In-situ observation of particles deposition process on a ferromagnetic filter during high-gradient magnetic separation process

In-situ observations of particles deposition process on a ferromagnetic filter in high gradient magnetic separation were carried out under high magnetic fields to obtain information for the optimization of separation condition. The spike-like deposition structure was observed on the upper stream of the magnetic filter, different from the conventional deposition image obtained for paramagnetic particles. The length of the spike structure tends to be long with lower flow velocity and lower applied magnetic field. It was also observed that the chain structure or the bundle of such chaines were formed on the way to the filter under the condition of the low applied magnetic field and low flow rates. Results obtained here indicate that the effect of deposited particles on the spatial distribution of the magnetic field and the hydrodynamics, they are often ignored in the simulation so far, should be considered appropriately. •In-situ observation of particles deposition process on a ferromagnetic filter in HGMS.•The spike-like deposition structure was observed on the upper stream.•Longer spike structure formed under lower magnetic fields and lower flow rates.•Effect of the magnetization of deposited particles should be considered appropriately.