Combined grinding and leaching process for ores and wastes and apparatus thereof

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A method of extracting at least one metal from an ore or waste by performing a combined attrition and leaching step on the ore or waste in an aqueous inorganic acid at a concentration of 1-9 molar and a temperature lower than 100 0C. Metal dissolves into the leachate which is then separated from the gangue. The process can be used to extract uranium, caesium, mercury, thorium and/or rare earth elements, e.g. from cemented radioactive waste or radioactive mine waste. The waste can be previously crushed or screened and be present in the range 50-500 g/l. Suitable acids are sulphuric, nitric, hydrochloric, and/or phosphoric, with the addition of a halogen salt or a mercury salt (e.g. KI or mercury nitrate, mercury chloride, mercury iodide and/or mercury iodate). The method can be preceded by a combined attrition and base leaching step and/or comprise multiple combined attrition and acid leaching steps. Suitable apparatus comprises an attrition mill with a disposable grinding chamber with deviation bars on an internal surface thereof and attrition arms mounted on a shaft located therein and an integrated air floatation system.