Pattinson’s process

A process to separate silver from lead through gradual crystallisation.

The process, known as Pattinson’s process or pattinsonisation, was discovered in 1829 by Hugh Lee Pattinson and patented in 1833. It is based on the fact that when raw lead containing precious metals cools, a lead with a lower precious metal content first separates out. The remaining metal is now richer in the precious metal.

The process can be used to transform silver-poor raw lead, from which it is no longer possible to extract silver economically, into lead with a higher silver content. Large quantities of low-grade lead were melted in cast-iron pots and allowed to cool slowly. Pure lead formed as crystals on the surface, and the silver remained behind in the molten mass. The crystals were removed by ladles, and the remaining silver-rich lead removed by cupellation.

Cite as: Pattinson’s process. In: Travel Reports of a Pioneer: Digital Edition of the Travel Journals of Johann Conrad Fischer 1794–1851. Published by Franziska Eggimann. Edited by Franziska Eggimann, Nicolau Lutz, Valerija Rukavina und Christopher Zoller-Blundell. Schlatt 2023, Version 1.2, https://johannconradfischer.com/en/keywords/gfa-keywords-8478, viewed on 7 June 2025.