The characteristic of the type of liquation refining process of molten metals depending on the impurity elements is given. The efficiency of extraction-crystallization- liquation refining (EKL process) of magnesium molten metals depending on the metallic impurity using additive elements (Ti, Zr, Mn) is showed. Values ​​of the interaction parameters in these ternary systems (Mg-Ti-X, Mg-Zr-X, Mg-Mn-X) were fitted. The effect of addition of titanium, zirconium, and manganese feedings on the iron activity is showed.