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In recent years, with the continuous mining of ores, rich ores have become increasingly depleted. However, with the rapid economic and social development, the repair of ore materials has also grown rapidly. Due to the increasing scarcity of rich ores, the mining and utilization of low-grade, refractory ores has gradually attracted attention. Due to the complex mineral composition and material composition of these ores and the low grade of raw ore, their beneficiation becomes more difficult. Representative types of refractory minerals mainly include limonite ore, lead-zinc oxide ore, low-grade copper oxide ore, refractory gold ore and bauxite. The following mainly introduces you to the beneficiation process of limonite ore. As the main ore type of iron ore, the beneficiation process of limonite mainly includes magnetic separation, flotation, magnetic flotation combined beneficiation and reduction roasting-magnetic separation process.
Use the table of contents below to navigate through the guide:
Limonite exhibits weak magnetism, so it needs to be processed by a strong magnetic separator. Intense magnetic separation is widely used in limonite beneficiation plants, and is mainly suitable for the separation of coarse-grained and medium-grained limonite. For fine-grained limonite, a combined process of strong magnetic separation and flotation is required. During the strong magnetic separation of limonite ore, a permanent magnet roller type strong magnetic separator can be used for separation, which can improve the recovery rate of the concentrate. The strong magnetic separator is not suitable for recovering iron ore with a particle size of less than 30 microns, so the flocculation-strong magnetic separation process can be used. This process can strengthen the dispersion of the sludge and effectively recover the fine-grained iron minerals in the ore, and is precise. The ore recovery rate index is good.
(Magnetic separation equipment)
When the flotation process treats limonite ore, it is mainly divided into two types: forward flotation and reverse flotation. For difficult-to-select low-grade limonite, a low dosage of sodium petroleum sulfonate is used to flotate mud in a weakly alkaline medium, and then sodium petroleum sulfonate and auxiliary collector oxidized paraffin soap are used to flotate in a weakly acidic medium. Limonite can obtain good flotation indicators. However, due to the complex properties of low-grade refractory limonite, it is necessary to develop a reasonable flotation process based on the ore dressing test results in order to obtain better separation indicators.
Due to the special properties of limonite raw ore, it is difficult to obtain good beneficiation indicators using a single flotation process or magnetic separation process. Therefore, it is necessary to use a combined beneficiation process, such as magnetic separation-flotation combined process, strong magnetic-positive flotation-strong magnetic Separation process, strong magnetic separation-reverse flotation process, strong magnetic separation-strong magnetic separation-forward flotation process, etc. The limonite is first subjected to strong magnetic separation using a wet strong magnetic separator and tailing desliming to improve the recovery rate. The magnetic separation of the coarse concentrate is followed by reverse flotation of quartz to improve the iron grade.
After reduction roasting, limonite can remove crystal water and improve the grade of raw ore. At the same time, reduction roasting can also reduce limonite and turn it into magnetite with strong magnetic separation for subsequent magnetic separation. When the reduction roasting-magnetic separation process is compared with other combined processes, the roasting magnetic separation process can improve the grade and recovery of iron concentrate. Since limonite is a difficult-to-select iron ore, the reduction roasting-magnetic separation combined process is a method with better technical indicators. However, due to the high cost of roasting and magnetic separation, it can be considered when the ore selection site has sufficient coal and natural gas resources.
(Mineral processing equipment)
The above is a beneficiation method for difficult-to-separate low-grade limonite ore. At present, the commonly used combined processes in mineral processing plants include weak magnetic separation-strong magnetic separation-positive flotation process, classification-gravity separation-flotation process, strong magnetic separation- Positive flotation - strong magnetic separation process, strong magnetic separation - reverse flotation process and strong magnetic - strong magnetic - positive flotation process, etc. Although these processes are relatively complex, their costs are low and they have been widely used in mineral processing plants. In actual production, the ore composition and properties of different mines are different. It is recommended that active mineral processing experiments be conducted to determine a reasonable limonite mineral processing process.