论文部分内容阅读
Nb(Ⅴ)—5-Br-PADAP光度法测定微量铌,是目前最灵敏的方法之一。为了适应稀土氧化物中铌的测定,根据文献进行了改进。在pH1.5～4的条件下,选用Al-CyDTA或Ca—CyDTA作掩蔽剂,有效地对铁、钛、铝、锰、镍、锌和稀土等离子进行掩蔽;以邻菲啰啉掩蔽少量钴的干扰(2毫升5％邻菲啰啉可掩蔽110微克钴)。 当测定稀土氧化物、稀土矿和铝基合金中微量铌时,共选择性、灵敏度、稳定性和重现性等方面,均获得较满意的结果。本法适用于0.005～0.5％Nb_2O_5试样的测定。 一、试剂与仪器 铌标准溶液:准确称取Nb_2O_5(99.9％)0.0716克于瓷坩埚中,用0.3—1.0克焦硫酸钾加盖熔融(700℃)。冷却后用45毫升15％酒石酸浸取,移入500毫升容量瓶中,用6％酒
The determination of trace niobium by Nb (Ⅴ) -5-Br-PADAP spectrophotometry is one of the most sensitive methods. In order to meet the determination of niobium in rare earth oxides, improvements have been made according to the literature. At pH1.5 ~ 4, Al-CyDTA or Ca-CyDTA was chosen as the masking agent to effectively mask the iron, titanium, aluminum, manganese, nickel, zinc and rare earth ions; (2 ml of 5% o-phenanthroline masks 110 μg of cobalt). When measuring trace amounts of niobium in rare earth oxides, rare earth minerals and aluminum-based alloys, the results are more satisfactory in terms of selectivity, sensitivity, stability and reproducibility. This method is suitable for the determination of 0.005 ~ 0.5% Nb 2 O 5 sample. First, the reagents and equipment Standard solution of niobium: Accurately weighed Nb_2O_5 (99.9%) 0.0716 grams in a porcelain crucible, with 0.3-1.0 grams of potassium pyrophosphate capped melting (700 ℃). After cooling it was leached with 45 ml of 15% tartaric acid and transferred to a 500 ml volumetric flask with 6% alcohol