To provide a leaching method which is easily incorporated in an existing zinc smelting system, has a high leaching rate without needing a long time for leaching soluble substances from a raw material, and reduces costs of the facility and the operation, in a leaching process for collecting valuable metals such as zinc, lead and silver, and elemental sulfur from a zinc concentrate.
This leaching method comprises causing a leaching reaction in a slurry consisting of a zinc concentrate, sulfuric acid and iron ions under an oxygen atmosphere pressurized in an autoclave, and repeatedly supplying one part of the oxygen to a leaching solution in the autoclave to continue the leaching reaction. The leaching method further comprises classifying the slurry after the leaching step according to the particle diameter through a plurality of coordinated cyclones to collect coarse elemental sulfur and fine metallic particles like lead and silver, and returning the unleached concentrate having intermediate particle sizes and fine sulfur to the leaching solution.
KANNO MANABU
NARUMI AKIRA
Komatsu Taka
Koji Hagiwara
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