Terbium belongs to the lanthanide or “rare earth elements (REE)” group of elements in the periodic table. However, rare earth elements are dispersed and they are not generally found concentrated as rare earth minerals (REM) in economically exploitable ore deposits. Terbium only occurs in trace quantities even in its ores. It is found in some minerals such as bastnaesite, monazite, xenotime, euxenite and gadolinite ores, but in low concentrations, on the order of 1%.
Terbium and its compounds are used as phosphors. Terbium phosphors give off a green light when struck by electrons. Phosphorescent terbium compounds are used in cathode ray tubes, light-emitting diodes, lasers, sensors, etc. Thus, terbium extraction processes need to be further studied and improved to include more economical and profitable methods.
Choe Kyong Mun, a researcher at the General Assay Office, has investigated the electrochemical behaviors of terbium in TbCl3-1-ethyl-3-methyl-imidazolium tetrafluoroborate [EMIm]BF4 electrolytes and TbCl3-1-ethyl-3-methyl-imidazolium dicyanamide [EMIm]DCA.
X-ray diffraction analysis results of electrodeposits from TbCl3-[EMIm]BF4 electrolytes and TbCl3-[EMIm]DCA electrolyte prove that metallic terbium is obtained.
For more information, please refer to his paper “Electrochemical behaviors of terbium from TbCl3-EMImBF4 and TbCl3-EMImDCA ionic liquid electrolytes: a comparative study” in “Journal of Solid State Electrochemistry” (SCI).