The extraction behaviors of zinc by β-diketone extractant named as Mextral54-100 (HA), from Zn(Ⅱ)-NH4Cl-NH3 complex solution were investigated. The effects of initial pH, temperature, extractant concentration, chloride ions and total ammonium concentrations of aqueous phase on the zinc extraction were examined. The results show that aqueous pH and total ammonium concentration are more significant to zinc extraction. The distribution ratio of zinc decreases with the increase of total ammonium concentration and initial pH when aqueous pH>6.81. The effect of chloride ions on the extraction is attributed to zinc chloride complexes formed, hence, zinc extraction decreases with increasing chloride ions concentration. The result of extraction mechanism indicates zinc extraction is exothermic and reaction enthalpy change is−4.720kJ/mol at T=298 K. Increasing temperature causes a negative effect on zinc extraction. Zinc is extracted as free zinc ion and extracted complexes is in the form of ZnA2. FT-IR results indicate that keto-enol tautomeric structure ofβ-diketone involves in the formation of coordination bond, and zinc ammine complexes are not extracted.%研究了采用β-二酮类萃取剂Mextral54-100(HA)从Zn(Ⅱ)-NH4Cl-NH3配合物溶液中萃取锌的行为，考察了溶液初始pH、温度、萃取剂浓度、氯离子浓度和总氨浓度对锌萃取的影响，结果表明：溶液pH、总氨浓度对锌萃取率的影响较显著。总氨浓度的增加降低了锌的分配比。当水相初始pH＞6.81时，分配比随着pH的增加而下降。萃取过程由于受锌氯配位影响，分配比随氯离子浓度升高呈下降趋势。萃取过程是一个放热的反应，298 K下，反应焓变为−4.720 kJ/mol，温度升高不利于锌的萃取；锌以自由锌离子被萃取，萃合物的组成为ZnA2。萃合物的红外光谱表明：萃取剂分子中的β-二酮互变为烯醇式参与配位键的形成，锌氨络合物不被萃取。
展开▼
