Regeneration of resins used for decolorization of sugar solutions is done with concentrated salt solutions. Nanofiltration membranes have been proven effective, in terms of industrial efficiency in decreasing salt consumption. More than 90% of the salt that is necessary for regeneration can be recycled through a combination of direct recycling of intermediate eluates, the separation of colored compounds by use of very selective nanofiltration membranes and a system to concentrate salty permeates. According to specific local conditions on energy supply and cost, the concentration of salty permeates can be either a multiple effect evaporator or a combination of electrodialysis and reverse osmosis. The desalted color compound solution is sent to the molasses, limiting considerably the effluent to be treated. Starting from a liquor of 800 IU, the water requirement is limited to less than 100 L/t of sugar and the amount of wastewater can be reduced to less than 40 L/t of sugar.
PROSPECTS OF RARE ELEMENTS SORPTIVE RECOVERY AND ION-EXCHANGE SEPARATION FROM COMPLEX SALT SOLUTIONS
