Electrowinning of tellurium from alkaline leach liquor of cemented Te

The electrochemical behaviour of tellurium in 2.5 M NaOH solution was studi ed for the recovery of tellurium from alkaline leach liquor of cemented Te using steady state polarization and cyclic voltammetry. The deposition char acteristics and the potential range for a stable deposit of tellurium were also investigated. The morphology of deposited Te in alkaline solution show ed a very porous nature and needlelike radial growth. The potential range f or stable electrodeposition was between -0.8 V and -0.95 V (vs Hg/HgO elect rode), but electrowinning could be carried out at more negative potentials due to the disproportionation reaction of Te-2(2-). Laboratory-scale electr owinning experiments were performed under different operating voltages, tem peratures and initial Te concentrations. The current efficiency was about 8 5-90% for 50% recovery and about 50-60% for 90% recovery. The purity of ele ctrodeposited Te was higher than 99.95%.