Phase separation of a hafnium alkoxide-modified polysilazane upon polymer-to-ceramic transformation—A case study Journal of the European Ceramic Society, 2012 Gerd Buntkowsky
The solvent extraction was investigated by varying shaking time and HCl concentration. The extraction and strip reached equilibrium within 30 s (8 M HCl feed and 2 M HCl strip concentration).The separation factor as a function of HCl concentration is presented in Fig. 2.It was observed that a third phase was produced between the aqueous and organic phases …
The polymer-to-ceramic transformation of the hafnium alkoxide modified polysilazane HTT1800 was also investigated by means of 29 Si MAS NMR. The sample pyrolyzed at 400 °C shows the presence of Si sites with mixed bonds (SiC x N 4−x), thus a signal at ca. −4 ppm was assigned to SiC 2 N 2 sites (with sp 3 hybridized C), whereas the signals at −25.6 ppm …
2004518A method is provided to optimie separation of irconium from hafnium by extraction of a feed mix including ZrHfOCl 2 with a thiocyanatecontaining organic phase. The method includes maintaining the TAMO 2 ratio in a range from greater than about 2.55 to about 3.5.
1. 1-29. (canceled) 30. A process for separation of hafnium and zirconium from a mixture containing ZrCl 4 and HfCl 4, the process comprising: introducing the mixture of ZrCl 4 and HfCl 4 in vapour form into a continuous extractive distillation column; selective absorption of the ZrCl 4 and HfCl 4 vapours by an extraction solvent circulating in a counter-current to a …
The influence of the aqueous acidity on the extraction of hafnium and zirconium by the mixture of DIBK and P204 was investigated in the range of 1.0 to 7.6 mol/L.In these experiments, the conditions of 5% (v/v) P204 and 95% (v/v) DIBK as organic phase, 117.1 g/L zirconium, 2.89 g/L hafnium, 3.0 mol/L NH 4 SCN and 15 min extraction time were kept.
The extraction chromatography behavior of zirconium and hafnium is studied using tri-n-octylamine (TNOA) and tri-caprylyl-monomethyl ammonium chloride We use cookies to enhance your experience on our website.By continuing to use our website, you are agreeing to our use of cookies.
The extraction chromatographic behavior of zirconium(IV) and hafnium(lV) was investigated using di(1-methylheptyl) methylphosphonate (DM HP) as a stationary phase in the media of hydrochloric acid-ammonium chloride by a batch method. Through a log-log analysis and the IR spectra the extractable species has been proposed to be (DMHPH + ) 2 ZrCl 6 2- and (DMHPH + ) 2 HfCl …
The optimum conditions for hafnium and zirconium separation were that the aqueous acidity is 1.0 mol/L, the concentration of P204 in the organic phase is 10% (v/v), the contacting time is 15 min, the concentration of NH4SCN is 4.0 mol/L, and the concentration
The optimum conditions for hafnium and zirconium separation were that the aqueous acidity is 1.0 mol/L, the concentration of P204 in the organic phase is 10% (v/v), the contacting time is 15 min, the concentration of NH 4 SCN is 4.0 mol/L, and the concentration of NaCl is about 2.0–3.0 mol/L. Under this condition, the separation factor of ...
Abstract: Zirconium and hafnium are separated by distribution of the oxychlorides between an aqueous chloride ion-containing solution and a liquid halogenated hydrocarbon containing a dissolved organic amine. The process may be continuous or discontinuous and may be repeated several times. The zirconium predominantly goes into the organic phase ...
Synthesis of N-Benzoyl Phenyl Hydroxyl Amine Derivative of Styrene Divinyl Benzene Copolymer and Its Application in Separation of Zirconium from Hafnium. Analytical Letters 1992, 25 (4 ... Solvent and Reversed-Phase Extraction Chromatographic Separation of Niobium, Zirconium, and Hafnium with Aliquat 336. Bulletin of the Chemical Society of ...
Abstract. 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 zirconium concentrates in the vapor phase.
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 oxide ...
Zirconium from the aqueous phase was deter-mined spectrophotometrically with Arsenazo III at 650 nm, while hafnium was determined with Xylenol Orange at 540 nm. The separation of zirconium from hafnium was achieved by stripping hafnium with 9 M hydrochloric acid followed by stripping zirconium with 2 M hydrochloric acid. They were also ...
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 …
Aliquat 336 has been employed as an effective anionic extractant for the radiochemical separation of niobium, zirconium, and hafnium in mixtures using solvent extraction and reversed phase extraction chromatography (RPEC). In solvent extraction, niobium and zirconium are extracted with reagent solutions in the respective concentration ranges <0.001–0.04 mol dm−3 …
The current work consists in the separation of zirconium and hafnium by the ion-exchange method in order to obtain a pure zirconium concentrate, suitable to be used in the production the zirconium sponge. ... in the liquid phase at equilibrium (mmol L-1), V is the volume of the solution (L) and m is the mass of the exchanger (g). The maximum ...
： The extraction of Zr and Hf from sulphuric acid systems by solutions of Primene JMT (a long-chain primary amine) in kerosene, is described. The effect of contact time, free acidity, solvent concentration and temperature, has been thoroughly examined.
I claim: 1. In a process for separation of zirconium from hafnium by solvent extraction of an aqueous sulfuric acid feed solution containing the metals with an organic extractant comprising a solution of a high molecular weight tertiary amine in an organic solvent and separation of the organic and aqueous phases, the improvement comprising adding to the feed solution prior to …
We have used X-ray absorption near-edge fine-structure (XANES) analysis of oxygen K-edges in combination with high-resolution transmission …
THE technique of reversed phase partition chromatography is being increasingly used for the separation of metals of similar chemical behaviour. Siekierski and Fidelis1,2 describe the application of this technique to the separation of the rare-earth metals, using tributyl phosphate absorbed on kieselguhr as the stationary phase, and nitric acid in various concentrations as …
Chemistry of nuclear fuel, M, 1956, s-522). There is a method in which the separation of zirconium and hafnium regulate by changing the concentration of HNO 3 and NaNO 3 to recognize the nom solution. First, when the total concentration of acid and vicariates 1,5÷3.5 mol/l extract the main part of zirconium, and then at a concentration of HNO ...
This paper presents a new chemical separation method for Hf and Zr from rocks using extraction chromatographic resins prepared from inert polymeric supports and the liquid anionic exchangers tri-n-octylamine or trioctylmethylammonium chloride (Aliquat 336). The method was developed using basaltic and trachyandesitic rocks with high contents of Al, Fe, and Ti. A 100 …
The distribution ratios, K d, for zirconium and hafnium were measured in the hydrochloric acid-TBP-celite system, the acid concentration being varied from 5 N to 8 N.The data obtained showed that the separation factor for the above elements, K d zr ⁄K d Hf, is fairly high, –4, in the 7–8 N hydrochloric acid range. Thus, the separation of these elements was carried …
Process for the separation of zirconium and hafnium US3658466D () US3658466A () NIPPON MINING CO; …
L'invention concerne un procédé de séparation des tétrachlorures de zirconiu m et de hafnium à l'aide d'un solvant comprenant d'une part un solvant métallique alcalin formé d'un sel d'un chlorure de métal alcalin et d'un chlorure métallique acide A, par exemple, ...
The difficulties encountered in separating hafnium from zirconium are well known [6, 7].1 It has been shown [1] that a separation of hafnium and zirconium can be obtained by anion-exchange in sulfuric acid solution. The method described here has been used to determine hafnium and zirconium in mixtures of the
2) Hydrochloric medium. Figure 3 shows the results of the extraction of zirconium and hafnium using the acid extractants DEHPA, IONQUEST ® 801 and CYANEX ® 272 in a hydrochloric medium. Table 3 shows the separation factor of Zr/Hf …
：Process for separation of hafnium tetrachloride from zirconium tetrachloride and electrode ：Tomoo Kirihara,Ippei Nakagawa,Yoshinobu Seki,Yutaka Honda,Yasuo Ichihara ：US07/330893
Based on this model, we designed and verified an induced CTCF phase separation system in embryonic stem cells (ESCs), which facilitated inter-A compartment interactions, improved self-renewal of ...
Extraction and separation of zirconium from hafnium using Cyanex 923 as extractant cannot be performed for the zirconium concentrations of higher than 8 g/l, due to formation of third phase. As is obvious from Table 4, the separation factor of 186 reported in this work for the separation of zirconium and hafnium is significantly higher than ...
The separation of hafnium from zirconium is the key. of the nuclear grade zirconium production. Most of the commer-. cially used separation …