1. MONAZITE BENEFICIATION BY FLOTATION: A LITERATURE REVIEW Abstract Technology advancement has led to a rise in the demand of rare earth elements, which is also reflected in increasing research on the recovery of rate earth elements. Monazite, the second most important rare earth bearing mineral, can be concentrated using gravity separation or flotation. Literature on the flotation of monazite is scarce. The existing literatures are focused on the separation of monazite form bastnaesite, rutile, steenstrupine, xenotime, ziron. Introduction Monazite is a rare earth phosphate mineral. It is the second most important rare earth mineral after basnaesite. Monazite contains up to 70% of rare earth elements, 4-12% thorium, and small amount of uranium (Jordens and al., 2012). Rare earth elements are extracted from monazite by alkaline leaching or acid leaching followed by solvent extraction to remove the thorium content. (Barghusen and Smutz 1958). Due to its high specific gravity, monazite can be recovered together with heavy minerals by gravity concentration. However, this process becomes less efficient as particle size decrease. Hence, the concentration by flotation is used. Recent trend in the market of rare earth metals has led countries other than China to invest in researches on the beneficiation and recovery of rare earth elements. Gangue Minerals Available researches are focused on the separation of monazite from its gangue mineral including bastnaesite (Ren et al. 1999), Rutile (Pavez and Peves 1992, Abeidu 1972), Steenstrupine (Sorensen and Lundgaard 1966), xenotime (Cheng 1999), zircon (Pavez and Peves 1994). Monazite in deposits can also be associated with apatite, quartz, ilmenite, etc… Zeta Potential The zeta potential of monazite in water is negative at high pH, and increases towards positive values at lower pH. There is a wide range of PZC of monazite from published literature (Cheng 1999). The difference of PZC is attributed to impurities, differences in mineral composition and experimental methods. PZC of MonaziteReferences 1.1 – 3.2Houot et al., 1991 3.1Harada et al., 1993 3.4Houot et al., 1991 5.0Luo and Chen, 1984 5.1Harada et al., 1993 5.2Paves and Peres, 1993 5.3Cheng et al., 1993 5.5Houot et al., 1991 5.5Houot et al., 1991 5.5Harada et al., 1993 6.1Houot et al., 1991 6.4Salatic, 1967 6.8Harada et al., 1993 9.0Houot et al., 1991 Flotation Results The flotation of monazite is similar to that of its gangue minerals. Addition of 600 mg/L sodium metasilicate reduces the recovery of rutile and zircon to 20% or less, while keeping the recovery of monazite at 80%. Addition of potassium alum enhances the separation of monazite from basnaesite by depressing monazite. Monazite and xenotime can be separated at pH 7 using sodium oleate at 7 E-6 M. Mr. Josue Nduwa Mushidi Advisor : Dr. Corby G. Anderson The Kroll Institute of Extractive Metallurgy. Colorado School of Mines, Golden, Colorado USA Contact Mr. Josue Nduwa Mushidi Kroll Institutefor Extractive Metallurgy Colorado School of Mines. Golden, Colorado USA 80401 Email: jmushidi@mines.edu Tel: 720-934-4640jmushidi@mines.edu