METHOD OF PREPARING FERROMAGNETIC LIQUID Russian patent published in 2011 - IPC H01F1/28 

FIELD: chemistry.

SUBSTANCE: method of preparing ferromagnetic liquid involves precipitation of finely dispersed magnetite from aqueous solutions of di- and trivalent iron salts with excess divalent iron with an ammonium solution, washing the precipitate with distilled water, simultaneous activation and stabilisation of the magnetite while heating with a mixture of acetic acid and a surfactant which contains a fatty acid, washing the stabilised magnetite with distilled water and peptisation while heating in a liquid carier based on synthetic hydrocarbon oil, characterised by that peptisation is carried out in 4-6 hours immediately after washing the stabilised magnetite with distilled water, the surfactant used is oleic acid, the acetic acid is glacial acetic acid and the synthetic hydrocarbon oil is alkarene.

EFFECT: high quality of ferromagnetic liquid as an end product, simple method of preparation, low power consumption of the process and high environmental safety of the process.

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