The RDN regeneration method for decalcification of thin juice

A new, flexible regeneration method, “RDN” (ResinDioN), is presented for thin juice decalcification by ion exchange. Hereby NaOH is added to thick juice and this syrup is used as regenerant. The high ability of thick juice and alkaline thick juice as regenerant was demonstrated by equilibrium and dynamic model experiments. Laboratory tests proved the effectiveness of the RDN method. Two possible methods with varying amounts of added NaOH are outlined, whose use depends on juice quality, lime salts’ content, necessity for alkali addition, or other aims in beet processing. The following benefits can be expected by applying the RDN method: – low quantity of NaOH; – lower, or eliminated alkali addition (if alkali addition is necessary, cost-effective chemicals can be used, i.e. Na2CO3); – long life of resin, because no precipitations are formed in the course of regeneration; – conservation of heat energy: cooling of thick juice is necessary only in the alkaline regeneration step, and only down to a temperature (ca. 60 °C) at which colour formation is avoided in alkaline media; – the calcium concentration in molasses can be regulated as desired. The RDN method has been tested in factories successfully. Up to now there have been no reports on long-term technical application.