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Chemical modelling of pore water composition from PFBC residues

Abstract

The concentration of trace elements varies depending on the source of the coal and also due to the combustion process used. Mercury is one important element among the trace elements in the coal residues, generally recognised as potentially harmful to the biological system. To predict the pore water concentrations of mercury and other important constituents leached from coal combustion residues disposal sites, mechanistic data on chemical reactions are required. The present study is an application of a basially thermodynamical approach using the geochemical code EQ3NR. The presence of discrete solid phases that control the aqueous concentrations of major elements such as aluminium, calcium and silicon are identified. Solid phases are modelled in equilibrium with a hypothetical pore water at a pH range of 7-11. In this study the thermodynamic database of EQ3NR has been complemented with data for cadmium, mercury and lead taken from the OECD/NEA Thermodynamic Database and from a compilation made by Lindsay. Possible solubility limiting phases for the important trace elements arsenic, cadmium, chromium, copper, mercury, nickel and lead have been identified. Concentrations of these trace elements as a function of pH in the hypothetical pore water were calculated using mechanistic thermodynamial data. The thermodynamical approach in  More>>
Authors:
Karlsson, L G [1] 
  1. Kemakta Consultants CO, Stockholm (Sweden)
Publication Date:
Feb 26, 1991
Product Type:
Technical Report
Report Number:
VF-UM-92-4
Reference Number:
SCA: 010900; 200200; PA: SWD-93:007099; SN: 93000968093
Resource Relation:
Other Information: PBD: 26 Feb 1991
Subject:
01 COAL, LIGNITE, AND PEAT; 20 FOSSIL-FUELED POWER PLANTS; FLUIDIZED BED BOILERS; ASHES; SOLUBILITY; PRESSURIZATION; CADMIUM; ARSENIC; MERCURY; ALUMINIUM; CHROMIUM; COPPER; PH VALUE; LEAD; NICKEL; LEACHING; 010900; 200200; ENVIRONMENTAL ASPECTS; WASTE MANAGEMENT
OSTI ID:
10141273
Research Organizations:
Vattenfall AB, Vaellingby (Sweden)
Country of Origin:
Sweden
Language:
English
Other Identifying Numbers:
Other: ON: DE93778462; TRN: SE9307099
Availability:
OSTI; NTIS; INIS
Submitting Site:
SWD
Size:
50 p.
Announcement Date:
Jul 05, 2005

Citation Formats

Karlsson, L G. Chemical modelling of pore water composition from PFBC residues. Sweden: N. p., 1991. Web.
Karlsson, L G. Chemical modelling of pore water composition from PFBC residues. Sweden.
Karlsson, L G. 1991. "Chemical modelling of pore water composition from PFBC residues." Sweden.
@misc{etde_10141273,
title = {Chemical modelling of pore water composition from PFBC residues}
author = {Karlsson, L G}
abstractNote = {The concentration of trace elements varies depending on the source of the coal and also due to the combustion process used. Mercury is one important element among the trace elements in the coal residues, generally recognised as potentially harmful to the biological system. To predict the pore water concentrations of mercury and other important constituents leached from coal combustion residues disposal sites, mechanistic data on chemical reactions are required. The present study is an application of a basially thermodynamical approach using the geochemical code EQ3NR. The presence of discrete solid phases that control the aqueous concentrations of major elements such as aluminium, calcium and silicon are identified. Solid phases are modelled in equilibrium with a hypothetical pore water at a pH range of 7-11. In this study the thermodynamic database of EQ3NR has been complemented with data for cadmium, mercury and lead taken from the OECD/NEA Thermodynamic Database and from a compilation made by Lindsay. Possible solubility limiting phases for the important trace elements arsenic, cadmium, chromium, copper, mercury, nickel and lead have been identified. Concentrations of these trace elements as a function of pH in the hypothetical pore water were calculated using mechanistic thermodynamial data. The thermodynamical approach in this study seems justified because most solid residues that are either present or expected to form during weathering have relatively fast precipitation/dissolution kinetics. (21 refs., 18 figs., 5 tabs.).}
place = {Sweden}
year = {1991}
month = {Feb}
}