HEAVY METAL REMOVING METHOD AND HEAVY METAL REMOVING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide a method and apparatus for removing heavy metal, which enable usage amounts of a neutralizing agent to be reduced.SOLUTION: A neutralization tank includes: a vertical-type cylindrical reaction vessel 110; agitation blades 120 provided inside the reaction vessel 110; an annular aeration tube 130 provided to a bottom part of the reaction vessel 110 and further provided with a plurality of air outlets 131; and a baffle plate 151 provided inside the reaction vessel 110. A leaching residue and a nickel barren solution are process solutions which include, as a heavy metal, at least one ion of divalent iron ions and divalent manganese ions and which are discharged from a wet smelting plant for nickel oxide ore. In the neutralization tank, while the leaching residue and the nickel barren solution are agitated by the rotation of the agitation blades 120, aeration is performed by introducing an oxidizing gas from the plurality of air outlets 131 in the aeration tube 130, thereby neutralizing the leaching residue and the nickel barren solution.