Download High Current Density Operation at Los Bronces Electrowinning Plant

ABSTRACT FOR IMPC 2016
ELECTROMETALLURGY SESSION
Title:
High Current Density Operation at Los Bronces Electrowinning Plant
Authors:
Gabriel Zarate, Anglo American Chile, Santiago, Chile
Contact:
[email protected]
Los Bronces has two ROM dump leach operations designated Leach I and Leach II. Leach I was commissioned
in 1998 and stopped in 2014 due to the mine requirements. Leach II plant, commissioned in early 2002, was
built to treat around 700 million tons of marginal ROM ore averaging 0.45 % total copper. The mineralogy of
this material is estimated to be 70% chalcopyrite, 20% chalcocite/covellite and the balance oxides.
The original electrowinning plant design capacity for copper production was nominal 19,500 tonnes per year at
a current density of 276 A/m2 and a current efficiency of 92%. Presently, Los Bronces typically operates at
current densities between 390 and 440 A/m2, much higher than the average in the industry, with current
efficiencies around 93% and a maximum copper cathodes production of 37,200 tonnes per year.
In order to get these achievements, a number of modifications in the process conditions, in the cell hardware and
in the operational procedures have been implemented. In the first case, the specific flowrate, copper
concentration and temperature of the electrolyte were modified. In the cell hardware, six cells were added,
equipotential inner cell busbars were installed and the cross section of the cathode bars was increased.
Operational procedures like short circuit detection and cathode weight control were improved.
The modifications implemented and the results obtained are discussed in this paper.