Allanite

Lanthanum is found in rare-earth minerals such as cerite, monazite, allanite, and bastnasite. Monazite and bastnasite are principal ores in which lanthanum occurs in percentages up to 25 percent and 38 percent respectively. Misch metal, used in making lighter flints, contains about 25 percent lanthanum. 

Also includes Pb, U and Th data for accessory phases allanite, leucite and aenigmatite Mineral abbreviations ... 

Other accessories that may play an important role in the fractionation of some U-series elements, include, monazite, apatite, allanite, titanite, thorite and chevkinite. Hermann (2002) has recently determined experimentally the partitioning of U, Th and lanthanides between allanite and granitic melt at 2.0 GPa and 900°C. He finds D ] = 20 and Z)tii = 60, confirming that allanite can play an important role in controlling U-Th budgets in silicic melts. The very high Z La in the same experiment (-200), indicates that allanite will also be an important host for Bi and Ac. 

Hermann J (2002) Allanite thorium and hght rare earth element carrier in subducted crust. Chem Geol 192 289-306... 

The suggestion recently made by Heumann et al. (2002) that U-Th crystallization ages in Long Valley rhyolites can reflect crystallization of accessory minerals like zircon or allanite and not of major minerals, needs to be seriously considered in other studies as... 

Rare Earth Allanite Monazite Gadolinite Fergusonite Euxenite REE, Y, U Kobe, Japan Barringer Hill, Texas Ytterby, Sweden Shatford Lake, Manitoba... 

Praseodymium is the 41st most abundant element on Earth and is found in the ores of mona-zite, cerite, bastnasite, and allanite along with other rare-earths. Praseodymium is also the stable isotope resulting from the process of fission of some other heavy elements, such as uranium. 

Although neodymium is the 28th most abundant element on Earth, it is third in abundance of all the rare-earths. It is found in monazite, bastnasite, and allanite ores, where it is removed by heating with sulfuric acid (H SO ). Its main ore is monazite sand, which is a mixture of Ce, La, Th, Nd, Y, and small amounts of other rare-earths. Some monazite sands are composed of over 50% rare-earths by weight. Like most rare-earths, neodymium can be separated from other rare-earths by the ion-exchange process. 

Europium is the 13th most abundant of all the rare-earths and the 55th most abundant element on Earth. More europium exists on Earth than all the gold and silver deposits. Like many other rare-earths, europium is found in deposits of monazite, bastnasite, cerite, and allanite ores located in the river sands of India and Brazil and in the beach sand of Florida. It has proven difficult to separate europium from other rare-earths. Today, the ion-exchange... 

Dysprosium is the 43rd most abundant element on Earth and ranks ninth in abundance of the rare-earths found in the Earth s crust. It is a metallic element that is usually found as an oxide (disprosia). Like most rare-earths, it is found in the minerals monazite and allanite, which are extracted from river sands of India, Africa, South America, and Australia and the beaches of Florida. It is also found in the mineral bastnasite in California. 

Several minerals have been identified in polished thin sections of various rock types including massive sulphide, gossan, intermediate crystal-lapilli tuff, and felsic ash tuff (Fig. 2). These minerals include apatite, monazite, zircon, allanite, titanite, xenotime, magnetite, cassiterite, cobaltite-gersdorffite, rutile, ilmenite, goethite, sphalerite, galena, arsenopyrite, chalcopyrite, pyrite, and pyrrhotite. These minerals range in size from 20 pm to 250 pm and represent potential Indicator minerals. 

HREE Y, whereas monazite, allanite, synchysite and bastnaesite contain most of the LREE. Based on quantitative data approximately half of the fergusonite mass% is associated mainly with zircon, and <2% of the zircon with fergusonite (i.e., reflecting mass distribution differences in the samples). Therefore, in order to recover the HREE, both minerals must be processed and recovered together. The LREE carriers can be recovered as a group. 

Biotite and magnetite are also usually present and visible in hand specimen, muscovite may be present, and more rarely other oxides may be seen. Field estimates of modes ranged from 20-35 vol.% quartz, 15-35 vol.% plagioclase, 30-50 vol.% potassium feldspar, and 1-10 vol.% biotite. Accessory minerals include magnetite, muscovite, monazite, xenotime, zircon, apatite, epidote, ilmenite, titanite, allanite, molybdenite, and galena. The major U and Th minerals are uraninite and uranothorite. 

Neodymium occurs in nature in the minerals hastnasite, monazite, cerite and allanite. The element always is associated with other rare earths, especially cerium group elements. Its abundance in the earth s crust is about 0.0024%. 

Annabergite HYDROXIDES Acmite-Aegerine Allanite Chalcopyrite... 

Alkali metal azides, 1 79 2 139 Alkali metal cyanates, 2 86 Alkali metal pyrosulfites, 2 162 Alkali metal sulfites, 2 162 Alkaline earth azides, 1 79 Allanite, extraction of, 2 44 Allophanyl azide, formation of, from allophanyl hydrazide, 5 51 Allophanyl hydrazide (1-amino-biuret), 5 48 hydrazones of, 5 51 from methyl and ethyl alloph-anates, 5 50 salts of, 5 51... 

Dollase, W. A. (1971) Refinement of the crystal structures of epidote, allanite and hancockite. Amer. Mineral., 56,447-64. 

Allanite Silicate Monoclinic 3.5—4.2 5.5-6 Greenland, Scandinavia, Germany (Saxony), Russia, U.S.A., Japan, Madagascar, India, Australia and Brazil... 

Since oil shale is fine-grained and typically does not contain any trace element-loaded minor minerals such as allanite or zircon, inhomogeneity of the pulverized sample is not likely. Table II shows analytical results for rubidium and strontium on different 0.500-g splits (16) and 300-/xg replicates (21), For most of the elements studied, homogeneity is retained down to the SOO-fig sample sizes. 

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