Production of Bitumens and Humic Matter from Lignite in China: A Theoretical and Practical Review

Abstract

This review of the literature on research into bitumens (waxes and resins) and humic matter in China shows that China has sufficient reserves of lignite suitable for the production of bitumens and humic matter. Most research is devoted to the composition and properties of the waxy component of bitumens (bitumen wax) and the most representative fractions of humic matter (humic and fulvic acids). The resinous component of bitumens (bitumen resin) and the derivatives of humic acids (humous and hymatomelanic acids) have not been studied enough to permit their effective and safe practical application. Data on the composition and properties of Chinese lignite indicate promising applications in cosmetology, medicine, the food industry, and the chemical industry. Convincing evidence shows that humic and fulvic acids are very effective as plant growth stimulators and as reagents for soil reclamation and water treatment, with applications also in animal husbandry. Promising and widely used technologies are noted. Enterprises in the Chinese market are characterized, along with their notable bitumen and humic products. The review indicates that two-step extraction of bitumens and humic matter, with subsequent separation into narrower fractions, makes more complete use of the chemical potential of lignite and is more economical.