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Natural Mg silicates with different structures and morphologies: Reaction with K to produce K2MgSiO4 catalyst for biodiesel production

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International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 46-54页

作者： Fabiane Carvalho Ballotin Mayra Nascimento Sara Silveira Vieira Alexandre Carvalho Bertoli Ottávio Carmignano Ana Paula de Carvalho Teixeira Rochel Montero Lago Departamento de Química Universidade Federal de Minas GeraisBelo HorizonteBrasil Doutorado Inovação/Mineradora Pedras Congonhas Universidade Federal de Minas Gerais31270-901 Belo Horizonte-MGBrazil

In this work, different magnesium silicate mineral samples based on antigorite, lizardite, chrysotile(which have the same general formula Mg3Si2O5(OH)4), and talc(Mg3Si4O10(OH)2) were reacted with KOH to prepare catalysts for biodiesel production. Simple impregnation with 20 wt% K and treatment at 700–900°C led to a solid-state reaction to mainly form the K2MgSiO4 phase in all samples. These results indicate that the K ion can diffuse into the different Mg silicate structures and textures, likely through intercalation in the interlayer space of the different mineral samples followed by dehydroxylation and K2MgSiO4 formation. All the materials showed catalytic activity for the transesterification of soybean oil(1:6 of oil : methanol molar ratio, 5 wt% of catalyst, 60°C). However, the best results were obtained for the antigorite and chrysotile precursors, which are discussed in terms of mineral structure and the more efficient formation of the active phase K2MgSiO4.

关键词： silicate serpentinite lizardite antigorite talc chrysotile biodiesel

In situ characterization of forearc serpentinized peridotite from the Sulu ultrahigh-pressure terrane: Behavior of fluid-mobile elements in continental subduction zone

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Geoscience Frontiers 2021年第4期12卷 110-121页

作者： Zhipeng Xie Keiko Hattori Youpu Dong Jian Wang Department of Earth Sciences Kunming University of Science and TechnologyKunming 650093PR China Department of Earth and Environmental Sciences University of OttawaOttawa K1N 6N5Canada College of Earth Sciences Jilin UniversityChangchunJilin 130061PR China

Serpentinized peridotites in the Yangkou(YK),Suoluoshu(SLS) and Hujialin(HJL) areas in the Sulu ultrahighpressure terrane represent the relic of ancient subcontinental lithospheric mantle below the North China *** protoliths,harzburgite and dunite,were variably hydrated by aqueous fluids released from subducting Yangtze *** rocks are enriched in fluid-mobile elements(FME) including Sb(42–333 times the depleted mantle value) and Pb(30–476 times).The degrees of the FME enrichment are comparable to that of the Himalayan forearc serpentinites,and greater than forearc mantle serpentinites from Marianas,suggesting that the degrees of FME enrichment in the forearc serpentinites are greater in continental subduction zones than those in the oceanic subduction *** after olivine in the SLS serpentinite shows higher degrees of enrichment in Sb and As than those for antigorite after both olivine and orthopyroxene in the YK *** antigorite has highly enriched in Pb,U,Cs,and LREE,but not for the *** abundance of FME in two different species of serpentine reflects the different temperature of *** temperature lower than 300 ℃,formed lizardite at shallow depths of the mantle wedge incorporates elements that are fluid mobile at low temperatures,such as Sb and *** the temperature greater than 300 ℃,formed antigorite at a relatively deep mantle wedge incorporate more FME from the subducting continental slab(or fragments),including Pb,U,Cs,LREE as well as Sb and *** eventual breakdown of antigorite(600–700 ℃) in prograde metamorphism would discharge water as well as FME into the subducting channel and/or the overlying mantle.

关键词： Continental subduction channel Subcontinental lithospheric mantle Fluid-mobile element Serpentinite antigorite Lizardite

THE RELATIONSHIP BETWEEN CONTENT, VALENCE STATE OF Fe AND COLOUR IN XIUYAN JADE

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Nuclear Science and Techniques 1992年第2期3卷 126-130页

作者：邱兆明穰玫黄俊杰

Having beautiful colours and fine features, Xiuyan jade is famous in the world. Mineralogically, Xiuyan jade is serpentine jade. XRD, IR and TEM studies indicate that the jade consists mainly of antigorite (m{Mg3(1-1/m)[Si2O5](OH)1+3(1-2/m}) with a minor amount of chrysotile. Two favourite samples (PxA, Px1-1), chosen for research on Fe Mossbauer spectra, are only antigorite. Studies indicate that: a. iron ion in antigorite enters the lattice as impurity; b. Fe2+ and Fe3+ substitute for Mg in the coordination octahedron; and c. the colour of jade is related to content of Fe, and Fe2+/Fe3+≤1 is favourite for colour-forming.

关键词： Xiuyan jade antigorite Mossbauer spectra