Solar pond technology for large-scale heat processing in a Chilean mine
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Date
2012
Journal Title
Journal ISSN
Volume Title
Publisher
AMER INST PHYSICS
Abstract
Copper mining is the largest industrial activity in Northern Chile, a region that relies mostly on imported energy resources thus making the mining sector vulnerable to the rising cost of fuel oil and electricity. The extraction of copper is mostly accomplished by hydrometallurgy, a three-step low energy process consisting of heap leaching, concentration by solvent extraction, and metal recovery by electro-winning. Since the content of copper in its ore tends to degrade as the mining operation proceeds, higher leaching temperatures would be needed along with increasing energy requirements. In order to address this demand and considering that the region has one of the highest levels of solar radiation and clear skies, the authors assessed the solar pond technology for rising the temperature of the leaching stream. The working principle of such technology is presented, as well as its mathematical formulation, restrictions, and assumptions, aiming to simulate the performance of a solar pond and to size a suitable setup. The results indicate that this technology can provide sufficient heat to raise the temperature to a range of 50 to 70 degrees C throughout the year with an annual gross thermal supply of 626 GWh. In order to minimize the loss of water and salt from the pond, a closed salt cycle is suggested. Savings of up to 59 000 tons of diesel oil per year and the avoidance of 164 000 tons of CO2 per year could be achieved with a solar pond effective area of 1.43 km(2) reaching an average efficiency of 19.4%. Thus, solar pond technology is suitable for attaining the goal of increasing the leaching temperature while diminishing fuel costs and greenhouse emissions. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4757627]
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Keywords
THERMAL-BEHAVIOR, SIMULATION