In this work, high temperature in situ X-ray diffraction and in situ analysis of energy dispersive spectrometer were used to find the essence of the roasting of vanadium- bearing stone coal. In the process of roasting, vanadium-bearing muscovite with quartz was converted to feldspar group minerals (albite, orthoclase and anorthite), during which Al(V) AO bonds in muscovite were broken. Meanwhile, vanadium was liberated from muscovite, which was the precondition that vanadium can be recovered. These findings were useful for proposing some measures, such as adding quartz, to recover the vanadium from stone coal more efficiently in practice. (C) 2016 The Society of Powder Technology Japan. Published by Elsevier B. V. and The Society of Powder Technology Japan. All rights reserved.