Keyword : detergent fractionation

The process involves crystallization of the oil and separation of fractions aided by a detergent ( sodium lauryl sulphate solution ) and an electrolyte ( magnesium sulphate ). The electrolyte helps in agglomeration of oil droplets formed during the mixing process. The detergent helps in fractionation as it wets the stearin crystals and displaces occluded and entrained olein. The lower density olein can be separated from the stearin-detergent mixture of higher density by centrifuging. The traces of detergent in olein can be removed by washing. The heavier stearin phase containing most of the detergent is heated to melt the stearin and then sent to a second centrifuge where the stearin is separated from the detergent. The detergent separated from the stearin is then recycled.