DRY PROCESSING OF BORAX BY CALCINATION AS AN ALTERNATIVE TO WET METHODS

Beneficiation of borax in the Kirka concentrator, Turkey is presently accomplished by wet processing techniques involving scrubbing of the m inus 6 mm borax to remove the undesirable clayey impurities followed b y cyclone and spiral classification of the fine fraction. The fine bor ax tailings assaying as high as 20% B2O3 mostly below 0.2 mm is dispos ed into the environment. Over a quarter million tons of borax in the s aturated brine have now accumulated in vast tailing ponds for a new re mediation technology. Zn this study, a new alternative technology to w et processing is proposed, This technique encompasses the calcination of borax at 450 degrees C to a maximum growth in size followed by frag menting and air classification of the fine gangue minerals. Comparison of the wet and dry processing schemes reveals that the dry technique yields superior results in terms of the concentrate recoveries and tai lings grade. The results of the air separator show a concentrate grade of 51.05% B2O3 With 93.75% recovery. A thermodynamic analysis conduct ed on pure borax along with other boron minerals is presented to expla in the relationship between the maximum growth of borax and the optimu m upgrading conditions. These results indicate that the dry processing not only provides a successful beneficiation scheme but also a plausi ble alternative for the abatement of the environmental pollution from boron concentrators. (C) 1998 Elsevier Science B.V. All rights reserve d.