Distribution and content of bromine in Chinese coals

The bromine content of 305 coal samples from 27 provinces, municipalities and autonomous regions of China were tested, then the distribution of bromine with different geological ages, coal ranks, coal-cumulating areas was analyzed. The results show that the coals with moderate and low bromine content are predominant in China. The bromine content ranges from 0.12 to 69.66 μg/g, and it follows a logarithm normal distribution. Thus the geometric mean, 7.04 μg/g, is regarded as the average bromine content in Chinese coals. This is less than that in many countries and close to the average bromine content (7.10 μg/g) in Japanese coals. In Chinese coals, the average bromine content is less than 5 μg/g in 13 districts, 5–15 μg/g in 9 areas, and more than 15 μg/g in 5 regions. Based on coal rank, bromine content decreases gradually from bituminous coal, anthracite, lignite to subbituminous coal. As for coal-forming period, bromine content decreases from Early carboniferous through Late Permian, Late Carboniferous, Early Permian, Middle Jurassic, Late Triassic, Early Jurassic, Late Jurassic, Tertiary to Middle Carboniferous. According to coal-cumulating areas, bromine content decreases from northwestern China, northern China, southern China, Yunnan and Tibet to northeastern China. But all of them have no notable effect on the bromine content in Chinese coal.