Fine-particle separation in heavy metal soil remediation using innovative hydrocyclone technology.

Heavy metal pollution in soils poses significant threats to ecosystems and human health. Traditional remediation methods (such as phytoremediation, thermal treatment, and electrokinetic remediation) are frequently limited by high costs and low efficiency. This study presents a novel approach using a small-scale hydrocyclone designed through numerical simulations to effectively separate fine-particle-contaminated soil. While heavy metals primarily adhere to particles smaller than 20 μm, previous studies have focused on rough separation of particles up to 200 μm. Our design innovation focuses specifically on the key particle size range of 20 μm. Using the Reynolds Stress Model (RSM), Volume of Fluid model, and discrete phase model, we investigated the effects of vortex finder diameter on flow field and classification efficiency and analyzed particle trajectories and separation performance. Under optimal conditions (1:25 water-to-soil ratio, 1.1 m/h flow rate), the <20 μm particle fraction in overflow increased from 76.3 % to 89.2 %, while underflow desorption efficiencies reached 88.7 % (Cu), 84.5 % (Pb), and 80.4 % (Cd). This approach demonstrates significant improvements in fine particle classification and precise reduction of contaminated soil volume. Our findings offer a cost-effective and efficient solution for soil remediation, addressing a major environmental challenge and providing a promising avenue for future research and application in environmental restoration.