Walthal : An obsolete process for obtaining alumina from clay. The clay was roasted, extracted with sulfuric acid, and the aluminum sulfate dried and calcined
Comyns, Alan E. Dictionary, Encyclopedic Dictionary of Named Processes in Chemical Technology (3rd ed.), Alan E. Comyns (Ed.), Boca Raton, FL, CRC Press LLC, USA 2000, http://worldtracker.org/media/library/Science/Chem istry/Synthesis/Encyclopedic%20Dictionary%20of%20N amed%20Processes%20in%20Chemical%20Technology.pdf, (Named Chem Procss - Amer) {35}
