The leaching behaviour of a uranium ore, with sulfuric acid and sodium chlorate, has been investigated in agitated tanks. Data from conventional leaching studies has been supplemented with mineralogical characterisation and SEM analysis of selected samples. A technique known as block leaching was also used, which allows individual grains of both the ore and gangue minerals to be studied before and after leaching under different conditions. As a result of the experimental investigation a detailed description of the leaching behaviour of the ore has been compiled. The experimental data have been used to prepare a leaching model that describes uranium extraction as a function of residence time, acid strength, temperature and redox potential. In addition, the dissolution behaviour of the key gangue minerals as a function of leaching conditions has been determined. On the basis of ore and gangue mineral dissolution, the consumption of acid has been predicted with good agreement with experimental data. Although the model is largely empirically based, it provides a useful tool for optimising plant operation
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