Activated Fuller’s Earth used in the contact process employed for decolorizing oils (edible & petroleum), greases and waxes is in the powder form. It highly improves its Tintometer readings.
CONTACT PROCESS CLAY
Contact filtration process: Contact filtration is the direct agitation of a mixture of a very fine clay and oil, usually at elevated temperature, for a definite period of time to accomplish a desired result.
Bleaching: The selective removal of pigments from oils and fats by adsorption on clay, specially chosen and activated for specific effects is a term known as bleaching.
PERCOLATION PROCESS CLAY
Activated Fuller’s Earth is also used in the percolation filter process is in the granular form, this process is usually used for light colour oils like base oil distillates, mainly to improve it UV and PNC values.
Percolation: The term ‘percolation‘ is given to that method of filtering in which the oil to be decolorized is passed through a bed of granular adsorbent aided via the help of gravity.
Filtration: Filtration is the general term applied to the process of removing colour and suspended matter from base stocks for specialty products.