ABSTRACT
Ultimate analysis refers to the determination of those elements which are the main constituents of coal. These are carbon, hydrogen, nitrogen, sulphur, and oxygen. The first four elements are determined directly, but as there is no satisfactory method for the direct determination of oxygen in coal, the amount of oxygen is found by difference, subtracting the total percentage of the other four elements, expressed on a dry, mineral matter free basis, from 100. By contrast with proximate analysis, the determinations of carbon, hydrogen, nitrogen, and sulphur, are all of an absolute and finite nature. Analytical accuracy only is to be attained to ensure the reproducibility of results.
