Magnetic liquid

摘要

The invention relates to the composition, production and use of environmentally friendly aqueous magnetic fluids, which can be used in particular for separating non-magnetic materials using the method of floating/sinking separation in the magnetic field gradient, as a marking material for analysis of ground erosion, and as a calibration substance in magnetic measurement instruments. The magnetic iron oxide particles are protected against agglomeration by means of a monomolecular fatty acid layer and by means of a second layer of alkoxylated fatty alcohols and end-group capped ethoxylated fatty alcohols, and are dispersed colloidally in water. The sedimentation stability can be improved by the addition of water soluble substances.