MAGNETIC FLUID CONCENTRATE AND ITS PRODUCTION PROCESS Russian patent published in 1996 - IPC

FIELD: separation of nonmagnetic materials. SUBSTANCE: magnetite is settled down from aqueous solution prepared from mixture of bivalent and trivalent iron salts with ammonium excess by joint drain of reagents in presence of buffer solution NH₄OH-NH₄Cl at pH = 9-10 and at 40-60 C in turbulence ideal-displacement reactor performed continuously. Colloidal stability of magnetic fluid is attained by using solution of oleic acid in kerosene (15 g of oleic acid per 100 g of dry magnetite) for extraction and peptization, with components taken in the following proportion, mass percent: magnetite - 51; oleic acid - 8; kerosene - 41; density ρ = 1,45 g/cm³; magnetic saturation M_s= 50 кA/м. EFFECT: improved stability of magnetic fluids in nonuniform strong magnetic fields; enlarged functional capabilities. 3 cl, 3 dwg