Under the optimal technological conditions: TBP addition 20% (v/v), aqueous phase acidity 3.0 mol/L, ammonium sulfate addition 0.8–1.25 mol/L, room temperature and extraction time 10 min, the ...

Furthermore, as an excellent extractant for the separation of zirconium and hafnium in solvent extraction, 2-ethylhexyl phosphonic acid mono-(2-ethylhexyl) ester (P507) was carefully selected to modify C(Zn/Co-ZIF) to obtain C(Zn/Co-ZIF)@P507 by impregnation [10]. ... (IV) for C(Zn/Co-ZIF)@P507. This work not only provides an …

This paper provides an overview of the processes for separating hafnium from zirconium. The separation processes are roughly classified into hydro- and pyrometallurgical …

Separation of Zirconium and Hafnium: Commercial Processes. Alternative Separation Processes. Reduction to the Metals. Alternative Reduction Processes. …

Zirconium is an ideal material for nuclear reactors due to its low absorption cross-section for thermal neutrons, whereas the typically contained hafnium with strong neutron-absorption is very harmful for zirconium. This paper provides an overview of the processes for separating hafnium from zirconium. The separation processes are roughly ...

The results show that the extraction of zirconium and hafnium fit with pseudo-first order reaction, and the extraction kinetic of zirconium is governed by chemical reactions at bulk phase with ...

For the organic phase containing 2.5 mol L⁻¹ of TBP and an aqueous/organic ratio of the 1/1, 94% of the Zr was extracted and a separation factor of the 13.8 was obtained in one contact of the ...

A new process for the separation of hafnium from zirconium has been developed. This process is based on the repeated reaction of the mixed tetrachloride …

S. N. FLENGAS AND J. E. DUTRIZAC. A new process for the separation of hafnium from zirconium has been developed. This process is based on the repeated reaction of the mixed tetrachloride vapors of zirconium and hafnium with alkali metal chloride salts in a solid form; hafnium tends to remain in the condensed phase while …

February 13, 2023. Editors' notes. Highly efficient separation and enrichment of hafnium achieved by advanced membrane separation system. by Liu Jia, Chinese Academy of Sciences. Graphical...

The phase ratio (O/A) was fixed at 1:1 with a constant total volume. As. Conclusions. BEAP (B) was used to separate zirconium from hafnium with a separation factor of 6.8 under optimum conditions. The content of HfO 2 in ZrO 2 product was decreased from 3% in the feed to 0.6% in the Zr product after counter-current operation.

For the organic phase containing 2.5 mol L⁻¹ of TBP and an aqueous/organic ratio of the 1/1, 94% of the Zr was extracted and a separation factor of the 13.8 was obtained in one contact of the ...

The solvent extraction method in wet separation is widely used in the separation of zirconium and hafnium because of its low cost, high yield and thorough …

From the above studies, we unambiguously state that the adsorption and separation of zirconium and hafnium can be achieved under the mild operating condition i.e. in the pH range of 0.5–3.0 (Fig. 3). A good separation factor (~11) has been obtained using the AAPPFSG ligand (Table 4) using the eluent solution with pH 0.65. Another …

The NCACs were preconcentrated on neutral alumina followed by a group separation on a hafnium(IV) modified silica into four subfractions containing: (1) the nitrogen-free polycyclic aromatic compounds (PAC); (2) the neutral polycyclic aromatic nitrogen heterocycles (PANH) together with the nitriles, (3) the aminosubstituted PACs; and (4) the ...

Under the optimal operating conditions of 10 % HCl, 1.5 M KF, 15 minutes and an organic-to-aqueous phase ratio of 2:1, the extraction percentage of zirconium and hafnium is 94.3 % of Zr and 64.3 % of Hf and a separation factor of 9.2 for 2-octanol and 93.1 of Zr and 60.9 % of Hf and a separation factor of 8.7 %. 2-octanol shows a slightly ...

The suppression of phase separation was observed in hafnium-silicate films with high nitrogen contents. Moreover, small hysteresis changes were observed in the C-V curves. The negative shift of ...

The NCACs were preconcentrated on neutral alumina followed by a group separation on a hafnium(IV) modified silica into four subfractions containing: (Citation 1) the nitrogen-free polycyclic aromatic compounds (PAC); (Citation 2) the neutral polycyclic aromatic nitrogen heterocycles (PANH) together with the nitriles, (Citation 3) the ...

Effect of solvent on Zr and Hf distribution ratio and separation factor using 5 % wt Aliquat 336; HCl 7M, phase ratio ¼ 1. Zr/(Zr þ Hf) ¼ 0.71, [Zr] i ¼ 2340 mg. L 21 and [Hf] i ¼ 1800 mg. L ...

Under the optimal operating conditions of 10 % HCl, 1.5 M KF, 15 minutes and an organic-to-aqueous phase ratio of 2:1, the extraction percentage of zirconium and hafnium is 94.3 % of Zr and 64.3 % ...

The separation of zirconium and hafnium isotopes from the early actinides and rare earth elements (REE) with Eichrom's Pb resin has been studied. Batch studies were performed to characterize the behavior of actinium, thorium, zirconium, hafnium, lutetium, and yttrium on Pb resin from HCl solutions (0.001 M to 11 M). The early …

Under optimum conditions, the separation factor of Zr over Hf was found to be 6.8. The extracted complexes were determined to be ZrO(HSO 4) 2 ·3B and HfO(HSO 4) 2 ·2B. The extractions of zirconium and hafnium are both exothermic. A counter-current operation was conducted, in which the content of HfO 2 was decreased from 3% to 0.6% …

Under the optimal operating conditions of 10 % HCl, 1.5 M KF, 15 minutes and an organic-to-aqueous phase ratio of 2:1, the extraction percentage of zirconium and hafnium is 94.3 % of Zr and 64.3 % ...

Abstract. Extraction and separation of hafnium (Hf) from zirconium (Zr) in HNO 3 solution were carried out with Cyanex572 as extractant. Hf could be selectively extracted with an optimized extraction rate of 76.8%, and the separation factor between Hf and Zr could reach up to 15.7 when the concentration of Zr(IV), Hf(IV), H +, NO 3-and (NH 4) 2 SO 4 …

The maximum separation factor of zirconium over hafnium was around 6.8, and the extracted complexes in the organic phase were suggested to be ZrO(HSO 4) 2 ·3B and HfO(HSO 4) 2 ·2B. Banda et al. [ 19 ] proposed a technology for the effective extraction of two metals from hafnium under 2.5–3 mol/L HCl conditions using trioctylphosphine …

The solvent extraction of Zr and Hf was studied and it was found that decalin (decahydronaphthalene) was the best solvent among 14 solvents studied and the optimum aqueous phase was 2 mol·dm−3 HCl or HNO3. The solvent extraction of Zr and Hf was studied using 444-trifluoro-1-(2-thienyl)-1,3-butanedione (TTA) from a multitracer solution …

THE technique of reversed phase partition chromatography is being increasingly used for the separation of metals of similar chemical behaviour. Siekierski and Fidelis 1,2 describe the application ...

In this paper, we exploit a novel technique for preparing high density HfO/sub 2/ nanocrystals with an average size > 10nm using spinodal phase separation of Hf-silicate thin film by 900/spl deg/C rapid thermal annealing for nonvolatile memories. The density can be as high as 0.9/spl sim/1.9/spl times/10/sup 12/cm/sup -2/. Owing to the fact that …

Hence, hafnium is extracted into the organic phase preferentially, while zirconium remains in the water phase. (2) TBP-HNO 3 and TBP-HNO 3 -HCl systems, in which tributyl phosphate (TBP) is used as the extractant to extract and separate zirconium and hafnium, which is the earliest method adopted in China to produce nuclear …

Separation of lanthanum, hafnium, barium and radiotracers yttrium-88 and barium-133 using crystalline zirconium phosphate and phosphonate compounds as prospective materials for a Ra-223 radioisotope generator. ... Both are layered compounds with the α-ZrP phase having an interlayer spacing of 7.6 ...