N263萃取分离锌铁及其热力学研究

Extraction Separation of Zinc and Iron with N263 and Its Thermodynamics

研究了用N263从氯化物体系中萃取Zn^(2+)、Fe^(2+)和Fe^(3+),考察了振荡时间、萃取剂浓度、改性剂浓度、相比(O/A)、盐酸浓度对Zn^(2+)、Fe^(2+)和Fe^(3+)萃取率的影响。结果表明,在有机相组成为20%N26^(3+)20%正己醇+60%260#溶剂油、相比O/A=1GA6FA1、振荡时间5 min和25℃条件下,Zn^(2+)、Fe^(2+)和Fe^(3+)的单级萃取率分别为90.97%、0.79%和75.85%,分离系数βZn^(2+)/Fe^(2+)和βZn^(2+)/Fe^(3+)分别为1260和3.21。经过2级逆流萃取,水相中Zn^(2+)浓度从9.61 g/L降至0.36 g/L,负载有机相采用0.5 mol/L H2SO4反萃,Zn^(2+)的反萃率为41.86%,Fe^(3+)的反萃率大于97%。N263萃取金属离子的机理是阴离子交换反应,计算了萃取反应相关的热力学函数值,结果表明,N263萃取Zn^(2+)为放热反应,Fe^(3+)的萃取反应为吸热反应,常温下Zn^(2+)和Fe^(3+)的萃取反应均可自发进行。

The extraction of zinc and iron with N263 from chloride solution was studied.The effects of oscillation time,extractant concentration,modifier concentration,phase ratio(O/A),and hydrochloric acid concentration on the extraction rate of zinc and iron were investigated.The results showedthe extraction rate of Zn^(2+),Fe^(2+) and Fe^(3+) were 90.97%,0.79%and 75.85%,respectively,and the separation coefficient of βZn^(2+)/Fe^(2+) and βZn^(2+)/Fe^(3+) were 1260 and 3.21,respectively,under the conditions of extractant composition of 20%N26^(3+)20%n-hexanol+60%260#solvent oil,phase ratio(O/A)of 1GA6FA1,oscillation time of 5 min,25℃.Meanwhile,the concentration of zinc in the aqueous phasedecreased from 9.61 g/L to 0.36 g/L by two-stage countercurrent extraction.The stripping rate of Zn^(2+) was 41.86%and more than 97%of Fe^(3+) was stripped with 0.5 mol/L sulfuric acid.Additionally,the mechanism of extraction of metal ions by N263 is anion exchange reaction.The extraction equilibrium isotherms of zinc and iron were plotted,and the thermodynamic functions of the extraction reaction were calculated.The results indicated that the extraction of Zn^(2+) by N263 is exothermic,and the extraction of Fe^(3+) is endothermic.The extraction of Zn^(2+) and Fe^(3+) can proceed spontaneously at room temperature.