BACKGROUNDWith the increasing demand for scandium resources, countries around the world have carried out scandium metallogenic mechanism research and prospecting in recent years. One of the key research contents is to clarify the occurrence characteristics of scandium. According to previous studies, scandium mainly exists in the form of isomorphism and ion adsorption in various scandium deposits. At present, more than 800 kinds of scandium-bearing minerals have been found. The scandium resource of the Bayan Obo deposit is large, which has the characteristics of dispersed distribution and low content. Scandium enters other minerals in the form of isomorphism and no independent scandium mineral is found. Due to the limitation of testing technology and sampling, there is no accurate quantitative research to systematically explore the occurrence characteristics of scandium in different minerals in the Bayan Obo deposit. Therefore, the identification of the main scandium-bearing minerals is insufficient, which is not conducive to further exploration of the enrichment mechanism of scandium and the utilization of scandium resources in the deposit.
OBJECTIVESTo understand the occurrence of Sc in different minerals of the Bayan Obo deposit.
METHODS34 kinds of minerals in the Bayan Obo deposit were systematically determined by electron probe microanalyzer (EPMA) technology.
RESULTSThe test results showed that the average scandium content (Sc2O3) in 6 minerals was more than 0.100%. They were samarskite (with average Sc2O3 content of 2.485%), columbite (1.263%), manganocolumbite (0.251%), dark purple fluorite (0.181%), thorianite (0.145%) and Y-rich aeschynite (0.124%) from high to low. Samarskite had the highest scandium content (3.093%). The content of scandium in 16 minerals ranged from 0.004% to 0.067%, which were fergusonite (with average Sc2O3 content of 0.067%), alkaline amphibole (0.062%), ferrothorite (0.060%), pyrochlore (0.049%), fersmite (0.031%), bastnaesite (0.028%), apatite (0.028%), britholite (0.025%), monazite (0.023%), aegirine (0.02%), biotite (0.019%), humite (0.011%), fergusonite-(Ce) (0.008%), feldspar (0.007%), magnetite (0.005%), albite (0.004%). Scandium was not detected in the other 12 minerals.
CONCLUSIONSSamarskite has the highest scandium content in the deposit, and the 6 main scandium-bearing minerals are samarskite, columbite, manganocolumbite, dark purple fluorite, thorianite and Y-rich aeschynite. Among the 34 minerals, the content of scandium in 22 minerals is higher than the detection limit of EPMA, and scandium is distributed in a dilute manner. The occurrence of scandium is related to titanium, yttrium and thorium, and the correlation coefficients are 0.869, 0.835 and 0.720, respectively. Scandium is closely related to niobium minerals such as columbite, manganocolumbite, fersmite and Y-rich aeschynite. It can be considered to comprehensively utilize scandium and niobium resources at the same time.