To provide a method for treating fine powder, capable of maintaining the addition amount of a sulfating agent for generating lead sulfide at an optimum value at all times by a simple method without measuring the content of lead in the fine powder containing a calcium component and a lead component, and recovering the lead at a high recovery rate at all times as a result.

The method for treating the fine powder containing the calcium component and the lead component includes: (A) a process of mixing the fine powder which is a treatment object, water and the sulfating agent to obtain slurry containing the lead sulfide; (B) a process of measuring the redox potential of the slurry and adjusting the addition amount of the sulfating agent in the process (A) so that the value of the redox potential is within the range of -230 to -670 mV; (C) a process of adding sulfuric acid to the slurry which has gone through the process (B) to adjust pH to 1.5 to 7.5 and obtaining the slurry containing the lead sulfide and calcium sulfate; (D) a process of adding a collector to the obtained slurry and hydrophobing the lead sulfide; and (E) a process of performing floatation treatment to the obtained slurry and obtaining float containing the lead sulfide and precipitation containing the calcium sulfate.

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