The liquidus temperature of the ternary Fe-Co-Cu alloy was investigated using differential thermal analysis (DTA). The alloy composition was within the range of ferrocobalt produced from the smelting of copper waste slag to recover cobalt and copper. The general behaviour of the ternary alloy with respect to the liquidus temperatures is characterised by the ratio of iron to copper. It has been observed in this work that the liquidus temperature is more strongly dependent on the copper content than the cobalt content. The results obtained were found to compare well to those calculated using FACTSage™ if the SGTE database was used.