Enhanced Recovery of Potassium from Sugarcane Molasses for Fertilizer

Sugarcane molasses, by-product of sugar production, contains potassium at relatively high ratio and it has a high potential for the source of potassium fertilizer. The present study proposed a simple two-step precipitation method for the recovery of potassium-containing solid, syngenite, from sugarcane molasses. The first precipitation with water recovered more than 30% of potassium in the original molasses. The second precipitation with the mixture of calcium acetate and sulfuric acid resulted in about 40% of the original molasses. Totally, more than 70% potassium was successfully recovered. The applicability of this method was examined with eight kinds of molasses obtained from eight factories in Japan. For all the molasses, syngenite was successfully recovered without any difficulties in processing, and the recovery ratio was more than 70%. Thus, the method will satisfy the growing demand of potassium fertilizer and also to enhance the sustainability of sugarcane sugar production.