FROTH FLOTATION OF MONAZITE AND XENOTIME

The flotation of monazite and xenotime using sodium oleate as collector has been investigated using a modified Hallimond tube and also by a technique which measures particle-bubble adhesion strength. The zeta potential of both minerals was also measured. There has been a wide range of values reported in the literature for the point of zero charge (pzc) of monazite, the results here indicate the pzc occurs at pH 5.3. For xenotime the pzc was found to occur at about pH 3.0, there appear to be no other values reported. Maximum floatability of both minerals occurred at pH values greater than 7, where the mineral surfaces were negatively charged suggesting that the anionic oleate collector is not physically adsorbed. The flotation results were found to correlate well with the distribution of Re(OH)2+ species in aqueous solution, suggesting the collector is chemisorbed. The results also confirm previous indications that xenotime is slightly more floatable than monazite.