溶媒抽出法による原子炉級酸化トリウムの製錬
1961 年 77 巻 874 号 p. 265-270
詳細
1961 年 77 巻 874 号 p. 265-270
A semi-pilot plant by T. B. P.solvent extraction process was constructed to study several process variables in controllng impurity content and particle sizes of ThO2 for nuclear use.
The results obtained are as follows:
(1) Mnch care should be taken to adjust the concentration of thorium as well as the acidity in feed solution. High thorium and nitric acid concentration gave best results.
Scrubbing stage was also important. Use of high nitric, acid solution in a small ratio was necessary to obtain high purity ThO2.
(2) A typical analysis of the purified ThO2 was as follows: Gd, Sm, Eu, Dy, Nd, Pr, La and Ce, were less than 0.25 ppm respectively, B was less than 0.25 ppm, Fe, Cu, Mg and Mn were less than 2.5 ppm respectively.
(3) Particle sizes of the products could be controlled to give <1 micron to several microns by selecting the conditions to prepare the preceding thorium oxalate precipitates.
(4) The reactor grade ThO2 plant could run economically on its semi-pilot plant basis (several hundred kgs of ThO2 per month).
