The selective dielectric heating with microwave energy to convert a portion of pyrite particles to moderately magnetic pyrrhotic has been suggestedto enhance the magnetic separation of inorganic sulfur from coal. The results of Mossbaueranalysis show that a considerable amount of pyrrhotite produced during microwave irradiation

carrying with some of non- magnetic pyrite（unconverted）

ferrous sulfate

and troilite

is completely removed from coal after magnetic separation. The optimum desulfurization efficiency can be obtained by appropriately controlling the irradiation time to maximize the amount of pyrrhotite formed during pyrite decomposition.Excessive irradiation would be unfavorable for approving magnetic separation due to further decomposition of pyrrhotite to antiferromagnetic troilite.