Based on the analysis of the literature data, it is determined that as a result of the expanding directions of application of the magnetic fluid, more and more magnetite is required to obtain it. The most common method of obtaining magnetite by chemical condensation makes magnetic fluid very expensive, one liter of which is sold for more than 500 USD. To reduce its cost, the paper proposes the methods of high-temperature reduction of iron-containing wastes to magnetite, which are metallurgical dust caught by electrofilters. As a reducing agent the waste activated carbon and carbon black (soot) are used the codes of which are included in the Federal classification catalog of waste (FKKO) and reflect a significant amount of their formation. After mixing iron-containing waste, activated carbon waste and carbon black, they are gradually heated to a temperature of 900 °C. These conditions create the possibility of the appearance of ferrous iron ions, which, occupying vacant places in the crystal lattice of iron oxide (III), contribute to the formation of magnetite. The magnetite was identified by X-ray technique and evaluated by the indicator of saturation magnetization in comparison with the natural magnetite appeared to be almost identical. The resulting magnetites were dissolved in hydrochloric acid and precipitated with ammonium hydroxide. Repeated determination of saturation magnetization did not show any difference in its level. In the suspension of magnetite, a dispersant in the form of oleic acid and a dispersion medium – kerosene was introduced during heating and stirring. The saturation magnetization and stability of the obtained magnetic fluid satisfied its application for water purification from oil and oil products spill.