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Recovering dissolved metal from waste produced when manufacturing phthalocyanine pigments, etc. by adding strong acid, adding complex to precipitate metal and filtering off precipitate
Recovering dissolved metal from waste produced when manufacturing phthalocyanine pigments, etc. by adding strong acid, adding complex to precipitate metal and filtering off precipitate
Metal dissolved in acidic and/or basic waste from an organic chemical process is recovered by adding a strong acid to adjust and maintain its pH to 0 - 4. Then a complex is added to precipitate the metal and this is allowed to settle. The solution is filtered to produce an acid sludge including the metal and a filtrate with a reduced metal content. Preferred Features: Preferably sulfuric acid is added to reduce the pH to 3 and sodium dimethyldithiocarbamate is added to precipitate the metal. Then a potential = 150 - 300 mV is applied via a silver/silver chloride electrode. Ferric chloride in the solution assists settling of the precipitate before it is separated using a filter press. The metal recovered is iron, cobalt, nickel or copper.
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