Iron Ore Beneficiation Process Details: the Transformation Journey from Ore to Concentrate

Iron ore processing plant in South Africa

Iron ore is an important raw material for iron and steel production, and its beneficiation process has a direct impact on the quality and production cost of iron and steel products. This article will introduce the various steps of iron ore beneficiation, to help you understand the transformation process from ore to concentrate.

Iron ore is mainly divided into magnetite, hematite, limonite, rhodochrosite and vanadium-titanium magnetite. Different types of iron ore due to its mineral composition and physical properties of the differences, beneficiation process is also different.

Magnetite ore can be divided into single magnetite and polymetallic magnetite according to the different types of iron-bearing minerals. Single magnetite is often used weak magnetic separation method for selection, its composition is simple, magnetic, easy to grind and easy to select. Multi-metal magnetite ore is mostly used in the joint process for separation, in order to improve the grade of concentrate.

Hematite as a weakly magnetic iron ore, often using re-election, flotation, magnetic separation and its joint process for separation. Due to the hematite ore impurities embedded in uneven particle size and more fine-grained content, ore properties are more complex, usually need to use a variety of process combinations for processing.

1. Hematite re-election process: 

Because most of the weakly magnetic iron ore concentrate grade of strong magnetic separation is not high, and re-election process unit capacity is low, it is often used in strong magnetic separation - re-election joint process. First use strong magnetic separation process to discard a large number of unqualified tailings, and then use re-election process to further process the strong magnetic concentrate, improve the grade of concentrate.

2. Hematite Roasting-Magnetic Separation Process: 

This method is to magnetize and roast the hematite ore, so that the hematite or pseudo-hematite is transformed into magnetite, and then use the weak magnetic field magnetic separator for sorting, which is suitable for hematite ore whose mineral components are more complicated and it is difficult to reach the ideal concentrate grade by using other beneficiation methods.

3. Hematite strong magnetic - flotation process: 

Under the condition of coarse grinding, through the strong magnetic separation to recover the fine particles of hematite, discharge the monomer quartz in the ore and easy to sludge chlorite and other vein minerals, play a double role of desliming and tailing, so as to create better conditions for flotation operations. This method is mainly suitable for separating fine-grained hematite ore.

After fine crushing or grinding of limonite ore, it is washed, screened, graded and deslimed. Coarse grains use re-election method to get concentrate, intermediate grains use roller magnetic separator to select the concentrate, fine grains and sludge use high gradient magnetic separator to select the concentrate. In order to improve the recovery of iron metal, re-election in the ore can be considered to regrind and re-election, can significantly improve the iron grade concentrate, at the same time, due to the recovery of fine-grained level and sludge in the iron minerals, can obtain a higher recovery rate.

Vanadium and titanium magnetite is not only an important source of iron, but also accompanied by vanadium, titanium, chromium, cobalt, nickel, platinum and scandium and other components, has a high value of comprehensive utilization. Vanadium-titanium magnetite is usually divided into low vanadium-titanium magnetite and high vanadium-titanium magnetite.

1. Low vanadium and titanium magnetite beneficiation process:

Low vanadium and titanium magnetite ore magnetic iron between 4-8%, the current commonly used beneficiation process for the original ore crushing to 3-5mm or so, increase the more crushed and less grinding, grinding and selection of the process is basically the same as the conventional single magnetite process. Vanadium is mainly associated in titanomagnetite, other associated useful elements are more different, some mine tailings to increase the recovery of copper, gold, silver, cobalt flotation process. If necessary, the weak magnetic separation tailings and then strong magnetic pre-selection, improve apatite grade, flotation recovery of apatite process.

2. High vanadium and titanium magnetite ore beneficiation process: 

Similar to the single magnetic mine recovery magnetite process, some mines use permanent magnet high gradient magnetic separation before grinding to throw away the waste, weak magnetic separation tailings recovery ilmenite. Recovery of ilmenite is often used re-election, strong magnetic separation or joint process pre-enrichment, flotation to improve concentrate grade.

Through the above introduction, I believe you have a deeper understanding of iron ore beneficiation process. Iron ore beneficiation is a complex and delicate process, which requires the selection of a suitable process according to the specific nature of the ore in order to maximize the concentrate grade and recovery.