The best solution to meet national standards for removing heavy metals in the production of zinc chloride

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Personal experience sharing: In the production process of zinc chloride, zinc chloride is produced by reacting by-product industrial hydrochloric acid with zinc-containing waste materials. The reaction is stopped when the pH of the mixture reaches 4-5. Then, a fixed amount of potassium chlorate is added to the reaction vessel to oxidize ferrous iron to ferric iron. Subsequently, filtration takes place; potassium permanganate is added to the filtered solution to cause ferric iron to precipitate as iron hydroxide. After precipitation, zinc powder is added to displace the heavy metals, and finally the material enters the evaporation stage, resulting in the final product. This is the conventional method; originally, using iron tower factories or high-quality zinc ash was sufficient. Recently, we have imported a large amount of imported waste zinc ash, but the products produced are always light green in color. Analysis shows that the levels of heavy metals such as nickel, chromium, and copper are relatively high. The conventional methods didn’t work; after a month of effort, the problem was solved. Once, I added a few drops of potassium permanganate solution to the purified liquid in a beaker; the solution turned pink. When heated, the pink color disappeared ； Potassium permanganate was added again, and heating caused the color to disappear once more, until no color change was observed any longer. Then zinc powder was used to replace the heavy metals, and after testing, the resulting material met battery standards. In actual production, when adding potassium permanganate, the solution is heated to 70–80 degrees using boiler steam; when using zinc powder for displacement, the reaction mixture is heated to 60 degrees. By doing so, the product will definitely meet the national standards. This post was last edited by Canghai Yili Sha on 2009-2-12 at 19:44.]