J. Lei B. Zheng X. Tang M. Wang Jiawen Hu S. Li B. Wang R. B. Finkelman D. Wu 2011 Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg. application/pdf 10.1007/s11631-011-0506-6 en Nitrogen in Chinese coals article