应用化学 ›› 1984, Vol. 0 ›› Issue (1): 13-20.

• 研究论文 • 上一篇    下一篇

以二苯基羟乙酸测定钪的重量法

梁树权, 王志   

  1. 中国科学院化学研究所
  • 收稿日期:1983-09-30 修回日期:1983-10-25 出版日期:1984-03-10 发布日期:1984-03-10

GRAVMETRIC DETERMINATION OF SCANDIUM WITH BENZILIC ACID

Liang Shuquan(Shu-Chuan Liang), Wang Zhi   

  1. Institute of Chemitsry, Academia Sinica, Beijing
  • Received:1983-09-30 Revised:1983-10-25 Published:1984-03-10 Online:1984-03-10

摘要: 本文提出用二苯基羟乙酸晶体作沉淀剂,以代替文献中所用的钠盐或氨性溶液。将溶液酸度自pH 1调至2.0—2.5便可获得颗粒状钪沉淀。从钪沉淀的热分解曲线找出其组成为Sc[(C6H5)2C(OH)COO]3及一水合物。除可干燥称衡外,亦可在650℃灼烧为氧化物。沉淀的最佳溶液酸度、试剂用量、电镜显微照片和共存离子的影响均曾涉及。最后殿以应用实例与本法的精确度。

Abstract: This paper reports the use of benzilic acid [(C8H5)2 C(OH) COOH]crystals as the precipitant for scandium, instead of its sodium salt or am-monium solution. By adding the crystals to acidic solution of scandium andthen adjusting the acidity to pH 2.0-2.5, pure scandium benzilate can beobtained. This mode of precipitation prevents the formation of scandiumbasic salt and/or hydroxide. From the thermogravigram of the precipitateso obtained, it has been shown that precipitates dried at 160° and 140℃ cor-respond to Sc[(C6H5)2C(OH)COO]3 and its monohydrate respectively. From592℃ upward, the precipitate becomes scandium oxide. To ensure completeconversion, 650℃ should be used for ignition. Quantitative precipitation ofscandium benzilate can be achieved from solutions of pH 2.0-5.0.Beyond pH5, the precipitate hydrolyzes to basic salt. The amount of benzilicacid needed for quantitative precipitation is 1.5 to 5 fold of the theoretical value. The interference of iron(Ⅲ) can be avoided by (a) reducing to ferrousstate with ascorbic acid, or(b) masking with citric acid--triethanolaminemixture. The latter masks aluminum (Ⅲ) too. Hydrogen peroxide maskingeliminates the interference of titanium(Ⅳ). Yttrium(Ⅲ), larithanum (Ⅲ)and cerium (Ⅲ) benzilates begin to precipitate at pH 1.3, 3.1 and 2.6,respectively. Therefore it is impossible to determine scandium in theirpresence, unless separation is carried out beforehand.