Mineral tanning involves tanning with a group of tanning agents. These do not include vegetable tannins. Salts of various minerals have tanning properties. The tannins of the vegetable tannins are water-soluble. In the case of mineral raw materials, the water-soluble salts must be obtained by means of extensive chemical processes. The tanning ability of chromium, aluminium, zirconium, titanium and iron salts is known. In the area of mineral tanning, chrome tanning is by far the most important.
Chromium (III) oxide in powder form.