Present in the metallurgical industry one of the most frequently problem is the presence of Fe and his compound in secondary aluminum melting. This problem appears when using chip inadequate technologies. This work makes a survey on the problems which can appear because of the presence of Fe and his compound in aluminum. Two systems, Al-Si and Al-Si-Li, are analyzed, by taking into consideration metallographies, as well as the systems mechanical properties. The end presents metallographic evidence of the problems which Fe and his compound can cause in secondary aluminum meltings.