Limonite is an iron-containing mineral. To be precise, it is not a single mineral, but a mixture with hydrous iron oxide as the main component. Its grade is usually low, but it varies greatly. Generally speaking, the grade of limonite can range from 20% to 45%, depending on the geological conditions of the deposit.

Its physical properties:

Color: The color of limonite is usually yellow-brown to dark brown, sometimes it can appear reddish brown or other shades of brown.

Streak: Streak refers to the color of the mineral powder. For limonite, the streak is usually yellow-brown.

Luster: Because limonite contains water and its texture can vary from dense to loose, the luster can be dull or semi-metallic.

Hardness: The hardness of limonite varies depending on its specific composition and texture. The hardness of dense massive limonite rich in silica is higher, reaching about 5.5, while the hardness of earthy limonite rich in mud is lower.

Morphology: It can present different forms, such as massive, earthy, stalactite or grape-like. Sometimes, when limonite replaces the original crystal structure of other minerals (such as pyrite), it can maintain the crystal shape of these replaced minerals, which is called an illusion.

Transparency: Limonite is usually opaque.

Fracture: The fracture of limonite is irregular.

Relative density (specific gravity): The relative density also varies depending on the type and amount of impurities contained.

In addition, limonite has a certain degree of magnetism, but this magnetism is weaker than that of magnetite. Because the composition of limonite is complex, its physical properties can also vary greatly. This leads to many difficulties in its sorting and processing:

1. Low iron content: Compared with other types of iron ore, limonite usually has a lower iron content, which means that more ore needs to be processed to extract the same amount of iron, increasing the processing cost.

2. Large composition changes: In addition to iron, limonite may contain other metal elements or impurities. These changes in composition will increase the complexity and difficulty of the processing process.

3. Fine embedded particle size: The embedded particle size between iron minerals and other minerals in limonite may be very fine, making it difficult to effectively separate by traditional physical sorting methods (such as gravity separation or magnetic separation).

4. Low sorting index: Due to the above reasons, the sorting index of limonite (such as recovery rate, concentrate grade, etc.) is usually not as good as other types of iron ore.

In view of these difficulties, a variety of beneficiation methods are usually used in combination. At the same time, in order to improve the beneficiation performance, pretreatment measures may be taken, such as enhanced desludging, slurry dispersion, pre-selection enrichment, etc., to improve the effect of subsequent sorting steps.

Because limonite contains more water and a high impurity content, it usually needs to be enriched in industry to increase its economic value. According to the special chemical composition and physical properties of limonite, photoelectric intelligent sorting machine or X-ray intelligent sorting machine can be used for enrichment treatment. These two sorting technologies have their own advantages and are suitable for different scenarios.

Photoelectric intelligent sorting machine

Photoelectric intelligent sorting machine mainly relies on the optical properties of mineral particles such as color, shape, and gloss to achieve sorting. This equipment is usually equipped with high-resolution cameras and other optical sensors that can quickly identify and sort different types of mineral particles. For limonite, if there is a significant difference in color or gloss between its color and the gangue mineral, then an optoelectronic intelligent sorter may be a suitable choice.

X-ray intelligent sorter

X-ray intelligent sorters use the different absorption characteristics of minerals to X-rays for sorting. The ability of X-rays to penetrate matter is related to its atomic number, so minerals of different densities or elemental compositions can be distinguished. For some types of limonite, especially those with a large difference in density from the gangue mineral, X-ray intelligent sorters can separate them more effectively.

Application considerations

The choice of optoelectronic intelligent sorting or X-ray intelligent sorting depends on the specific properties of the limonite and the expected sorting results. Here are a few considerations:

1. Mineral characteristics: If the optical properties between limonite and gangue are significantly different, MINGDER optoelectronic sorting may be a better choice; if the minerals are mainly distinguished by density or elemental composition,MINGDER X-ray sorting is more applicable.

2. Cost-effectiveness: The initial investment, operating costs and maintenance costs of the two types of equipment are different, and economic benefits need to be considered comprehensively.

3. Technology maturity: Both technologies have mature solutions in the market, but they may focus on specific application areas.

Ultimately, in order to determine the most suitable sorting solution, it is recommended to conduct laboratory-scale experimental research first, evaluate the effects of different technologies, and make a comprehensive judgment based on actual production conditions. At the same time, it is also possible to consider combining multiple sorting technologies to improve overall sorting efficiency and concentrate quality.