Method for separating first type particles from a mixture of at least first type particles and second type particles, the method comprising: (A) contacting in a dispersion medium first type particles and second type particles with magnet type particles, so that in the dispersion medium first type particles agglomerate to magnet type particles to obtain magnetic agglomerates; (B) separating magnetic agglomerates from second type particles by applying a magnetic field; wherein the magnet type particles are hydrophobized by treatment with a hydrophobizing agent, wherein the hydrophobizing agent is a compound of the general formulas R 5 v -Si(OR 6 ) 4-v (IV), derivatives thereof, wherein each R 5 is independently selected from hydrogen, linear or branched, optionally substituted C 1 -C 30 -alkyl, each R 6 is independently selected from hydrogen, linear or branched, optionally substituted C 1 -C 30 -alkyl, linear or branched, optionally substituted C 2 -C 30 -alkenyl, linear or branched, optionally substituted C 2 -C 30 -alkynyl, optionally substituted C 3 -C 26 -cycloalkyl, optionally substituted C 3 -C 20 -cycloalkenyl, optionally substituted C 1 -C 20 -heteroalkyl, optionally substituted C 5 -C 22 -aryl, optionally substituted C 6 -C 23 -alkylaryl, optionally substituted C 6 -C 23 -arylalkyl or optionally substituted C 5 -C 22 -heteroaryl, v is the integer 1, 2 or 3, and r is an integer from 1 to 100; wherein during step (A) an amount of specific mechanical shear energy of 0.001 - 10 kWh/m^3 is transferred into a mixture of the dispersion medium, first type particles, second type particles and magnet type particles, wherein the specific mechanical shear energy is introduced into the dispersion by a stirred vessel, milling aggregates, rotor stator mixing devices, by a turbulent flow of the dispersion through a pipe conveyed by pumps or by gravity, static mixers, and/or counter current flow mixers, and wherein a C 1 -C 30 alkyl means methyl or ethyl. (A) contacting in a dispersion medium first type particles and second type particles with magnet type particles, so that in the dispersion medium first type particles agglomerate to magnet type particles to obtain magnetic agglomerates; (B) separating magnetic agglomerates from second type particles by applying a magnetic field; derivatives thereof, wherein each R 5 is independently selected from hydrogen, linear or branched, optionally substituted C 1 -C 30 -alkyl, each R 6 is independently selected from hydrogen, linear or branched, optionally substituted C 1 -C 30 -alkyl, linear or branched, optionally substituted C 2 -C 30 -alkenyl, linear or branched, optionally substituted C 2 -C 30 -alkynyl, optionally substituted C 3 -C 26 -cycloalkyl, optionally substituted C 3 -C 20 -cycloalkenyl, optionally substituted C 1 -C 20 -heteroalkyl, optionally substituted C 5 -C 22 -aryl, optionally substituted C 6 -C 23 -alkylaryl, optionally substituted C 6 -C 23 -arylalkyl or optionally substituted C 5 -C 22 -heteroaryl, v is the integer 1, 2 or 3, and r is an integer from 1 to 100; wherein during step (A) an amount of specific mechanical shear energy of 0.001 - 10 kWh/m^3 is transferred into a mixture of the dispersion medium, first type particles, second type particles and magnet type particles, wherein the specific mechanical shear energy is introduced into the dispersion by a stirred vessel, milling aggregates, rotor stator mixing devices, by a turbulent flow of the dispersion through a pipe conveyed by pumps or by gravity, static mixers, and/or counter current flow mixers, and wherein a C 1 -C 30 alkyl means methyl or ethyl. <EOS>