A treatment technique involving three sequential stages (demineralization,
activation and sulphur dispersion) was developed for the production of suitable
activated carbons from Greek lignite. Demineralisation included three steps of
acid treatment and samples received were characterized by X-ray diffraction (XRD).
A two stage activation procedure (pyrolysis under nitrogen, followed by
activation under carbon dioxine atmosphere) was used for the production of
activated samples. Sulphur impregnation of activated carbons was performed by
heating with high purity elemental sulphur flakes under nitrogen flow at
temperatures up to 600oC. SEM and line scattering techniques were
used to evaluate sulphur distribution in the impregnated activated carbons.
Adsorption of N2 at 77oK and CO2 at 298oK was used for the characterization of products. Sulphur impregnated activated carbon samples were proven unreactive and stable at the flue gases temperature.
Keywords : Lignite, Active carbon production, Toxic emissions