Johnson Matthey Technology Review - Current Issue

The concept of a circular economy for rare earth elements (REEs) is being developed. The circular economy involves optimising the lifecycle of products to achieve sustainable and efficient consumption. REEs are considered critical elements of high economic value. Considering limited rare earth reserves, secondary source REEs are very important to sustainable use. Spent nickel-metal hydride (Ni-MH) batteries are electronic waste containing valuable REEs. Ni-MH batteries that have reached their age limit, if thrown away, will become hazardous waste. Recycling Ni-MH battery waste efficiently enables REEs to be recovered and reused. The REE recovery process has challenges that must be considered such as efficiency, low REE concentration, environmental concerns and scalability, thus requiring the development of new, efficient recovery methods and processes for REE. Currently the hydrometallurgical method is preferred for REE recovery from Ni-MH batteries because it has high yields, low energy requirements, ease of separation from base metals and low greenhouse gas emissions. One such REE recovery using hydrochloric acid on a pilot scale yielded 91.6% lanthanum.

Floating offshore wind (FOW) farms are key in meeting Europe’s renewable energy targets, harnessing wind energy from waters 60 m or deeper, where bottom-fixed farms are unfeasible. Additionally, floating structures allow for the installation of larger turbines than stationary farms, which in turn leads to a greater energy output. However, cable failures dramatically impact the energy transmission from the farms and cause most of the financial losses. Monitoring and maintenance tasks are challenging due to the harsh ocean conditions. The FLoating Offshore Wind turbine CAble Monitoring (FLOW-CAM) project, supported by European Union’s HORIZON 2020 programme, studies the structural health monitoring (SHM) of defects in the power cables of the FOW farms which encompass inspection and detection applications. An SHM system integrated with a remotely operated vehicle (ROV) was developed for underwater inspection and maintenance, supporting collection and presentation of essential data through an advanced interface. Part I details the technologies and methods used in this research.

Part II reports on a new structural health monitoring (SHM) system integrated with a remotely operated vehicle (ROV) developed for underwater inspection and maintenance, part of the FLoating Offshore Wind turbine CAble Monitoring (FLOW-CAM) project, supported by European Union’s HORIZON 2020 programme. Image data from underwater systems are analysed using computer vision techniques. Investigations into cable defect detection and the estimation of corrosion and remaining useful life (RUL) have been held to monitor cable health, achieving results close to reality. FLOW-CAM’s collective works establish a basis for advancing underwater inspection and maintenance, concentrating on the development of practical and effective tools and strategies to optimise the functionality and reliability of floating offshore wind (FOW) farms.

One of the key aspects in the field of nanotechnology is the production of consolidated nanomaterials, which have unique properties and can be used in various fields, such as electronics, medicine, energy and others. Severe plastic deformation (SPD) methods can provide formation of nanostructures in various materials. However, resulting grain size and nature of the emerging structure depend not only on the SPD method used, but also on the processing modes, phase composition and initial microstructure of the material. This review discusses various methods for producing consolidated nanomaterials based on SPD, such as: extrusion, pressure processing, rotation, thermomechanical processing, equal-channel angular pressing (ECAP), water impact processing, vibration processing, electron beam processing and magnetic processing. Their influence on the structure and properties of metallic materials, as well as some areas of the most effective application, have been studied. This article discusses ways to obtain the minimum grain size in various materials and considers data on the evolution of the microstructure during intense deformations.

Neodymium-iron-boron is a rare earth element (REE)-based permanent magnet material. Its main magnetic phase is Nd2Fe14B and it has minor phase neodymium-rich or α-iron. The neodymium-iron-boron permanent magnet has a remarkable maximum energy product ((BH)Max) reaching 474 kJ m⁻³ or nearly 60 mega-gauss-oersteds (MGOe), making neodymium-iron-boron magnets highly suitable for wide use in various technological applications. A commercial neodymium-iron-boron magnet contains 22–32 wt% of REEs such as neodymium, dysprosium, praseodymium and lanthanum. As a result of increasing demand for these materials, the availability of REE from natural resources are decreasing and several REEs such as neodymium, dysprosium and praseodymium are in the critical category. Recycling neodymium-iron-boron magnet waste to recover the REEs is one possible solution to provide raw materials for the permanent magnet industry while minimising electronic device waste. Pyrometallurgical and hydrometallurgical metal extraction processes are commonly used for REE recovery. These two methods are excellent for REE recovery and relatively easy to conduct, allowing pyrometallurgical and hydrometallurgical methods to be adopted on industrial scale to benefit the availability of raw materials for the neodymium-iron-boron magnet industry.

Permanent magnets are crucial materials for the development of electronics and telecommunications technology. During the early modern era, the development of permanent magnet materials focused on finding new materials to meet maximum energy product ((BH)Max) criteria. Currently, rare earth-based alloy permanent magnet materials, such as samarium-cobalt and neodymium-iron-boron, are the most advanced permanent magnet materials and have superior magnetic properties compared to other magnetic materials. Research and development in permanent magnets currently focuses more on engineering existing magnetic materials to develop a sustainable and environmentally friendly rare earth permanent magnet production system, in order to realise a circular economy system in the permanent magnet industry.

In this work, we review the latest progress in single atom alloy (SAA) catalysis and its applications to thermo-, photo- and electro-catalytic processes. Part I discusses SAA catalyst preparation methods as well as characterisation techniques.

This work completes our review of the latest progress in single atom alloy (SAA) catalysis and its applications. We provide an overview of conventional and emerging applications as well as perspectives on scalability and potential manufacturing routes. Lastly, we discuss the challenges and opportunities in SAAs, when moving towards industrial exploitation and realising the benefits offered by SAAs beyond laboratory-based research.

Industry 4.0 is built upon the foundations of converting real world analogue effects into digitised binary data suitable for a computer to process. This needs to be done with care, particularly when the data is ingested by a safety critical system. A numerical study probing the limits of a typical analogue to digital converter (ADC) is presented here, highlighting some potential issues that should be identified. Initially a Monte Carlo approach is used to probe the impact of digitisation on an ADC using traditional experimental error analysis. A constant test signal 2.5 ± 0.01 V is used to understand the optimum level of digitisation. The analogue signal is assumed to have Gaussian noise which is then processed by a 5 V ADC. This investigation suggests an optimum digitisation level should be related to the standard error of a measured signal. The use of Bayesian inferencing using the Python package PyMC is then used to gain a better estimate of the underlying standard deviation when the signal has been digitised at the 8-bit level.

The article presents the results of a study of the influence of normalising at 900°C and high-temperature tempering at 650°C on the microstructure and mechanical properties of cast steel 20GL. Heat treatment modes with and without high-temperature tempering were analysed taking into account the geometric dimensions of the specimens. The microstructure and structural-phase composition of cast steel specimens after heat treatment were studied using transmission and scanning electron microscopy (SEM) and X-ray diffraction analysis. Results showed that the selected mode ensures noticeable changes to ferrite-pearlite, homogeneous, fine-grained structure with grain size number 9 and 170 Brinell hardness number (HB). Mechanical tests for static tensile and impact strength resulted in selection of the optimal content of manganese in studied cast steel as 1.2 wt%. It has been established that the processes of final deoxidation have the greatest influence on the mechanical properties of steel determining the nature and character of non-metallic inclusions.

The purpose of this paper is to investigate the effects of Cattaneo-Christov double diffusion on a steady, viscous, magnetohydrodynamic, incompressible, electrically conducting flow of an Oldroyd-B fluid flow over a stretched sheet with mixed convection account taken into consideration along with the presence of a magnetic field, nanofluid particles, thermal diffusion and diffusion thermoeffects. In addition, the characteristics of chemical processes, the Schmidt number, thermophoresis, the Prandtl number and Brownian motion effects are taken into consideration in this research. As a result of the present use of similarity variables, the scope of application for constitutive equations that deal to mass, energy and concentration has been expanded. Making use of the bvp4c solver, which is a computational platform that runs on MATLAB^®, in order to find answers for the problem of governing equations that has been presented. In order to get an accurate measurement of the shear stress as well as the rates of heat and mass transfer at the boundary, the Sherwood number, the Nusselt number and the skin-friction coefficients are used. Tables are a useful tool for doing accurate computations using numerical values. In order to undertake a comprehensive analysis of the dynamics of the problem, we carry out an in-depth research of the concrete repercussions that are caused by a number of different aspects. After then, we use graphic approaches to accentuate and show the implications that have resulted from the situation. In addition, to get a more thorough knowledge of the memory effects, it is beneficial to do a comparative assessment of the present results and the outcomes from the past.