Zone Refining of Zirconium in an Electric Field

Kozhevnikov, O.E.; Pylypenko, M.M.; Stadnik, Yu.S.; Azhazha, R.V.

doi:10.46813/2020-125-027

Cited by 2 publications

(2 citation statements)

References 2 publications

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“…Îleh Å. Êîzhevnikov, Mykola M. Pylypenko et al Small amounts of these impurities lower the melting point of zirconium, and for them k 0i < 1 [11]. For effective refining of zirconium from metal impurities with k ei < 1, two or three passes of the zone melting with a low speed v = 2 mm/min are sufficient (Table 1).…”

Section: Eejp 1 (2021)mentioning

confidence: 99%

“…This significantly increased the efficiency of refining by the ZMEF method. In work [14], the parameters of the ZMEF process were calculated for interstitial impurities: the values of the impurity ion mobility U, the diffusion coefficient D, the movement velocity of the impurity ion v', the effective impurity distribution coefficient ke'. In carrying out the calculations, the values of the melting parameters were used: the electric field strength E = 0.013 V/cm, the melting speed v = 0.066 cm/s (Table 2).…”

Section: Eejp 1 (2021)mentioning

confidence: 99%

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Zone Recrystallization of Zirconium and Hafnium

Kozhevnikov

Pylypenko

Kozhevnikova

2021

EEJP

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The work studied the possibility of obtaining of the high-purity samples of zirconium and hafnium by the method of zone recrystallization of round rods with electron-beam heating in a vacuum of 1∙10-4 Pa. Some meltings were carried out in a constant electric field with the variability of its connection. It is shown that the simultaneous passage of several refining processes (evaporation of highly volatile metallic impurities, zone recrystallization with directional displacement of impurities to the end of the sample, electrotransport) made it possible to efficient refining of zirconium both from metallic impurities and from interstitial impurities. The best degree of purification was achieved when zone melting carrying out in an electric field directed opposite to the zone movement. In this case, the displacement of interstitial impurity ions coincided with the direction of movement of the liquid zone. Samples of zirconium with a purity of 99.89 wt. % were obtained (the concentration of aluminum was reduced by 5, iron - 11, copper - 45, chromium - 75, silicon - 10, titanium - 2.5, oxygen - 3.3, nitrogen - 3, carbon - 2 times). The hafnium samples refined by the zone recrystallization method were characterized by a purity of 99.85 wt. %. The concentrations of both all metal impurities and interstitial impurities were significantly reduced (concentration in wt% oxygen was 0.011, carbon - 0.0018, nitrogen - 5∙10-5). A study of gas evolution from samples of iodide hafnium and refined hafnium was carried out. It was found that the maximum gas release peak fell on the temperature range of 500 ... 550 °C. The use of an integrated approach, including high-temperature heating, stages of zone melting at different rates, and thermal cycling in the range of the polymorphic transformation temperature, made it possible to obtain single-crystal hafnium samples. According to X-ray diffraction data, the parameters of the hafnium crystal lattice were determined: а = (0.31950 ± 5·10-5) nm and с = (0.50542 ± 5·10-5) nm (at 298 K), which corresponds to the density ρ = 13.263 g/cm3 and axial ratio с/a = 1.5819.

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Section: Eejp 1 (2021)mentioning

confidence: 99%

Section: Eejp 1 (2021)mentioning

confidence: 99%

Zone Recrystallization of Zirconium and Hafnium

Kozhevnikov

Pylypenko

Kozhevnikova

2021

EEJP

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Obtaining and Application of Some High-Pure Metals

Pylypenko,

Drobyshevska,

Kozhevnikov

2024

Problems of Atomic Science and Technology

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The results of systematic research on the complex refining of some chemical-activity and rare metals, and some applications of these are represented. Methods of melting, crystallisation, distillation and electrotransport in high vacuum and different combinations of these methods were mainly used for the refining of metals. Complex refining based on the use of complementary physical-chemical, physical methods and wide use ultrahigh vacuum technology, achieves the highest degrees of purification and obtaining metals in its purest form.

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Zone Refining of Zirconium in an Electric Field

Cited by 2 publications

References 2 publications

Zone Recrystallization of Zirconium and Hafnium

Zone Recrystallization of Zirconium and Hafnium

Obtaining and Application of Some High-Pure Metals

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