Features of Loparite Dissolution in Aluminosilicate Melts (Experimental Investigation)

The solubility of loparite (Na,Ce,Ca)₂(Ti,Nb)₂O₆) in aluminosilicate melts of various compositions was experimentally studied at T = 1200 and 1000°C and P = 2 kbar under dry conditions and in the presence of 10 wt % H₂O in a high gas pressure vessel with a duration of 1 day. The starting material was previously melted artificial glasses of malignite, urtite and eutectic albite–nepheline compositions, as well as natural loparite from the Lovozero massif. The dependence of the loparite solubility on the composition of the aluminosilicate melt (Ca/(Na + K), (Na + K)/Al) has been revealed. Partition coefficients of a number of elements (Ti, Nb, Sr, REE) between silicate melt and loparite crystals (K_i = \({{C_{i}^{{{\text{melt}}}}} \mathord{\left/ {\vphantom {{C_{i}^{{{\text{melt}}}}} {C_{i}^{{{\text{lop}}}}}}} \right. \kern-0em} {C_{i}^{{{\text{lop}}}}}}\) ) were estimated.