Elusi isokratik dan bertahap pada pemisahan Zr-Hf dengan continuous annular chromatography (CAC)

Isocratic and stepwise elution on Zr-Hf separation with continuous annular chromatography (CAC). Zirconium as anuclear reactor fuel cladding such as pressurized water reactors (PWR) and boiling water reactor (BWR), impurity of Hf in nuclear grade Zr limited to less than 100 ppm. Cross section of zirconium (Zr) is 0.18 barn while hafnium (Hf) 600 time sof Zr in absorbing thermal neutrons so that Hf must be separated from Zr. The purpose of this research was to study the isocratic and stepwise elution method to separation of Zr-Hf with CAC in order to obtain a decrease in the concentration of Hf/Zr maximum. Feed of Zr-sulfate obtained from the processing of zircon sand concentration of 91.57 g/L containing Hf 1.594%. Isocratic and stepwise elution each carried out with a solution of 2M H2SO4 and 4M H2SO4. Isocratic elution of 2M H2SO4carried out for 8 hours, 4M H2SO4 for 9 hours while stepwise elution carried out for 4 hours. Feed entered together with the elution solution. Analysis Zr the results of elution fractions in each number carried out every 1 hour in a back titration using Bi (III) 0.05 M as titrant thiourea as indicator 2.5%. Neutron Activation Analysis (NAA) is used for the analysis of Zr and Hf. Obtained results, isocratic elution for 8 hours is not enough to get results in decreased concentrations of Hf/Zr meaning. By increasing the concentration of acidity elution into 4M H2SO4, on the tenth hour can decrease the concentration of Hf/Zr as much as 35.699 % that is from 13215.431ppm to 8497.63 ppm. By way of stepwise elution can shorten the time, on the fouth hour can lower the concentration of Hf/Zr to 89 564 % that is from 1445.856 ppm to 364, 461 ppm.

Keywords : Separation, zirkonium-hafnium, elution, continuous annular chromatography (CAC)