Frasch, Herman

[frash] (1851–1914) German–US industrial chemist: devised process for extraction of sulphur from underground deposits.

Frasch was the son of a prosperous pharmacist in Württemberg and began his training in pharmacy when he emigrated to the USA in 1868 at age 17. Industry was expanding after the Civil War and he soon interested himself in the new petroleum industry. One of its problems was that some wells yielded a ‘sour’ oil (nicknamed skunk oil) containing sulphur and organic sulphides. Frasch found a method for removing these by reaction with metal oxides. His interest in sulphur changed direction in 1891, when he began work on the problem of obtaining sulphur from deposits overlain by a limestone caprock and by quicksand. His method (the Frasch process) was to sink a trio of concentric pipes into the deposit; superheated water was pumped down one to melt the sulphur (m.p. 119°C) and air down another, to bring up a froth of molten sulphur through the remaining pipe. The process gave an abundant supply of 99.5% pure sulphur and broke the Sicilian supply monopoly after about 1900.