Improved Phosphate Flotation with Nonionic Polymers
Bench scale flotation experiments have been conducted to study the effect of nonionic PEO (polyethylene oxide) polymer surfactants on the flotation of Florida phosphate rock. It has been found that PEOs having a molecular weight from 1,200 to 8,000 are effective. Flotation results demonstrate that the addition of nonionic PEO has a favorable effect on phosphate flotation, especially on the flotation of coarse phosphate feed. At about the same collector level, phosphate recovery can be improved by 10-30% with PEO addition.
The surface chemistry of phosphate flotation using the fatty acid/fuel oil/PEO system has also been studied to better understand the phenomena involved. The increase in phosphate recovery with PEO addition has been attributed to improve dispersion of fatty acid, which leads to better froth stability and a more hydrophobic surface state.
Economic analysis of the bench scale experimental results indicates that the high price of PEO can be justified by the improved phosphate recovery and the reduced reagent addition required. It has been calculated that an annual savings of about $280,000 would be generated for a plant processing 4 million tons of phosphate rock per year.