2024-03-29T10:04:24Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1679002021-12-15T10:58:10Zcom_10261_35com_10261_5col_10261_288
Juan Mainar, Roberto
Ruiz Alares, M. Carmen
Andrés Gimeno, José Manuel
Estévez, Mercedes
2018-07-25T10:41:07Z
2018-07-25T10:41:07Z
1990-02
Fuel 69(2): 161-165 (1990)
0016-2361
http://hdl.handle.net/10261/167900
10.1016/0016-2361(90)90167-O
The alkaline oxidation of four Spanish coals by air was studied using a two-level factorial design with four variables: temperature, time, alkali concentration and coal-to-alkali ratio. The main aim was to increase the humic acid content of these coals. The best results were obtained at the highest temperature, longest time and lowest alkali concentration and coal-to-alkali ratio. Lower rank coals yielded the highest humic acid concentrations after oxidation, while the subbituminous coals were only slightly affected by treatment under the test conditions. A detailed study of the elemental composition of the coal and the generation of oxygen-containing functional groups is reported. The evolution of sulphur forms during the process is also described.
eng
openAccess
Lignite
Subbituminous coal
Oxidation
Production of humic acids from lignites and subbituminous coals by alkaline-air oxidation
artículo