THE NEWEST ANALYTICAL TECHNOLOGIES FOR DETERMINING RARE-EARTH ELEMENTS IN GRANITOIDS OF THE UKRAINIAN SHIELD

Abstract

Introduction. To date, rare earth elements (REE) are used to manufacture most high-tech goods and are crucial in defense technologies (lasers, radars, and electromagnetic weapons), nuclear engineering, metallurgy, and others. All this determines the relevance of their study to assess the rare earth mineral resource base of Ukraine. Problem Statement. The determination of REE in rocks and minerals is a fundamental problem in geochemistry and petrology for understanding the processes of rock formation. However, it is a complex analytical task related to the similar chemical properties of these elements, which are caused by the "lanthanide compression effect". Purpose. The purpose is to develop analytical technologies for determining REE content by the ICP-MS method, to evaluate their content and distribution in granitoids of the Ukrainian Shield. Materials and Methods. The hybrid method of ICP-MS analysis and microwave decomposition of rocks and minerals has been used to measure the REE content. This technique has been tested and used to estimate the content and distribution of REE in fluorites and rare-metal granitoids of the Rusko-Polyanskyi massif of the Korsun-Novomirgorod pluton of the Ukrainian Shield. Results. Analytical technologies for determination of REE in granites and minerals have been developed. The method for determining REE in fluorites and granites without their prior concentration in the range from 0.01 to 1000 ppm with a relative standard deviation of 0.01–0.10 has been described. The content of rare earth elements in the Rusko-Polianskyi granites increases (218–797 g/t), the main concentrator of these elements is fluorite (692–26933 g/t REE). An inverse relationship has been observed between the REE content in fluorites and granites. Conclusions. The developed analytical technologies are the basis for establishing quality assessment criteria and developing principles for the rational use of rare-earth granitoids to create a rare-earth mineral resource base in Ukraine.