Rare Earth Magnets and Limescale: Analysis of Magnetic Water Treatment Using a Dynamic Scale Rig

Abstract

Treatment of limescale build-up in process- and municipal pipes by magnetic water treatment has been a topic of research for decades. However, there is no realistic mechanistic hypothesis as to why such treatments would be effective. Therefore, a test regime was established to explore scale inhibition by means of magnetic forces in a robust and reproducible manner. In this study, two magnetic devices were developed using Neodymium-based rare earth magnets for the application of static magnetic fields. One device, based on a Halbach array, is designed to test high-intensity (965 mT) magnetic fields. The other is based on a Halbach trap arrangement, designed to test high magnetic field gradients (490 mT, 82.5 T/m). The precipitation reactions of calcium carbonate, calcium sulfate, and calcium phosphate were monitored in real-time to determine the effectiveness of these devices for inhibiting scale. No magnetic treatment effects were observed.