氨-硫酸铵溶液中萃取分离锌镍

Extraction and separation of zinc and nickel from Ammoniacal-ammonium sulfate solutions

研究Mextral54-100(HA)和Mextral54-100+TRPO(HA+TRPO)两种萃取体系从氨-硫酸铵溶液中萃取分离锌镍的性能,确定锌镍分离的最佳工艺。结果表明:HA萃取体系在初始pH为9.0时对镍具有较高的选择性萃取能力,而HA+TRPO萃取体系在初始pH为7.2时对锌具有较高的选择性萃取能力。综合考虑,宜先采用HA体系萃取镍,然后采用HA+TRPO体系萃取锌。对于镍的萃取,在萃取体系为0.5mol/LHA、温度为25℃、初始pH为9.0和相比(O/A)为1:1的条件下,经4级萃取,镍的萃取率为98.5%,锌的共萃率小于6%;对含镍2.01g/L的镍负载有机相,经2级反萃,镍反萃率为99.8%。对于锌的萃取,在萃取体系为0.4mol/L HA+0.05mol/L TRPO、温度为25℃、初始pH为7.2和O/A为1:1的条件下,经2级萃取,锌萃取率为99.8%;对含锌3.12g/L的锌负载有机相,经2级反萃,锌反萃率为99.9%。通过采用不同的萃取体系和选择合适的萃取条件,获得氨-硫酸铵溶液中萃取分离锌和镍的最佳工艺流程和技术参数。

The performances of extraction systems, Mextral54-100（HA） and Mextral54-100＋TRPO（HA＋TRPO） on extraction and separation of zinc and nickel from ammoniacal-ammonium sulfate solutions were investigated, and the optimal process of zinc-nickel separation was determined. The results show that high selective extractability of nickel is obtained with HA extraction system at initial pH 9.0, while high selective extractability of zinc is achieved with HA＋TRPO extraction system at initial pH 7.2. After comprehensive consideration, it is supposed to extract nickel with HA system firstly, and then extract zinc with HA＋TRPO system. In regard to extraction of nickel, the extraction rate of nickel is 98.5% with four extraction stages under the conditions of 0.5mol/L HA extraction system, 25 ℃, initial pH of 9.0 and phase ratio（O/A） of 1：1, while the extraction ratio of zinc is less than 6% under the same conditions. For loaded organic phase containing 2.01 g/L nickel, the stripping rate of nickel reaches 99.8% with two stripping stages. For extraction of zinc, the extraction rate of zinc reaches 99.8% with two extraction stages under the conditions of 0.4 mol/L HA ＋ 0.05 mol/L TRPO extraction system, 25 ℃, initial pH of 7.2, and phase ratio（O/A） of 1：1. For loaded organic phase containing 3.12 g/L zinc, the stripping rate of zinc is 99.8% with two stripping stages. By means of employing different extraction systems and selecting the appropriate extraction conditions, the best technical process and parameters for extraction and separation of zinc and nickel from ammoniacal/ammonium sulfate solutions were acquired.