Cs Speciation in Cements

2000 ◽  
Vol 663 ◽  
Author(s):  
J. V. Hanna ◽  
L. P. Aldridge ◽  
E. R. Vance
Keyword(s):  
Silica Fume ◽  
Blast Furnace Slag ◽  
Room Temperature ◽  
Ordinary Portland Cement ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Water Leaching ◽  
Sharp Signal ◽  
Angle Spinning ◽  
Furnace Slag

ABSTRACTSolid-state 133Cs magic angle spinning nuclear magnetic resonance (MAS NMR) measurements have been used to investigate Cs speciation in cements designed for immobilizing low-level nuclear wastes. Cs in ordinary Portland cement cured for only 10 days at room temperature appears to only inhabit aqueous solutions, as evidenced by a sharp signal with no sidebands, whether or not substantial quantities of blast furnace slag or silica fume are present. No significant 133Cs spectral differences were observed when slag or silica fume were present for curing periods of 10 days, but differences due to Cs partly inhabiting crystalline sites instead of water solutions were observed after 12 months in the slag-containing cement. Pre- incorporation of Cs in various zeolites, followed by mixing the zeolites into the cement, leads to enhanced Cs retention in the cement when it is subject to water leaching at 25°C.

scholarly journals Utilization of Calcium Carbide Residue Using Granulated Blast Furnace Slag

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3511 ◽  
Author(s):  
Joonho Seo ◽  
Solmoi Park ◽  
Hyun No Yoon ◽  
Jeong Gook Jang ◽  
Seon Hyeok Kim ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Calcium Carbide ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Granulated Blast Furnace Slag ◽  
Calcium Carbide Residue ◽  
Angle Spinning ◽  
Furnace Slag

The solidification and stabilization of calcium carbide residue (CCR) using granulated blast furnace slag was investigated in this study. CCR binding in hydrated slag was explored by X-ray diffraction, 29Si and 27Al magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy, and thermodynamic calculations. Mercury intrusion porosimetry and and compressive strength tests assessed the microstructure and mechanical properties of the mixtures of slag and CCR. C-A-S-H gel, ettringite, hemicarbonate, and hydrotalcite were identified as the main phases in the mixture of slag and CCR. The maximum CCR uptake by slag and the highest volume of precipitated solid phases were reached when CCR loading in slag is 7.5% by mass of slag, according to the thermodynamic prediction. This feature is also experimentally observed in the microstructure, which showed an increase in the pore volume at higher CCR loading.

scholarly journals Preparation of Li3PS4–Li3PO4 Solid Electrolytes by Liquid-Phase Shaking for All-Solid-State Batteries

2021 ◽  
Vol 2 (1) ◽  
pp. 39-48
Author(s):  
Nguyen H. H. Phuc ◽  
Takaki Maeda ◽  
Tokoharu Yamamoto ◽  
Hiroyuki Muto ◽  
Atsunori Matsuda
Keyword(s):  
Solid Solution ◽  
Solid State ◽  
Liquid Phase ◽  
Room Temperature ◽  
Reaction Medium ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Synthesis Methods ◽  
Magic Angle ◽  
Angle Spinning

A solid solution of a 100Li3PS4·xLi3PO4 solid electrolyte was easily prepared by liquid-phase synthesis. Instead of the conventional solid-state synthesis methods, ethyl propionate was used as the reaction medium. The initial stage of the reaction among Li2S, P2S5 and Li3PO4 was proved by ultraviolet-visible spectroscopy. The powder X-ray diffraction (XRD) results showed that the solid solution was formed up to x = 6. At x = 20, XRD peaks of Li3PO4 were detected in the prepared sample after heat treatment at 170 °C. However, the samples obtained at room temperature showed no evidence of Li3PO4 remaining for x = 20. Solid phosphorus-31 magic angle spinning nuclear magnetic resonance spectroscopy results proved the formation of a POS33− unit in the sample with x = 6. Improvements of ionic conductivity at room temperature and activation energy were obtained with the formation of the solid solution. The sample with x = 6 exhibited a better stability against Li metal than that with x = 0. The all-solid-state half-cell employing the sample with x = 6 at the positive electrode exhibited a better charge–discharge capacity than that employing the sample with x = 0.

scholarly journals Room-Temperature Reduction of Graphene Oxide in Water by Metal Chloride Hydrates: A Cleaner Approach for the Preparation of Graphene@Metal Hybrids

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1255
Author(s):  
Patrick. P. Brisebois ◽  
Ricardo Izquierdo ◽  
Mohamed Siaj
Keyword(s):  
Graphene Oxide ◽  
Metal Oxide ◽  
Room Temperature ◽  
Structural Integrity ◽  
Metal Oxide Nanoparticles ◽  
Particle Diameter ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Angle Spinning ◽  
Metal Hybrids

Headed for developing minimalistic strategies to produce graphene@metal hybrids for electronics on a larger scale, we discovered that graphene oxide (GO)-metal oxide (MO) hybrids are formed spontaneously in water at room temperature in the presence of nothing else than graphene oxide itself and metal ions. Our observations show metal oxide nanoparticles decorating the surface of graphene oxide with particle diameter in the range of 10–40 nm after only 1 h of mixing. Their load ranged from 0.2% to 6.3% depending on the nature of the selected metal. To show the generality of the reactivity of GO with different ions in standard conditions, we prepared common hybrids with GO and tin, iron, zinc, aluminum and magnesium. By means of carbon-13 solid-state nuclear magnetic resonance using magic angle spinning, we have found that graphene oxide is also moderately reduced at the same time. Our method is powerful and unique because it avoids the use of chemicals and heat to promote the coprecipitation and the reduction of GO. This advantage allows synthesizing GO@MO hybrids with higher structural integrity and purity with a tunable level of oxidization, in a faster and greener way.

The Change of Silica Tetrahedron in Cement-Silica Fume Blends Hydration

2013 ◽  
Vol 743-744 ◽  
pp. 280-284
Author(s):  
Xiao Jun Wang ◽  
Xiao Yao Wang ◽  
Hong Fei Zhu ◽  
Xiao Ye Cong
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Stable State ◽  
Blended Cement ◽  
Hydration Product ◽  
Pozzolanic Reaction ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Strength Increase ◽  
Angle Spinning

The change of silica tetrahedron in cement-silica fume blends hydration is critical for blended cement application. 29Si solid-state magic angle spinning nuclear magnetic resonance (MAS NMR) investigations on the change of silica tetrahedron, which were Portland cement hydration, silica fume in simulated hydration and cement-silica fume blends hydration, were characterized and compared in this paper. The experimental results revealed that the amorphous silica tetrahedron structure in silica fume changed into Q1 and Q2 silica tetrahedrons, the same as silica-oxide structure of cohesive gel in the hydration of Portland cement. The coexistence of Q1 and Q2 silica tetrahedron in hydration product was beneficial to the strength increase of blend paste with silica fume. The amount of Q2 silica tetrahedron in cement-silica fume blends was higher than that in Portland cement. The pozzolanic reaction of silica fume accelerated the course of the silica tetrahedron in blended paste turning into the stable state of Q2 silica tetrahedron and existing principally in blended paste. That is reason that the physical properties of cement-silica fume blends are better than those of Portland cement.

Synthesis and characterization of new inorganic polymeric composites based on kaolin or white clay and on ground-granulated blast furnace slag

2003 ◽  
Vol 18 (11) ◽  
pp. 2571-2579 ◽  
Author(s):  
I. Lecomte ◽  
M. Liégeois ◽  
A. Rulmont ◽  
R. Cloots ◽  
F. Maseri
Keyword(s):  
Blast Furnace ◽  
Vickers Hardness ◽  
Blast Furnace Slag ◽  
Polymeric Materials ◽  
Magic Angle Spinning ◽  
Alkali Activation ◽  
Magic Angle ◽  
Scanning Calorimetry ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Alkali activation of dehydroxylated kaolin or clay yielded high-strength polymeric materials, so-called geopolymers. They were synthesized by mixing the aluminosilicate with solutions of sodium metasilicate and KOH followed by adding 45 wt.% of ground-granulated blast furnace slag. The influence of the aluminosilicate source, its activation temperature, and the order of mixing raw materials were studied on the workability of the blending paste, the microstructure, and the Vickers hardness of the geopolymer samples. The polymeric material is completely amorphous according to x-ray diffraction. Solid-state 27Al and 29Si magic-angle-spinning nuclear magnetic resonance showed that the geopolymer consists of AlO4 and SiO4 tetrahedra linked together through a polymeric network constituted by branched entities SiQ4(4Al) and SiQ4(3Al), but also by less-polymerized silicates SiQ1 and SiQ2. Scanning electron microscopy showed a homogeneous polymeric gel matrix containing unreacted slag (and quartz) grains; thermogravimetric analysis and differential scanning calorimetry exhibited a high content of water and an elevated melting point (1260°C). Vickers hardness values are in the range of 200 MPa.

Intercalation of molecular species into the interstitial sites of fullerene

1992 ◽  
Vol 7 (8) ◽  
pp. 2136-2143 ◽  
Author(s):  
Roger A. Assink ◽  
James E. Schirber ◽  
Douglas A. Loy ◽  
Bruno Morosin ◽  
Gary A. Carlson
Keyword(s):  
Molecular Species ◽  
Room Temperature ◽  
Primary Resonance ◽  
Magic Angle Spinning ◽  
Hydrogen Gas ◽  
Magic Angle ◽  
Hydrogen Molecules ◽  
Fcc Lattice ◽  
Angle Spinning ◽  
A Minor

Molecular species were found to diffuse readily into the octahedral interstitial sites of the fcc lattice of C60. The 13C NMR spectrum of C60 under magic angle spinning (MAS) conditions consisted of a primary resonance at 143.7 ppm and a minor peak shifted 0.7 ppm downfield. The downfield shift obeys Curie's law and is attributed to the Fermi-contact interaction between paramagnetic oxygen molecules and all 60 carbon atoms of rapidly rotating adjacent C60 molecules. Exposure of C60 to 1 kbar oxygen for 1.75 h at room temperature resulted in a spectrum of seven evenly spaced resonances corresponding to the filling of 0 to 6 of the adjacent octahedral interstitial sites with oxygen molecules. The distribution of site occupancies about a C60 molecule provided evidence that the intercalation process is controlled by diffusion kinetics. Exposure to 0.14 kbar hydrogen gas at room temperature for 16 h filled a substantial fraction of the interstitial sites of C60 and C70 with hydrogen molecules.

Cocation Effects in Rhodium-Exchanged Y Zeolites

1987 ◽  
Vol 111 ◽  
Author(s):  
R. K. Shoemaker ◽  
R. A. Johnson ◽  
T. M. Apple
Keyword(s):  
Room Temperature ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Internuclear Separation ◽  
Y Zeolites ◽  
Yield Information ◽  
Acid Centers ◽  
Angle Spinning ◽  
Metal Electron ◽  
C Nmr

AbstractMagic-angle spinning13C NMR spectra of carbon monoxide adsorbed on rhodium/Y zeolites yield information about the proportioning of CO in the various possible adsorption states; linear, bridged and dicarbonyl. The relative amounts of these adsorbed types, particularly the ratio of bridged to linear CO is influenced by the nature of the majority cations present with the rhodium. Reduced Rh-Na(+) and Rh-Li(+) zeolites form all three CO surface species, while acidic Rh zeolites, formed by the introduction of the co-cations Ca(2+) and H(+), exhibit no bridged carbonyls. The suppression of the bridged moiety results from the withdrawal of electrons from rhodium by the acid centers making the metal electron deficient (more oxidized).Rh(I) dicarbonyl species form on all samples studied, however these species are indistinguishable from the linear monocarbonyls based solely upon the isotropic chemical shift obtained from magic-angle spinning. The number of dicarbonyl species can be quantitatively determined by the Carr- Purcell-Meiboom-Gill sequence, the powder pattern or by selective exchange experiments. At room temperature the two CO molecules in the gemdicarbonyl appear to undergo a mutual hopping exchange. This motion is frozen out at 198K. The carbon-carbon internuclear separation in the gemdicarbonyl is 3.3 Å.Catalysts pre-adsorbed with13CO undergo exchange of the dicarbonyl species upon exposure at 198 K to12CO, however they also react to form13CO2. When exposed to CO at room temperature no CO2formation is detected.

Physico chemical and thermal resistance properties of fly ash/ground granulated blast furnace slag based geopolymer mortar

2021 ◽  
Vol 25 (8) ◽  
pp. 110-120
Author(s):  
M. Sivasakthi ◽  
R. Jeyalakshmi ◽  
N.P. Rajamane ◽  
J. Baskarasundararaj
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Elevated Temperatures ◽  
Linear Thermal Expansion ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

The present study investigated the physicochemical and thermal properties of fly ash and ground granulated blast furnace slag (GGBS) based geopolymer mortars exposed to elevated temperatures under different reaction conditions. The compressive strength results shows that fly ash based geopolymer mortar exhibits retention of compressive strength up to 800⁰C whereas the addition of GGBS increases the ambient temperature compressive strength, however, thereafter the retention of strength is observed as 66% at 400˚C and 30% at 800˚C. Fourier transform infra-red spectroscopy (FT- IR) and 29Si and 27Al Magic angle spinning nuclear magnetic resonance (MAS-NMR) spectrum confirmed the alumino-silicate network structure of the geopolymer. Thermogravimetry with differential thermal analysis (TGA/DTA) showed that most of the % weight loss occurred in the temperature range between 30-250ºC due to the water loss after that it was stabilized till 1000⁰C. Thermal conductivity has the direct relationship with the temperature whereas it is vice versa for the % linear thermal expansion. The Scanning electron microscopy (SEM) analysis was performed to identify the morphology changes before and after thermal exposure.

scholarly journals Hydration of Ordinary Portland Cement in Presence of Lead Sorbed on Ceramic Sorbent

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 19 ◽  
Author(s):  
Martin Keppert ◽  
Lenka Scheinherrová ◽  
Miloš Jerman ◽  
Barbora Doušová ◽  
Libor Kobera ◽  
...  
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Low Cost ◽  
Waste Product ◽  
Industrial Effluents ◽  
Magic Angle Spinning ◽  
Resonance Spectroscopy ◽  
Magic Angle ◽  
High Sorption ◽  
Angle Spinning

Lead, a highly toxic element, is frequently present in various solid wastes as well as in industrial effluents. Sorption with a low cost sorbent is a simple way of Pb removal from liquid streams, but stabilization of spent sorbent has to be ensured in order to prevent Pb leaching out and possible environmental contamination. In previous research, ceramic sorbent, generated as waste product in brick industry, was tested as sorbent and proved high sorption capacity for lead. Lead was sorbed partially as hydrocerussite and partially as adsorbed surface layer. The Pb leaching from sorbent was very high and thus further immobilization of sorbent was necessary. Lead, as well as other heavy metals, is known as retarder of the hydration process of Ordinary Portland Cement (OPC), used for the immobilization. In this paper, influence of sorbed Pb and PbO, as reference compound, on cement hydration was studied by calorimetry, thermogravimetry and Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy (MAS NMR). The sorbed lead was found to be less detrimental to hydration retardation due to the lower solubility of precipitated hydrocerussite in basic environment compared to PbO, which forms plumbate anion.

113Cd NMR studies of Hofmann-type clathrates and related compounds: Evidence for two room temperature orientational glasses

1990 ◽  
Vol 68 (12) ◽  
pp. 2270-2273 ◽  
Author(s):  
S. Nishikiori ◽  
C. I. Ratcliffe ◽  
J. A. Ripmeester
Keyword(s):  
Chemical Shift ◽  
Room Temperature ◽  
Magic Angle Spinning ◽  
Great Sensitivity ◽  
Magic Angle ◽  
Nmr Studies ◽  
Static Disorder ◽  
Orientational Glass ◽  
Angle Spinning ◽  
Related Compounds

113Cd magic angle spinning NMR, with and without 1H cross-polarisation and decoupling, has been used to study a number of Hofmann-type clathrates and related compounds. The 113Cd chemical shift shows a great sensitivity to the environment of Cd, even for complexes with closely related structures. The presence of five resonances due to Cd surrounded by CxN(4–x) (where x = 0 to 4) in Cd(CN)2 and Cd(CN)2•C6H12 indicates a static disorder of the CN groups, which makes these materials orientational glasses. Keywords: 113Cd NMR, Hofmann-type clathrates, Cd(CN)2, disorder, orientational glass.

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