Separation of Lithium from Aluminum-Containing Clay Mineral Leachate Solution Using Energy-Efficient Membrane Solvent Extraction.

This study investigated a novel membrane solvent extraction (MSX) process for the recovery and separation of lithium (Li) from clay minerals using a cation exchange organic extractant [di-(2-ethylhexyl)phosphoric acid] (DEHPA). The Li is selectively extracted from clay mineral leachate solution using highly efficient aluminum hydroxide sorbents to form lithium aluminum double hydroxide sulfate (LDH sulfate) as the precipitate. Several delithiation methods have been explored to separate Li from aluminum (Al). LDH sulfate is dissolved in dilute H2SO4 and used as the feed solution, and DEHPA is used to selectively separate Li and Al from the feed solution. The MSX process immobilizes DEHPA in the microporous membrane pores and continuously removes Al from the feed solution to obtain pure Li. The efficiency of DEHPA for the selective separation of Li from Al is determined by measuring its distribution coefficient. This study used the optimum feed solution pH of 3, strip solution concentration of 2 mol/L H2SO4, and an organic phase composition of 30% v/v DEHPA in Isopar-L. The MSX process achieved a Li yield of about 92% and a purity of ⩾ 94%. The results suggest that the innovative MSX technology is a time- and energy-efficient approach for the recovery and separation of high-purity Li for application in Li-ion batteries and other clean energy technologies.

Topological Superconductors from a Materials Perspective.

Topological superconductors (TSCs) have garnered significant research and industry attention in the past two decades. By hosting Majorana bound states which can be used as qubits that are robust against local perturbations, TSCs offer a promising platform toward (nonuniversal) topological quantum computation. However, there has been a scarcity of TSC candidates, and the experimental signatures that identify a TSC are often elusive. In this Perspective, after a short review of the TSC basics and theories, we provide an overview of the TSC materials candidates, including natural compounds and synthetic material systems. We further introduce various experimental techniques to probe TSCs, focusing on how a system is identified as a TSC candidate and why a conclusive answer is often challenging to draw. We conclude by calling for new experimental signatures and stronger computational support to accelerate the search for new TSC candidates.

Additively Manufactured NdFeB Polyphenylene Sulfide Halbach Magnets to Generate Variable Magnetic Fields for Neutron Reflectometry.

Halbach arrays are the most efficient closed structures for generating directed magnetic fields and gradients, and are widely used in various electric machines. We utilized fused deposition modeling-based Big Area Additive Manufacturing technology to print customized, compensated concentric Halbach array rings, using polyphenylene sulfide-bonded NdFeB permanent magnets for polarized neutron reflectometry. The Halbach rings could generate a 0 ≤ B ≤ 0.30 T field, while preserving 90% polarization of an axial neutron beam. Polarized neutron beams are used to study a wide range of structural and magnetic phenomena spanning physics, chemistry, and biology. In this study, we demonstrate the effectiveness of additive manufacturing for producing prototype Halbach arrays, characterize their magnetic properties, and generated magnetic fields, and discuss the conservation of neutron beam polarization as a function of magnetic field.

Additive Manufacturing of Isotropic NdFeB PPS Bonded Permanent Magnets.

Extrusion based additive manufacturing of polymer composite magnets can increase the solid loading volume fraction with greater mechanical force through the printing nozzle as compared to traditional injection molding process. About 63 vol% of isotropic NdFeB magnet powders were compounded with 37 vol% of polyphenylene sulfide and bonded permanent magnets were fabricated while using Big Area Additive Manufacturing without any degradation in magnetic properties. The polyphenylene sulfide bonded magnets have a tensile stress of 20 MPa, almost double than that of nylon bonded permanent magnets. Additively manufactured and surface-protective-resin coated bonded magnets meet the industrial stability criterion of up to 175 °C with a flux-loss of 2.35% over 1000 h. They also exhibit better corrosion resistance behavior when exposed to acidic (pH = 1.35) solution for 24 h and also annealed at 80 °C over 100 h (at 95% relative humidity) over without coated magnets. Thus, polyphenylene sulfide bonded, additively manufactured, protective resin coated bonded permanent magnets provide better thermal, mechanical, and magnetic properties.