To carry out, when treating a zinc raw material using an acid solution of sulfuric acid in the treatment of the zinc raw material in a zinc hydrometallurgy, the precipitation of silica etc. eluted in the above acid solution of sulfuric acid rapidly in a state where solid-liquid separation is facilitated.

In this treatment method, a liquid portion of an electrolytic tailing solution and a liquid after iron removal in the zinc hydrometallurgy are mixed to prepare a leaching solution. After heating, a prescribed amount of Pb/Ag residue produced in the zinc hydrometallurgy is fed as an additive to the leaching solution to leach out a roasted matter of the zinc raw material. After the completion of the leaching, a coagulating agent is added to the resultant leaching solution, and eluted silica etc. are separated as a slurry.

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