According to the different types of iron-bearing minerals, magnetite ore can be divided into single magnetite and mixed ore.
Generally, single magnetite ore is often separated by weak magnetic separation method, while polymetallic magnetite ore and mixed ore are mostly separated by a combined process composed of a variety of beneficiation methods, including magnetic separation method, flotation method, gravity separation method, and magnetization roasting. Magnetic separation method, reduction roasting magnetic separation method, etc.
1. Single magnetite beneficiation method
Most of the iron minerals in single magnetite are magnetite. Because single magnetite has simple composition, strong magnetism, easy grinding and easy selection, weak magnetic separation method is often used for separation.
◆ When the grinding particle size is greater than 0.2mm, most iron ore magnetic separation plants often use a one-stage grinding-magnetic separation process;
◆ When the grinding particle size is less than 0.2mm, a two-stage grinding-magnetic separation process is adopted;
◆ If qualified tailings are separated in the rough grinding stage, the magnetite magnetic separation plant should adopt the stage grinding-magnetic separation process;
◆ For dry and water-deficient areas, the magnetite processing plant can consider adopting the dry grinding-dry magnetic separation process;
◆ For the enriched magnetite-rich ore or magnetite-lean ore, generally, the gangue can be removed by the dry magnetic separation process first, and after the massive rich ore is obtained, the concentrate can be obtained through the grinding-magnetic separation process.
In order to obtain high-grade concentrates, the magnetite concentrates can be treated by methods such as reverse flotation or high-frequency fine sieves. In addition, in order to further improve the recovery rate, processes such as tailings reselection can also be considered to further recover magnetic minerals.
2. Method for beneficiation of polymetallic magnetite
The polymetallic magnetite gangue often contains silicate or carbonate minerals, associated cobalt pyrite, chalcopyrite and apatite, etc. Generally, the combined process of weak magnetic separation and flotation is used, that is, the use of weak magnetic separation The process recovers iron, and then sulfides or apatite, etc. are recovered through a flotation process.
Generally, the combined weak magnetic separation-flotation process of polymetallic magnetite ore can be divided into weak magnetic separation-flotation and flotation-weak magnetic separation. The difference lies in the conjoined body of magnetite and sulfide. Going different.
For the weak magnetic separation-flotation process, the conjoined bodies mainly enter the iron concentrate; for the flotation-weak magnetic separation process, the conjoined bodies mainly enter the sulfide concentrate. Therefore, under the same grinding particle size, iron concentrate with lower sulfide content and sulfide concentrate with higher recovery rate can be obtained from the process of flotation first and then magnetization.
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