Deposition rate of hafnium crystal bar by iodide process

Single variable and deposition weight methods were adopted in the experiment. The hafnium crystal bar was fabricated by the iodide process. Influence of hafnium filament temperature（K value）, temperature controlling method, types of feed, and the loading methods on the deposition rate were studied. The results show that the K value, temperature control method, types of feed, and the loading methods have obvious effects on the deposition rate of the hafnium crystal bar. The deposition rate increases with the K value rising in the range of certain temperature;the salt bath controlling temperature method could effectively obtain the better deposition rate; the greater the contact areas of the feeds are, the faster the deposition rate is.So, the optimal iodide deposition techniques of preparing hafnium crystal bar are as follows： hafnium turnings as feed,molybdenum feed retainer charging, salt bath temperature controlling under the higher K value.

Technological conditions for purification of hafnium by iodide process

In nuclear industry,the purity of hafnium control rod is usually significant,and the process parameters will affect the impurity contents.In this study,the four key factors(filament temperature,retort materials,feeds,and iodide reaction time)were investigated.It is found that the impurity contents of Fe,Ni in the hafnium crystal bar decrease with the K value rising.Both the retort materials and feed types have obvious influence on the impurity contents of hafnium crystal bar.The iodide reaction time has little effect on the impurity contents of hafnium crystal bar.