Chromium alum – Kcr(SO4)2.12H2O

History of Chromium Alum

The name “chrome” comes from the Greek word chroma, which means “color”, because of the large number of brightly colored compounds of this element.

The first minerals containing chromium (or rather, a lead chromate) were found in 1761 in the Ural Mountains, and initially identified as a compound of lead, selenium and iron.

In 1770 was found in the same site another red “lead mineral”, that could be used as a pigment for paints.

This mineral, called Siberian red lead, developed rapidly.

In 1797, by mixing crocoite (a mineral containing chromium) with hydrochloric acid, chromium oxide (VI) (Cr03) was obtained for the first time. A year later it was discovered that metallic chromium could be obtained by heating the oxide in a bed of coal.

From then on, chromium was identified and classified as a chemical metallic element.

During the 19th century chromium was mainly used to prepare various paints and pigments. Today the main use of chromium (85% of the total) is for metal alloys (stainless steel in particular), with the rest divided between the chemical industry (tanneries, pigments for paints and ceramics) and foundries.