Empirical constraints on partitioning of platinum group elements between Cr-spinel and primitive terrestrial magmas

Park, J.W.,Kamenetsky, V.,Campbell, I.,Park, G.,Hanski, E.,Pushkarev, E. Pergamon Press 2017 Geochimica et cosmochimica acta Vol.216 No.-

Recent experimental studies and in situ LA-ICP-MS analysis on natural Cr-spinel have shown that Rh and IPGEs (Ir-group platinum group elements: Ru, Ir, Os) are enriched in the lattice of Cr-spinel. However, the factors controlling the partitioning behaviour of these elements are not well constrained. In this study, we report the Rh, IPGE, and trace element contents in primitive Cr-spinel, measured by LA-ICP-MS, from nine volcanic suites covering various tectonic settings including island arc picrites, boninites, large igneous province picrites and mid-ocean ridge basalts. The aim is to understand the factors controlling the enrichment of Rh and IPGEs in Cr-spinels, to estimate empirical partition coefficients between Cr-spinel and silicate melts, and to investigate the role of Cr-spinel fractional crystallization on the PGE geochemistry of primitive magmas during the early stages of fractional crystallization. There are systematic differences in trace elements, Rh and IPGEs in Cr-spinels from arc-related magmas (Arc Group Cr-spinel), intraplate magmas (Intraplate Group Cr-spinel), and mid-ocean ridge magmas (MORB Group Cr-spinel). Arc Group Cr-spinels are systematically enriched in Sc, Co and Mn and depleted in Ni compared to the MORB Group Cr-spinels. Intraplate Group Cr-spinels are distinguished from the Arc Group Cr-spinels by their high Ni contents. Both the Arc and Intraplate Group Cr-spinels have total Rh and IPGE contents of 22-689ppb whereas the MORB Group Cr-spinels are depleted in Rh and IPGE (total<20ppb). Palladium and Pt contents are below detection limit for all of the studied Cr-spinels (<1-5ppb). The time-resolved spectra of LA-ICP-MS data for Cr-spinels mostly show constant count rates for trace element and Rh and IPGEs, suggesting homogeneous distribution of these elements in Cr-spinels. The PGE spikes observed in several Cr-spinels were interpreted to be PGE-bearing mineral inclusions and excluded from calculating the PGE contents of the Cr-spinels. On primitive mantle normalized diagrams the Arc Group Cr-spinels are characterized by a fractionated pattern with high Rh and low Os. The Intraplate Group Cr-spinels show flat patterns with positive Ru anomalies. Our results, together with the experimental and empirical data from previous studies, show that PGE patterns of Cr-spinel largely mimic that of the rock in which they are found, and that Rh, Ir and Os contents increase with increasing Fe<SUP>3+</SUP> contents (i.e. magnetite component) in Cr-spinel, although Ru does not. These observations suggest that the enrichment of Rh and IPGEs in Cr-spinel is controlled by a combination of the Rh and IPGE contents in parental melts and the magnetite component of the spinel. Empirical partition coefficients (D) for Rh and IPGEs between Cr-spinels and silicate melts were calculated using the Rh and IPGE contents of the Cr-spinel and their host volcanic rocks after subtracting the accumulation effect of Cr-spinel. The D values for the Intraplate and MORB Group Cr-spinels increase with increasing magnetite component in Cr-spinel and range from 6 to 512, which is consistent with previously reported experimental and empirical values. In contrast, the Arc Group Cr-spinels have significantly higher D values (e.g. up to ~3700 for Ru) than those of the Intraplate and MORB Group at the same magnetite concentration in the Cr-spinel, suggesting Rh and IPGEs dissolved in silicate melt have stronger affinity for Cr spinel under arc magma conditions than in intraplate magmas. This may be partly attributed to the low temperature of arc magmas relative to intraplate magmas, which leads to the Arc Group Cr-spinels having more octahedral sites at the same magnetite components than the Intraplate Group Cr-spinels. Because of significantly higher D values for the Arc Group Cr-spinels, compared with the Intraplate Group and MORB Group spinels, fractional crystallization of Cr-spinel will more efficiently fractionate Rh and IPGE fro

CaO-Al$_2$O$_3$-SiO$_2$계 슬래그와 스피넬의 반응에 미치는 스피넬중의 MgO함유량의 영향

조문규,홍기곤 한국세라믹학회 1999 한국세라믹학회지 Vol.36 No.4

The reactivity of three kinds of spinels which CaO-Al2O3-SiO2 slag was investigated in terms of mineral phases and microstructures. New crystal products were not formed by reaction of 12CaO.7Al2O3 in the slag with spinels and free MgO components was preferenctially dissolved into slag for MgO-rich spinel and stoichiometric spinel. Meanwhile mineral phase was changed from 12CaO.7Al2O3 to CaO.Al2O3 to CaO.2Al2O3 finally to CaO.6Al2O3 having high melting point for Al2O3 -rich spinel. The Fe-oxide component of the slag was taken up by only stoichiometric spinel grains within the spinel clinker and the trapped amount of Fe-oxide was independent of MgO content of MgO in spinel clinker the more th resistance to slag corrosion but the less resistance to slag penetration.

단신 : K-Birnessite를 이용한 Li-Mn Spinel 나노입자 합성 및 전기화학적 특성 평가

김준일 ( Jun Il Kim ),이재원 ( Jae Won Lee ),박선민 ( Sun Min Park ),노광철 ( Kwang Chul Roh ),선양국 ( Yang Kook Sun ) 한국공업화학회 2010 공업화학 Vol.21 No.5

본 연구에서는 리튬 2차 전지의 양극물질 중 하나인 Li-Mn spinel (LiMn2O4)을 합성하기 위해 전구체로 K-Birnessite(KxMnO2·yH2O)를 이용하였다. K-Birnessite는 과망간산칼륨[KMnO4]과 우레아[CO(NH2)2]를 사용하여 수열합성법으로 합성하였고, K-Birnessite와 LiOH를 수열 반응시켜 Li-Mn spinel 나노입자를 제조하였다. 리튬함량에 따른 Li-Mn spinel의 구조 및 형상 변화와 전기화학적 특성에 대한 경향성을 알아보기 위해 LiOH와 K-Birnessite의 몰 비를 조절하여 Li-Mn spinel를 합성하였다. 합성된 분말은 X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), thermogravimetry (TG)를 이용하여 물질의 구조 및 형상을 분석하였고, 정전류법으로 양극재의 용량과 율 특성을 비교 분석하였다. 그 결과 LiOH/K-Birnessite의 몰 비가 0.8일 때 가장 큰 용량(117 mAhg-1)을 나타냈고, 몰 비가 증가할수록 Li-Mn spinel 중 리튬함량이 증가하여 용량은 감소하였으나, 입자 크기는 작아져서 율 특성은 점점 향상되는 경향을 보였다. Li-Mn spinel (LiMn2O4) is prepared by a hydrothermal process with K-Birnessite (KxMnO2·yH2O) as a precursor. The K-Birnessite obtained via a hydrothermal process with potassium permanganate [KMnO4] and urea [CO(NH2)2] as starting materials are converted to Li-Mn spinel nanoparticles reacting with LiOH. The molar ratio of LiOH/K-Birnessite is adjusted in order to find the effect of the ratio on the structural, morphological and electrochemical performances of the Li-Mn spinel. X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and thermogravimetry (TG) are used to investigate the crystal structure and morphology of the samples. Galvanostatic charge and discharge are carried out to measure the capacity and rate capability of the Li-Mn spinel. The capacity shows a maximum value of 117 mAhg-1 when the molar ratio of LiOH/K-Birnessite is 0.8 and decreases with the increase of the ratio. However the rate capability is improved with the increase of the ratio due to the reduction of the particle size.

하소온도에 따른 인공치관용 스피넬-유리 복합체의 기계적 특성

이득용,이준강,김대준 한국결정성장학회 2002 한국결정성장학회지 Vol.12 No.5

하소온도를 $1000^{\circ}C$ ~ $1300^{\circ}C$ 로 변화시킨 스피넬 분말을 용융침투법으로 스피넬-유리 치관용 복합체를 제조하여 하소온도가 복합체에 기계적 특성에 미치는 영향을 조사하였다. 하소온도가 상관없이 분말의 평균 입도는 2.8 ~3.0 $\mu$m로 유지하다가 $1300^{\circ}C$ 에서 4.66 $\mu$m로 증가하였다. 하소온도가 증가하메 따라 전성형체의 수축률과 기공크기는 각각 감소하고 증가하였다. 따라서, 하소온도에 의한 분말의 입도 및 입도 분포가 치밀화에 지대한 영향을 미치는 것으로 추정된다. 최적의 기계적 특성을 가진 스피넬-유리 복합체의 하소온도는 $1200^{\cire}C$이었으며, 강도와 인성 값은 각각 284$\pm$40 MPa, 2.5$\pm$0.1 MPa $m^{1/2}$이었다. 투광성 실험결과, 상용 알루미나-유리 복합체보다 가시광선 영역에서 투과율이 두배이상 우수한 심미성이 관찰되었다. The spinel was calcined at temperatures in the range of $1000^{\circ}C$ to $1300^{\circ}C$ with $100^{\circ}C$ interval to evaluate the effect of calcination temperature on mechanical properties of spinel-glass dental composites. Although the average particle size of spinel calcined at temperatures from $1000^{\circ}C$ to $1200^{\circ}C$ was within 2.8~3.0 $\mu\textrm{m}$, the spinel calcined at $1300^{\circ}C$ was 4.66 $\mu\textrm{m}$ due to abnormal grain growth. Shrinkage and pore size of the spinel preform decreased and increased, respectively, as calcination temperature increased, indicating that the calcination temperature was significant to the powder compaction and the densification of the composites as a result of particle size and distribution. The optimum strength and the fracture toughness of the composite calcined at $1200^{\circ}C$ were 284$\pm$40 MPa, 2.5$\pm$0.1 MPaㆍ$m^{1/2}$ respectively. Optical experimental results showed that transmittance of the spinel-glass composite in the visible region was twice higher than that of the alumina-glass composite, suggesting that the spinel-glass composites possessed better aesthetic properties for all-ceramic dental crown application.

Spinel compositions and tectonic relevance of the Bibong ultramafic bodies in the Hongseong collision belt, South Korea

Oh, C.W.,Rajesh, V.J.,Seo, J.,Choi, S.G.,Lee, J.H. Universitetsforlaget ; Elsevier Science Ltd 2010 Lithos Vol.117 No.1

The Hongseong area in the western Gyeonggi Massif, South Korea, is characterized by the occurrence of several isolated ultramafic lenses in close association with metabasites within the granitic gneiss. Most of these bodies suffered various degrees of serpentinization and also have been highly deformed and metamorphosed. The Bibong ultramafic rock is assumed to be a mantle section of a probable Neoproterozoic supra-subduction zone (SSZ) and its evolution involved two igneous stages overprinted by later stage metamorphism. The compositions of the chromian spinel cores and olivines representative of the igneous stages were used to deduce the petrogenesis and tectonic environments for the formation of the Bibong ultramafic rocks. Spinel Cr# (100@?Cr/(Cr+Al)) for the igneous stages in lherzolite, harzburgite and chromitite are 24.5-33.3, 37.4-61.2 and 37.3-50.9, respectively. During the first stage, magma formed in the nascent back-arc basin spreading center by a small degree of partial melting of wedge mantle intruded the preexisting lithospheric mantle causing the melt/rock interaction that resulted in lherzolite with Al-rich chromian spinel. During the second stage more evolved magma formed in the mature back-arc basin by high degrees of partial melting due to the increased supply of fluid or melt from the subducting oceanic crust and intruded the lherzolitic mantle forming harzburgite with chromian spinel (with high Cr#) through the coupled process of olivine precipitation and dissolution of pyroxene. The Bibong ultramafic rocks have later undergone three metamorphic episodes. The first stage is evidenced by development of medium to fine grained olivine, orthopyroxene, clinopyroxene and amphibole around orthopyroxene porphyroblasts. The second stage is serpentinization which is followed by the third stage amphibolite facies metamorphism as evidenced by Fe-rich rims around Al-rich chromian spinel due to the diffusional exchange of Al, Mg, Cr, and Fe between chromian spinel and adjacent silicate minerals. The spinel composition shows that the transition from the nascent back-arc basin to mature back-arc basin tectonic setting may have been caused by trench roll back during the Neoproterozoic in the Hongseong area, and the serpentinization and amphibolite facies metamorphism could have occurred during uplift after Triassic collision between the North and South China blocks.

⁹⁹Tc immobilization from off-gas waste streams using nickel-doped iron spinel

Wang, Guohui,Um, Wooyong,Kim, Dong-Sang,Kruger, Albert A. Elsevier 2019 Journal of hazardous materials Vol.364 No.-

<P><B>Abstract</B></P> <P>Technetium-99 (<SUP>99</SUP>Tc) incorporation within stable spinel phases is a novel method for <SUP>99</SUP>Tc removal and immobilization from waste streams. In this study, transformation of Ni-doped Fe(OH)<SUB>2</SUB>(s) to spinel minerals, e.g. trevorite (NiFe<SUB>2</SUB>O<SUB>4</SUB>), is explored as a method for removing <SUP>99</SUP>Tc from Hanford Waste Treatment and Immobilization Plant (WTP) primary off-gas waste stream simulant. The Fe(OH)<SUB>2</SUB>(s) transformation process was found to reduce <SUP>99</SUP>Tc(VII) to <SUP>99</SUP>Tc(IV) and incorporate reduced Tc(VI) into the produced spinel simultaneously. Nickel doping was applied in the mineral transformation to inhibit potential reoxidation of <SUP>99</SUP>Tc(IV). Solid phase characterization by XRD and XANES confirmed the formation of nickel substituted ferric-spinel, and suggest incorporation of <SUP>99</SUP>Tc(IV) in the final spinel. Furthermore, in the primary off-gas stream, which contains both redox-sensitive contaminants Cr(VI) and <SUP>99</SUP>Tc(VII), results from solution analysis and solid digestion indicate that nearly 100% Cr and over 80% <SUP>99</SUP>Tc can be simultaneously removed by adding Fe(OH)<SUB>2</SUB>(s) to solution with a solid to solution ratio of 5 g/L under near neutral and alkaline conditions. The <SUP>99</SUP>Tc removal approach developed herein provides an alternative treatment method to eliminate the proposed recycle process of the off-gas waste stream, which ultimately can reduce WTP mission cost and operation time.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ni-doped Fe(OH)<SUB>2</SUB>(s) – spinel transformation process at low temperatures. </LI> <LI> <SUP>99</SUP>Tc(VII) reduced to <SUP>99</SUP>Tc(IV) and incorporated into produced spinel simultaneously. </LI> <LI> Fe(OH)<SUB>2</SUB>(s) can remove both Cr and <SUP>99</SUP>Tc from an off-gas simulant. </LI> </UL> </P>

Spinel granulite in Odesan area, South Korea: Tectonic implications for the collision between the North and South China blocks

Oh, C.W.,Kim, S.W.,Williams, I.S. Elsevier 2006 Lithos Vol.92 No.3

<P><B>Abstract</B></P><P>Spinel granulite formed in the Fe–Al-rich layers in migmatitic gneiss adjacent to a late Paleozoic collision-related mangerite intrusion in the Odesan area, eastern Gyeonggi Massif, South Korea, contains the high-temperature (HT) assemblage Crd+Spl+Crn. Spinel and cordierite compositions indicate peak metamorphic conditions of 914–1157?°C. Retrograde metamorphism reached amphibolite facies where garnet and cordierite broke down to biotite, sillimanite and quartz. These conditions, and the reactions inferred from mineral textures, are consistent with a clockwise <I>P</I>–<I>T</I> path. Metamorphic zircon overgrowths in the spinel granulite and enclosing migmatitic gneiss, dated by SHRIMP U–Pb, yield Permo-Triassic ages of 245±10 and 248±18?Ma respectively, consistent with the metamorphism being a product of the late Paleozoic collision between the North and South China blocks within South Korea. The zircon core ages and textures suggest that the ultimate source of the spinel granulite was a Paleoproterozoic (1852±14?Ma) igneous rock. The protolith of the host migmatitic gneiss was a sediment derived principally from 2.49, 2.16 and 1.86?Ga sources. The age and conditions of spinel granulite metamorphism are similar to those of spinel-bearing granulite in the Higo terrane in west-central Kyushu (250?Ma, >950?°C at 8–9?kbar), consistent with a continuation of the Dabie-Sulu collision zone into Japan through the Odesan area.</P>

Fabrication and electrical properties of sintered bodies composed of Mn(1.75-1.25X)Co2.5XNi1.25(1−X)O4 (0 ≤ X ≤ 0.6) with a cubic spinel structure

Takashi Yokoyama,Masaru Nakamura,Junichi Tatami,Toru Wakihara,Takeshi Meguro 한양대학교 세라믹연구소 2009 Journal of Ceramic Processing Research Vol.10 No.5

Preparation of cubic spinel-type oxides, Mn(1.75−1.25X)Co2.5XNi1.25(1−X)O4 (0 ≤X≤ 0.6), and their electrical properties were investigated. The starting oxides, containing metals with a prescribed molar ratio, were heated to 1400℃ and held for 3 h in argon. The sintered bodies were cooled to 800 oC and then oxidized for 48 h in air to convert them into a cubic spinel structure. The electrical conductivities of the sintered bodies were confirmed to increase exponentially with an increase in the temperature, indicating that they have intrinsic NTC thermistor characteristics. In the region of 0 ≤ X≤ 0.4, the electrical conductivity increased with an increase in X and decreased with an increase in X in the region of 0.4 < X ≤ 0.6. The concentration of Mn4+ in the octahedral sites of the spinel structure was considered to be larger than that of Mn3+ because the sintered bodies were n-type semiconducting. The electrical conduction of the oxides prepared in this study was concluded to be controlled by a small polaron hopping mechanism. Preparation of cubic spinel-type oxides, Mn(1.75−1.25X)Co2.5XNi1.25(1−X)O4 (0 ≤X≤ 0.6), and their electrical properties were investigated. The starting oxides, containing metals with a prescribed molar ratio, were heated to 1400℃ and held for 3 h in argon. The sintered bodies were cooled to 800 oC and then oxidized for 48 h in air to convert them into a cubic spinel structure. The electrical conductivities of the sintered bodies were confirmed to increase exponentially with an increase in the temperature, indicating that they have intrinsic NTC thermistor characteristics. In the region of 0 ≤ X≤ 0.4, the electrical conductivity increased with an increase in X and decreased with an increase in X in the region of 0.4 < X ≤ 0.6. The concentration of Mn4+ in the octahedral sites of the spinel structure was considered to be larger than that of Mn3+ because the sintered bodies were n-type semiconducting. The electrical conduction of the oxides prepared in this study was concluded to be controlled by a small polaron hopping mechanism.

Evaluation of Ag-doped (MnCo)₃O₄ spinel as a solid oxide fuel cell metallic interconnect coating material

Lee, Kunho,Yoon, Byoungyoung,Kang, Juhyun,Lee, Sanghun,Bae, Joongmyeon Elsevier 2017 International journal of hydrogen energy Vol.42 No.49

<P><B>Abstract</B></P> <P>To suppress vaporization of Cr oxides from the metallic interconnects of solid oxide fuel cells, studies on ceramic coating materials have been widely conducted. Among the studied materials, Mn-Co spinel has been a point of focus because of its benign reaction with metal substrates. This paper presents the evaluation results for a modified Mn-Co spinel. Ag was selected as a dopant for Mn-Co spinel, and various experiments were carried out to investigate the suitability of the doped spinel as an interconnect coating material. First, the lattice parameters were demonstrated to be stably maintained even though the Ag dopant is a precious metal. Second, the electrical conductivity was confirmed to be increased upon doping, and the thermal expansion coefficient of the doped material well matched that of AISI444. Third, through long-term oxidation and single-cell tests, the Ag-doped Mn-Co spinel was shown to be a useful coating material for compatible metallic interconnects in solid oxide fuel cell cathodes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ag can be doped into Mn-Co spinel, and the resultant material shows high electrical conductivity. </LI> <LI> A long-term stability test shows that Ag-doped Mn-Co can effectively prevent metal oxidation. </LI> <LI> Ag-doped Mn-Co can successfully protect cathode triple phase boundaries against Cr deposition. </LI> </UL> </P>

Effects of excess Li on the structure and electrochemical performance of Li_1+<i>z</i>MnTiO₄₊ <i> _δ </i> cathode for Li-ion batteries

Vu, Ngoc Hung,Arunkumar, Paulraj,Won, Seob,Kim, Ha Jun,Unithrattil, Sanjith,Oh, Yoong,Lee, Jong-Won,Im, Won Bin Elsevier 2017 ELECTROCHIMICA ACTA Vol.225 No.-

<P><B>Abstract</B></P> <P>Spinel-based LiMn<SUB>2</SUB>O<SUB>4</SUB> is the most attractive cathode for Li-ion battery due to high voltage, low cost, and non-toxicity. The cycle life of the spinel cathodes could be improved by replacing Mn<SUP>4+</SUP> with Ti<SUP>4+</SUP> leading to the formation of new spinel cathode, LiMnTiO<SUB>4</SUB>. However, its application is restricted due to the associated loss in the specific capacity. In this work, spinel-layered Li<SUB>1+<I>z</I> </SUB>MnTiO<SUB>4+<I>δ</I> </SUB> (<I>z</I> =0, 0.5, and 1.0; <I>δ</I> is the value to reflect the composite character of the material) cathodes were fabricated to achieve long cycle life, without compromising on the specific capacity. Cathodes with excess Li (<I>z</I> =0.5 and 1.0) formed a spinel-layered composite structure with notation (1-<I>a</I>)LiMn<SUB>2-<I>x</I> </SUB>Ti<I> <SUB>x</SUB> </I>O<SUB>4</SUB>.<I>a</I>Li<SUB>2</SUB>Mn<I> <SUB>y</SUB> </I>Ti<SUB>1-<I>y</I> </SUB>O<SUB>3</SUB> [<I>y</I> =0.5–((1/<I>a </I>−1)(1− <I>x</I>))]. These cathodes exhibited an enhanced specific capacity of ∼218mAhg<SUP>−1</SUP> (20% higher), with a capacity retention of 94% after 60 cycles. The structural and electrochemical properties of these cathodes were investigated using X-ray diffraction, galvanostatic cycling, cyclic voltammetry, and the galvanostatic intermittent titration technique to understand the mechanisms underlying the enhanced capacity and cycle stability. The effect of the Li-rich layered phase on the electrochemical performance of the Li<SUB>1+<I>z</I> </SUB>MnTiO<SUB>4+<I>δ</I> </SUB> cathodes was also investigated.</P>