Bleaching Clay

A type of Clay which is highly adsorptive and consists mainly pf hydrated aluminium silicates. It is used as a bleaching agent, and as an adsorbent in decolorizing and refining oils and fats. Fuller's earth is a mineral substance characterized by the property of absorbing basic colors and removing them from oils. It is composed mainly of alumina, silica, iron oxides, lime, magnesia, and water, in extremely variable proportions and is generally classified as a sedimentary clay. In color it may be whitish, buff, brown, green, olive, or blue. It is semiplastic or nonplastic and may or may not disintegrate easily in water. It was originally used in the fulling of wool to remove oil and grease but is now used chiefly in bleaching and clarifying petroleum and secondarily in refining edible oils. Before it can be used, it has to be crushed and dried. In general Bleaching Earth is a decolourising agent which will change the tint of any coloured oil to a lighter shade by changing the basic colour units in oil, without altering the chemical properties of the oil. Bleaching Earths are special clays activated by physical or chemical processes.

Typical Applications:
* bleaching and clarifying petroleum
* refining edible oils