Graphite-Clay Crucible: Plumbago and Fireclay, the Battersea Works Way (Thorpe 1912)

A graphite (plumbago) crucible is a melting pot of graphite bound with clay: fine grained, it stands the highest heats and sudden changes of temperature, and Thorpe counts it of great value for melting metals. Thorpe's Dictionary of Applied Chemistry (1912) gives the Battersea works process: Ceylon plumbago ground, sifted and digested with dilute sulphuric acid to take out most of its iron, kneaded with about its own weight of fine fireclay, pugged, cut into blocks, pugged again, thrown on a wheel or moulded, dried and baked in saggars. Acid strength, sizes and baking heat are not given. Source: Thorpe, Dictionary of Applied Chemistry vol. II (1912), CRUCIBLES, p. 170. Picture: that paragraph.