Size-based separation of fine mineral particles using inertial microfluidics: A case of jarosite and anglesite

Many metal phases in industrial hazardous waste coexist as fine mineral particles (FMPs, with particle sizes of 0.01 mu m-10 mu m) in a physical mixture, making conventional methods unable to achieve separation. Advanced microfluidics has demonstrated its potential in the separation of FMPs, as exemplified by jarosite and anglesite. Our study innovatively proposed an inertial microfluidic method for the separation of FMPs by force difference in curved microchannels, thus produced two distinct migration behaviors and subsequent separation. In addition, the computational fluid dynamics (CFD) simulation model was constructed to predict and analyze the migration behavior and separation trend of FMPs through flow field simulation and particle trajectory tracking. The results indicated that 2.1 mu m and 3.6 mu m small particles migrated to the outer outlet of the microchannel due to the dominant Dean vortex force, while 7.2 mu m and 9.4 mu m large particles migrated to the inner outlet relying on inertial focusing. At a flow rate of 1.2 mL/min, the separation efficiency of 3.6 mu m jarosite and 9.4 mu m anglesite has achieved a leap from 0 % to 60.7 %. This discovery provided feasibility and insights into the application of microfluidic technology for particle separation, and offered enormous potential for practical iron residue treatment.