The magnetic response of the mixture of 1-butyl-3-methylimidazolium tetrachloroferrate ([bmim]FeCl4) and water was investigated. The [bmim]FeCl4 rich phase in the mixture forming two phases was easily separated under an external magnetic field. The homogeneous mixtures of [bmim]FeCl4 and water were also attracted to the direction of the magnetic field. Under a gradually varied magnetic field, the concentration of the mixture varied as a function of the magnetic field strength. We confirmed the possibility of a magnetic recovery system using the mixtures of [bmim]FeCl4 and water.