A Micro Mechanical and Chemical Analysis of a New Vitrified Rock Material for use in Environmental Sustainability

Extraction of the energy available via geothermal heat in the Earth could provide substantial contributions to U.S. energy needs long-term. However, there are major technical and economic limitations with the current technology available for Enhanced Geothermal Systems (EGS). I work on a new technology in the field of EGS that uses a millimeter (MM) wave gyrotron, which allows for more efficient ultra-deep drilling. The gyrotron heats rock to temperatures ranging from 1500 to 3000°C, transforming the rock into its liquid state. Upon cooling, the new material solidifies around the circumference of a well bore hole, creating a vitrified lining.<br/><br/>I have conducted an in-depth micro-mechanical and chemical analysis of the vitrified material from the melting and re-solidifying of basalt. Basalt is an igneous rock that forms from the solidification of molten lava and primarily consists of minerals such as plagioclase, feldspar, pyroxenes, and olivine. And thus, when heated, the elements within these minerals go through transformation processes; this includes the formation of iron oxides as well as the possible reduction of iron. To do my study I used a combination of experimental methods including Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), optical imagery, micro-and nano-indentation, and Raman spectrometry. These experiments allow me to quantify the micro- and nano-scale properties. The presence of mineral phase changes and elemental differences in the basalt pre- and post-melting are evident and thus understanding these differences can give insight into the future use of this material in the field of EGS, sustainable mineral extraction, and beyond.