This work presented a novel approach to beneficiate ultrafine phosphate, aiming to recover phosphate particles that are smaller than 20 μm in size, which have long been considered unrecoverable in the industry. Traditionally, the phosphate industry has followed a standard practice of separating and discarding these ultrafine particles due to processing difficulties such as high viscosity and poor flotation recovery. In contrast to established phosphate beneficiation methods that utilize hydrocyclone classification to remove ultrafines as tailings, the method invented by ChemFit enabled the high recovery of ultrafines through flotation without prior separation.

This work investigated various variables and their impact on the flotation recovery of ultrafine phosphate, including pulp density, water quality during conditioning and flotation, the type of flotation machine used, and reagents employed to depress Fe2O3 and Al2O3. Promising results were obtained using samples containing up to 75 wt% of particles smaller than 20 μm. For instance, from a low feed grade, a P2O5 recovery of more than 93% was achieved, resulting in a concentrate grade of more than 40% P2O5. Similarly, from a feed grade of more than 11% P2O5, a P2O5 recovery of approximately 96% was attained, yielding a concentrate grade of about 35% P2O5. In this work, we found the most effective depressant for Fe2O3, while Al2O3, being hydrophilic, exhibited low recovery levels in the concentrate, irrespective of the use of a depressant. The results were used to specifically design a process to recover phosphate from ores containing particles of up to 80wt% passing 20 μm, employing flotation.