De-coloring of vegetable oil, fats and mineral oils has remained in practice for centuries. Raw material used consists mainly of Bentonite Clay or Montmorillonite, which has little or no decolorizing property in raw state. By treatment with acid, the bleaching power has considerably exceeded that of natural clay. This characteristic is developed due to surface alter, and important changes in its chemical or physiochemical nature.
Term “BLEACHING” is reserved for the treatment designed solely to reduce the color of the oils. The standard method of bleaching by using Activated Bleaching Earth is based on bleaching by adsorption. In addition to its power to remove Red and Yellow pigments, Acid Activated Bleaching Earth is also quite effective in removing Phosphatides and various mucilaginous materials present in most of the oils, referred to commonly as “Gum” or “Slime”.