The reaction thermodynamics for these three reactions was estimated via the HSC software and the results of standard reaction Gibbs energy are introduced in Table 2.
The fact that the formation of strontian via the reaction of single oxides and binary oxide intermediates according to Eqs. ((8), (9) and (10) is not preferred from the thermodynamic point of view provides the explanation for experimentally observed mechanism using the non-equilibrium melt. The three independent reactions are the formation of strontian, the formation of gehlenite and the transformation of gehlenite into strontian. This conclusion is in agreement with experimental results in Fig. 6(a).