which V is present in coal, oil, and bitumen has resulted in many studies on porphyrin complexes ofV and V. ... 

Another source of vanadium, of interest in biological and environmental contexts, are fossil fuels such as peat, coal, bitumen, oil-shales, asphalts and crude oil. The vanadium content of hard coal can vary from 0.007 to 0.34%. Crude oil from Albania (0.034%), the Volga-Ural region (0.061%) and Venezuela (0.12%) (upper limit in all three cases) is particularly rich in vanadium.I l A high vanadium content is often associated with high sulfur contents. The reasons for the notable enrichment of vanadium in fossils compared with bio-mass precursors such as bacteria, protozoans, algae, plants and animals are still under debate. Possible mechanisms for a secondary input of vanadium in decaying... 

Organic vanadium in residual fuel oil is converted to particulate vanadium oxide. Part of the calcium carbonate in the ash fraction of coal is converted to calcium oxide and is emitted to the atmosphere through the stack... 

Industrial processing of certain mineral ores (ore smelters, cement, and phosphate rock plants) and the burning of coal and oil will increase the deposition of vanadium residues in soils. The combustion of vanadium-rich fuel oils is an especially serious source of vanadium in soils (Kabata-Pendias and Pendias 1992). 

Oil combustion. Much higher proportions of sodium are encountered in fuel oils than in coal, and there are relatively high levels of vanadium, an element not usually found in coal. Furthermore the total non combustible fraction of oil is likely to be as low as 0.1%, whereas for poor quality coal it might be as high as 50%. 

The mineral silica is available from a number of sources ranging from natural deposits to byproducts from chemical processing. It is generally available as a finely divided powder which facilitates its use as an additive. It has been employed to reduce deposition and corrosion problems associated with vanadium in fuel oil. In some coal fired equipment silica has been added with copper oxychloride to control slagging [Radway and Hoffman 1987]. 

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