Phase diagram of Fe-Cu-Si ternary system above 1523 K

Fe-Cu-Si ternary alloy phases are commonly formed during melting in a treatment process of domestic waste incineration that is currently being developed. The alloy phases appear in the incineration residue. Experiments were performed to observe phase equilibria in solid Fe+liquid, solid Si+liquid, the compound of FeSi liquid, and so forth, in the range 1523 to 1723 K. Then the phase diagram of Fe-Cu-Si ternary was thermodynamically assessed based on the present experimental results and literature data. It was found that this system has a wide liquid miscibility gap, and this two-liquid region is stable up to about 1900 K. The phase diagram of Fe-Cu-Si system assessed in the present work is much different from an earlier proposed diagram, but is very close to one recently evaluated. From the results obtained, the appropriate condition is discussed for the operation of the melting furnace for ash from municipal solid waste incinerators.