オキシン容量法によるフェロニオブ中のニオブ定量法

概要

論文の詳細を見る
Niobium was separated from tantalum by precipitating quantitatively with oxine from a solution of pH 4.5 containing ammonium tartrate. A sample was fused with potassium pyrosulfate, and niobium and tantalum were separated from the matrix elements as their hydroxides by hydrolysis method. The precipitate was dissolved into a potassium hydroxide solution with hydrogen peroxide. Ammonium tartrate was added after the decomposition of hydrogen peroxide by boiling, and the whole was diluted with water to a definite volume. An appropriate aliquot (corresponding to ca. 25 mg of Nb) was taken, EDTA and ammonium tartrate were added, and the pH was adjusted to 4.5. Niobium was precipitated by adding oxine. The precipitate was dissolved in hydrochloric acid, and niobium was determined by conventional bromate titration. The precipitate was assumed to have a composition NbO(C9H6ON)3, 1 ml of 0.1 N potassium bromate solution corresponding to 0.7742 mg of niboium. Common impurities, i. e., less than 7.5% of aluminum, manganese and tin, and less than 5% of titanium and tungsten did not interfere.
社団法人日本分析化学会の論文