Extraction of Humic Acid from Lignite by KOH-Hydrothermal Method
Humic acid (HA) was extracted by a hydrothermal method from Huolinhe lignite from Inner Mongolia.The effects of the alkali-to-carbon mass ratio, water-to-coal mass ratio, reaction temperature, and reaction time on the HA yield were investigated.The physicochemical characterization of the products was performed, and the reaction mechanism was explor