There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Analysis of XPS spectra of Fe2+ and Fe3+ ions in oxide materials

An assessment of high voltage electron microscopy (HVEM). An invited review

Rapid growth in the market for electric vehicles is imperative, to meet global targets for reducing greenhouse gas emissions, to improve air quality in urban centres and to meet the needs of consumers, with whom electric vehicles are increasingly popular. However, growing numbers of electric vehicles present a serious waste-management challenge for recyclers at end-of-life. Nevertheless, spent batteries may also present an opportunity as manufacturers require access to strategic elements and critical materials for key components in electric-vehicle manufacture: recycled lithium-ion batteries from electric vehicles could provide a valuable secondary source of materials. Here we outline and evaluate the current range of approaches to electric-vehicle lithium-ion battery recycling and re-use, and highlight areas for future progress. Processes for dismantling and recycling lithium-ion battery packs from scrap electric vehicles are outlined.

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Recycling lithium-ion batteries from electric vehicles

Phase equilibrium and thermodynamic experimental data available in the literature on the FeO-Fe2O3-SiO2 (FeO-Si) system were critically reviewed and used to obtain a self-consistent set of parameters for thermodynamic models for all oxide phases using the FactSage computer package. The present optimisation covers the range of oxygen partial pressures from equilibrium with pure oxygen to metal saturation and temperatures from 25 degrees C to above the liquidus. The present thermodynamic optimisation was performed as part of the development of a thermodynamic database for the multi-component system Al-Ca-Fe-Mg-O-Pb-Si-Zn; the thermodynamic parameters for the Fe-O-Si system therefore were chosen to be consistent not only with the experimental data in this ternary system, but also with the data in higher-order systems. The modified quasichemical model was used for the liquid slag phase. Sublattice (based upon the compound-energy formalism) and polynomial models were used for the spinel (magnetite) and monoxide (wustite) solid solutions, respectively. The use of physically reasonable models means that the models can be used to predict thermodynamic properties and phase equilibria in composition and temperature regions where experimental data are not available. From these model parameters, the optimised ternary phase diagram of the FeO-Fe2O3-SiO2 (Fe-O-Si) system was back calculated. The database of the model parameters can be used in conjunction with computer software for Gibbs-free-energy minimisation in order to calculate all thermodynamic properties and any type of phase-diagram section in the FeO-Fe2O3-SiO2 (Fe-O-Si) system.

Thermodynamic optimisation of the FeO-Fe2O3-SiO2 (Fe-O-Si) system with FactSage

The reduction of FeO from iron-saturated FeO-CaO-Al2O3-SiO2 slags by graphite, coke and coal char at 1 673 K has been investigated using a sessile drop technique. Metallographic analysis of samples quenched from the reaction temperature, and in situ observations of the reaction interface, reveal significant differences in the slag/carbon contact, and in the morphologies of the product iron and its composition; these differences were found to depend on the carbon type used in the reduction. In particular it has been shown that, in the case of graphite and coke, liquid Fe-C droplets were rapidly formed at the slag/C interface. Reactions of the slag with coal chars, in contrast, result predominantly in the formation of solid iron. These observations indicate that the reaction pathways, and hence reaction kinetics, are dependent on carbon type.

Observations of the reduction of FeO from slag by graphite, coke and coal char

The rates of reduction of FeO from iron-saturated FeO-CaO-Al2O3-SiO2 slags by graphite, coke, bituminous coal and anthracitic coal chars at temperatures in the range 1 673-1873 K have been measured using a sessile drop technique. The extents of reaction were determined using EPMA analysis of quenched samples, and on line gas analysis using a quadrupole mass spectrometer. The reaction rates have been shown to be dependent critically on carbon type. For the reaction geometry used in this investigation the reduction rates of graphite and coke are observed to be faster than with coal chars. This unexpected finding is shown to be associated with differences in the dominant chemical and mass transfer mechanisms occurring at the reaction interface. High reaction rates are observed to occur with the formation of liquid Fe-C alloy product and the associated gasification of carbon from the alloy. The rates of reduction by coal chars are determined principally by the chemical reaction at the carbon/gas interface and slag phase mass transfer.

Kinetics of Reduction of FeO from Slag by Graphite and Coal Chars

The reduction of dense magnetite samples in H2/H2O and H2/N2 gas mixtures between temperatures of 723 and 1373 K has been investigated. A detailed study of partially reduced samples using conventional metallographic and scanning electron microscopy (SEM) techniques has enabled the conditions for the formation of a number of different product microstructures to be clearly defined. The reaction mechanisms involved in various continuous and discontinuous growth processes are discussed.

Microstructural changes occurring during the gaseous reduction of magnetite

The reported experimental work on the systems PbO
 x
 -CaO and PbO
 x
 -CaO-SiO2 in air is part of a wider research program that combines experimental and thermodynamic computer modeling techniques to characterize zinc/lead industrial slags. Extensive experimental investigation by high-temperature equilibration and quenching techniques followed by electron probe microanalysis was carried out in the temperature range 640 °C to 1500 °C (913 to 1773 K) and in the composition ranges 0 to 65 mol pct SiO2 and 0 to 42 mol pct CaO. Liquidus and solidus data were reported for most of the primary phase fields. Liquidus surfaces in the systems CaO-Pb-O and PbO
 x
 -CaO-SiO2 in air were completely reconstructed. Extensive solid solutions of PbO in α′ dicalcium silicate and Ca2Pb3Si3O11 were measured.

Peter C. Hayes

Papers

Thermodynamic optimisation of the FeO-Fe2O3-SiO2 (Fe-O-Si) system with FactSage

Observations of the reduction of FeO from slag by graphite, coke and coal char

Kinetics of Reduction of FeO from Slag by Graphite and Coal Chars

Microstructural changes occurring during the gaseous reduction of magnetite

Experimental Study of Phase Equilibria in the Systems PbO x - CaO and PbO x -CaO-SiO 2