I am in the field of chemical manufacturing in india at nagpur and have a unit named as cawnpore chemical works the said unit has a great history beyond its name the main product of the unit was sodium dichromate the said unit never use lime at its process and sucseefully create the said product ince 1928 to 1996 than after the said unit has been closed to its internal reasons after its closure when i made further search than i found that the outcome of the unit which shall be fe203 as per the formula but i found magnatite properties in the said outcome when i got tested the said outcome with IBM than they confirm the said now I have again installed a new unit but not getting the same results I think that it is possible only at highly free stage of air thus the design of reverbatory furnace is very necesary in this unit thus some body tell me the basic of reverbatory furnace in view of aforesaid discussion