On a single day, April 2, 1889, Charles M. Hall was awarded five patents for his discovery of the electrolysis process for extracting aluminum metal from aluminum oxide. To honor and celebrate Hall's breakthrough discovery under the CCB program of the Division of the History of Chemistry, it was necessary to identify which of the patents disclosed the breakthrough method. All five patents were carefully reviewed, as were the circumstances of the applications for the patents. As part of this evaluation, the question of why so many patents arose. Was more at stake than an inventor attempting to make the patent claims as broad as possible? The evidence reveals that problems with the original process on the small scale propelled Hall's determined investigation of alternative formulations of electrolyte baths and of different cell designs. Based on this analysis, one of the five patents was signaled out and was honored by the CCB award.

Charles M. Hall's patent for refining aluminum metal by electrolysis

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.