The differences in XRD patterns, elemental compositions, FT-IR spectra and TG-DSC curves of extract residues obtained by NaOH, and NaOH assisted with anthraquinone (AQ) extraction procedures were studied. The extract residues are mainly comprised of humin fractions associated with inorganic minerals. XRD analysis shows that there is no typical peak of organic carbon because those organic humin fractions appear as a highly disordered substance. The peak of quartz is dominant. The elementary analysis shows that assistant AQ in NaOH solution can break the link of organic humic substances with inorganic minerals. And aromatization degree of humin fractions obtained by NaOH is smaller than that obtained by NaOH assisted with AQ. FT-IR analysis displays that various groups exist in those two humin fractions obtained by different extraction procedures. There are some differences in FT-IR curves between two humin fractions. TG-DSC analysis shows that thermal decomposition occurs during the heating of testing samples. By contrast, the humin fractions associated with inorganic minerals obtained by NaOH possess a higher thermal decomposition range. The differences in XRD patterns, elemental compositions, FT-IR spectra and TG-DSC curves of extract residues obtained by NaOH, and NaOH assisted with anthraquinone (AQ) extraction procedures were studied. The extract residues are mainly comprised of humin fractions associated with inorganic XRD analysis shows that there is no typical peak of organic carbon for those organic humin fractions appear as a highly disordered substance. The peak of quartz is dominant. The elementary analysis shows that assistant AQ in NaOH solution can break the link of organic humic And aromatization degree of humin fractions obtained by NaOH is smaller than that obtained by NaOH assisted with AQ. FT-IR analysis displays that various groups exist in both two humin fractions obtained by different extraction procedures. There are some differences in FT-IR curves between two humin fractions. TG-DSC analysis shows that thermal decomposition occurs during the hea ting of testing samples. By contrast, the humin fractions associated with inorganic minerals obtained by NaOH possess a higher thermal decomposition range.