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→11.2.3 Chemical Refining
===11.2.3 Chemical Refining===
Special refining scrap, i.e. used precious metal electrolytes, salts, gold plated printed circuit boards, IC scrap, metallic scrap with high melting components such as Ag/W, or composite materials like Ag/Ni, Ag/MeOx and others, precious metal pastes or paste coated substrates, cannot be refined economically in the processes described above. <figure id="fig:Processes for the refining of precious metal scrap">
[[File:Processes for the refining of precious metal scrap.jpg|right|thumb|Processes for the refining of precious metal scrap]]
</figure>
The term chemical refining is used for all refining processes that employ the classic separation methods – dissolving, precipitation, filtration, washing. As opposed to the other methods, the chemical refining process rarely allows the collection of a representative sample. The precious metal amounts contained in the supplied scrap can usually only be determined at the completion of processing. Only for electrolytes and rinse waters is it possible to obtain the expected amount of recovered precious metals through an upfront chemical analysis.
<xr id="fig:Processes for the refining of precious metal scrap"> Fig. 11.3: Processes for the refining of precious metal scrap
