Due to the unstable chemical composition of limonite, the iron content has variability, and the grinding process is prone to argillization, which is extremely difficult to select iron ore. With the increasingly serious trend of iron ore resources being poor, fine, miscellaneous and scattered, and the rapid development of the iron and steel industry, the supply of iron ore resources is extremely tight. Therefore, the efficient beneficiation technology of limonite has gradually become the main research direction of beneficiation workers, and significant progress has been made in the beneficiation technology of limonite.
About Limonite
The term "limonite" is not a species name of a mineral, but a general term for iron-bearing ores such as goethite and hydrogoethite. Because these minerals are so small that they are difficult to distinguish, they are collectively referred to as "limonites". A common iron ore, often formed in the oxidation zone of iron ore deposits, mostly in the form of secondary ore. It is also often formed in riverbeds, seabeds, and swamps due to sedimentation. Limonite comes in a variety of shades of brown, generally stalactite, grape-like, dense or loose lumps or even earthy, and also has pyrite-like crystal shapes (called artifacts). Limonite can be used as a pigment in addition to iron extraction. The color of loess is also mainly shaped by the presence of them.
Limonite Beneficiation Process
The main methods of limonite beneficiation are gravity separation, magnetic separation and flotation separation process.
1. Gravity separation is the use of gravity for separation. As the main separation method of limonite, in most cases, it is used to process coarse-grained inlaid ore. In order to further improve the quality of high-quality products, most limonite concentrators usually adopt the ore washing-gravity separation process. First, the ore is washed with equipment such as trommel screen washing machine, trough washing machine and trommel scrubber, and then the gravity separation equipment such as heavy media and jig separator is used for separating, which is mostly used for sorting limonite and false hematite. The advantages of the limonite beneficiation method are that the gravity separation method is simple in equipment, low in cost, and low in power consumption.
2. Magnetic separation: Limonite is weakly magnetic, while its common contiguous gangue mineral has little or no magnetism. In addition, due to the weak magnetic properties of limonite, strong magnetic separation is generally used to separate limonite. Limonite ore is mainly processed by magnetic beneficiation, and the equipment used includes jaw crusher, classifier, ball mill, magnetic separator, thickener and so on.
3. Flotation separation: The single flotation method has a better recovery effect on fine-grained iron minerals, but the flotation effect is seriously affected by the easy sliming of limonite ore. Therefore, it is very important to consider desliming or strengthening the dispersion of sludge before flotation. . Due to the fine particle size, it is difficult for the slime to adhere to the surface of the bubbles, and a separate mineralized foam layer is formed, which is easy to adhere to the coarse-grained surface. The limonite particles are loosely crystallized and have a large specific surface area, which is easy to adsorb and consume a large amount of chemicals during the flotation process.
When gangue mud is attached to the surface of coarse-grained limonite, its selectivity and buoyancy decrease significantly; the specific surface and surface energy (activity) of ore mud are larger. Therefore, the limonite beneficiation method should adopt the flotation process of multi-stage dosing and multi-stage separation. At the same time, the closed-circuit flotation process formed by the return of medium ore will reduce the beneficiation index. Other indicators have less impact.
Limonite Processing Plant
Limonite beneficiation adopts flotation and magnetic separation process, and its process flow is divided into crushing, grinding, magnetic separation, flotation, drying and other links. including below main equipment:
- jaw crusher
- ball mill
- spiral classifier
- magnetic separator
- flotation machine
- rotary dryer
The specific process steps are as follows:
1. Crushing and grinding: The limonite is initially crushed by the jaw crusher to realize the simple dissociation of the gangue minerals; the crushed limonite is further ground and processed by the ball mill, and is reasonably classified into multiple pieces by the spiral classifier. Different specifications, the crushed stone that does not meet the requirements will be returned to the ball mill for grinding again;
3. Magnetic separation: The sand after classification is separated by a magnetic separator, and the magnetic substances in the mixture can be separated by the difference of the magnetic susceptibility between the metal ores and the non-metals.
4. Flotation: The mineral particles initially separated by the magnetic separator are sent to the flotation machine, and different drugs are added according to different mineral properties to separate the desired minerals from other substances.
5. Drying: The iron concentrate slurry obtained after separation contains a lot of water, so it needs high-energy concentration and precipitation of the concentrator, and then it is dried and dehydrated by the dryer to obtain the finished iron concentrate powder.
Notes: The beneficiation of limonite is particularly susceptible to the influence of mud content. When the content of fine-grained argillaceous minerals is high, it will cause a decrease in concentrate grade and a decrease in beneficiation recovery. Therefore, in the wet magnetic separation operation of limonite, it is necessary to ore washing and desliming when the sludge is more serious.
Although limonite is difficult to separate, the comprehensive utilization value of limonite is also considered if a suitable beneficiation method is selected. In order to effectively select the appropriate beneficiation method. JXSC is a professional manufacturer with more than 35 years of beneficiation experience. It conducts beneficiation test analysis on the properties of limonite minerals, and then customizes the limonite beneficiation process for you according to the actual situation according to the analysis results.