Recovery of magnetite-hematite concentrate from iron ore tailings

The research is aimed at study of the probable recovery of iron from the tailings of the Olcon mining company located in the north-western Arctic zone of Russia. Material composition of a sample from a tailings dump was analysed. The authors have developed a separation production technology to recover magnetite-hematite concentrate from the tailings. A processing flowsheet includes magnetic separation, milling and gravity concentration methods. The separation technology provides for production of iron ore concentrate with total iron content of 65.9% and recovers 91.0% of magnetite and 80.5% of hematite from the tailings containing 20.4% of total iron. The proposed technology will increase production of the concentrate at a dressing plant and reduce environmental impact.

Production of hematite concentrate from hematite-magnetite ore

The main useful minerals in composition of hematite-magnetite ore are magnetite and hematite. Magnetite is extracted by wet magnetic separation in weak magnetic field with production of magnetite concentrate and nonmagnetic product. The nonmagnetic product is a feed of the processing circuit for hematite. It is difficult to produce concentrate with iron content of 58-60 mass % if hematite grains are smaller than 0.05 mm. For hematite concentrate production from finely disseminated hematite-magnetite ore, the magnetic-gravitation and magnetic- flotation circuits are designed. This article discusses the magnetic-gravitational separation circuit for hematite grains smaller than 0.05 mm. The first stage of this circuit is fine screening intended to remove large particles. The second stage is high-gradient magnetic separation. The high-gradient separator performance depends on the mineral composition of initial ore and on the rate of mineral dissociation. In finely disseminated hematite-magnetite ore, the associate minerals are mainly represented by quart and amphiboles. Magnetic properties of hematite and amphiboles are similar. For this reason, the high-gradient magnetic separation product contained hematite, amphiboles and quartz-magnetic accretions. The iron content of the magnetic product was 28.9 %. Thus, additional treatment is required, and separation by gravity is applicable in this case. The gravitational separation was carried out on centrifugal concentrator, jigging machine, spiral separator and sluice, and on concentration table. The best results are obtained on the concentration table. The iron content of the final concentrate was 62.3 %.

Modification of the Hematite Filling Surface of New Composition Material during High Pressure Testing

The paper presents the results of the researches on structure modifications of the surface of iron-ore hematite concentrate under the pressure up to 20000 MPa with the use of modern research method – scanning electron microscopy. Hematite iron-ore concentrate (hematite) is the filling for the newest composite material which can be used in the domain of nuclear building. Such composite material has the same aluminum containing matrix in its base and it contains significant amount of such filling. This modern composite material can be used for engineer structures that can experience high pressure even in extreme cases (fires, sharp dynamic load and strikes). The images of the surface of hematite particles under the pressure of 5000 MPa, 10000 MPa, 15000 MPa and 20000 MPa were studied.