Extraction of humic acids from Kansko-Achinsk lignite

A method has been developed for practically complete alkaline extraction of humic acids from Kansko-Achinsk lignite. The maximum yield of humic acids may be ensured by correct selection of the extractant and the extraction temperature and time. The content of functional groups in the humic acids is determined, and their NMR spectra are analyzed. Their ability to bind heavy metals is assessed. Their stimulation of plant growth is studied, and the biological activity of the humic acids is assessed.