The heat generated during copper production extraction processes can be harnessed and transferred back into the system using heat exchangers, resulting in significant energy savings and unparalleled yield, says evaporative water cooling specialist Industrial Water Cooling (IWC) CEO Roger Rusch.

Compact heat exchangers, such as gasketed and welded plate heat exchangers, as well as spiral heat exchangers, are the most efficient technology for heat transfer, says Rusch.

“Their close temperature design, high internal turbulence and large heat-transfer areas combine to recover up to 25% more energy, compared with conventional shell-and-tube heat exchangers. This excess energy can be recycled and used in other applications within the copper processing plant,” he explains.

During the initial copper extraction process, plate heat exchangers are used to control chemical temperatures within the autoclave where crushed copper ore is leached with sulphuric acid to produce impure solutions of copper sulphate.

Spiral heat exchangers are then incorporated to recycle the rich acid’s low-grade heat, which is, in turn, used to preheat the lean acid coming back from solvent extraction.

Another area where plate heat exchangers deliver enhanced heat recovery is during the electrowinning process where copper ions are extracted from the copper sulphate, says Rusch.

The electrowinning cell consumes nearly 80% of total energy required for the production of copper.

“Here, steam is used to heat rich electrolyte before it enters the electrowinning cell. Gasketed plate heat exchangers reduce net consumption of energy in the plant by recovering low-grade heat during the process and using it to preheat the rich electrolyte,” he adds.

Plate heat exchangers are low cost and low maintenance and are up to 90% smaller than the equivalent shell-and-tube heat exchangers.