| 摘要 |
A method of recovering gold and palladium from foamed organic substances used for cleaning devices in manufacturing electronic components with the screen process method with the use of conductive pastes including gold, palladium and possibly other noble metals, by means of digestion in sulphuric acid, characterized in that organic substances including noble metals are digested in sulphuric acid whose concentration is not lower than 94 percent, in a temperature between 288 and 303 degrees K, with the mass ratio of the solid phase to the liquid phase falling into the range between 1:14 and 1:60, whereas in the final digestion phase ethyl alcohol is added in the amount of 1.5 - 2.0 parts by volume per one part of the sulphuric acid used. The ethyl alcohol is added in portions and at the same time the temperature of the slurry at a level not higher than 313 degrees K, and after the digestion process is finished, deposit constituting high-grade concentrate of gold and palladium is separated from the solution. The concentrate is then processed according to an already known method.
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