TG/DTA/MS study of the thermal decomposition of FeSO4•6H2O

The thermal decomposition of FeSO4 center dot 6H(2)O was studied by mass spectroscopy coupled with DTA/TG thermal analysis under inert atmosphere. On the ground of TG measurements, the mechanism of decomposition of FeSO4 center dot 6H(2)O is: i) three dehydration steps FeSO4 center dot 6H(2)O (70-100 degrees C) under right arrow FeSO4 center dot 4H(2)O+2H(2)O FeSO4 center dot H2O (95-190 degrees C) under right arrow FeSO4 center dot+H2O+3H(2)O FeSO4 center dot H2O (245-310 degrees C) under right arrow FeSO4+H2O ii) two decomposition steps 6FeSO(4) (525-650 degrees C) under right arrow Fe-2(SO4)(3)+2Fe(2)O(3)+2SO(2) Fe-2(SO4)(3) (625-710 degrees C) under right arrow Fe2O3+3SO(2)+3/2O(2) The intermediate compound was identified as Fe-2(SO4)(3) and the final product as the hematite Fe2O3.