How to beneficiate hematite with different particle sizes?

The beneficiation process of hematite is closely related to the properties of hematite. Generally, hematite beneficiation methods include gravity separation, strong magnetic separation, magnetization roasting, flotation, etc. In actual production, the most commonly used method for purifying hematite is gravity separation. The gravity separation production line is relatively low-cost, has high mineral processing efficiency and is environmentally friendly.

The hematite gravity beneficiation production line uses a jig as the core beneficiation equipment. The function of the jig is to separate minerals of different densities. The density of iron minerals is generally greater than that of associated gangue. Especially for coarse-grained hematite, after monomer dissociation is achieved through crushing and screening, better beneficiation effects can be obtained on the jig.

The gravity beneficiation production line, which is combined with a jig, also includes crusher equipment. Hematite generally adopts two stages of crushing. For coarse crushing, simple and practical jaw crushing is used, while for fine crushing, hammer crushing or cone crushing is used depending on the situation. The crushed materials enter the circular vibrating screen for screening, and the materials that meet the particle size requirements are sent to the jig for gravity separation.

According to the difference in particle size of hematite embedded materials, hematite selection methods can also be divided into the following types:

1. Coarse-grained hematite beneficiation

Coarse-grained hematite refers to iron minerals embedded in the ore with a size of more than 2 mm. This type of hematite is easier to extract. Generally, mineral processing methods such as ore washing, gravity separation, dry or wet strong magnetic separation are used for mineral processing.

In actual production, more than 80% of the iron minerals are soft laterite-like hematite, and the rest are hard black crystalline hematite. The iron content of raw ore from the concentrator is 42%. After washing, jigging and spiral beneficiation of this type of hematite ore, the mixed concentrate obtained is generally more than 50%, and the recovery rate is more than 90%.

2. Medium grain embedded hematite mineral processing

Medium-grained embedded hematite refers to ores with embedded minerals with a particle size of 0.3-2mm. The main beneficiation methods for processing this type of iron ore are gravity separation and magnetization roasting.

After the raw ore is crushed, screened and washed, it enters the jig, spiral concentrator and other gravity separation equipment for mineral processing, and the ideal concentrate grade can be obtained. The magnetic roasting method can also be used for ore beneficiation, but the investment in magnetic roasting equipment is huge and the cost of beneficiation is also high. Generally, small mineral processing plants do not recommend using magnetic roasting to process medium-grained hematite.

3. Fine-grained hematite beneficiation

Fine-grained embedded hematite refers to ore whose monomer dissociated particle size is between 0.2-0.043mm. This type of hematite mostly belongs to sedimentary lithology iron deposits, such as taconite, iron quartzite, etc. This type of ore accounts for a large proportion of weakly magnetic iron ores with currently proven reserves.

Fine-grained hematite is generally considered a refractory iron ore. Methods for processing this type of iron ore include magnetic separation - magnetic separation, flotation, gravity separation, strong magnetic separation and a combination of various processes. The roasting magnetic separation method is a relatively mature method to treat fine-grained hematite.