Ultrasonically enhanced coal desulphurization
1993; Elsevier BV; Volume: 33; Issue: 2 Linguagem: Inglês
10.1016/0378-3820(93)90048-9
ISSN1873-7188
Autores Tópico(s)Metallurgical Processes and Thermodynamics
ResumoUltrasound promoted desulphurization of low rank coals using dilute solutions (0.025–0.5 M) of sodium hydroxide has been investigated at 30 and 70°C. High extraction values were obtained for samples sonicated at a lower temperature, and a reduction of 34 wt% in total sulphur was achieved in one high sulphur lignitic coal employing a 0.025 M NaOH solution at 30°C compared with 2.5 wt% at 70°C. By treatment with a 0.2 M NaOH solution at 70°C 12–19 wt% of the total sulphur was removed in other coals. The increase in the ash content varied between 2 and 18 wt% for different coals and an increase in ash up to 14 wt% was observed in one lignitic coal with an increase in alkali concentration from 0.025 to 0.2 M. Particle size variation from 60 to 120 mesh did not influence the formation of ash in lignitic coals whereas a 17 wt% reduction in the removal of sulphur was obtained on 60 mesh coal compared with 5 wt% on 120 mesh samples of the same coal.
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