Palladium is a platinum element, which has a wide range of applications in automobile exhaust purification, petroleum hydrogenation, pharmaceutical synthesis and other fields. Palladium catalyst is a substance that uses the catalytic action of palladium to accelerate chemical reactions, it usually exists in solid or liquid form, palladium catalyst will gradually fail or pollute during use, forming palladium-containing waste, today we share a method of refining palladium in palladium catalyst waste.
The palladium catalyst waste is crushed, screened, washed and other processes to remove organic matter, oxides and other impurities attached to the surface to reach a certain particle size.
Then, the pretreated palladium catalyst waste and the reducing agent ammonia are placed in the reactor, and the reduction reaction is promoted by controlling the conditions such as temperature and pressure, and the reducing agent forms a complex with the palladium in the waste, and finally reduces to pure palladium, and the time and temperature of the reaction are the key parameters, and the optimal conditions need to be determined by experiments to improve the efficiency of the reaction and the purity of the product.
The reduced palladium appears in the form of a precipitate, and in order to separate the palladium from the reaction mixture, the precipitant sodium hydroxide is usually used to form a poorly soluble precipitate of palladium, and after the reaction, the resulting palladium precipitate is separated by centrifugal filtration.
The separated precipitate containing palladium still contains a small amount of impurities, so solvent extraction is required to further improve the purity, here we choose the organic solvent dimethylbenzene as the extractant, generally after multiple extractions to effectively remove the residual impurities, in the process of solvent extraction, palladium is dissolved in the organic phase in the form of complexes, while other impurities are left in the aqueous phase.
The extracted organic phase contains high-purity palladium, which can be extracted from the organic phase by steaming, in which the organic phase is heated and distilled, and the palladium is evaporated at boiling point temperature and condensed into a liquid in a condenser.
Finally, it is put into a high-temperature furnace for smelting, poured into the mold after smelting, cooled to obtain bulk metal palladium, the refined palladium is analyzed and detected to ensure that its quality meets industrial requirements, spectroscopy, mass spectrometry and chemical analysis are generally used to ensure the stability of the refining process and the high purity of palladium.
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