Pneumatic Transport, Triboelectric Beneficiation for the Florida Phosphate Industry
The beneficiation of phosphate ores, fine feeds, rougher concentrates and flotation concentrates from the Four Conner and Hopewell, Florida plants of IMC was investigated using pneumatic transport, triboelectric separation technology. Because the system relies on establishing bipolar charge on physically distinct particles, four types of charging configurations were used, including horizontal and vertical tube chargers, and circular and octagonal triboroller chargers. Process parameters, including electric field strengths, gas transport speeds within the chargers and electric field zone, phosphate feedrates and triboroller rotation speeds were varied to examine their effect on removing silica and other insolubles from the phosphates.
Since triboelectric beneficiation is a dry technology, a cost estimation was performed for drying phosphates from 15% moisture down to 4% moisture. It is suggested that moisture below a 4% level is located within macropores or cracks within the particles.
The products from triboelectric separation had grades and P2O5 recoveries equivalent to the currently used wet, beneficiation technology for phosphate upgrading. Because triboelectric technology is not limited to processing only the +105 µm (150 mesh) particles, its application could be beneficial for the phosphate industry if precise cost calculations were performed to establish niche product applications and process drying requirements.