Liquation is a metallurgical process for separting metals. It was particularly used for extracting silver from copper. The copper is heated in a furnace or cupel with a larger quantiry of lead. This leads to the silver migrating into the lead. The metal is tapped and allowed to solidify. The two metals separate as they solidify, with the silver in the lead phase. Heating the result to red heat causes the argentiferous lead to melt and flow out leaving a porous mass of copper behind. The silver can then be extracted from the lead by cupellation, or some more recent process.

References

• R. F. Tylecote, A history of metallurgy (2nd edn, Institute of Materials, London 1992), 89-90.