The Generation of Absorption Qualities of Lignite Absorbents under Conditions of Alkali Activation

Abstract

The article presents the research of absorbent qualities of carbon materials generated by an alkali activation of lignite from the Kharanorsk deposit. The mass ratio of potassium hydroxide/lignite RKOH=1 g/g under thermal impact and further thermolysis for 60 min at 800 °C allowed to create samples with almost 100% iodine absorbent activity (1000 mg/g). In order to improve economic and environmental performance of absorbent production with lignite activation by potassium hydroxide, the research explored qualitative characteristics of absorbents generated with RPH< 1 g/g: 0.25; 0.5 and 0.75 g/g. It has been established that if the ratio of KOH/lignite is lowered to 1.0-0.25 g/g, the absorbent activity for iodine reduces without any significant impact on the output of the product. The iodine adsorption activity for generated carbon materials at RPH< 1 g/g meets the requirements for this indicator of industrially produced activated carbons that are in demand in the market. To generate absorbents from Kharanorsk lignite with iodine adsorption activity not less than 40%, the recommended ratio of KOH/lignite RKOH=0.25 g/g and the duration of isothermal exposure is t=30 min; NTL 80 % - RKOH=0.5 g/g and t=30 min; NLT 90 % - RKOH=1,0 g/g and t=30-60 min.

Research of efficiency of lignite chemical modification and steam-gas activation combining for sorbents preparation*

“…In the laboratory of complex coal use of Mining Institute of the North (MIN SB RAS) the activation method of the Kharanorsk deposit lignite with potassium hydroxide was developed, the studies on influence of KOH/lignite ratio, temperature and thermolysis modes on adsorption activity of the obtained samples were carried out. The optimal parameters of chemical (alkaline) activation of the Kharanorsk lignite have been revealed: impregnation of lignite material with potassium hydroxide with the 1 g/g, ratio, thermolysis in the thermal shock mode at 800° С with subsequent 60 min isothermal time without air access [18,19].…”