An Investigation into Separation of Impurity from Saffron Stigma Using an Electrostatic Separator

In the present study, a laboratory electrostatic separator was constructed and its separation potential of white saffron impurities from stigma was investigated. The device was comprised of a nylon ribbon which moves in contact with a woolen brush and was charged by the triboelectric effect. The charged ribbon, then, moved over the material pan. Since the electrostatic behavior vary from various materials, their attraction to the ribbon differ. The separation tests were conducted at three levels of ribbon position (with 1.5, 2.5 and 3.5 cm from the material pan), three drum speeds (50, 60 and 70 rpm) and three working times (120, 18 and 240 seconds). The results showed that material absorption increased as working time increased and the ribbon distance decreased. Meanwhile, rising the speed from 50 to 60 rpm improved material absorption while, more increasing from 60 to 70 rpm reduced the absorption. A maximum impurity separation of 97% was observed with ribbon distance of 1.5 cm, ribbon speed of 60 rpm and working for 240 seconds. The minimum stigma losses were found to be about 2% when the ribbon distance and speed were 3.5 cm and 70 rpm, respectively, and the separator worked for 120 seconds