Chemical composition of coal and fly ash

A method for the analysis of the inorganic constituents of coal has been developed. Thermal neutron activation analysis and Ge(Li)γ-spectrometry was used to determine 43 elements simultaneously. Oxygen and silicon were simultaneously determined after a single irradiation with 14 MeV neutrons, producing respectively the isotopes 16N and 28Al. Lead was determined by atomic absorption spectrometry. The accuracy of the methods was investigated by analysing NBS coal and fly ash reference materials. The methods described were used in the analysis of a large number of coal, coal ash and fly ash samples. The elements in coal were divided into a mineral and an organic fraction, based on the correlation between the concentrations in the coal and the ash content of coal. The fly ash emissions from combustion of coal were studied in a large and a small heating facility. Based on their mass size distributions, the elements could be divided into 3 groups: a first group associated with large particles and depleted in fly ash relative to the coal composition, a second group associated with small particles and enriched in fly ash, and a third group with intermediate behaviour. (author)