从镍电镀污泥回收的硫酸镍溶液的深度净化

对于镍电镀污泥的硫酸浸出液所回收得到的粗硫酸镍溶液，采用镍皂化的P507萃取剂净化。考察了料液pH、相比、萃取时间、温度对萃取过程的影响，绘制萃取等温线；考察负载有机相中主要杂质离子用不同浓度H₂SO₄反萃的效果及规律，提出用H₂SO₄反萃再生有机相的方案。结果表明，以体积含量为10%的P507+磺化煤油的有机相，通过直接皂化的方法制备镍皂有机相, 在皂化率80%、料液pH=2.2、相比V_O/V_A=1/8、温度30 ℃、时间5 mins条件下，经过6级逆流萃取可以使料液的铁降低到40 mg.L-1左右；对于除铁后料液，在皂化率80%、料液pH=3.3、相比V_O/V_A=1/8、温度30 ℃、时间5 mins的条件下，经过4级逆流萃取剩余杂质降至深度净化达标范围；负载有机相用4 mol.L-1 H₂SO₄按V_O/V_A=5/1、30 ℃、5 min，经过3级逆流反萃可达到再生有机相的目的。反萃水相可返回至电镀污泥浸出工序回用。 

Deep purification of nickel sulfate solution produced by Ni-electroplating sludge recycling process

The crude nickel sulfate solution recycled from nickel electroplating sludge leaching solution of sulfuric acid was purified by Nickel saponified P507 extracting agent. The extraction isotherm was drawn by analyzing the effects of feed solution pH, phase ratio, extraction time and temperature on the extraction process. The back-extraction rule of the main impurity ions by different concentrations H 2SO4 was investigated. The results show that under the following optimum conditions, that is, using 10 % P507 (volume fraction) plus sulphonated kerosene as the extractant, Nickel saponification rate is 80 %, pH= 2.2, VO/VA=1/8, in 30 ℃ and reaction time is 5 min, the concentrate of Fe3+ion can be decreased close to 40 mg/L after a six stage counter current extraction. After iron removal process the Nickel sulfate solution can be deep purified under the following optimum conditions, that is, 80 % saponification rate, pH = 3.3, VO/VA=1/8, in 30 ℃ and reaction time is 5 min, after a four stage counter current extraction the concentrate of the rest impurity ions can be decreased to reach the range of deep purification standard. The purification loaded organic can be stripped using 4 mol/L H2SO4 solution under the following condition: VO/VA =5/1, in 30 ℃ and reaction time is 5 min, after a four stage counter current stripping the organic phase can be reused. The tripping liquor can be reused by the stage of electroplating sludge leaching.