Method for leaching uranium from low grade uranium ore by utilizing acid-alkali-combination technology

The invention discloses a method for leaching uranium from low grade uranium ore by utilizing an acid-alkali-combination technology. The object of the invention is to provide the method for leaching uranium from the low grade uranium ore by utilizing the acid-alkali-combination technology. The method for leaching uranium from the low grade uranium ore by utilizing the acid-alkali-combination technology is characterized by comprising the following steps: (1) soaking the low grade uranium ore with alkali liquor to destroy the gangue composition, thus obtaining alkali liquor soaked uranium ore; (2) stirring the alkali liquor soaked uranium ore in step (1) with sulfuric acid and leaching the uranium ore, thus obtaining low grade uranium ore leaching liquor. The particle size range of the low grade uranium ore is 75-400[mu]m. The alkali liquor is sodium carbonate solution or sodium hydroxide solution, and the concentration range of the alkali liquor is 10-20g/l. The liquid-solid ratio between the alkali liquor and the uranium ore soaked in the alkali liquor is 10:1-15:1, at the same time the alkali liquor and the uranium ore should be stirred slowly at the speed of 200-300r/min and the uranium ore should be soaked in the alkali liquor for 1-1.5h. The content of uranium of the low grade uranium ore is 0.008-0.04%. The concentration of the sulfuric acid is 50-80g/l. The liquid-solid ratio range between the sulfuric acid and the uranium ore is 15-20:1, the leaching time is 0.5-1h and the stirring speed is 400-600r/min. The method is mainly used for leaching the uranium from the low grade uranium ore.