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Title: Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash

Abstract

Cementitious compositions useful as lightweight aggregates are formed from a blend of spent bed material from fluidized bed combustion and fly ash. The proportions of the blend are chosen so that ensuing reactions eliminate undesirable constituents. The blend is then mixed with water and formed into a shaped article. The shaped article is preferably either a pellet or a "brick" shape that is later crushed. The shaped articles are cured at ambient temperature while saturated with water. It has been found that if used sufficiently, the resulting aggregate will exhibit minimal dimensional change over time. The aggregate can be certified by also forming standardized test shapes, e.g., cylinders while forming the shaped articles and measuring the properties of the test shapes using standardized techniques including X-ray diffraction.

Inventors:
 [1]
  1. (Aston, PA)
Publication Date:
Research Org.:
Valley Forge Labs., Inc., Devon, PA (United States)
OSTI Identifier:
869516
Patent Number(s):
US 5350549
Assignee:
Valley Forge Laboratories, Inc. (Devon, PA) CHO
DOE Contract Number:
FG02-90ER81006
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
synthetic; aggregate; compositions; derived; spent; bed; materials; fluidized; combustion; fly; ash; cementitious; useful; lightweight; aggregates; formed; blend; material; proportions; chosen; ensuing; reactions; eliminate; undesirable; constituents; mixed; water; shaped; article; preferably; pellet; brick; shape; crushed; articles; cured; ambient; temperature; saturated; found; sufficiently; resulting; exhibit; minimal; dimensional; change; time; certified; forming; standardized; shapes; cylinders; measuring; properties; techniques; including; x-ray; diffraction; bed material; shaped articles; x-ray diffraction; bed combustion; cementitious compositions; fly ash; fluidized bed; ambient temperature; shaped article; ensuing reaction; compositions useful; dimensional change; spent bed; exhibit minimal; aggregate composition; cementitious composition; /264/106/436/

Citation Formats

Boyle, Michael J. Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash. United States: N. p., 1994. Web.
Boyle, Michael J. Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash. United States.
Boyle, Michael J. Sat . "Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash". United States. doi:. https://www.osti.gov/servlets/purl/869516.
@article{osti_869516,
title = {Synthetic aggregate compositions derived from spent bed materials from fluidized bed combustion and fly ash},
author = {Boyle, Michael J.},
abstractNote = {Cementitious compositions useful as lightweight aggregates are formed from a blend of spent bed material from fluidized bed combustion and fly ash. The proportions of the blend are chosen so that ensuing reactions eliminate undesirable constituents. The blend is then mixed with water and formed into a shaped article. The shaped article is preferably either a pellet or a "brick" shape that is later crushed. The shaped articles are cured at ambient temperature while saturated with water. It has been found that if used sufficiently, the resulting aggregate will exhibit minimal dimensional change over time. The aggregate can be certified by also forming standardized test shapes, e.g., cylinders while forming the shaped articles and measuring the properties of the test shapes using standardized techniques including X-ray diffraction.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Jan 01 00:00:00 EST 1994},
month = {Sat Jan 01 00:00:00 EST 1994}
}

Patent:

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  • Some of the features of the fluidized-bed combustion (FBC) process have a direct bearing on the particulate properties that most strongly influence filtering pressure drop. A laboratory program was conducted to experimentally determine the relative pressure drop characteristics of ashes from the TVA-EPRI 20-MW bubbling bed, atmospheric pressure FBC (AFBC) pilot plant and six pulverized-coal combustion (PC) units. The combined influences of measured particle and dust cake properties on filtering pressure drop were estimated with existing filtration theories. These theories predict a higher pressure drop for a dust cake produced with the AFBC ash than one consisting of any ofmore » the PC ashes. Laboratory measurements were made of the flow resistance of idealized, simulated dust cakes to confirm these predictions. Field operating data from the fabric filters collecting some of the tested ashes were available to validate the laboratory results. The laboratory and field data show relatively good agreement. The AFBC ash must be treated as a special case for fabric filters, and careful selection of cleaning method and fabric must be made to minimize the inherently high pressure drop characteristics of this ash.« less
  • Two respirable coal fly-ash samples (<3MUm) were evaluated for physical properties, chemical composition and biological activity, including cytotoxicity and mutagenicity. The two fly-ash samples were collected from a pressurized fluidized-bed combustion miniplant and from a conventional-combustion plant, both burning eastern US coal. The two samples were found to have different physical and chemical properties. Both samples were toxic in two mammalian cell systems, with fluidized bed combustion fly ash showing higher toxicity in both assay systems. For conventional-combustion fly ash, no mutagenicity was detected in bioassay of the whole particles. A series of organic solvents was employed to identify themore » most efficient solvent for removing mutagens from coal fly ash. Extracts of fluidized-bed combustion fly ash were found to be mutagenic when dichloromethane, acetone or cyclohexane were employed: much lower mutagenic activity was found in dichloromethane and acetone extracts of conventional combustion fly ash.« less
  • Trace element constituents in fly ash from an experimental atmospheric fluidized bed combustor (AFBC) are reported and compared with pulverized coal combustor (PCC) data and those from other fluidized bed combustors. Bulk and size-separated particles were collected and analyzed using spark source mass spectrometry. Fluidized bed combustion ash was similar to PCC ash in minor and trace element composition, but AFBC ash showed less size dependence of elemental composition. Bulk particle elemental composition varied with sampling position within the effluent stream. Penetration of elements through each cleanup stage and elemental enrichment were a function of the cleanup stage and themore » element under consideration.« less
  • Fluidized bed coal combustion is a promising technology for using coal in an environmentally acceptable manner. Trace elemental constituents in fly ash from an experimental atmospheric pressure fluidized bed combustor (AFBC) are reported and compared with pulverized-coal combustor (PCC) ash data and those from other fluidized bed combustors. Bulk and size-separated particles were collected and analyzed by using spark source mass spectrometry.Fluidized bed combustor ash was similar to PCC ash in minor and trace element composition. However, AFBC ash showed less size dependence of elemental composition than has been reported for PCC ash. Bulk particle elemental composition varied with samplingmore » position within the effluent stream. Penetration of elements through each cleanup stage and elemental enrichment were a function of the cleanup stage and the element under consideration.« less
  • Fly ash from a fluidized-bed coal combustor was neutron-activated and administered to male Fischer 344 rats by a single nose-only inhalation exposure. The activated fly ash contained /sup 46/Sc and smaller amounts of other gamma-emitting radionuclides. Whole-body clearance of radioactivity of 127 d was described by an exponential equation, with the long-term component having a biological half-life of 78 d. High-resolution gamma spectra of the lungs was obtained with a Ge(Li) detector and the relative activities of several fly ash constituents were compared. The activities of /sup 152/Eu, /sup 134/Cs, /sup 54/Mn, and /sup 60/Co significantly decreased with time relativemore » to those of /sup 46/Sc and /sup 59/Fe. These results indicate that the clearance of fly ash is similar to that of other relatively insoluble particles and that some elements may have been preferentially dissolved from the fly ash particles in vivo.« less