Bulk Ash Research Articles

Solubility of Trace Metals from Fly Ash from the Combustion of Lignite in an Atmospheric Fluidized Bed Combustor

Abstract Fly ash has been collected from the baghouse of an experimental atmospheric fluidized bed combustor (AFBC) burning Beulah, N.D., lignite. The bulk ash has been size-separated after collection, and chemical analyses have been performed on the largest fraction, which had a mass median diameter of 2.μm. This lignite AFBC ash lacks the predominant aluminosilicate core characteristic of fly ash from the combustion of pulverised bituminous coal. Instead, it consists primarily of calcium carbonate. It appears that a large fraction of the ash is derived from the limestone bed material, rather than from the lignite fuel. The bulk concentrations of trace metals are within normal ranges, although the enrichment factors for Mn, Cr, Mg, Ni, K, and Ca are exceptionally large.

Influence of carbonaceous particles on the interaction of coal combustion stack ash with organic matter

Stack ash samples were fractionated by aerodynamic size, and the largest particle size fraction was separated into constituent particle type subfractions. Comparison of the mineral, magnetic, and carbonaceous particles showed that coked coal is responsible for the sorptivity of the large particle size fraction for carbon-14 labeled benzo(a)pyrene ((/sup 14/C)BaP) and for low solvent extraction recoveries. Elevated levels of organic matter and surface area also are contributed by the carbonaceous particles. In contrast, solvent extraction recoveries of polar degradation products of (/sup 14/C)BaP are attributable more to the mineral and magnetic particles and to exposure of the ash to light and oxygen. Analysis of bulk ash samples may not fully reflect the true organic composition of stack ash. 27 references, 1 figure, 4 tables.

Analysis of fly ash by X-ray emission spectroscopy and proton microbeam analysis

The use of X-ray emission spectroscopy for the study of properties of fly-ash particles is reported where different techniques of sample excitation were used. The elemental composition of bulk ash was obtained by exposing the samples to radiation from radioactive sources, X-ray tube and synchrotron radiation. Proton microbeam was used to measure the concentration profiles of different elements in individual ash particles.

Characterization of a Lignite Ash from the METC Gasifier III. Correlations of Leaching Behavior and Mineralogy

AbstractLignite gasification ash from the Morgantown Energy Technology Center (METC) gasifier was subiected to two short-term leaching treatments. The cnncentrations of regulated elements in the EPA EP procedure leachate from the bulk METC ash did not exceed the “EP Trigger Limits.” A modification of this procedure that uses a basic synthetic groundwater instead of the acid EP extractant was also performed on the bulk ash and its eleven size fractions. Water equilibria modeling was used to explain the concentrations of major elements in solution. Corcentrations of minor and trace elements in solution after leaching with synthetic groundwater were also below “EP Trigger Limits.”

Ice nucleus characteristics of Mount St. Helens effluents

Aerosols were studied in situ and captured on membrane filters from an aircraft flown around Mount St. Helens during its phreatic period in April 1980. Bulk samples of volcanic ash were collected at ground level 120 km downwind on May 19, 1980 and reaerosolized in a laboratory in ash cloud simulation studies. The aerosol and/or ash samples were tested for ice nucleus (IN) activity using four different IN measurement systems (NCAR acoustical counter, bulk drop freezing, NCAR dynamic thermal diffusion chamber, and filter drop freezing). Although threshold IN activity was observed at −8°C in bulk ash, in aerosols there were few IN active at temperatures warmer than −12°C. At −12°C, IN concentrations were less than 0.4 l−1 (400 m−3) even when the aerosol concentrations were as high as 3000 μg m−3. At aerosol concentrations of 500 μg m−3 and less, the IN content of the ash was below background threshold temperatures of −18°C.

Airborne aerosol measurements in the quiescent plume of Mount St. Helens: September, 1980

Atmospheric particulate matter and condensed volatile species were collected in the quiescent plume of Mount St. Helens volcano in Sept. 1980 using air filter systems mounted aboard a NASA turbo‐prop P‐3 aircraft. Concentrations of 27 elements were determined by instrumental neutron activation analysis and ion chromotagraphy. The volatile elements Cl, Br, F, Zn, W, In, S, Cd, Se, Sb, Hg, As and Au were enriched relative to bulk ash emitted during the earlier eruptions by factors of 50 to 20,000. Particulate S concentrations were ˜3 µg/m³ and accounted for 6% of the total plume sulfur. Gasphase Hg concentrations were 2.5 to 16 ng/m³. Fluxes of elements were estimated by normalizing elemental concentrations to the concurrently measured total sulfur flux. Emission rates vary from 3500 kg/day for particulate Cl to 3 kg/day for Au, with substantial quantities of the enriched elements Zn, As, Hg, Sb, Se, and Cd also being released. Estimated global fluxes of these elements from volcanoes to the atmosphere are in reasonable agreement with other literature estimates.

Water‐soluble material on aerosols collected within volcanic eruption clouds

In February and March of 1978, filter samplers mounted on an aircraft were used to collect the aerosol fraction of the eruption clouds from three active Guatemalan volcanoes (Fuego, Pacaya, and Santiaguito). The samples were collected on Teflon (Fluoropore) filters with a nominal pore diameter of 0.5μm. The mass of air sampled by the filters ranged from 0.15 to 6.6 kg. The particulate material collected consisted of fragments of angular silicate ash and droplets of what is interpreted as dilute H2SO4 and HCl. After collection of the samples, each filter was rinsed with 60 ml of distilled‐deionized water. Splits of each extract were centrifuged to remove particles greater than or equal to 0.1 μm in diameter, acidified, and analyzed for B, Ba, Be, Ca, Cd, Co, Cu, Fe, Li, Mg, Mn, Mo, Na, Pb, Si, Sr, V, and Zn by inductively coupled plasma—optical emission spectroscopy. Separate splits were analyzed for F and Cl by specific‐ion‐electrode methods and for U by a fission track technique. The elements dissolved in the aqueous extracts represent components of water‐soluble material either formed directly in the eruption cloud or derived from interaction of ash particles and aerosol components of the plume. Calculations of enrichment factors, based upon concentration ratios, showed the elements most enriched in the extracts relative to bulk ash composition were Cd, Cu, V, F, Cl, Zn, and Pb. These elements represent a subset (with the addition of Cl and F) of elements previously reported enriched in atmospheric aerosols in remote regions as well as in volcanic areas. This suggests that some of the enriched elements were widely dispersed as volatile halides emitted from a volcanic source.

The enrichment of volatile elements in the atmosphere by volcanic activity: Augustine volcano 1976

Samples of atmospheric particulate material were collected in the plume of Augustine volcano in February 1976 by using the high‐volume filtration system aboard the National Center for Atmospheric Research Lockheed Electra. The samples were analyzed for 38 elements by a combination of instrumental neutron activation analysis and atomic absorption spectrometry. The results indicate that the volatile elements Zn, Cu, Au, Pb, As, Cd, Cl, Br, Se, Sb, Hg, and S are enriched in the atmospheric samples in relation to bulk ash by factors ranging from 10 to several thousand. The enrichments compare closely with those observed for other volcanic emanations and for background aerosols in remote areas of the earth. Samples collected early in the eruption cycle had a much higher quantity of volatile elements in relation to ash than the later samples, indicating a substantial change in the emission of volatiles with time and eruptive cycle.