Alum

Alum

Description

A general name used for aluminum sulfate salts. Most commonly the term alum, or potash alum, refers to aluminum potassium sulfate. It is a colorless, crystalline material used in the tawing of skins and as a mordant for many natural dyes. For papermakers, the term alum, refers to aluminum sulfate or the mixture of aluminum sulfates obtained by treating pulverized bauxite with sulfuric acid. In cooking, the term alum refers to aluminum ammonium sulfate. Other materials referred to as alum are ferric ammonium sulfate, chromium sodium sulfate, and chromium ammonium sulfate.

FTIR

Synonyms and Related Terms

aluminum potassium sulfate; aluminum ammonium sulfate; aluminum sulfate; alum cake; alunite

Authority

• R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966 Comment: aluminum hydrate: uses the term 'alum'

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 32

• The Dictionary of Paper, American Paper Institute, New York, Fourth Edition, 1980

• E.J.LaBarre, Dictionary and Encyclopedia of Paper and Paper-making, Swets & Zeitlinger, Amsterdam, 1969

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• Susan E. Schur, Conservation Terminology: A review of Past & Current Nomenclature of Materials, Technology and Conservation, Spring (p.34-39); Summer (p.35-38); Fall (p.25-36), 1985