Zr(IV) with or without addition of Y3+ was extracted with tri-n-butyl phosphate (TBP) in kerosene from solutions of perchloric acid and nitric acid with the formation of the third-phase microemulsion. The loaded organic phase was precipitated with a controlled amount of 25% ammonia in aqueous solution. After washing with water and vacuum freeze-drying, the precipitate was calcined to oxide at 600 degrees C. The as-prepared powders were characterized by thermogravimetric differential thermal analysis (TG-DTA),BET adsorption, X-ray diffractometry (XRD), and transmission electron microscopy (TEM). It was found that the specific surface areas of ZrO2 and Y-doped ZrO2 powders were 30-58 m(2)/g and 233 m(2)/g respectively. The relative content of tetragonal ZrO2 decreased with increasing pH of precipitation. The Y-doped ZrO2 was found to be amorphous with flocculent morphology and without body pores. The particulate ZrO2 was 10 nm in diameter on average. Powders prepared in this way were tested by energy dispersive analysis with X-rays (EDAX) and were found to contain no other contaminants.