Utilisation of coal fly ash in the manufacture of useful materials

Fly ash, if not utilised, is considered a waste product. Zeolitisation of coal fly ash offers the opportunity to create an added value product from a waste stream. Optimisation of the two-step zeolitisation process is necessary in order to render the process profitable. The Objective of this thesis is to analyse the optimisation of Si extraction from fly ash and the conditions of crystallisation. The type of synthetic zeolites produced were found to be highly dependent on the conditions of the crystallisation process, which has produced zeolite Na-P1, sodalite, zeolite Na-A, zeolite K-A and other species. Crystallisation parameters explored by this thesis include pH, sodium aluminate addition, time at which ash and leachate are separated, length of crystallisation period, temperature, and control experiments on Si leaching from glassware. Further experimentation analysed the effects of a closed loop system on yield, variations in ash used in the leaching process, generation of floating zeolite via precipitation on cenospheres, highly caustic ash leaching, and Ga and Ge content analysis of ash leachate. Eight sets of cation exchange capacity tests were carried out using synthetic acid mine drainage and various zeolites, zeolitised ash, and untreated ash

Utilisation of fly ash in the manufacture of zeolites

Disposal of CFA is a problem of increasing concern, due to the environmental impact of CFA. Beneficiation processes such as the RockTron process are capable of producing various value-added products, and the Delta product is apt for use in the synthesis of zeolites. The current study explores hydrothermal Si extraction, fusion assisted extraction and a novel microwave fusion process with a performance comparable to the fusion process. The extraction process was optimised for the Delta ash, and compared to other ashes and rice husk ash. In the optimisation of the crystallisation process, the influence of sodium aluminate addition on the properties of zeolites was examined. The effects of alkalinity, sodium source and salt concentration were investigated using XRD, SEM, AAS, CEC and PSD. A concurrent decrease in Si and Al in the crystallisation solution was observed as amorphous material was consumed. This crystal growth phase occurs earlier with higher concentrations of sodium aluminate and NaCl. Addition of NaCl can improve crystallinity, yield and CEC and decrease particle size. Optimised results demonstrated good repeatability. The best estimated yield was 264 g/kg FA, with a CEC of 4.8 meq/g. Buoyant zeolites were synthesised through seeding of the crystallisation process with cenospheres. The products consisted of 77% cenospheres and 23% zeolite

Disassembly of Li Ion cells—characterization and safety considerations of a recycling scheme

It is predicted there will be a rapid increase in the number of lithium ion batteries reaching end of life. However, recently only 5% of lithium ion batteries (LIBs) were recycled in the European Union. This paper explores why and how this can be improved by controlled dismantling, characterization and recycling. Currently, the favored disposal route for batteries is shredding of complete systems and then separation of individual fractions. This can be effective for the partial recovery of some materials, producing impure, mixed or contaminated waste streams. For an effective circular economy it would be beneficial to produce greater purity waste streams and be able to re-use (as well as recycle) some components; thus, a dismantling system could have advantages over shredding. This paper presents an alternative complete system disassembly process route for lithium ion batteries and examines the various processes required to enable material or component recovery. A schematic is presented of the entire process for all material components along with a materials recovery assay. Health and safety considerations and options for each stage of the process are also reported. This is with an aim of encouraging future battery dismantling operations

Clustering of Very Red Galaxies in the Las Campanas IR Survey

We report results from the first 1000 square arc-minutes of the Las Campanas IR survey. We have imaged 1 square degree of high latitude sky in six distinct fields to a 5-sigma H-band depth of 20.5 (Vega). Optical imaging in the V,R,I,and z' bands allow us to select color subsets and photometric-redshift-defined shells. We show that the angular clustering of faint red galaxies (18 3) is an order of magnitude stronger than that of the complete H-selected field sample. We employ three approaches to estimate $n(z)$ in order to invert w(theta) to derive r_0. We find that our n(z) is well described by a Gaussian with = 1.2, sigma(z) = 0.15. From this we derive a value for r_0 of 7 (+2,-1) co-moving H^{-1} Mpc at = 1.2. This is a factor of ~ 2 larger than the clustering length for Lyman break galaxies and is similar to the expectation for early type galaxies at this epoch.Comment: 5 pages, 2 figures, 1 table. To appear in proceedings of the ESO/ECF/STScI workshop "Deep Fields" held in Garching, Germany, 9-12 October 200

A review of physical processes used in the safe recycling of lithium ion batteries

A review of separating methods used in domestic and electric vehicle lithium ion battery recycling is presented, focusing on physical processes which are commonly utilized prior to further chemical processing and purification steps. The four processes of stabilization, disassembly, separation and binder negation are reviewed and the strengths and weaknesses in current research identified. The main limitation with current recycling methods is the comminution step, which mixes, sometimes intimately, the materials from different cell components. This mixed waste stream requires further physical separation, and produces cross contamination in the different material streams. Effective separation of battery components, which produces enhanced purity of waste streams is essential to providing a cost-effective recycling process for direct or “closed loop” recycling. Improvements in the separation process are possible if the materials are separated prior to comminution, to prevent contamination of the different materials streams. In addition to purity of waste streams, one area mostly neglected in the literature is the health and safety implications and hazards associated with the chemicals contained within the cells. Little information is known about the chemical reactions which may occur during the physical separation processes and this has been identified as an area which needs substantially more investigation

A review of current collectors for lithium-ion batteries

Lithium-ion batteries are the state-of-the-art power source for most consumer electronic devices. Current collectors are indispensable components bridging lithium-ion batteries and external circuits, greatly influencing the capacity, rate capability and long-term stability of lithium-ion batteries. Conventional current collectors, Al and Cu foils have been used since the first commercial lithium-ion battery, and over the past two decades, the thickness of these current collectors has decreased in order to increase the energy density. However to improve the performance further, alternative materials and structures, as well as specific treatments such as etching and carbon coating, have also been investigated to enhance the electrochemical stability and electrical conductivity of current collectors, for next-generation lithium-ion batteries with higher capacities and longer service lifetime. This work reviews six types of materials for current collectors, including Al, Cu, Ni, Ti, stainless steel and carbonaceous materials, and compares these materials from five aspects of electrochemical stability, electrical conductivity, mechanical property, density and sustainability. The effects of three different structures of foil, mesh and foam as well as two treatments of chemical etching and coating are also discussed. Future opportunities are highlighted at the end of this review

Roadmap for a sustainable circular economy in lithium-ion and future battery technologies

The market dynamics, and their impact on a future circular economy for lithium-ion batteries (LIB), are presented in this roadmap, with safety as an integral consideration throughout the life cycle. At the point of end-of-life (), there is a range of potential options—remanufacturing, reuse and recycling. Diagnostics play a significant role in evaluating the state-of-health and condition of batteries, and improvements to diagnostic techniques are evaluated. At present, manual disassembly dominates disposal, however, given the volumes of future batteries that are to be anticipated, automated approaches to the dismantling of battery packs will be key. The first stage in recycling after the removal of the cells is the initial cell-breaking or opening step. Approaches to this are reviewed, contrasting shredding and cell disassembly as two alternative approaches. Design for recycling is one approach that could assist in easier disassembly of cells, and new approaches to cell design that could enable the circular economy of LIBs are reviewed. After disassembly, subsequent separation of the black mass is performed before further concentration of components. There are a plethora of alternative approaches for recovering materials; this roadmap sets out the future directions for a range of approaches including pyrometallurgy, hydrometallurgy, short-loop, direct, and the biological recovery of LIB materials. Furthermore, anode, lithium, electrolyte, binder and plastics recovery are considered in order to maximise the proportion of materials recovered, minimise waste and point the way towards zero-waste recycling. The life-cycle implications of a circular economy are discussed considering the overall system of LIB recycling, and also directly investigating the different recycling methods. The legal and regulatory perspectives are also considered. Finally, with a view to the future, approaches for next-generation battery chemistries and recycling are evaluated, identifying gaps for research. This review takes the form of a series of short reviews, with each section written independently by a diverse international authorship of experts on the topic. Collectively, these reviews form a comprehensive picture of the current state of the art in LIB recycling, and how these technologies are expected to develop in the future

Reclaimed and Up-Cycled Cathodes for Lithium-Ion Batteries

As electric vehicles become more widely used, there is a higher demand for lithium-ion batteries (LIBs) and hence a greater incentive to find better ways to recycle these at their end-of-life (EOL). This work focuses on the process of reclamation and re-use of cathode material from LIBs. Black mass containing mixed LiMn2O4 and Ni0.8Co0.15Al0.05O2 from a Nissan Leaf pouch cell are recovered via two different recycling routes, shredding or disassembly. The waste material stream purity is compared for both processes, less aluminium and copper impurities are present in the disassembled waste stream. The reclaimed black mass is further treated to reclaim the transition metals in a salt solution, Ni, Mn, Co ratios are adjusted in order to synthesize an upcycled cathode, LiNi0.6Mn0.2Co0.2O2 via a co-precipitation method. The two reclamation processes (disassembly and shredding) are evaluated based on the purity of the reclaimed material, the performance of the remanufactured cell, and the energy required for the complete process. The electrochemical performance of recycled material is comparable to that of as-manufactured cathode material, indicating no detrimental effect of purified recycled transition metal content. This research represents an important step toward scalable approaches to the recycling of EOL cathode material in LIBs

Roadmap for a sustainable circular economy in lithium-ion and future battery technologies

The market dynamics, and their impact on a future circular economy for lithium-ion batteries (LIB), are presented in this roadmap, with safety as an integral consideration throughout the life cycle. At the point of end-of-life (EOL), there is a range of potential options—remanufacturing, reuse and recycling. Diagnostics play a significant role in evaluating the state-of-health and condition of batteries, and improvements to diagnostic techniques are evaluated. At present, manual disassembly dominates EOL disposal, however, given the volumes of future batteries that are to be anticipated, automated approaches to the dismantling of EOL battery packs will be key. The first stage in recycling after the removal of the cells is the initial cell-breaking or opening step. Approaches to this are reviewed, contrasting shredding and cell disassembly as two alternative approaches. Design for recycling is one approach that could assist in easier disassembly of cells, and new approaches to cell design that could enable the circular economy of LIBs are reviewed. After disassembly, subsequent separation of the black mass is performed before further concentration of components. There are a plethora of alternative approaches for recovering materials; this roadmap sets out the future directions for a range of approaches including pyrometallurgy, hydrometallurgy, short-loop, direct, and the biological recovery of LIB materials. Furthermore, anode, lithium, electrolyte, binder and plastics recovery are considered in order to maximise the proportion of materials recovered, minimise waste and point the way towards zero-waste recycling. The life-cycle implications of a circular economy are discussed considering the overall system of LIB recycling, and also directly investigating the different recycling methods. The legal and regulatory perspectives are also considered. Finally, with a view to the future, approaches for next-generation battery chemistries and recycling are evaluated, identifying gaps for research. This review takes the form of a series of short reviews, with each section written independently by a diverse international authorship of experts on the topic. Collectively, these reviews form a comprehensive picture of the current state of the art in LIB recycling, and how these technologies are expected to develop in the future