Common Magnetite Beneficiation Process

As the main part of iron ore beneficiation, the common magnetite beneficiation processes mainly include the single magnetic separation process and weak magnetic separation-reverse flotation process.

1. Single magnetic separation process

Single magnetite is mainly sedimentary metamorphic magnetite, and most of the iron minerals in the ore are magnetite. This type of magnetite is a strongly magnetic mineral with simple ore composition, and high-grade, high-recovery iron concentrate can be obtained by the weak magnetic separation method.

• Grinding particle size is greater than 0.2-0.3mm, often use a stage grinding + magnetic separation process.

• The two-stage grinding + magnetic separation process used for Grinding particle size is less than 0.2-0.3mm.

• If the qualified tailings are separated by rough grinding, the stage grinding + magnetic separation process is adopted.

• If there is a certain amount of single gangue minerals in the ore, a dry magnetic separator is used for pre-selection before grinding.

2. Weak magnetic separation-reverse flotation process

When the magnetite contains silicate or carbonate minerals with associated cobalt pyrite, chalcopyrite, and apatite, the weak magnetic separation-reverse flotation process can be used. That is, the use of weak magnetic separation process to recover iron and then through the reverse flotation process to recover sulfide or apatite, etc. According to the type of collector, the weak magnetic separation-reverse flotation process can be divided into weak magnetic separation-cation reverse flotation process and weak magnetic separation-anion reverse flotation process.

A. Weak magnetic separation-cation reverse flotation process

In this method, starch is used as an inhibitor of magnetite, and amines such as dodecyl amine are used as collectors. The pulp is neutral, which is especially suitable for processing magnetite with high silicon content. The process agent system is single and simple, the flotation temperature is low, it is suitable for field application, the operation is simple and reliable, the adjustment and changes are fast, and the adaptability to process changes is strong.

B. Weak magnetic separation-anion reverse flotation process

The weak magnetic separation-anion reverse flotation process is suitable for magnetite ore with more iron-containing silicate minerals. Because siliceous minerals are selectively activated and iron minerals are inhibited in a strongly alkaline medium, the floatability of iron minerals and siliceous minerals is greatly different, and the flotation selectivity is improved. Therefore, the high-quality iron concentrate can be obtained, and low-grade tailings can be discarded, and it has good adaptability to changes in the properties of floating materials.

Weak magnetic-reverse flotation combines the magnetic separation method and reverses the flotation method, which solves the problems of difficulty in improving the grade of concentrate and high silica content in iron concentrate, and realizes the complementary advantages in the process of magnetite ore separation. Compared with a single magnetic separation process, anion and cation reverse flotation has a better effect on anion and cation reverse flotation due to the variety of agents, which enhances the adaptability of the process flow and improves the quality improvement effect.