The Series Iron Oxides‐lime*

A bstract The literature in general shows a considerable divergence of opinion regarding the basicity of the ferrite formed in steelmaking slags. Evidence is presented which indicates that when mixtures of iron oxide and lime are melted under oxidizing conditions in contact with metallic iron a ternary system between CaO‐FeO‐Fe 2 O 3 prevails and that the compound formed between lime and ferric oxide has the composition 3CaO‐Fe 2 O3, except possibly for melts containing somewhat less than 10 mol.% CaO. A eutectic was found between FeO and 3CaO Fe 2 O 3 , which contains approximately 40 mol.% CaO. It is believed that when basic steelmaking slags are considered, the ternary system CaO‐FeO‐Fe 2 O 3 should be substituted for the binary system CaO‐Fe2O 3 , which has been used generally in the past.