A shrinking particle—shrinking core model for leaching of a zinc ore containing silica |
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| Authors: | Vida Safari Gilnaz Arzpeyma Fereshteh Rashchi Navid Mostoufi |
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| Institution: | aDepartment of Chemical Engineering, University of Tehran, PO Box 11155/4563, Tehran, Iran;bDepartment of Metallurgy and Materials Engineering, University of Tehran, PO Box 11155/4563, Tehran, Iran |
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| Abstract: | A new mathematical model was developed for leaching of zinc ores containing silicates such as hemimorphite which produce a gel during leaching with sulfuric acid. This model is based on the shrinking core model in which the particle size and the reacting core shrink simultaneously. It was shown that the actual dissolution time of the ore particles is longer than the time corresponding to the dissolution of chemical zinc oxide itself. It was suggested that because of the existence of silicates in the ore, a gelatinous layer was formed around the reacting core. Since the gel product is soft, it breaks apart when the particles collide and as a result, the particles shrink. However, a thin gelatinous layer always covers the reacting core which increases the mass transfer resistance and increases the leaching time. This model was applied to leaching of a zinc-rich tailing containing hemimorphite and the thickness of the gelatinous layer as well as the diffusion coefficient in this layer was determined. |
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| Keywords: | Leaching Kinetics Zinc silicate Shrinking core model Gelatinous silica layer |
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