Improving Productivity and Energy Efficiency in Copper Electrowinning Plants
This paper presents strategies to improve energy efficiency and productivity in copper electrowinning (EW) plants. Plant modeling is based on updated technical data and specific measurements obtained in a tankhouse during a complete production cycle (four to five continuous days). The industrial EW plant site examined produces 180 000 ton/year with an operating current density of 300 A/m2 and a current dispersion of 8.5%. Proposals are based on the use of Optibar intercell bars and the reduction of distance between electrodes. Due to these changes, an improvement of +4.3% in energy efficiency combined with an increase of +3.4% in production can be accomplished. The productivity improvement projected for the plant is U.S.$ 10 million/year.
Enhancement of operating current density in a copper electrowinning cell
Abstract Efforts have been made to enhance the operating current density of an open channel cell to obtain high-quality cathode copper. Since increase of copper concentration and circulation rate did not improve the nature of the cathode deposit, the cell was modified to circulate the electrolyte through jets parallel to the cathode surface. With the modified cell it was possible to achieve quality deposits at a current density as high as 400 A m −2 . The hydrodynamic conditions of the cell were studied in detail. The results show that high limiting current densities and high mass transfer coefficient values are possible due to increase in the linear velocity. It has also shown that there are four distinct regions of limiting current distribution on the cathode plate. Since there is no turbulence up to ∼ 3.0 cm height from the bottom edge of the cathode plate (dead zone), the cell with a jetting system may be used as a high current density copper electrorefining cell.
Specifying DC chopper systems for electrochemical applications
This paper deals with information that customers, suppliers and consultants should consider when specifying a high current DC chopper system. It deals with specification of the major components such as transformers, rectifiers, unregulated DC distribution bus, disconnect switches, choppers and cooling systems.