HYDROTALCITE-LIKE COMPOUND AND ITS MANUFACTURING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a hydrotalcite-like compound (a lamellar double hydroxide) containing metal ingredients originating from melting dust and its manufacturing method. SOLUTION: Acid-soluble metal ingredients (including iron and zinc) are extracted by treating melting dust discharged from a melting furnace for cast iron with hydrochloric acid. Hydrogen peroxide solution is added to the extracted liquid to oxidize residual bivalent iron to make it trivalent iron. A magnesium-containing salt (such as magnesium chloride) is blended in the liquid and the pH of the liquid is controlled so as to precipitate a product. The precipitated product is separated and is treated by alkaline water heat treatment if necessary. The obtained product shows XRD pattern characteristic of the hydrotalcite-like compound and has good ion-exchange performance, especially with nitrate ion.