materials Article Ironsand (Titanomagnetite-Titanohematite): Chemistry, Magnetic Properties and Direct Applications for Wireless Power Transfer Jérôme Leveneur 1,2, * , William J. Trompetter 1 , Shen V. Chong 2,3 , Ben Rumsey 4 , Vedran Jovic 1,2 , Seho Kim 5 , Murray McCurdy 1 , Emma Anquillare 6,7 , Kevin E. Smith 6 , Nick Long 3 , John Kennedy 1,2 , Grant Covic 5 and John Boys 5   Citation: Leveneur, J.; Trompetter, W.J.; Chong, S.V.; Rumsey, B.; Jovic, V.; Kim, S.; McCurdy, M.; Anquillare, E.; Smith, K.E.; Long, N.; et al. Ironsand (Titanomagnetite- Titanohematite): Chemistry, Magnetic Properties and Direct Applications for Wireless Power Transfer. Materials 2021, 14, 5455. https://doi.org/10.3390/ ma14185455 Academic Editor: Artur Chrobak Received: 27 August 2021 Accepted: 15 September 2021 Published: 21 September 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Earth Resources & Materials, Geological and Nuclear Science, National Isotope Centre, 30 Gracefield Road, Lower Hutt 5040, New Zealand; b.trompetter@gns.cri.nz (W.J.T.); v.jovic@gns.cri.nz (V.J.); m.mccurdy@gns.cri.nz (M.M.); j.kennedy@gns.cri.nz (J.K.) 2 The MacDiarmid Institute for Advanced Materials and Nanotechnology, Victoria University of Wellington, Wellington 6140, New Zealand; shen.chong@vuw.ac.nz 3 Robinson Research Institute, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5010, New Zealand; nick.long@vuw.ac.nz 4 Verum Group, 68 Gracefield Road, Lower Hutt 5010, New Zealand; b.rumsey@verumgroup.co.nz 5 Department of Electrical and Computer Engineering, Faculty of Engineering, University of Auckland, Auckland 1142, New Zealand; s.kim@auckland.ac.nz (S.K.); ga.covic@auckland.ac.nz (G.C.); j.boys@auckland.ac.nz (J.B.) 6 Department of Physics, Boston University, Boston, MA 02215, USA; eanquill@bu.edu (E.A.); ksmith@bu.edu (K.E.S.) 7 Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA * Correspondence: j.leveneur@gns.cri.nz Abstract: Ironsand is an abundant and inexpensive magnetic mineral resource. However, the magnetic properties of unprocessed ironsand are often inadequate for any practical applications. In this work, the applicability of ironsand for use as a component in a soft magnetic composite for large- scale inductive power transfer applications was investigated. After magnetic separation, the chemical, structural and magnetic properties of ironsand sourced from different locations were compared. Differences observed in the DC magnetic properties were consistent with changes in the chemical compositions obtained from X-ray Absorption Near-Edge Spectroscopy (XANES), which suggests varying the titanohematite to titanomagnetite content. Increased content in titanomagnetite and magnetic permeability correlated well with the total Fe content in the materials. The best-performing ironsand with the highest permeability and lowest core losses was used alongside Mn,Zn-Ferrite particles (ranging from „100 μm to 2 mm) to fabricate toroid cores with varying magnetic material loading. It was shown that ironsand can be used to replace up to 15 wt.% of the magnetic materials with minimal impact on the composite magnetic performance, thus reducing the cost. Ironsand was also used as a supporting material in a single-rail wireless power transfer system, effectively increasing the power transfer, demonstrating potential applications to reduce flux leakage. Keywords: magnetic materials; inductive power transfer; ironsand; titanomagnetite; titanohematite; soft magnetic composite; X-ray Absorption Near-Edge Spectroscopy (XANES) 1. Introduction Ironsand is an important resource for steel and titanium production but has seen limited application beyond that. For example, New Zealand’s ironsand with its iron content in the form of titanomagnetite and titanohematite also makes it a useful supply for titanium. While this ironsand has been exported and used in New Zealand for steel manufacturing for more than 40 years [1,2], there is still ample research to simplify the processing mechanisms and expand the applications of this inexpensive commodity. Recently, for instance, groups Materials 2021, 14, 5455. https://doi.org/10.3390/ma14185455 https://www.mdpi.com/journal/materials