Study on beneficiation process scheme of a small hematite ore

front It is said that hematite accounts for a considerable proportion in China’s iron ore resources. Compared with magnetite, most hematite has fine embedded particle size, large mud content and great difficulty in beneficiation. Therefore, since the sixth five year plan, China has regarded hematite as a national scientific research project and achieved fruitful results.

Some large hematite mines have accumulated a lot of experience in beneficiation process, equipment and reagent, and achieved good beneficiation indexes. Due to the disadvantages of complex process flow, large equipment investment and high beneficiation cost, these processes are difficult to be adopted for some small and medium-sized hematite mines, especially those mixed with hematite and magnetite. There are few large hematite mines in China, while there are many small and medium-sized hematite mines.

Therefore, it is particularly important to study the beneficiation process suitable for small and medium-sized hematite mines. In this paper, the beneficiation test of a small hematite mine with short service life is carried out, which provides an economic and reasonable beneficiation process for the small hematite mine. This study can also serve as a reference for other small hematite concentrators.

1、 Ore properties

• main chemical composition of the ore. the ore belongs to Anshan sedimentary metamorphic oxidized hematite and magnetite deposit. The main chemical composition of the ore is listed in.
• Mineral composition magnetite is mostly metasomatized by hematite in varying degrees, forming false and semi false hematite, a small amount of limonite, with deep oxidation degree. The iron ore is disseminated in gangue as granular single crystal or aggregate, and distributed in strips with gangue minerals (mainly quartz, a small amount of chlorite, etc.). Metal minerals are mainly pseudohematite, magnetite and semi pseudohematite, and gangue minerals are mainly quartz and chlorite.
• Embedding characteristics of iron minerals 1. Magnetite (Fe3O4) magnetite is semi idiomorphic granular single crystal or aggregate, which is disseminated in gangue or alternated with gangue in strip distribution. Most of magnetite is metasomatized by semi pseudo hematite along edges and fractures. Semi pseudo hematite is difficult to separate from magnetite, so it shows ferromagnetism. Magnetite is embedded in coarse, medium and fine particles, and the embedded particle size of magnetite is 0.02 ~ 0.6mm.

2. Hematite

(Fe203) semi false hematite is in grid shape, irregular granular and vein shape, metasomatized along the edge and fracture of magnetite, and completely metasomatized by hematite (in the false image of magnetite) or trace magnetite residue. Pseudo hematite does not show ferromagnetism, but shows strong electromagnetism. The particle size of semi pseudo hematite is 0.015 ~ 1.6mm. The particle size of pseudo hematite is 0.01 ~ 1mm. 3. Limonite (Fe203 · NH20) limonite is vein, irregular granular, honeycomb and star shaped embedded in gangue. The particle size of limonite is 0.005 ~ 0.6mm. 2、 Beneficiation test

• combined process scheme test of magnetic separation gravity separation (gravity separation adopts single shaking table equipment). Since the mine is a mixed mine of hematite and magnetite, magnetic separation is carried out to recover magnetite first, and then magnetic separation tailings. The test results show that when the combined process of magnetic separation and gravity separation (gravity separation adopts single shaking table equipment), the total iron concentrate with yield of 38.43%, iron grade of 64.42% and iron recovery of 70.53% can be obtained.
• Magnetic separation gravity separation (spiral chute is selected for roughing and shaking table for cleaning) combined process test because the shaking table is used as hematite separation equipment in the magnetic gravity combined process, there are many shaking tables, large floor area and large investment, so the spiral chute with large treatment capacity is used to treat the magnetic separation tailings, the tailings are dumped in advance, and the coarse concentrate is cleaned by shaking table, The number of Shakers can be reduced. Therefore, the magnetic separation tailings are tested. The test results show that when the magnetic gravity combined process is used to treat the iron ore, the gravity separation uses the spiral chute to throw the tail in advance, and the spiral chute concentrate is selected with the shaking table. The high-quality iron concentrate with iron grade of 65.56% and iron recovery rate of 63.11% can be obtained. Combined with the recovery rate of iron in the shaking table, the total iron recovery rate is 69.78%, At this time, the grade of iron concentrate is 63.41%.
• After detailed grinding fineness test, collector type test, sodium carbonate dosage test, inhibitor type test, inhibitor dosage test and collector dosage test, the best flotation test process is finally determined. In order to recover the iron lost in flotation tailings, a weak magnetic separation test was carried out on flotation tailings. The test process is shown in Figure 3 and the test results. The test results show that the total iron concentrate with yield of 40.27%, grade of 62.37% and recovery of 72.36% can be obtained by using the combined flotation magnetic separation process.
• Results discussion from the above test results, it can be seen that the magnetic separation iron concentrate with yield of 17.09%, iron grade of 69.40% and iron recovery of 33.79% can be obtained when the iron ore is treated by the combined process scheme of magnetic separation gravity separation (gravity separation adopts single shaking table equipment), and the magnetic separation tailings can be treated by shaking table with yield of 21.34% and iron grade of 60.43% The iron recovery rate of gravity concentrate is 36.74%, the iron grade of total iron concentrate is 64.42%, and the iron recovery rate is 70.43%. Although the recovery rate of iron separation by shaking table is high, the number of shaking tables required for magnetic separation of tailings by shaking table is large, the floor area is large, and the investment is relatively large. In order to save investment, the spiral chute with large processing capacity is used to treat the magnetic separation tailings, and the tailings are removed in advance.

The spiral chute concentrate is selected by shaking table. Although the iron recovery rate is a little low, the iron concentrate quality is high. More importantly, the process is simple, adaptable, investment saving and simple, which is conducive to speeding up the production of small mines. The combined flotation magnetic separation process scheme is used to treat the iron ore. although the iron recovery rate is high, the grade of iron concentrate is low, and a large amount of flotation reagent needs to be consumed during flotation treatment, which increases the production cost. For small hematite concentrators, it is not conducive to maintenance and management. Therefore, it is more suitable for the small hematite concentrator to use the combined process of magnetic separation and gravity separation (gravity separation uses the combination of spiral chute and shaking table). The process is simple, technically and economically reasonable, and has strong adaptability to changes in ore properties. 5、 Knot (I) the hematite is treated by the magnetic gravity combined process. The spiral chute is selected for pre tailing. When the spiral chute concentrate is cleaned by the shaking table, the high-quality iron concentrate with iron grade of 65.56% and iron recovery rate of 63.11% can be obtained. Combined with the iron in the shaking table, the total concentrate with iron concentrate grade of 63.41% and iron recovery rate of 69.78% can be obtained. （2） The process has the advantages of simple process, strong adaptability, investment saving and easy operation. For small hematite mines with short service life, it is conducive to accelerating production and quickly recovering costs. This process can also serve as a reference for other small hematite concentrators.