What are the beneficiation processes for hematite?

Hematite is formed through prolonged chemical reactions involving iron-bearing minerals. When iron sulfide ore deposits exposed at the Earth's surface undergo prolonged oxidation, they transform into hematite. Therefore, hematite is an iron oxide mineral primarily composed of Fe₂O₃ and crystalline water.

The crystal structure of hematite belongs to the triclinic system. The iron ions in it possess spin and orbital angular momentum, so hematite exhibits certain magnetic properties. However, the magnetic susceptibility of hematite is relatively weak, classifying it as a weakly magnetic mineral. Typically, strong magnetic separation is required to achieve optimal separation efficiency.

Single gravity separation of hematite

Single gravity separation is a traditional mineral processing method that offers advantages such as a simple process flow, low equipment investment, and ease of management and operation. However, due to factors such as the generally fine-grained size of hematite, difficulty in achieving single-particle liberation, and high hardness, its separation efficiency is poor, recovery rates are low, and it cannot meet the steel industry's demand for high-quality, high-grade iron concentrate. Currently, only a few companies still use single gravity separation for easily separable hematite deposits.

 Single magnetic separation of hematite

Magnetic separation is an efficient and economical process for separating magnetic minerals. Limonite is a weakly magnetic mineral, and strong magnetic separation equipment is primarily used for magnetic separation operations. The widespread application of this equipment has enabled efficient separation of limonite and other weakly magnetic minerals. Weakly magnetic target minerals are separated from gangue minerals under the combined effects of magnetic force, gravity, and fluid flow.

Strong Magnetic Separation-Reverse Flotation for Limonite

The combined strong magnetic separation-reverse flotation process is an effective separation method for limonite, which typically has a complex mineral composition and is often associated with various impurity minerals. In this process, strong magnetic separation equipment is first used for strong magnetic tailings removal and impurity removal, typically employing high-gradient magnetic separators. The resulting concentrate is then subjected to a reverse flotation process for further impurity removal, yielding high-grade iron concentrate. This process achieves excellent results in improving the grade of hematite concentrate.

 Hematite Flocculation-Strong Magnetic Separation

In the strong magnetic separation process for hematite, due to its fine grain size, the minerals are prone to muddification, often leading to the loss of a portion of the fine-grained target minerals to the tailings due to water flow washing. To improve the recovery of fine-grained hematite minerals, these fine-grained target minerals are first subjected to flocculation treatment before strong magnetic separation, thereby significantly enhancing metal recovery rates.