Determination of optimum process conditions for the extraction and separation of zirconium and hafnium by solvent extraction

Taguchi's method was used to determine the optimum conditions for separation of zirconium from hafnium by solvent extraction. The experimental conditions were studied in the range of 0.1 to 2.0 M for three different acids and TBP, D2EHPA or Cyanex 272 as extractant. The optimum extraction of zirconium was 71% when 2.0 M nitric acid and Cyanex 272 were used. The optimum zirconium/hafnium separation was also achieved using this combination.     

A Chemometric Study of the Adsorption of Zr(IV) Ions from Aqueous Solutions onto TBP-Surface-Modified Magnetic Fe3O4 Nanoparticles as a New Adsorbent

Radiochemistry - Chemometric experimental design methods were used to optimize the adsorption of Zr(IV) ions from an aqueous solution. Tributyl phosphate functionalized magnetic nanoparticles...     

Extraction of indium from zinc plant residues

The main purpose of this study was to extract indium from the Irankoh zinc plant residue. The Irankoh zinc plant residue contained 145 ppm indium. The optimum conditions for leaching of indium and reduction of ferric ion in reductive leaching were obtained at temperature of 90 °C for a leaching duration of 3 h with sulfuric acid concentration of 100 g/L and the amount of required sodium sulfide for reduction of ferric was 1.5 times of stoichiometric quantity of iron. Then, to prepare concentrated indium solution, indium was selectively precipitated from the leach solution. The pH of leach solution was adjusted to 6 with ammonia solution in 90 °C for selective indium precipitation, and reaction time was considered to be 10 min. Then the resulting precipitation was dissolved using hot sulfuric acid solution, and the solution was subject to solvent extraction and cementation using zinc powder to recover indium.     

Intensification of zirconium and hafnium separation through the hollow fiber renewal liquid membrane technique using synergistic mixture of TBP and Cyanex-272 as extractant

The novel synergistic mixture of TBP and Cyanex-272 is used as the extractant in the hollow fiber renewal liquid membrane(HFRLM) technique for Zr/Hf separation.The effects of the chemical and operational parameters such as HNO_3 concentration in the donor phase,NH4 F concentration in the acceptor phase,Cyanex-272 and TBP concentration in the liquid membrane phase,the lumen and shell side flow rates,and aqueous/organic volume ratio on the mass transfer and separation performance of HFRLM method were investigated.The obtained results reveal the intensification potential of proposed HFRLM technique for selective extraction of Zr over Hf with separation factor higher than 100.The HFRLM method provides two times higher mass transfer flux in comparison with hollow fiber supported liquid membrane(HFSLM).Also,the HFRLM method shows satisfactory stability for 700 min of continuous operation.The Zr ion transport through the LM phase follows the coupled co-transport mechanism and the diffusion in the renewal layer is recognized as the rate-controlling step in the HFRLM process.Moreover,the Zr mass transfer coefficient and molar flux in the HFRLM method are calculated in the range of 1×10~(-8)to 8.4×10~(-7) m·s~(-1) and 4.9×10~(-6) to 20.1×10~(-6) mol·m~(-2)·s~(-1),respectively.     

Selective zirconium stripping of a loaded Cyanex 272 using Taguchi orthogonal array design

In this study the effects of various stripping parameters such as complexing agent (EDTA), organic to aqueous ratio (0.5, 1.0, 2.0), acid type (hydrochloric, sulfuric, sulfuric + hydrogen peroxide) and their concentrations (0.5, 1.0, 2.0 N) were investigated on zirconium stripping efficiency from loaded Cyanex 272 in kerosene. Results showed that, all of these parameters had significant effect on the selective zirconium stripping.