Separation mechanism and experimental investigation of pulsating high gradient magnetic separation

Abstract

Pulsating high gradient magnetic separation (PHGMS) has been widely used for separating magnetic minerals in the past decades. In practice, magnetic field and flow field are the main factors that affect the capture of magnetic particles by medium wires. Therefore, an insight into the magnetic field distribution and the flow field distribution around the matrix would provide a crucial foundation for understanding the separating mechanism. In this investigation, the magnetic field and the flow field in the PHGMS process are simulated. Furthermore, the capture of hematite on matrix and its dependence on the key parameters of the PHGMS separator, i.e., wire diameter of rod matrix, particle size, magnetic induction and flow velocity are analyzed. The results indicate that the slurry forms a roundabout flow around the wire and the fluid velocity around the magnetic wire’s left and right sides is far greater than that of the upper and lower sides; with the increase of distance from the magnetic wire surface, the magnetic induction intensity around the magnetic wire decreases gradually. It all proves that the magnetic particles are mostly captured on the upper and lower surface of the magnetic wires in the matrix. The optimized parameters obtained from pilot-scale, the rod diameter of 2 mm, particle size of 60%, magnetic field intensity of 0.9 T and re-cleaning magnetic field intensity of 1.1 T. When all the parameters are optimized, a full-scale PHGMS process produced a magnetic concentrate assaying 63.24% Fe with 93.67% recovery from the hematite feed assaying 49.22% Fe.

Keywords

• Pulsating high gradient magnetic separation
• Hematite
• Magnetic field
• Flow field
• Simulation