Geochemistry of beryllium in coals: A review with emphasis on Chinese coals

Beryllium (Be), one of the lightest metals, is widely used at a high cost and considered as a critical element in many strategic fields. Beryllium is traditionally extracted from pegmatites and hydrothermal deposits. Although Be in coals is of both resources and environmental significance, it has been incidentally reported in most Chinese coals. A special synthesis of Be in Chinese coals, however, is unavailable. Based on the accessed data on Be concentrations in Chinese coals and authors’ case study, a compilation of its abundance, temporal and spatial distribution, modes of occurrence, enrichment factors, behavior and fate during coal utilization, and environmental and health effects of Be was conducted. The background Be concentration of Chinese coals was 1.58 mg/kg. There were no centralizing trends and an enrichment or mineralization belt of Be in Chinese coals. Beryllium commonly displayed a marginal enrichment effect in one coalbed. The relationships of Be concentration to coal rank and coal-forming period were not clear. Beryllium was generally associated with organic matter, to a lesser extent occurred in silicate/clay minerals and displayed a mixed organic and inorganic affinity. Sediment source rocks, volcanic ash fallout, and hydrothermal solutions were major contributors for the Be enrichment in Chinese coals. Beryllium was difficult to remove during coal preparation and was concentrated in the clean coals. Beryllium was partially volatilized and concentrated in relatively finer residues during coal combustion and presented a low volatility and was generally enriched in the residue after coal gasification and liquification as well. Although certain Chinese coals had elevated Be concentrations, both environmental and health risks of Be from coal were negligible