Investigation of Effects of Nanobubbles on Phosphate Ore Flotation

Abstract

Phosphorous is vital for life, including plants, animals, and human beings and it is an essential component in agricultural fertilizers and phosphorous-based chemicals. Phosphate ores, mainly in the form of apatite and collophanite, are non-renewable natural resources of phosphorus. Froth flotation has been used in the phosphate industry for more than half a century as the primary technique for upgrading phosphate. Nevertheless, flotation does not produce satisfactory performance for phosphate beneficiation in many cases, especially for very fine and coarse phosphate particles. This study was performed with an aim to develop a nanobubble enhanced flotation process to enhance phosphate flotation efficiency. A specially designed flotation column featured with a nanobubble generator and a conventional bubble generator was employed to assess the effects of nanobubbles on the phosphate ore flotation performance under different operating conditions. Flotation process parameters investigated include feed flow rate, dosage of collector, dosage of frother, flotation time, etc.  The flotation results have shown that use of nanobubbles increased P 2 O 5 recovery by up to 30% for a given Acid Insoluble (A.I.) rejection, depending on phosphate concentrate grade. Nanobubbles reduced the collector and frother dosage by about 50% and also increased flotation kinetics. The improved flotation performance can be attributed to increased collection efficiency and surface hydrophobicity in the presence of nanobubbles.