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.
Copper electrowinning using a pulsed bed three-dimensional electrode
Abstract This work concerns the electrowinning of copper from an acidic medium using a membraneless three-dimensional pulsed bed electrode (PBE). The effect of current density ( i ), packed bed time ( t p ), and fluidized bed time ( t f ) on current efficiency (CE), energy consumption (EC), and space-time yield ( Y ) was investigated using a fractional factorial design (FFD). The results showed that the most important variables affecting the electrodeposition process were i and t p . Experiments using i greater than 3000 A m − 2 and t f lower than 2 s revealed that the process rapidly short circuited, mainly due to a non-uniform overpotential distribution inside the porous cathode. An important improvement of the reaction kinetics and EC was achieved by increasing t p and decreasing t f . The best values of CE (76.7%) and EC (2.5 kWh kg − 1 ) were obtained by applying 3000 A m − 2 , with t f  = 2 s and t p  = 60 s. Although the CE value was lower than reported elsewhere, the EC value was within the range commonly found for industrial processes. The FFD results indicated ways by which copper electrowinning using a PBE reactor could be further optimized.
PASSIVE AND LOW-ENERGY RESEARCH AND PRACTICES-DEHUMIDIFICATION
Methods of achieving acceptable indoor conditions in overheated, temperate, and underheated humid climates are discussed and compared. Desiccants and desiccant systems utilizing solid and liquid sorbents and various low-energy mechanical systems are described and evaluated.