Zirconium hafnium separation by means of fluorine enriched oxygen plasma
Introduction
The separation of zirconium and hafnium is an important process to produce nuclear grade materials. The applications of both these elements range from nuclear fuel processing, aerospace, and for alloys forming for industrial applications. Zirconium and hafnium are two neighbouring elements on the periodic table and have similar physical and chemical properties. Their relative abundances are 0.5-0.8% and 0.0-0.1%, respectively, making their direct separation difficult.
In conventional technology, the separation of zirconium and hafnium is achieved by solvent extraction or by ion-exchange. Both these methods yield intermediate products that are difficult to manage and involving of a number of steps. The use of fluorine enriched oxygen plasma has been proposed as an alternative method to separate zirconium and hafnium. Fluorine enriched oxygen plasma is a method that selectively dissolves and reacts with hafnium compound and leaves zirconium compounds behind as a solid. This project aimed to study the efficacy of fluorine enriched oxygen plasma for the separation of zirconium from hafnium from nuclear grade material.
Materials & Method
Materials
The materials used for this study comprised of 500g of nuclear grade zirconium and hafnium containing compounds that were prepared by fusion of oxide compounds. The oxide compounds were a mixture of zirconia (ZrO2) and hafnia (HfO2) that were obtained from standard suppliers. The oxide compounds were pre-treated with nitric acid before being fused and the nuclear grade compounds were extracted and purified using conventional methods.
Methods
The experimental setup consisted of a fluorine enriched oxygen plasma reactor. The reactor was modified to allow a higher concentration of fluorine (20% by volume) to be used. The reactor was operated at a pressure of 0.1 Torr and heated to a temperature of 1700 K. The reactor was then filled with the nuclear grade compounds suspended in a fluorine enriched oxygen plasma.
It was found that when the reactor was operated at 1700K and at a pressure of 0.1 Torr, fluorine enriched oxygen plasma selectively dissolves hafnium compounds and leaves zirconium compounds behind as a solid. After separation, the remnants of the plasma was treated with phosphate buffer and neutralized. The resulting solution was then collected and the separation of zirconium and hafnium was determined by ICP-OES.
Results
The results from the experiment showed that the separation of zirconium and hafnium by means of fluorine enriched oxygen plasma was successful. It was observed that the hafnium concentrations were reduced by 67% and the zirconium concentrations were increased by 40%. These results indicate that fluorine enriched oxygen plasma is a viable method for the separation of zirconium and hafnium from nuclear grade material.
Discussion
The results of this experiment indicate that fluorine enriched oxygen plasma is an efficient method for the separation of zirconium and hafnium. The separation yield was significantly higher than that of the conventional methods. This demonstrates the potential of the technique for the separation of these two elements from nuclear grade material.
This study also provides an insight into how fluorine enriched oxygen plasma can be used in the preparation of materials for other applications. Fluorine enriched oxygen plasma has several advantages over traditional methods. It is a relatively low cost process and is also environmentally friendly. The process also offers the possibility of scaling up or down depending on the desired size and concentration of materials.
Conclusion
Fluorine enriched oxygen plasma is an effective method for the separation of zirconium and hafnium from nuclear grade material. The results obtained from this experiment demonstrate the potential of the technique for efficient separation of these two elements. Fluorine enriched oxygen plasma offers several advantages over conventional methods and is a viable option for the large scale production of nuclear grade materials. This study has highlighted the need for further research and development in the area of fluorine enriched oxygen plasma for the production of nuclear grade materials.
