Layered oxides are important as electrode materials for batteries and because of the strong electronic correlations resulting from their unique structure. Electrochemical investigations of the layered P2-NaxVO2 system in sodium batteries together with in situ X-ray diffraction experiments now result in the elucidation of the room-temperature phase diagram of this system.

P2-NaxVO2 system as electrodes for batteries and electron-correlated materials

Syntheses and structures of compounds with YBaCo4O7-type structure

Titania-rich slags with 80 mass percent TiO2 are produced in the electric arc furnaces of QIT-Fer & Titane, Inc., by the continuous smelting of hemo-ilmenite ore with anthracite coal. Titania slag represents an important feedstock for the manufacture of titanium dioxide pigment by the sulphate process. Moreover, part of the production of the titania-rich slag is further acid-leached under a high-pressure and moderate-temperature hydrometallurgical process to yield an upgraded titania slag with 94.5 mass percent TiO2, which is used in the chloride process. After describing in detail the beneficiation, chemistry, and mineralogy of the hemo-ilmenite ore, this article reviews the unique crystallochemistry and mineralogy of the titanate phases with pseudobrookite-karrooite structure and to a lesser extent silicates and oxides present in these titania-rich feedstocks, focusing on the chemical reactions occurring at each step of the pyro- and hydro-metallurgical processes. The behavior of major elements such as ...

Chemistry and mineralogy of titania-rich slags. part 1—hemo-ilmenite, sulphate, and upgraded titania slags

Materials discovery by crystal growth: Lanthanide metal containing oxides of the platinum group metals (Ru, Os, Ir, Rh, Pd, Pt) from molten alkali metal hydroxides

Calcium aluminate is the main constituent in calcium aluminate cements, used in a wide range of applications in construction and mining industries and recently also as biomedical implant. In applications that demand very precise reaction features, such as the biomedical ones, the phase purity is of very high importance. In this paper the formation of CaAl2O4 from CaCO3–Al2O3 powder mixtures has been studied, varying holding times between 1 and 40 h and temperatures between 1300 and 1500 °C. Phase formation was studied in samples both quenched from the holding temperatures and in samples slowly cooled. Samples were characterized by X-ray powder diffraction (XRPD), using Guinier-Hagg film data and the Rietveld method, and scanning (SEM) and transmission (TEM) electron microscopy. Samples for TEM with very high site accuracy were produced using focused ion beam microscopy. In addition to CA (CaAl2O4) the samples contained major amounts of CA2 (CaAl4O7), C12A7 (Ca12Al14O33) and minor amounts of un-reacted A (Al2O3). Trace amounts of C3A (Ca3Al2O6) were observed only for samples heated to 1500 °C. The amount of the Ca-rich phase C12A7 was found to decrease with time as it reacts with A and, to a less degree, CA2 to form CA. In agreement with previous studies the amount of CA2 formed decreases comparatively slowly with time. Its un-reactivity is due to that it is concentrated in isolated porous regions of sizes up to 100 μm. The formation of the Ca aluminates is found to be in response to local equilibriums within small inhomogeneous regions, with no specific phase acting as an intermediate phase. Samples quenched from 1500 °C were found to contain smaller amounts of poorly crystallized phases. A reaction between C and A takes place already at 900 °C, forming a meta-stable orthorhombic modification of CA. The orthorhombic unit cell with a = 8.732(2) A, b = 8.078(2) A, c = √3·a = 15.124(4) A was verified by electron diffraction, revealing frequent twinning and disorder of the crystallites.

Hk. Mueller‐Buschbaum

Papers

A New Structure Type with Face Connected BaO6-Octahedra: Ba6Nd2Al4O15.

The Crystal Chemistry of AM2O4 Oxometallates

BaIn2Zn3O7における部分的に正四面体の酸素配位をもつインジウム Ba2Ln2Zn8O13/BaLnAlZn3O7型についての考察

Ueber die farbe von “nio”

Compound formation meo:m2o3. iv. structure of monoclinic strontium aluminum oxide (sral2o4)