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Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Monazite is a phosphate mineral that contains rare earth metals in four different groups determined by the composition of the REMs present: Monazite-(Ce), (Ce, La, Nd, Th)PO4Monazite-(La), (La, Ce, Nd)PO4Monazite-(Nd), (Nd, La, Ce)PO4Monazite-(Sm), (Sm, Gd, Ce, Th)PO4 Monazite which may contain some silica is an important source of thorium [585], lanthanum and cerium [586]. Monazite, often found in placer deposits, is radioactive due to the presence of thorium and uranium.
Unusual REE fractionation and occurrence of monazite-(La,Ce) in single monazite grains from a “Central” gold-quartz vein at Muruntau (Uzbekistan)
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
U. Kempe, T. Graupner, D. Wolf, A.A. Kremenetsky
Our study confirms the occurrence of monazite-(La, Ce) in the Au-quartz veins of the Muruntau deposit (Uzbekistan). The Th-poor monazite shows strong light REE fractionation within single grains or aggregates. Additionally to the finding of monazite-(La,Ce), areas with common monazite-(Ce) or with monazite showing negative Ce anomalies were detected in the grains investigated. The distribution of these areas is related to the patchy internal structure revealed by BSE imaging. It may be assumed that the features observed are related to brecciation processes leading to highly heterogeneous P-T conditions, admixing of surface water, and unusal REE fractionation during monazite formation or alteration.
Lanthanides
Published in Alina Kabata-Pendias, Barbara Szteke, Trace Elements in Abiotic and Biotic Environments, 2015
Alina Kabata-Pendias, Barbara Szteke
LAs are constituents of several minerals, such as monazite [(La,Ce,Th)PO4], bastnasite [(Ce,F)CO3], and cheralite [(Ce,La,Y,Th)PO4]. Lanthanum is also associated with xenotime (YPO4). All these minerals are likely to be concentrated in phosphorites, which resulted in elevated amounts of some LAs in P fertilizers. In addition, some calcite rocks may contain higher amounts of LAs.
Critical review on lanthanum-based materials used for water purification through adsorption of inorganic contaminants
Published in Critical Reviews in Environmental Science and Technology, 2022
Koh Yuen Koh, Yi Yang, J. Paul Chen
Lanthanum oxide that synthesized through an ignition of lanthanum oxalate showed an adsorption behavior similar to the LH for the fluoride removal (Tokunaga et al., 1995). The sorption capacities were 0.588 and 5.888 mmol/m2 at initial pH 6.51 and 3.92, respectively, which are higher than the LH. In addition, the defluoridation of drinking water was studied with LO extracted from monazite-La mineral (Rao & Karthikeyan, 2012). A total fluoride removal of 90% for treating a 4 mg/L-fluoride solution was achieved within 30 min at a dosage of 6 g/L and pH < 9.5. The adsorption was greatly influenced by co-existing carbonate or bicarbonate ions. The spent LO can be regenerated for reuse by a 1% aluminum solution.