Beneficiation of a deslimed, +0.038/-0.25 mm in size, phosphate ore containing carbonate fluorapatite (francolite), calcite, dolomite, and quartz by froth flotation is accomplished by a special approach based on conditioning the ore with a micro-emulsion consisting of 20 wt.-% Custafloat AR27 (collector, blend of fatty acid soaps and sulfates), 55 wt.-% No. 5 fuel oil and 25 wt-% water at 70 wt-% solid content and subsequent flotation after pulp dilution with water to 25 wt.-% solids. A good selectivity of separation was achieved at pH 8.5 and after 1.5 min conditioning time with micro-emulsion and flotation of the diluted pulp in the next 2 min. The maximum curvature of the upgrading Halbich grade-recovery curve indicated that the most efficient separation for the deslimed phosphate ore having 16.86 wt.-% P_2O_5 in the feed occurred at 0.6 kg/Mg providing concentrates containing 33 wt.-% P_2O_5 with P_2O_5 recovery equal to 70 wt.-%. The same flotation reagents used in a traditional way provided much worse concentrates containing 27 wt-% P_2O_5 with recovery of 60 wt-% at 0.9 kg/Mg of reagents.
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