Sucrose - Beet juice decalcification

Sugar beet is a plant which is one of the main source of sucrose worldwide. The sugar campaign begins in September at the harvest period in Europe. The sugar beet are washed, sliced and passed through hot water, delivering the sugar in a form of concentrated but raw syrup.

This raw juice contains variable concentration of undesirable compounds to be removed before evaporation and crystallization. A first step of purification involves addition of lime (CaO) to remove many impurities by precipitation and filtration. At the step, the thin juice contains variable concentration of hardness ( depending the region of production of the beet) to be removed in order to avoid scaling of CaCO3 in the evaporator, or to get too large portion ending-up in the molasses.

The most frequent technique to remove Ca2+ is an exchange with Na+ on a Strong Acid Cation (SAC) resins in Na+ form, mostly supplied on gel type.

In order to be more environmental friendly, an innovative regeneration process (NRS process) has been developed on the fact that in alkaline conditions the calcium saccharate is soluble in water. So, the regenerant is a mixture of decalcified thin juice (cooled) and NaOH. The spent regenerant and backwash water are fully recycled in the process without waste disposal, the rinse is using hot decalcified juice.