3D-printed heart-shaped microreactor with mirror-scaling baffles for enhanced mixing and selective metal recovery from industrial waste

• Heart-shaped microreactor with mirror-scaled baffles amplifies Dean/secondary flows for enhanced chaotic mixing. • 3D-printed K8 concave baffle achieves MI > 0.9 at (Re = 25–75), 300 % higher mixing intensity vs. conventional designs. • Multi-physics simulation (COMSOL) coupled with Villermaux-Dushman reaction validates rapid mixing in 6 units (Re = 75). • Industrial application recovers 96.04 % In from In/Ge waste with record separation factor (β In/Ge = 359.78). • “Design-simulation-additive manufacturing” framework enables cost-effective industrial microreactor development. Laminar mixing is still the bottleneck of microreactor industrialization. In this study, a novel 3D printed heart-shaped microreactor with a mirror proportional baffle was introduced to enhance the Dean vortex and induce the secondary flow. Six kinds of baffle configurations (K1-K6) were prepared by stereolithography (SLA) and evaluated by iodide-iodate reaction method and COMSOL multi-physics simulation. The mixing index (MI) of the concave mirror baffle (K7/K8) is greater than 0.9 in the range of Reynolds number (Re) 25–75, and the chaotic convection intensity is more than 300 % higher than that of the straight baffle (K1). The optimized K8 reactor was used for indium recovery from industrial waste. The extraction rate was 96.04 %. When the flow rate was 0.145 mL/min, the maximum In/Ge separation coefficient was 359.78. The integrated “Design-Simulation-Additive Manufacturing” framework introduced here provides a new paradigm for the development of high-performance industrial microreactors.