The Study of Ultra-Clean Coal

Rajan, Thirukudanthai P. Soundara (1949) The Study of Ultra-Clean Coal. PhD thesis, University of Glasgow.

Abstract

The extraction of the mineral impurities in coal with acids is similar to the solution of solids in liquids. (1) The nature of the "solvent" - the maximum possible extraction (between 66 and 99 percent) of the mineral matter associated with the coal and cannel samples examined, could be effected by the use of 5 percent hydrofluoric and hydrochloric acids at their boiling point in an inert atmosphere. The use of stronger acids, though it would influence the period of treatment was unlikely to give a final product of lower ash content. If a mixture of the two acids was not used, it was advisable to start the initial extraction with dilute hydrofluoric acid; of the two acids, the latter was definitely the better 'solvent' for the mineral matter in bituminous coals and cannels. The efficiency of extraction was the same when using an acid to coal ratio (by weight) of either two or four. (2) The nature of the "solute" - The quality of the final product was not improved by grinding the initial sample to sizes finer that 72 mesh B.S.Sieve. The critical size was likely to be between 30 and 72 mesh B.S.Sieve. Better results could be obtained by the acid treatment of coals than of coke. Acid treatment under the suggested conditions effected a complete or near complete extraction of the water soluble portions and the silica of the mineral matter in coal. The efficiency of extraction of iron varied between 60 and 99 percent; of the different forms of iron present in the mineral matter, both the iron silicate and the dilute hydrochloric acid soluble iron were almost completely extracted; the overall efficiency of extraction of iron was determined mainly by the pyrite present. The mere addition of bromine water to the mixture of acids did not improve the percentage extraction of pyritic iron in the absence of an oxidising agent. There were reasons to believe that the extraction of alumina by the two acids was far from complete in some cases. The use of cold alkali had no influence while hot alkali attacked the coal substance as well as the alumina. (Abstract shortened by ProQuest.).

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Physical chemistry
• Date of Award: 1949
• Depositing User: Enlighten Team
• Unique ID: glathesis:1949-79771
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 03 Mar 2020 10:37
• Last Modified: 03 Mar 2020 10:37
• URI: https://theses.gla.ac.uk/id/eprint/79771