At present, red iron ore beneficiation process has the following three types:
1. Continuous grinding, weak magnetic-strong magnetic-anion reverse flotation process; it is characterized by high energy consumption and high beneficiation cost due to fine grinding particle size. And for the fine-grained specularite, it is difficult to recover in the strong magnetic separation stage, and the magnetic separation effect is poor.
2. Stage grinding, coarse and fine separation, gravity separation-magnetic separation-anion reverse flotation process;
3. Stage grinding, coarse and fine separation, magnetic separation-gravity separation-anion (cation) ion reverse flotation process.
The latter two characteristics are the use of gravity separation. For some specularites, because of their flake mineral structure, they are easy to deposit in gravity separation equipment, which is unfavorable to the separation effect of gravity separation.
However, in the flotation operation stage, the above-mentioned processes for selecting specular iron ore all have the problems that the slime is greatly affected, fine-grained iron minerals are easy to enter the tailings, and the flotation index is poor.

According to the mineral characteristics of specularite, the patent adopts the following process: one stage of grinding-classification-one stage of weak magnetic separation-one stage of strong magnetic separation to throw tailings; one stage of weak magnetic separation and one stage of strong magnetic separation for coarse concentrate pre-grading -Second stage grinding—concentrate obtained by second stage weak magnetic separation, concentrate obtained by second stage high magnetic separation; second stage high magnetic separation tailings (medium ore) are deslimed by selective flocculation—anion reverse flotation. This process has the following advantages:

(1) Using a section of strong magnetic separation, it can not only recover the weak magnetic specularite lost by a section of weak magnetic separation, but also throw away qualified tailings, which reduces the amount of subsequent grinding and separation of minerals and the consumption of chemicals, and reduces equipment consumption. The number of units, the effect of energy saving and consumption reduction is remarkable.

(2) Using two-stage weak magnetic separation and two-stage strong magnetic separation to obtain concentrate in advance can not only reduce the amount of ore in subsequent reverse flotation, reduce the number of equipment, but also reduce the amount of reverse flotation reagents and reduce production costs.

(3) For the second-stage strong magnetic separation tailings (medium ore), feed it into the concentrator, add dispersant and flocculant for selective flocculation and desliming, so that the gangue slime is dispersed and discharged from the overflow of the concentrator , which not only improves the feed grade of subsequent anion reverse flotation, but also creates conditions for anion reverse flotation, improves the selectivity of anion reverse flotation, and significantly reduces the adjustment agent, inhibitor, activator and collector usage.

(4) Compared with the "continuous grinding, weak magnetic-strong magnetic-anion reverse flotation process", the process flow is shortened, the workshop space is saved, and the gravity concentrate is replaced by the strong magnetic concentrate. The particle size composition makes the concentrate more suitable for transportation.

(5) Compared with the "stage grinding, coarse and fine separation, magnetic separation-gravity separation-anion (cation) ion reverse flotation process", due to the pre-obtained strong magnetic concentrate reduces the amount of ore entering the flotation operation, Therefore, the number of flotation machines used is reduced. Due to the adoption of the selective flocculation desliming process, the gangue slime which is harmful to flotation is removed, and the fine-grained iron minerals are flocculated and settled, and the reverse flotation efficiency is improved.

This patented technology has been applied in a mirror iron ore dressing plant in Anhui, which has improved the comprehensive iron concentrate grade and iron recovery rate, and reduced the comprehensive tailings iron grade.