Sensitive characterizations of rare earth ore in the Bayan Obo by terahertz time-domain spectroscopy

Abstract

Abstract The Bayan Obo deposit is the world's largest polymetallic associated minerals of rare earths, iron and niobium, and the rarity of its physical properties restrict the knowledge and understanding of its laws. Taking the high-grade mixed rare earth concentrate of Bayan Obo as the research object, THz-TDS, XRF, XRD, SEM and TG-DTA of characterization are adopted for the systematic investigation of high-grade rare earth concentrate. The absorption coefficient and refractive index of high-grade rare earth ores and their associated minerals of fluorite and dolomite, are all investigated by terahertz. time-domain spectroscopy. The terahertz spectral response is affected by the type of mineral and its content. Random forest as a machine learning algorithm is used to achieve quantitative detection of their concentrations and components, with a coefficient of determination R2 of the absorption coefficient of the optical parameter reaching 0.925. This work promotes to the growing understanding of terahertz transmission spectroscopy of rare earth-bearing minerals, which can be used to help guide the search for minerals, and to detect, identify as well as quantify them in geology. Terahertz time-domain spectroscopy supplies a new method for study of rare earth resources, and the comprehensive development and utilization of resources in the Bayan Obo deposit.