To provide a method for treating fine powder comprising a lead component and a calcium component in which the recovery rate of a lead component is high, and which can recover the lead component and the calcium component in a classified way.

The treatment method includes: a step (A) of mixing fine powder comprising a lead component and a calcium component (such as molten fly ash), water and a sulfurizing agent (such as sodium hydrosulfide) to obtain slurry comprising lead sulfide; a step (B) of adding hydrochloric acid to the obtained slurry, regulating its pH to 2 to 7, eluting out the calcium component in the fine powder to obtain slurry comprising the lead sulfide and the eluted-out calcium component; a step (C) of adding a hydrophobing agent to the slurry obtained in the step (B), and hydrophobing the lead sulfide to obtain slurry for floatation; and a step (D) of subjecting the slurry for floatation to floatation treatment to obtain a float comprising the lead sulfide.

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