Recovery of germanium from acid leach solutions of zinc refinery residue using an oxime extractant of HBL101

An oxime extractant of HBL101 was used to extract germanium from acid leach solutions of zinc refinary residues. The effect of acidity on extraction was investigated. Germanium was extracted from a sulphate acid solution with not too high acidity (1.0 similar to 1.2 mol/L H2SO4), while zinc, cadmium, iron, gallium and arsenic were not extracted. Only small amount of copper was co-extracted. The germanium was readily stripped from the loaded organic solution with NaOH solutions. After germanium stripping, the co-extracted copper can be stripped using 2 mol/L H2SO4 while the extract ant regenerated for recycling. The system was optimised in terms of organic composition and conditions of extraction and stripping and further characterised in terms of extraction and stripping kinetics and distribution isotherms. More than 98.5% of germanium was extracted in five-stage counter current extraction using an organic system of 30% HBL101 and 70% sulphonated kerosene and a feed containing 0.25 g/L Ge and 113 g/L H2SO4 with an A/O ratio of 4:1 at 25 degrees C for 20 min. The loaded organic containing 0.905 g/L Ge was stripped using 3.75 mol/L NaOH solution in five-stage counter current stripping with an A/O ratio of 1:4 at 25 degrees C for 25 min to selectively strip germanium followed by using 2 mol/L H2SO4 to strip co-extracted copper for recycling. The concentration of Ge in strip liquor reached 3.56 g/L.