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© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. Quantum optical information systems offer the potential for secure communication and fast quantum computation. To fully characterise a quantum optical system one has to use quantum tomography.1 The integration of quantum optics onto photonic chips provides advantages such as miniaturisation and stability, significantly improving quantum tomography using both re-configurable, and more recently, simpler static designs. These on-chip designs have, so far, only used probabilistic single photon sources. Here we are working towards quantum tomography using a true deterministic source-an InGaAs quantum dot.

© 2018, The Author(s). Quantum information systems are on a path to vastly exceed the complexity of any classical device. The number of entangled qubits in quantum devices is rapidly increasing, and the information required to fully describe these systems scales exponentially with qubit number. This scaling is the key benefit of quantum systems, however it also presents a severe challenge. To characterize such systems typically requires an exponentially long sequence of different measurements, becoming highly resource demanding for large numbers of qubits. Here we propose and demonstrate a novel and scalable method for characterizing quantum systems based on expanding a multi-photon state to larger dimensionality. We establish that the complexity of this new measurement technique only scales linearly with the number of qubits, while providing a tomographically complete set of data without a need for reconfigurability. We experimentally demonstrate an integrated photonic chip capable of measuring two- and three-photon quantum states with statistical reconstruction fidelity of 99.71%.

Quantum information systems are on a path to vastly exceed the complexity of any classical device. The number of entangled qubits in quantum devices is rapidly increasing, and the information required to fully describe these systems scales exponentially with qubit number. This scaling is the key benefit of quantum systems, however it also presents a severe challenge. To characterize such systems typically requires an exponentially long sequence of different measurements, becoming highly resource demanding for large numbers of qubits. Here we propose and demonstrate a novel and scalable method for characterizing quantum systems based on expanding a multi-photon state to larger dimensionality. We establish that the complexity of this new measurement technique only scales linearly with the number of qubits, while providing a tomographically complete set of data without a need for reconfigurability. We experimentally demonstrate an integrated photonic chip capable of measuring two- and three-photon quantum states with statistical reconstruction fidelity of 99.71%.

© 2017 IEEE. We formulate a method of quantum tomography that scales linearly with the number of photons and involves only one optical transformation. We demonstrate it experimentally for two-photon entangled states using a special photonic chip.

© Commonwealth Scientific and Industrial Research Organisation (CSIRO) 2017. Clays are increasingly becoming a major problem in the mining, extraction and value-adding processes for a wide range of commodity raw materials. Clays can impact negatively on virtually every unit process within the mining and minerals processing sector, having long-term environmental implications that go well beyond the lifetime of the mining operation. This book is the first to compile, explain and evaluate the effects of clays in the mineral processing value chain, from mining to minerals processing, and finally, tailings disposal. Focusing on topics from the chemistry and rheology of clays to their detection and dissolution behaviour, this book provides comprehensive coverage of the effects on processes such as settling, preg-robing, flotation and comminution. It is an excellent reference for professional mineralogists and geologists, industrial engineers, and researchers interested in clays and clay minerals.

© Commonwealth Scientific and Industrial Research Organisation (CSIRO) 2017. Introduction Clays represent the raw material for mankind's first transformed product, namely pottery (e.g. Schroeder and Erickson, 2014). While remaining important as a raw material on their own, they are increasingly seen as a major problem in the mining, extraction and value-adding processes for a wide range of commodity raw materials. Clays can impact negatively on virtually every unit process within the mining and minerals processing sector. The extent of this impact is shown schematically in Fig. 1.1. These impacts can vary from trivial problems such as cleaning mining machinery through to serious mining and materials handling safety issues. The common issues can be summarized as either relating to materials handling (rheological consequences and ‘stickiness’), rheological or chemical interference in a beneficiation (or upgrading) process and impacting upon general solid–liquid separation operations. The latter in particular is not only germane to many parts of the mineral processing operation (e.g. S/L in Fig. 1.1), but almost invariably is the last operation prior to tailings disposal. Moreover, these issues continue to operate, often with negative consequences, for tailings areas pre- and post-closure. Presence of clay(s) and clay behaviour can thus have long-term environmental implications that go well beyond the lifetime of the mining and refining operations. Mining and mineral processing are very energy intensive – in comparison to the agricultural sector, the energy intensity (per dollar added to the economy) is typically 2–3 times greater (Rábago et al., 2001). Whether the commodity is a high-value item such as gold (usually found in parts per million (ppm) concentrations) or an almost pure but low-value bulk commodity such as iron ore, typical operations handle many millions of tonnes of ore material each year. Every time material is handled and for every change in physical s

© Commonwealth Scientific and Industrial Research Organisation (CSIRO) 2017. Introduction This final chapter addresses priority research needs for either creating new knowledge of how clays affect one or more unit processes in the mineral processing value chain (MPVC) or to improve utilization of existing knowledge/techniques to assess the impacts or characteristics of clays through improved best practice. These are referred to in this chapter as knowledge and practice gaps, respectively. Knowledge gaps in general were synthesized by the respective chapter authors and the editors subsequently refined the distinction between knowledge and practice gaps. The knowledge and practice gaps are succinctly summarized in Table 10.1. All author teams have provided a conceptual view as to how the knowledge/practice gap could be addressed as well as what the perceived research outcomes would be. In total, the authors identified 15 knowledge/practice gaps and research needs based on the public domain literature surveyed. Review Statistics This review has compiled and processed information from more than 1100 references available in the public domain, not counting data compiled for the preg-robbing (74) and characterization (~ 400) tables in Chapter 1. The range of citations used per chapter was between 52 and 212 for a page range of 20 to 72; on average each chapter used 128 ± 49 citations or 3 ± 1 citations per page. Practice Gaps A principal outcome of this book has been a collation of established knowledge regarding clays and their impact upon mineral processing. Since clays affect a range of unit processes across commodities, site-specific studies can remain cloistered and not readily useful to new situations. While such site-specific information could provide useful hypotheses for clay behaviour at other mines (with different geology and processing operations), any casual application of such knowledge could be counterproductive. Likewise, insights offered by applied researc

Integrated optical circuits enable stable and scalable realization of quantum logic devices, which can form a basis for the mass production of photonic chips for quantum communications and computations. An important challenge is the integration of single-photon sources, which should provide on-chip generation and preparation of quantum photon states. Spontaneous parametric down-conversion (SPDC) provides an attractive solution for experimental generation of correlated and entangled photon pairs [1,2]. However, internal losses in the waveguides may still be present, affecting nontrivially the emerging photon state [3].

The mineral goethite (a-FeOOH) has previously been investigated as a thermodynamically stable repository for many potentially toxic metals (e.g., Cd, Pb, Cu). The substitution of uranium (U as uranyl, UO22+) for Fe, however, has been studied sparingly, and conclusive uranium incorporation into the goethite structure has been obscured by formation of ploymineralic Fe systems that all appeared involved in U's sequestration. In this study, we investigated the formation of goethite from FeCl2 in the presence of seven nominal uranyl concentrations (0.2-4mole percent, U/(U+Fe)×100) and characterised the solids using quantitative X-ray diffraction (QXRD), X-ray absorption fine structure (XAFS) spectroscopy at the U LIII edge (17,166eV), diffuse reflectance infrared Fourier Transform (DRIFT) spectrometry and congruency of acid dissolution. Our findings show that U does indeed, however sparingly, incorporate into the goethite structure. The unit cell volume, ascertained from Rietveld models of XRD patterns, increased linearly as a function of U content, which could be ascribed to a linear increase of the unit cell length a and c. The highest U-for-Fe substitution was 0.48mole percent, however, most U-containing goethite samples showed substitution levels around 0.2mole percent, which was in good agreement with previous findings. DRIFT spectra showed a shift of the symmetric Fe-O and asymmetric Fe-OH stretch modes (t-O and t-OH bands, respectively) to lower frequency, which by Hooks analogy, can only occur if a heavier atom substitutes for Fe, i.e., U. The congruency of acid dissolution results showed that fractional U release was greater than the corresponding fractional Fe release into solution, suggesting that U was overall more soluble. In two of the synthates, however, (initial U mole percent of 2 and 4), the dissolution was congruent. XAFS data collected on a selected subset of samples showed the disappearance of the uranyl moiety with higher levels of U incorporation a

Copyright © 2014 International Centre for Diffraction Data.A number of synchrotron X-ray fluorescence microprobes (XFMs) around the world offer synchrotron X-ray microdiffraction (µXRD) to enhance mineral phase identification in geological and other environmental samples. Synchrotron µXRD can significantly enhance micro X-ray fluorescence and micro X-ray absorption fine structure measurements by providing direct structural information on the identity of minerals, their crystallinity, and potential impurities in crystal structures. The information is useful to understand the sequestration of metals in mineral deposits, mineral processing residues, soils, or sediments. Synchrotron µXRD was employed to characterize a surficial calcrete uranium (U) ore sample and to illustrate its usefulness in conjunction with U LIII µXANES analysis. µXRD and U LIII µXANES revealed that the mineral carnotite [K2(UO2)2(V2O8)·nH2O, n = 0, 1, 2, or 3] was not the sole U bearing mineral phase present and that surface complexes and or an amorphous precipitate were present as well. Unit-cell analysis from the µXRD patterns revealed that the interlayer spacing of carnotite was not uniform and that significant unit-cell volume expansions occurred likely because of variable cations (K+, Rb+, and Sr2+) and variably hydrated interlayer cations being present in the interlayer. Oriented specimen, single crystal effects, and the fixed orientation of the sample relative to the incident beam and the charge-coupled device camera limit the number of visible reflections and complicate mineral phase identification. With careful analysis of multiple structural analysis tools available at XFMs, however, a strong link between X-ray amorphous and X-ray crystalline materials in geologic and environmental samples can be established.

Quantum entanglement became essential in understanding the non-locality of quantum mechanics. In optics, this non-locality can be demonstrated on impressively large length scales, as photons travel with the speed of light and interact only weakly with their environment. Spontaneous parametric down-conversion (SPDC) in nonlinear crystals provides an efficient source for entangled photon pairs, so-called biphotons. However, SPDC can also be implemented in nonlinear arrays of evanescently coupled waveguides which allows the generation and the investigation of correlated quantum walks of such biphotons in an integrated device. Here, we analytically and experimentally demonstrate that the biphoton degrees of freedom are entailed in an additional dimension, therefore the SPDC and the subsequent quantum random walk in one-dimensional arrays can be simulated through classical optical beam propagation in a two-dimensional photonic lattice. Thereby, the output intensity images directly represent the biphoton correlations and exhibit a clear violation of a Bell-like inequality.

Bauxite residue has been continuously produced since the inception of the alumina/aluminium industry in the late nineteenth century. The global inventory of bauxite residue reached an estimated 2.7 billion tonnes in 2007 increasing at 120 million tonnes per annum. This growth highlights the urgency to develop and implement improved means of storage and remediation, and to pursue large-volume utilization options of residue as an industrial by-product. This review looks at current management practices for disposal and amendment, and how each unit process influences residue properties. Since 1980 the trend has been away from lagoon-type impoundments towards "dry" stacking; this reduces the potential for leakage, reduces the physical footprint and improves recoveries of soda and alumina. Associated technical developments in residue neutralization are considered with possible future practices in residue disposal and how that might best integrate with future utilization. For example, hyperbaric steam filtration is an emerging technology that could discharge residue as a dry, granular material of low soda content. Such properties are beneficial to long term storage and remediation, but importantly also to future utilization. Although residue has a number of characteristics of environmental concern, the most immediate and apparent barrier to remediation and utilization (improved sustainability) is its high alkalinity and sodicity. The sustained alkalinity is the result of complex solid-state and solution phase interactions while its sodicity arises from the use of caustic soda (NaOH) for digestion. This is the first in a series of four related reviews examining bauxite residue issues in detail. © 2011 Elsevier B.V. All rights reserved.

Worldwide bauxite residue disposal areas contain an estimated 2.7 billion tonnes of residue, increasing by approximately 120 million tonnes per annum. The question of what to do with bauxite residue arose with the development of the Bayer process for alumina refining and the recognition that it generated a large amount of waste material. In the subsequent 120 years, residues have been primarily disposed into long-term storage, with a wide range of industry practice depending on local circumstances. Ideally this residue would be utilized as an industrial by-product for other applications, leading to a zero waste situation. Despite over 50 years of research and hundreds of publications and patents on the subject, little evidence exists of any significant utilization of bauxite residue. In this review of public domain information the reasons are examined, future opportunities are identified, and a way forward is proposed. All avenues of residue "re-use" (or more appropriately "use") are considered, but emphasis is on the few highest volume uses of lowest risk. Utilization is defined as taking the residue in some non-hazardous form (as a by-product) from the alumina refinery site and then using it as feedstock for another distinct application. Although residues from different bauxites have generic similarities, their specific make-up and residue location can influence their suitability for a given type of use. There are four primary reasons for inaction on residue use: volume, performance, cost and risk, with the last two probably being paramount. In terms of cost there are better options for raw material input from virgin sources (lower cost for better grades) that do not come with the same perceived risks as bauxite residue. The risks are composition based (technical and community perception) and relate to: soda, alkalinity, heavy metals and low levels of naturally occurring radioactive material (NORM). Amongst the outcomes of this review are priority research recomme

A detailed understanding of the complex buffering and neutralization chemistry of bauxite residue remains the key to improved management, both in terms of reduced environmental impact for current storage practices, legacy costs and for the utilization of the material as an industrial by-product for other applications. In spite of 120 years of continuous industrial production, the nature of residue and the chemistry of remediation is still poorly understood. This review brings together what is known of residue behavior and outlines the existing knowledge gaps in our understanding. It examines those aspects of the Bayer process that relate to the creation of the alkalinity in residue and discusses in detail the complex chemical reactions that govern the neutralization behavior. pH is the "master variable" in the chemistry of residue and is strongly buffered by the presence of multiple alkaline solids. The pH in untreated residue liquor (washer overflow) ranges over 9.2-12.8 with an average value of 11.3 ± 1.0. This high alkalinity is the primary reason for residue classification as a hazardous material, and in conjunction with the sodic content the primary reason that residue will not support plant life. The pH is highly buffered by the presence of alkaline solids (various hydroxides, carbonates, aluminates and aluminosilicates) that are formed by the action of caustic soda on bauxite in the Bayer process refinery. The presence of such Bayer process characteristic solids causes the acid neutralization behavior of residues to be highly complex and makes impractical the removal of alkalinity by simply washing with water. This chemistry also impacts physical properties e.g. bulk density, sedimentation rates and compaction, hydraulic conductivity, drying rates and dusting behavior, and physical strength after drying. Understanding how surface charge develops, distributes and abates in the residue mineral assemblage as a function of acid input will be paramount to understa

Worldwide bauxite residue disposal areas contain an estimated 2.7 billion tonnes of bauxite residue, increasing by ~ 120 million tpa. The future management of this residue is of increasing environmental concern. Ideally it would be utilized as an industrial by-product for other applications (the zero waste situation), but realistically the drivers for zero waste are not high and there are significant cost and liability barriers to implementation. Any future utilization will most likely be based on contemporary production and residue currently consigned to long-term storage is unlikely to be recovered, thus the environmental impact risk remains. This prompts the question as to whether remediation can be conducted in situ, i.e. changing the residue chemistry without specifically re-excavating for conventional processing. In this review the key parameters of residue chemistry and its physical properties are considered in the context of what is required for a remediated residue to support a viable eco-system, i.e. what is required for rehabilitation in terms of a series of easily understandable goals. Specifically residue characteristics of stable residue solution such that; pH of 5.5-9.0, sodium adsorption ratio (SAR) of = 7, exchangeable sodium percentage (ESP) of = 9.5, residual sodium carbonate (RSC) of = 1.25, electrical conductivity (EC) of < 4 mS/cm. These goals are a long way from typical existing residue. Bauxite residue itself is the by-product of an iconic hydrometallurgical process, namely the Bayer process. While understanding the hydrometallurgical consequences is one key to the successful implementation of a remediation strategy, it is also clear that the key to in situ remediation is most likely not conventional hydrometallurgy but a systematic and targeted bioremediation approach. The most promising pathway for an in situ rehabilitated bauxite residue disposal area would appear to be bioremediation based on strategies developed for saline-sodic soils

We describe the application of quantitative evaluation of mineralogy by scanning electron microscopy in combination with techniques commonly available at hard X-ray microprobes to define the mineralogical environment of a bauxite residue core segment with the more specific aim of determining the speciation of trace metals (e.g., Ti, V, Cr, and Mn) within the mineral matrix. Successful trace metal speciation in heterogeneous matrices, such as those encountered in soils or mineral residues, relies on a combination of techniques including spectroscopy, microscopy, diff raction, and wet chemical and physical experiments. Of substantial interest is the ability to define the mineralogy of a sample to infer redox behavior, pH buff ering, and mineral-water interfaces that are likely to interact with trace metals through adsorption, coprecipitation, dissolution, or electron transfer reactions. Quantitative evaluation of mineralogy by scanning electron microscopy coupled with micro-focused X-ray diff raction, micro-X-ray fluorescence, and micro-X-ray absorption near edge structure (µXANES) spectroscopy provided detailed insights into the composition of mineral assemblages and their effect on trace metal speciation during this investigation. In the sample investigated, titanium occurs as poorly ordered ilmenite, as rutile, and is substituted in iron oxides. Manganese's spatial correlation to Ti is closely linked to ilmenite, where it appears to substitute for Fe and Ti in the ilmenite structure based on its µXANES signature. Vanadium is associated with ilmenite and goethite but always assumes the +4 oxidation state, whereas chromium is predominantly in the +3 oxidation state and solely associated with iron oxides (goethite and hematite) and appears to substitute for Fe in the goethite structure. © 2011 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.