A method has been developed and tested for isolating humic acids and fulvic acids from lignite. The yields are high: up to 68.0% for humic acids; and up to 9.6% for fulvic acids. The composition of the initial and residual lignite from the Kansk-Achinsk and South Ural Basins and the extracted humic and fulvic acids is investigated by technical analysis, elemental analysis, FTIR spectroscopy, and ¹³C NMR (CPMAS) spectroscopy. The humic acids and fulvic acids from lignite differ in chemical and structural composition. The fulvic acids are characterized by higher content of oxygen-bearing aliphatic groups, with a predominance of carbonic acids and complex esters, as confirmed by their highly hydrophilic behavior. The humic acids are characterized by higher content of carbon, hydrogen, and aromatic fragments. That must be taken into account in their practical use.

已开发并测试了一种从褐煤中分离腐殖酸和富里酸的方法。收率高：腐植酸高达 68.0%；富里酸含量高达 9.6%。通过技术分析、元素分析、FTIR 光谱和¹³C NMR（CPMAS）光谱。褐煤中的腐植酸和富里酸在化学和结构组成上有所不同。富里酸的特点是含氧脂肪族基团含量较高，主要是碳酸和复合酯，这由它们的高度亲水性行为所证实。腐植酸的特点是碳、氢和芳香族碎片含量较高。在实际使用中必须考虑到这一点。