Solution

In recent years, the main beneficiation process of hematite is the reverse flotation process. The low-cost development of fine-grained hematite, the work of beneficiation technology is still centered on maximizing efficiency and saving costs. In addition, the main beneficiation methods of hematite include flotation, weak magnetic, gravity separation, roasting and beneficiation. The specific methods are as follows:

1. Hematite flotation beneficiation

Flotation includes positive flotation and reverse flotation.

Hematite positive flotation is a method of using anionic collectors to float iron minerals from the original ore. It can be thrown under coarser particle size without desliming. Commonly used collectors are fatty acids or alkyl sulfates and petroleum sulfonates.The multi-selection method is simple to use drugs, low processing cost, and has great advantages for processing single hematite ore. However, qualified hematite concentrates can only be obtained after multiple selections, and the foam is prone to stickiness, making the product difficult to concentrate and filter.

Hematite reverse flotation is a method of using anionic or cationic collectors to float gangue minerals from the original ore. Among them, the reverse flotation of anionic collectors is mainly used for the reverse flotation of the fatty acid collectors after the activation of calcium ions. Sodium hydroxide or it is mixed with sodium carbonate. When the pH is adjusted to above 11, starch and sulfonation are used. Lignin and dextrin inhibit iron minerals and realize reverse flotation. This method is suitable for the flotation of iron ore with high grade and easy to float gangue. Cationic collector reverse flotation is to use sodium carbonate to adjust the ore pulp to pH=8-9, use starch, dextrin, tannin, etc. to inhibit iron minerals, and use amine collectors to flotate quartz gangue to collect The first choice is the ether amine, and then the fatty amine. Cationic collector reverse flotation can be carried out under the condition of coarse grinding. As long as the slurry reaches the monomer dissociation, the amine collector can well float the monomer quartz. It is very suitable for the flotation of high-grade and complex iron ore.

In terms of the properties of hematite ore itself, reverse flotation has more advantages than positive flotation.

2. Hematite magnetic separation

The magnetic separation of hematite mostly adopts the weak magnetic-strong magnetic separation method, which is mostly used to process the magnet-hematite mixed ore. After the weak magnetic separation tailings are concentrated, the strong magnetic rough separation and sweep separation are carried out, and the strong magnetic coarse concentrate is concentrated. Selected by strong magnetic separator. This method is mainly due to the fact that a small amount of strong magnetic minerals in the ore is likely to cause the strong magnetic field magnetic separator to block. Therefore, when the strong magnetic separation process is used, it is usually necessary to increase the weak magnetic separation operation before the strong magnetic separation operation to remove Or sort out the strong magnetic minerals in the ore.

3. Hematite gravity separation process

There are two methods for heavy separation of hematite. One is coarse-grained gravity separation. The geological grade of the ore deposit is relatively high (about 50%), but the ore body is thinner or has more interlayers. The waste rock is mixed in during mining to dilute the ore. For this kind of ore, only crushing and not grinding can be used. In the case of coarser, coarse-grained tailings are discarded through re-election to restore geological grade.

The other is fine-grain gravity separation, which mostly deals with the hematite with finer grain size and high magnetic content. After crushing, the ore is ground to separate the mineral monomers, and the fine-grained high-grade is obtained by gravity separation. Concentrate.

4. Hematite roasting and magnetic separation

Roasting magnetic separation is one of the effective methods to separate fine to particulate (less than 0.02mm) hematite.

When the mineral composition is more complicated, and other beneficiation processes are difficult to obtain good beneficiation indicators, the magnetic roasting magnetic separation method is often used. Roasting of mineral raw materials is a pretreatment operation of chemical beneficiation or an independent chemical beneficiation operation. That is, under the appropriate conditions such as the appropriate roasting atmosphere and the temperature below the melting point of the mineral raw materials, the process of physical and chemical changes to the target minerals in the mineral raw materials by heating and roasting. Roasting can transform the target mineral into a mineral form that is easy to be separated by leaching or physical separation.