METHOD OF PREPARING MAGNETIC LIQUID Russian patent published in 2010 - IPC H01F1/28 H01F1/44 

FIELD: chemistry.

SUBSTANCE: method involves partial oxidation of iron (II) from an aqueous iron sulphate solution, precipitation of fine magnetite particles with an alkaline solution, stabilisation of the obtained magnetite particles and their dispergation in a dispersion medium. Partial oxidation of iron (II) is carried out simultaneously with precipitation of magnetite particles using an alkaline solution containing CuSO₄, after which the mother solution is removed through decantation, and after stabilisation of magnetite particles and their dispergation in a dispersion medium, the obtained emulsion is mixed with the mother solution removed earlier and the magnetic liquid is separated. CaO is added to the obtained mother solution while stirring and the CaSO₄ precipitate formed is separated, after which the mother solution is mixed with iron sulphate solution to obtain an extra amount of magnetic liquid. CuSO₄ is added in such a way that 1 mole of Fe²⁺ is required for 1 mole of Cu²⁺.

EFFECT: method enables to obtain high-quality magnetic liquid, increase efficiency due to wasteless technology, and obtain an extra product without lowering stability of the magnetic liquid in an inhomogeneous magnetic field.

2 cl, 3 ex