希硫酸浸出-溶媒抽出による混合メッキスラッジからの有価金属の分離 [in Japanese] Separation of Metal Values from Complex Plating Sludge by Dilute Sulfuric Acid Leaching and Solvent Extraction [in Japanese]
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A series of treatment flow consisting of sulfuric acid leaching, precipitating separation and solvent extraction has been studied for separation and recovery of metal values from complex plating sludge containing iron, copper, nickel, chromium and zinc. The results obtained are summarized as follows.<BR>(1) More than 90% of copper, zinc and nickel are extracted by the mild leaching condition in which iron leaching is lower than 10%. Leaching of iron largely depends on the sulfuric acid concentration. Leaching efficiencies of iron and chromium decrease with increasing leaching temperature in dilute sulfuric acid.<BR>(2) Iron in the leaching solution is selectively precipitated at pH 4 by pH control with ammonia solution. Other elements except iron are not able to be separated by pH control.<BR>(3) Zinc is selectively extracted at pH 2.5 by PC-88A. Zinc extracted by PC-88A is perfectly stripped to the aqueous phase at pH lower than 1.<BR>(4) Copper is selectively extracted at low pH by LIX84-I, and the selective extractability of copper is perfect up to pH 5. Extraction of nickel starts at pH 5, and almost all nickel is extracted at pH 7 by LIX84-I. Chromium is not extracted by the solvent.
Shigen-to-Sozai 123(1), 45-49, 2007-01-25
The Mining and Materials Processing Institute of Japan