结晶法和萃取法制备高纯氧化铌的研究

Study on Preparation of High-purity Niobium Oxide by Crystallization and Extraction

采用氟铌酸为原料,制备氟氧铌酸钾,过滤,洗涤,将氟氧铌酸钾溶解在氢氟酸的热溶液中,加入硫酸调整至酸度10 mol/L,溶液与MIBK进行逆流萃取,采用0.8 mol/L的硫酸进行反萃取,得到了氟铌酸溶液,沉淀过滤洗涤烘干焙烧后。采用结晶法,溶液中的砷锑钨等杂质,由于含量较低,大部分在结晶过程中留在溶液中,与铌进行了分离。在采用萃取法,将氟铌酸进行萃取和反萃取,进一步去除氧化铌中的钽等杂质,制备出的氧化铌纯度达到了99.998%,满足了铌酸锂晶体和光学玻璃的使用需求。

Potassium oxyfluoniobate was prepared by using niobic acid as raw material.After filtration and washing,potassium oxyfluoniobate was dissolved in the hot solution of hydrofluoric acid.Sulfuric acid was added to adjust the acidity to 10 mol/L.The solution and MIBK were countercurrent extracted.0.8 mol/L sulfuric acid was used for countercurrent extraction to obtain niobic acid solution.After precipitation,filtration,washing,drying and roasting,most of the As,Sb,W and other impurities in the solution remained in the solution during the crystallization process due to their low content,and were separated from niobium by crystallization.The purity of niobate was 99.998%,which met the demand of LiNbO3 crystal and optical glass.