Stone-cast matrix based on an alloy of basalt and metal oxides. Part I. System basalt–M<sub>x</sub>O<sub>y</sub> (M = Sr, Ln)

This work examines stone-cast matrices (SCM) obtained by fusing basalt and Sr, Ln (Ce, Nd, Gd) oxides. It has been established that, as a result of the fusion of basalt with SrO, matrices are obtained containing glass and clinopyroxene as the main phases. Strontium partially replaces calcium in clinopyroxene, but mostly enriches the melt in contact with crystallizing clinopyroxene. When this melt cools, glass is formed containing up to 31 wt% SrO. As a result of the alloying of basalt with oxides of rare earth elements (REE) MxOy: CeO2, Nd2O3, Gd2O3, taken in a mass ratio of 4 : 1 and 2 : 1, SCM are formed, the main permanent phases of which are glass and clinopyroxene. In addition, magnesioferrite can crystallize from a basaltic melt upon cooling, and, depending on the mass ratio of basalt to MxOy, phases of cerianite CeO2 or britholite Ca(Nd,Gd)4(SiO4)3O can crystallize.