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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.
Leaching with Acids
Published in C. K. Gupta, T. K. Mukherjee, Hydrometallurgy in Extraction Processes, 2019
Monazite sand, which is also known as black sand because of its black color, is usually found at the mouths of great rivers and is a complex mixture of minerals including ilmenite, magnetite, quartz, zircon, and monazite. The mineral monazite is a rare earth phosphate that contains appreciable amounts of thorium and small amounts of uranium, and although it may be present in the sand at a concentration of only 1 or 2%, it can be enriched easily to 80 to 85%. As a concentrate, monazite contains 24 to 29% P2O5, 55 to 60% rare earth metal oxides, 5 to 10% thorium oxide (ThO2), and 0.2 to 0.4% uranium oxide (U3O8). Monazite is the chief thorium ore and is chemically very inert.
Chemical Aspects of Nuclear Processes
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
The leachability of radioelements from minerals varies widely. Monazite, a mineral containing uranium and thorium, shows exceptional stability to radiation damage even after thousands of millions of years. Such materials are considered as model compounds for the incorporation of radioactive wastes, in particular those containing α-emitting transuranium nuclides.
Review on the environment friendly leaching of rare earth elements from the secondary resources using organic acids
Published in Geosystem Engineering, 2022
Riya Banerjee, Saswati Chakladar, Ashok Mohanty, Sanchita Chakravarty, Shyamal Kumar Chattopadhyay, M.K. Jha
The most commonly mined minerals for REEs are monazite, bastnaesite and xenotime, (Clark & Henderson, 1984; Jordens et al., 2013). The largest deposits of bastnaesite in the world are found in China and the United States. Monazite deposits are widespread, found primarily in Brazil, South Africa, China, India, Australia, Malaysia, Sri Lanka, Thailand and the United States. Xenotime, which is iso-structural with zircon, is found in Norway, Sweden, Brazil and North Carolina. Apatite, eudialyte, cheralite, loparite, phosphorites, secondary monazite and spent uranium solutions comprise the remaining resources. Another interesting occurrence of REEs is in the form of ion-adsorbed deposits, which are abundant in southern China. It is typically formed as a result of weathering which leads to adsorption of REEs onto the surfaces of clay minerals such as kaolin, feldspar and mica (Chi & Tian, 2008; Liu et al., 2018).
Occurrence, geochemistry and provenance of REE-bearing minerals in marine placers on the West Coast of the South Island, New Zealand
Published in New Zealand Journal of Geology and Geophysics, 2021
Stephanie L. Tay, James M. Scott, Marshall C. Palmer, Malcolm R. Reid, Claudine H. Stirling
As characterisation of monazite and xenotime has not been undertaken in New Zealand, the REE patterns of metamorphic and igneous monazite and xenotime in potential West Coast source rocks is unknown. However, the inspected monazite grains have REE patterns similar to those from minerals precipitated from a granitic magma (Zhu and O’Nions 1999). The analysed monazite grains contains on average 5 wt.% Th (6% ThO2) but can reach 25 wt.% Th (27% ThO2). Monazite forms solid solution with huttonite and thus REE can be substituted for Th and P can substitute for Si (Frondel 1958; Kucha 1980; Förster et al. 2000). Analysis GRY-33, which contains 25 wt.% Th, also contains elevated Si and depleted REE compared to other monazite grains. It appears that this grain is either a chemical hybrid of monazite and huttonite, or a composite grain. The high concentrations of Th would have a large implication in the potential mining of monazite because of its radioactive properties. Since no xenotime was found south of the Karamea Coast, it may have been supplied by a more local source such as the Foulwind Granite (Figure 6).
Recovery and Recycling of Cerium from Primary and Secondary Resources- a Critical Review
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Monazite is a phosphate mineral [(Ce, La, Nd, Th) (PO4, SiO4)], which constitutes around 42–51% Ce along with noteworthy elements such as La, Sm, Pr, and Nd, along with 4–12% thorium and a variable amount of uranium. It is found throughout the world in placer deposits, beach sands, and is a component of the Bayan Obo deposit. It is widely distributed in the Earth’s crust and occurs in small proportions in granites. When such rocks are weathered, grains of monazite are carried by water and are deposited at the mouth of the rivers, along with the heavier constituents of the parent rock, to form black sands known as monazite sand. The monazite in these sands is usually present as rounded grains, which shows that the grains have been previously rolled back and forth in streams of water.