Modeling of selenium and tellurium removal from copper electrowinning solution

• The kinetics and thermodynamics of selenium and tellurium removal with cuprous ion were reviewed.
• A comprehensive model capable of predicting the rate constants for selenium and tellurium reduction reactions was obtained.
• The rate constant model was validated and then used to estimate Se and Te removal times under Vale's ED plant conditions.

In this study, the kinetics of selenium and tellurium reduction by cuprous ions were reviewed and a comprehensive model capable of predicting the rate constants for various Cu+ 2–H2SO4 compositions and temperatures is presented. The rate constant data were fitted to the relationship: lnk1=A+BT+C+D×lnH2SO4+(E+FCu2+0.51+Cu2+0.5, where k1 is in M− 1 s− 1 and [Cu2 +] and [H2SO4] are in molar at temperature T (K), and A to F are empirical constants. The model was validated using different rate constant data points obtained during the reduction of SeVI and TeVI under different solution conditions. The rate constant k1 given by the comprehensive model was within a ± 3.3% for SeVI and ± 5.1% for TeVI reduction reactions compared to the rate constant determined using the experimental data. The model was used to estimate the selenium and tellurium reduction reaction times under Vale's (Sudbury, Canada) Electrowinning Department (ED) plant conditions. As a result, potential factors that may affect the selenium and tellurium removal rate at the ED plant of Vale were proposed and discussed.