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Molybdenum beneficiation process and important steps
Dec 04, 2024As a key strategic metal, molybdenum plays an important role in modern industry, especially in steel strengthening, alloy manufacturing, chemical catalysts and electronic products. In order to extract high-purity molybdenum concentrate from molybdenum ore, the entire beneficiation process is an extremely complex and sophisticated process, covering multiple important steps from initial ore crushing to final molybdenum concentrate purification. Below we will explore each stage in this process in depth.
1. Ore crushing
The first step in molybdenum ore beneficiation is crushing. The goal of this stage is to mechanically break down the mined raw molybdenum ore into smaller particles for subsequent processing. In this process, jaw crushers or gyratory crushers are usually used to coarsely crush large pieces of ore, and then cone crushers or impact crushers are used to further crush the ore to a particle size suitable for entering the mill. During the crushing process, it is necessary to pay attention to maintaining an appropriate crushing ratio to prevent excessive crushing from causing the loss of useful minerals, and it is also necessary to pay attention to the efficient use of energy.
2. Classification and cleaning
Classification and cleaning refers to the process of grading and cleaning the ore pulp after grinding. This step is mainly achieved by using equipment such as vibrating screens or hydrocyclones. Through these equipment, coarse and fine particles in the slurry can be effectively separated, and the mud and other fine-grained gangue attached to the surface of the mineral can be removed by washing water. The effect of graded washing is directly related to the success of subsequent flotation operations and the quality of the final molybdenum concentrate.
3. Pre-sorting and enrichment
Pre-sorting and enrichment is the process of pre-treating those lower-grade molybdenum ores. This process uses the surface physical property differences between molybdenum minerals and gangue(waste stone) to identify and separate them through visible light or x-ray intelligent sorting technology. This technology relies on image processing systems and artificial intelligence data processing systems to automatically identify and classify materials. In this way, the grade of molybdenum ore can be significantly improved, making ores that were originally not of economic value valuable.
4. Ore grinding
Grinding is an important step after crushing. It involves further refining the crushed molybdenum ore to ensure that the molybdenum minerals and the associated gangue can be fully dissociated. Commonly used grinding equipment includes ball mills, rod mills, and autogenous mills. At this stage, it is necessary to precisely control the grinding concentration, the proportion of the medium and the grinding time to ensure the best grinding effect. In addition, it is also necessary to pay attention to the energy consumption during the grinding process in order to achieve the goal of energy saving and environmental protection.
5. Flotation separation
Flotation is one of the core steps in molybdenum ore beneficiation. By adding flotation agents to the slurry and aerating and stirring, the molybdenum minerals are attached to the bubbles and float to the surface of the slurry to form a foam layer, while useless minerals such as gangue remain in the slurry. During the flotation process, the selection and dosage of the reagents and the specific flotation process (such as preferential flotation, mixed flotation and then separation, etc.) must be determined according to the specific properties of the ore to ensure the highest molybdenum recovery rate and concentrate grade.
6. Dehydration of concentrate
The molybdenum concentrate obtained after flotation contains a large amount of water, so it must be dehydrated to facilitate the storage and transportation of the concentrate. Dehydration is generally achieved by concentration, filtration and drying. Concentration refers to the use of gravity or centrifugal force to remove free water from the concentrate; filtration refers to the use of media such as filter cloth to intercept solid particles; and drying refers to heating the concentrate to a certain temperature through hot air or other heating means to evaporate the residual water.
7. Molybdenum concentrate purification
Molybdenum concentrate purification is to further improve the purity of molybdenum concentrate. Chemical or physical methods are usually used to remove impurities in the concentrate. Chemical purification methods may include leaching, purification and precipitation, while physical purification methods may involve gravity separation, magnetic separation or electrostatic separation. The purified molybdenum concentrate has a higher purity and is more suitable for the next step of smelting and refining.
8. Smelting and refining
The last step is to convert the purified molybdenum concentrate into metallic molybdenum or molybdenum alloy. This can be achieved by pyrometallurgy or hydrometallurgy. Pyrometallurgy involves roasting, reduction and smelting, while hydrometallurgy uses chemical reagents to react with molybdenum in molybdenum concentrate to form soluble molybdenum salts, and then extracts metallic molybdenum by electrolysis or precipitation. The refining stage is to further purify the obtained metal molybdenum or molybdenum alloy after smelting to meet various application requirements.
In summary, molybdenum ore beneficiation is a complex process with multiple steps and cross-disciplinary disciplines. Each link requires a high degree of professional knowledge and technical support to ensure the final output of high-quality molybdenum products.