Bone char (animal carbon) was the first decolourizer to be used in sugar industry. Initially, refineries were supplied with ox bones which, after burning, were mixed with liquors. Nowadays, char is used in columns where liquor flows through the char. After the decolourization cycle, char is washed and removed from the columns to be regenerated by heating to 550ºC, in presence of a limited air quantity (Riffer, 1993).
After the seventies of last century, char was almost completely replaced by vegetable granular activated carbons. These carbons are utilized in two forms granular (activated carbon - granular ) and powder (activated carbon - powder). They present a specific surface area ten times higher than char, and consequently, their decolourizing capacity is much higher (Field and Benecke, 2000). Less carbon is therefore needed to achieve the same colour removal.
Field P.J., H.P. Benecke, 2000, Granular carbon decolorization system, in
Handbook of Sugar
Refining, Ed. C.C. Chou, Pub. John Wiley & Sons Inc., 91-119
Riffer R., 1993, Decolorization, in Cane Sugar Handbook, Ed. J.P.C. Chen, C.C.
John Whiley & Sons Inc., 12ª ed, 460-467