China
Africa
Explore chapters and articles related to this topic
Scandium mineralization associated with hydrothermal lazulite-quartz veins in the Lower Austroalpine Grobgneis complex, Eastern Alps, Austria
Published in Adam Piestrzyński, Mineral Deposits at the Beginning of the 21st Century, 2001
The primary assemblage of lazulite-rich domains is pale green to pale blue lazulite (> 80 Vol%, XMg = 0.92-0.98), fluorine-bearing apatite, subordinate quartz and possibly muscovite. Ubiquitous primary accessory minerals are pretulite, florencite-(Ce), xenotime-(Y) and rutile. The size of pretulite crystals ranges from 1–200 µm. Small grains occur as inclusions in lazulite, whereas the larger grains appear to be confined to lazulite grain boundaries or fractures. Quartz-rich domains consist of recrystallized quartz, apatite and little rutile and xenotime-(Y) and are devoid of pretulite.
Recovery of Rare Earth Elements from Metallurgical Wastes
Published in Hossain Md Anawar, Vladimir Strezov, Abhilash, Sustainable and Economic Waste Management, 2019
Although there are many publications in regards to fly ash utilization, there are only a few looking into its potential as a resource of REE, and even fewer investigating coal fly ashes for extraction of REEs [65, 66]. A review of the occurrence and promising recovery methods of rare earth elements from coal and coal by-products was conducted extensively by Zhang et al. [67], which revealed that the amount of REEs in coal is associated with the inorganic (clay) and organic matrix. The composition of fly ash varies considerably depending on the fuel used in the combustion process, but it consists mainly of metal oxides in different proportions. The main components in coal fly ash are in decreasing order: SiO2, Al2O3, Fe2O3, CaO, MgO, K2O, Na2O, TiO2 with smaller amounts of trace and rare earth elements. Seredin and Dai [68] estimated the rare earth ash content in U.S., Chinese, and Russian coal sources contained concentrations within the range of mineral ore deposits. Lignite and sub-bituminous coal, a low-ranking type of coal, contain higher concentrations of rare earths. Franus et al. [65] reported that coal fly ash is a resource for rare earth elements with an average REE content of 445 ppm to the average global basis. In addition to varying metal content, different factions within coal or coal ash may contain higher levels of particular materials. On the other hand, Warren and Dudas [69] reported that REEs are mostly contained in the glassy phase of fly ash, with smaller amounts occurring in the ferromagnetic fraction. Researchers also reported that after classification the smaller non-magnetic inorganic part of the coal fly ash content has higher concentrations of REE [65, 70]. All the fly ashes have a broadly similar distribution of rare earth elements, with light REE being dominant. The distribution of REE in coal (and in rocks) is predominantly controlled by REE-bearing trace phases such as monazite ((Ce,La,Nd,Th)PO4), allanite ((Ce,Ca,Y)2(Al,Fe3+)3(SiO4)3(OH)), zircon (ZrSiO4), xenotime (YPO4) [71], rhabdophane ((Ce,La,Y)PO4·H2O) [72], florencite (CeAl3(PO4)2(OH)6), and Ce-Nd-bearing carbonates [73–76].
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
The Karamea Batholith is the largest of the Western Province batholiths. Contiguous plutons within the batholith belong to Karamea, Ridge, Foulwind, Tobin, Separation Point, Rahu suites, with the S-type Karamea Suite dominant (Tulloch 1988; Muir et al. 1995; Waight et al. 1997; Tulloch et al. 2009; Turnbull et al. 2016). The Karamea Batholith consists of mica- and quartz-rich granitoids that have accessory REE-bearing minerals including zircon, epidote, allanite, titanite, apatite, monazite and xenotime (Tulloch 1983; Minehan 1989; Muir et al. 1996; Christie et al. 2010). Averaging 10 km wide and 120 km long, the Early Cretaceous Separation Point Batholith is the most eastern batholith and is found within the Takaka terrane. Accessory REE-bearing minerals in this batholith include titanite, epidote, zircon, monazite and apatite (Tulloch 1983; Muir et al. 1995). The Rahu Suite is restricted to Victoria Range and Buller Valley area, Paparoa Range and along the Hohonu Range (Brathwaite and Pirajno 1993; Waight et al. 1997). Rahu Suite rocks contain allanite, monazite, titanite, epidote, apatite, zircon and garnet, as well as rare tourmaline (Graham and White 1990; Waight et al. 1997). Morgenstern et al. (2018) report that the Cretaceous French Creek Granite (Waight et al. 1998b) contains bastnäsite group minerals as well as allanite, zircon, fergusonite, (fluor)apatite, monazite, xenotime, florencite and perrierite–loparite. French Creek Granite has been the focus of REE exploration in the past.
Tectonothermal events in the Olympic IOCG Province constrained by apatite and REE-phosphate geochronology
Published in Australian Journal of Earth Sciences, 2018
A. R. Cherry, V. S. Kamenetsky, J. McPhie, J. M. Thompson, K. Ehrig, S. Meffre, M. B. Kamenetsky, S. Krneta
The apatite grains contain zones that are distinguished by differing BSE brightness (Figure 4) that also correspond to differences in trace-element concentration. Bright zones have elevated concentrations of trace elements (e.g. REE, Y, U, Th, Na, Si) relative to the dark zones (Figure 5; Supplementary Papers, Table S2). More than two shades of different BSE brightness are present in some samples (Figure 4c). The dark zones are commonly distributed as a fine network through the apatite grains (Figure 4d), as well as patches throughout or projecting inwards from the rims of apatite grains (Figure 4e). In contrast, the cores of some apatite grains in one sample (OD743) almost entirely comprise dark apatite surrounded by a rim of mostly bright apatite (Figure 4f). The dark zones contain abundant fine inclusions (<50 µm, e.g. monazite, xenotime, iron oxide, barite, florencite, chalcopyrite, pyrite) (Figure 6) and the darkest BSE zone is associated with the majority of the inclusions. Some dark zones have abundant fine pores (<10 µm) apparent under SEM. In contrast, the bright areas contain little-to-no inclusions and are texturally homogeneous. The dark zones of samples OD742 and OD743 appear to contain the highest abundance of inclusions whereas dark zones in OD306 have the lowest abundance of inclusions (e.g. Figure 4a–d)