2023年6月22日 The nepheline syenite formed through fractional crystallization of pristine mantle-derived basaltic melt modified by subduction-related components (chiefly
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2020年4月1日 The nepheline syenite samples collected from the field show differences in colour, grain size, texture and mineral compositions. In hand specimen, nepheline
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2023年1月1日 Abstract. The Triassic Saima alkaline complex on the northern margin of the North China Craton (NCC) is composed mainly of nepheline syenite, along with some
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intrusive rock. intermediate rock. nepheline syenite, medium- to coarse-grained intrusive igneous rock, a member of the alkali-syenite group ( see syenite) that consists largely of
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The Aohu nepheline syenite located in the middle of the TNCO and emplaced during the peak metamorphism (ca. 1.95–1.9 Ga). This leads to a hypothesis that the Aohu
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2011年12月16日 In addition, all the nepheline syenites in this study display relatively low radiogenic Sr (87 Sr/ 86 Sr) i (0.7042–0.7043) and positive ϵ Nd (t) (0.7–0.8). These
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2017年3月1日 Feldspars are a group of tectosilicate rock-forming minerals. The syenites are a group of intrusive rocks rich in feldspar minerals, and, unlike granites, they have
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In glass application, nepheline syenite primarily serves as an excellent fluxing agent and has the following advantages: Higher alumina content which improves matrix formation,
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2021年7月6日 More specifically, Nepheline syenite is used as an active agent for the formation of a glassy phase in ceramics that enhance the physical strength of the final
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Nepheline syenite ore is an essential constituent in ceramics and glass raw material meals, as a flux and as a source of alumina. The natural nepheline syenite rocks contain some
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1998年8月1日 Introduction. The North Nyasa Alkaline Province (NNAP, Bloomfield, 1970) of central and northern Malawi consists of seven intrusions (Kasungu, Chipala, Chikangawa, Mphompha, Telelele Hill, Ilomba, and Ulindi) that lie along a north–south trend roughly parallel to the current rift valley ().The dominant lithology is nepheline syenite, but alkali
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2006年2月7日 La syénite à néphéline est une ROCHE IGNÉE de couleur blanche à gris pâle et à grains moyens. Elle est constituée surtout de FELDSPAR sodique, de néphéline, de feldspar potassique et de minéraux accessoires riches en magnésium et en fer. L'industrie Canadienne de la syénite à néphéline débute en 1932 quand des concessions ...
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2020年4月1日 The intrusions indicated with asterisk (*) are known nepheline syenites while those indicated with double stars (**) comprise both carbonatite and nepheline syenite.
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nepheline syenite, medium- to coarse-grained intrusive igneous rock, a member of the alkali-syenite group (see syenite) that consists largely of feldspar and nepheline.It is always considerably poorer in silica and richer in alkalies than granite.The extraordinarily varied mineralogy of the nepheline syenites and their remarkable variation in habit, fabric,
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2020年1月1日 Nepheline syenite is a complex rock consisting of different mineral phases such as nepheline, alkali feldspar, and biotite. It is a promising source for the recovery of potassium and alumina values.
MoreNepheline syenite is a white to light grey medium-grained igneous rock. It consists mostly of soda feldspar, nepheline and potash feldspar, accessory magnesium and iron-rich minerals. The Canadian nepheline syenite industry began in 1932 when claims were staked on Blue Mountain near Peterborough, Ontario, where it is still produced.
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2011年3月1日 Nepheline syenite is a silica-deficient functional filler and additive used globally in a variety of coating, adhesive and ink applications. It is composed of three minerals: soda and potash feldspar, and the mineral nepheline. Although it is deficient in crystalline silica, nepheline syenite otherwise provides physical performance properties
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2024年4月1日 The samples were collected from two late Cretaceous syenite units in the Gejiu district. The collection comprised eighteen nepheline syenite samples from the Puxiong deposit (Fig. 2 a) and six nepheline syenite samples from the adjacent Baiyunshan (Fig. 2 b). The samples exhibit varying degrees of alteration.
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2019年2月16日 Nepheline syenite is the most important non-bauxite source for the extraction of alumina and is used in some countries (Kogel and Society for Mining M, Exploration 2006;Jena et al. 2016;Panov et ...
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2015年3月30日 Nepheline occurs in alkali-rich, silicon poor igneous rocks (nepeline syenite, foidite and phonolite). May be found in some contact metamorphosed rocks. Associated with: K-feldspar, Na-rich plagioclase, biotite, sodic and sodic-calcic amphiboles and pyroxenes, cancrinite, sodalite, melilite and leucite. Almost never occurs with quartz.
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2022年1月31日 Prepared by James J. Barry [(703) 648–7752, [email protected]] FELDSPAR AND NEPHELINE SYENITE (Data in thousand metric tons unless otherwise noted) Domestic Production and Use: U.S. feldspar production in 2021 had an estimated value of $43 million. Two leading companies mined and processed about 60% of
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2023年1月1日 The boundary between nepheline syenite and pegmatite is transitional, indicating that their formation was contemporaneous. According to unpublished reports, some of nepheline syenite has high Nb (195–560 ppm) and REE (La = 243–1820 ppm, Ce = 596–2415 ppm) contents (Table 1, from the Shenyang Geological Survey, China
MoreLongitudinal sections are usually rectangular. Color: Colorless (often cloudy). It may show rows of inclusions. Zonal structure may be due to arrangement of inclusions or to alternating layers richer and poorer in
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In glass application, nepheline syenite primarily serves as an excellent fluxing agent and has the following advantages: Higher alumina content which improves matrix formation, stabilization and physical resistance; Higher alkali volume and improves fluxing, which lowers the melting temperature of the batch and reduces the quantity of high-cost ...
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This Nepheline Syenite sample comes from East of Ledbeg, Sutherland, Scotland, and is part of the Borralan intrusion which lies in the SW corner of the Assynt region bordered by the Moine Thrust zone. This intrusive complex is the only plutonic complex composed largely of silica-undersaturated (i.e. feldspathoid-bearing) igneous rocks in the ...
MoreNEPHELYNE SYENITE. C'est un feldspath naturel qui contient des quantités anormalement élevées d'alcalin, de sodium-potassium, par rapport à sa teneur en silice et alumine; Par conséquent, son point de fusion est plus bas et cette caractéristique en fait un substitut souhaitable au feldspath lorsqu'une plage de cuisson plus basse est ...
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2010年10月21日 The nepheline syenite members have miaskitic mineralogy (i.e. zircon stable), except for a suite of late, mildly agpaitic pegmatites, which contain zirconium silicate minerals of the wöhlerite, rosenbuschite and eudialyte groups, in some cases together with zircon. These minerals form part of the liquidus mineral assemblage of the nepheline ...
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A 30-km long concordant nepheline syenite pluton occurs at Khariar, comprising syenite and nepheline syenite in addition to alkali granite, gabbro, essexite, malignite, shonkinite, and lamprophyre (Fig. 3.30).Smaller ultramafic bodies such as harzburgite, lherzolite, and pyroxenite are also observed in the close vicinity. The pluton displays well-preserved
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The Aohu nepheline syenite located in the middle of the TNCO and emplaced during the peak metamorphism (ca. 1.95–1.9 Ga). This leads to a hypothesis that the Aohu nepheline syenite is a syn-collisional pluton, genetically related to
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The Ditrău Complex of the Carpathian Mountains in Romania is a Mesozoic igneous complex (~ 200–230 Ma) generated in a continental rift environment. Felsic rocks of the Ditrău Complex consist of nepheline syenite, syenite, quartz syenite, quartz monzonite, monzonite and granite. The Ditrău rocks have mantle-like ɛNd values that range from +
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