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以二异丁基甲酮(DIBK)为萃取剂,二(2-乙基己基)磷酸酯(P204)为改质剂,利用对数函数外推法对DIBK-P204体系从HSCN介质中萃取锆和铪的热力学进行研究,结果表明:锆铪与SCN-所形成配合物的一级稳定性常数分别为1×1010.07和1×10-0.12,DIBK-P204体系萃取锆和铪的热力学平衡常数分别为lg(K12,Zr)=5.00和lg(K12,Hf)=-4.69,焓变分别为ΔHZr=-13.76 kJ·mol-1和ΔHHf=-13.05 kJ·mol-1,说明对锆铪的萃取反应为放热反应,升高温度不利于萃取反应的进行,并计算出常温下萃取反应的自由能变分别为ΔGZr=-28.06 kJ·mol-1和ΔGHf=26.32 kJ·mol-1,熵变分别为ΔSZr=48.78 J·(K.mol)-1和ΔSHf=-134.30 J·(K.mol)-1。
DIBK-P204 system was extracted from HSCN medium with diisobutyl ketone (DIBK) as extractant and bis (2-ethylhexyl) phosphate (P204) as modifier by extrapolation of logarithm function The results showed that the first-order stability constants of zirconium-hafnium complex with SCN- were 1 × 1010.07 and 1 × 10-0.12, respectively. The thermodynamic equilibrium constants of zirconium and hafnium extracted by DIBK-P204 were 1 g (K12, Zr) = 5.00 and lg (K12, Hf) = -4.69, the enthalpy changes were ΔHZr = -13.76 kJ · mol-1 and ΔHHf = -13.05 kJ · mol-1, respectively. The exothermic reaction and the increase of temperature are unfavorable to the extraction reaction. The free energy variation of extraction reaction at room temperature is calculated as ΔGZr = -28.06 kJ · mol-1 and ΔGHf = 26.32 kJ · mol-1, respectively. ΔSZr = 48.78 J · (K.mol) -1 and ΔSHf = -134.30 J · (K.mol) -1.