Discrete Element Method Simulations of an Innovative Magnetic Stirred Device for the Top-down Production of Ferromagnetic Nanoparticles

Nanoparticles (NPs) are relevant in several industrial applications due to their peculiar properties with respect to their bulk precursor material. Hence, there is a growing need to develop novel technical solutions to synthetize such NPs by simple, eco-friendly, and cost-effective processes. In this regard, the authors have recently proposed a strategy for the safe and sustainable production of NPs involving a mechanical refining using magnetic agitation in wet-operating stirred media, which minimizes the NPs air dispersion and improves the control over the final product specifics. However, the magnetic agitation poses heavy limits of applicability in the case of synthesis of ferromagnetic NPs. In the present contribution, an alternative device configuration developed to overcome this limitation is investigated though a numerical approach. Discrete element method (DEM) simulations are performed to model the grinding and primary particles collisions and to clarify the effect of the parameters involved in both process setup and operation. The results are reported in terms of frequency and velocity of collision and compared to those of the standard device configuration to derive useful information about the functioning and capabilities of the novel system.