SOME ASPECTS ON THE FROTH FLOTATION PROCESS OF ULTRAFINE KAOLIN

This paper aims to upgrade an Egyptian kaolin by the conventional frot h flotation technique to reduce its anatase impurities (TiO2%) to be s uitable for paper coating and fine ceramic industries. The flotation t ests were carried out on a kaolin preconcentrate sample of about 80 wt . % below 1.95 mu m The tests were performed using sodium silicate as a depressant and oleic acid as a collector. The different operating pa rameters were studied. The results showed that the mechanical factors, such as the speed and time of conditioning, played the vital role in determining the efficiency of the flotation process for such ultrafine particles. For example, changing the dosage of collector or the pH of the medium have no influence on the grade of the produced concentrate s when the flotation process was performed at low conditioning speed o r for short conditioning time. However, the reverse trend was noticed when the flotation tests were carried out at high conditioning speed a nd after long conditioning time. Meanwhile, the presence of an activat or or raising the conditioning temperature to about 40 degrees C can r educe further the TiO2 content. At the optimum operating conditions a concentrate of about 0.63 % TiO2 with a % removal of 77.5 was obtained from a feed containing 1.52% TiO2. Also, the whiteness degree was sig nificantly improved to 79 ire comparison with 56 for the flotation fee d.