GENERATION expensive metal hafnium and zirconium can be increased
In the State Unitary Enterprise All-Russian Scientific Research Institute of Chemical Technology has been debugged new technology of rare earth metals - hafnium and zirconium, which can greatly simplify the production process and increase the volume of production of pure alloys in ingots.
Advantages of hafnium v special properties of silver-white metal v its melting point is 2230 | C, and the density is 13.35 g/cm3. Zirconium has almost the same properties of hardness and high melting point, and although his performance and lower (mp - 1855 |, the density v 6,51 g/cm3), its alloys almost equal in terms of hafnium alloys.
Therefore, these rare earth metals, particularly precious and expensive, as are the materials, control rods and the protection of nuclear reactors, electrodes and torches. Components of heat-resistant and refractory alloys based on them are indispensable for the aviation and missile technology.
However, hafnium and zirconium in pure form not found in nature and are prepared by metallurgists comprising kaltsietermicheskoe tetrafluoride recovery of these elements in the presence of additives and the subsequent removal of iodide refining additives and electron beam remelting.
This technology is not perfect, as applicable to a limited number of alloys and requires two refining operations - iodide refining and refining.
Technology that can produce any alloys also have significant drawbacks, which provide low purity of the materials obtained, which requires further purification - iodide refining - a process accompanied by an increased consumption of materials - calcium and iodine. This production is carried out under high pressure, which develops during the melting process due to partial evaporation of iodine, which leads to the necessity of carrying out the process in a bomb.
This not only complicates the production, but also leads to a rise in the cost of works.
In the All-Russian Research Institute of Chemical Technology research group - Kotsar ML, Vladimir Shatalov, V. Nikonov and GS Cheremnyh was debugged the new technology of production of the rare earth elements, which simplifies the process and at the same time increases the volume of net production of hafnium or zirconium and their alloys in ingots.
With the new technology could receive them hafnium and zirconium alloys containing 99/1 wt.% Hafnium and a 1/99 wt.% Zirconium.
Used as additives in aluminum, allows you to start the process of deoxidation in the stages of refining and smelting reduction remelting. This measure makes it possible to use as raw unsublimated tetrafluoride, hafnium or zirconium with oxygen content of 0.2-0.5 wt.% Relative to the metal which after recovery and refining zirconium or hafnium is reduced to 0.01-0.1 wt.% .
Ultimate vacuum heat treatment to reduce the nitrogen content in the resulting metal content decreases as the air adsorbed on the surface tetrafluoride approximately 4 times and then is filled with an inert gas such as argon.
This technology can greatly simplify the process of production of the rare earth elements by eliminating iodide refining operations, increase direct hafnium or zirconium and their alloys in ingot.
Contact information:
115230, Moscow, Kashirskoe., 33, VNIIKhT
