A high efficient hydrometallurgical process for Zr, Hf and Nb recovery from eudialyte is developed and optimized. The origin of this doctoral work is the EURARE project. Following the initial hydrometallurgical extraction of REE from the eudialyte concentrate from TANBREEZ, the residue was known to contain additional valuable metals. The designed hydrometallurgical process for their recovery can be summarized acid dry digestion—leaching—separation and concentration of metals from sulfuric acid leach solution—preparation of Zr product. The proposed pre-processing step was sulfuric acid dry digestion, which was held above the boiling point of water. The treated residue was then leached with water and H2O2 was added to promote the leaching of Zr, Hf and Nb. The subsequent stage focused on the recovery and separation of Zr, Hf and Nb from the resulting leach solution together with impurities. This stage consisted of precipitation of Nb—selective precipitation of basic zirconium sulfate, or precipitation of Nb— ion exchange for preparing Zr and Hf-bearing eluate. Finally, the preparation of Zr products could be connected to the conventional technology in the Zr production from zircon, which is the preparation of zirconium oxychloride (ZrOCl2•8H2O) by evaporative crystallization in the chloride solution. Zirconia (ZrO2) could be obtained calcining ZrOCl2•8H2O. In this work, two ZrO2 products were prepared. The contents of ZrO2+HfO2 were both high than 99% and ZrO2 prepared from the eluate contained less HfO2.weiterlesen