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In the dolomite processing process, the removal of calcite impurities is a major challenge. Since dolomite and calcite have similar physical and chemical properties, the types of impurities are diverse, and their associations are complex. Only by formulating a scientific beneficiation process and applying efficient beneficiation equipment can the added value and economic benefits of dolomite products be enhanced.
This article introduces the key equipment and process flow of dolomite processing.
Mineral processing is a systematic project, and each link is closely connected. Process design is very important. The main process flow of the dolomite processing production line is as follows:
After mining, the large pieces of raw ore must first be crushed to reduce the particle size. The crushing process usually involves two-stage or three-stage crushing to achieve the target particle size. The coarse crushing equipment is mainly jaw crushers, and cone crushers are mostly used for medium and fine crushing.
During the crushing process, vibrating screens should be used for screening. Qualified ore blocks enter the grinding stage, and unqualified ore blocks continue to be crushed.
The crushed material enters the grinding stage to achieve full dissociation of the target mineral and gangue minerals. In the grinding process, the grinding fineness should be determined according to the results of the mineral processing test. Over-grinding will increase the amount of slimes and affect the separation. The grinding process usually adopts two-stage or three-stage grinding, and the equipment used includes ball mills or rod mills.
Classification is carried out using spiral classifiers or hydrocyclones. Qualified materials enter the separation stage, and unqualified materials continue to be ground to the target fineness.
The process of impurity separation is the process of beneficiation. Depending on the nature of the impurities, the separation process may use scrubbing, gravity separation, magnetic separation, flotation, and photoelectric separation.
(1) Scrubbing
Scrubbing is used to remove clay and slimes from the surface of the ore. This method is particularly suitable for weathered ores. Commonly used beneficiation equipment in this process includes agitator washers, drum scrubbers, and spiral scrubbers.
(2) Gravity separation
The principle of gravity separation is to use density differences to remove impurities. It is suitable for removing heavy impurities such as quartz and iron-bearing minerals in dolomite ore, especially coarse-grained impurities, which are more suitable for gravity separation. The beneficiation equipment used in this process includes jigs, shaking tables, and spiral chutes.
(3) Magnetic separation
Dolomite usually contains more iron impurities, including magnetite, ilmenite, and some iron-bearing silicates. Therefore, magnetic separation is an important step in dolomite purification. The principle of magnetic separation is to use the magnetic properties of iron minerals to separate them. The mineral processing equipment used includes dry/wet magnetic separators, permanent magnetic drum separators, and high-gradient magnetic separators.
(4) Flotation
Flotation is the core difficulty and focus of the entire process. In this process, impurities such as calcite and silicates must be removed. Reverse flotation can be used to float calcite and silicates, while the dolomite concentrate remains in the tank. Positive flotation can also be used to float dolomite and obtain dolomite concentrate.
A scientific reagent system should be formulated during the flotation process, and flotation reagents such as collectors, inhibitors, and regulators should be used appropriately. The reagent system is the key to flotation!
Flotation equipment mainly includes mechanical agitation flotation machines, air-inflation flotation machines, etc.
(5) Photoelectric separation / color sorting
The color and gloss of some impurities differ significantly from those of dolomite. At this point, photoelectric separation or color sorting can be used to remove impurities and improve the purity of dolomite.
When the impurities are successfully separated and a high-purity dolomite concentrate slurry is obtained, dewatering treatment is required to produce the final concentrate product. Commonly used equipment in this process includes thickeners, filters, filter presses, etc. If drying is needed, a dryer is also required.
The above is the entire process of dolomite beneficiation and purification. The formulation of the process needs to comprehensively consider the properties of the raw ore, the processing capacity, and the requirements of the target product for scientific design and optimization.
Xinhai Mining provides customers with customized beneficiation services. First, the ore is subjected to beneficiation tests. According to the grade, impurity types and content, particle size distribution, and slime content, the beneficiation process is designed and reasonable beneficiation targets are formulated. Then, a series of measures such as equipment selection, installation, commissioning, and the integration of various process flows are taken to ensure that standards are met and production is achieved.
In the entire dolomite processing production line, each device performs its duties and jointly completes the beneficiation and purification work. Due to the large number of equipment and limited space, we only introduce some of the key equipment.
In the field of crushing, jaw crushers always occupy an important position. The jaw crusher independently developed by Xinhai has the characteristics of high efficiency, low energy consumption, and precise particle size control. It is suitable for various crushing scenarios and can excellently complete the coarse crushing operation.
Grinding accounts for the largest energy consumption in the entire beneficiation plant, and its energy usage represents almost half of the total consumption. Therefore, energy saving is the key to selecting a ball mill. The energy-saving ball mill produced by Xinhai adopts large double-row spherical roller bearings, which greatly reduce friction and can save 20–30% of energy.
The energy-saving ball mill produced by Xinhai also adopts a PLC automatic control system, featuring intelligence, high production efficiency, and stable operation.
Commonly used classification equipment includes spiral classifiers and hydrocyclones. Hydrocyclones are usually used in secondary grinding circuits and operate in conjunction with overflow ball mills to process fine-grained materials. They are compact and occupy a small footprint, yet have high classification efficiency and precise control of returned sand.
The hydrocyclones produced by Xinhai are lined with our proprietary wear-resistant rubber, which has 1.28 times the wear resistance of ordinary rubber. Therefore, these hydrocyclones are highly durable, and the frequency of replacing flow parts is low.
When dolomite contains more clay and slime, scrubbing as a pre-treatment step can improve the efficiency of beneficiation and enhance economic returns. The high-efficiency stirring scrubber produced by Xinhai Mining has the characteristics of compact structure and small footprint. The main shaft rotates at high speed, driving the impeller to strongly scrub the material, achieving excellent scrubbing performance. The blades, shafts, and tanks are all lined with Xinhai's wear-resistant rubber.
The spiral chute developed by Xinhai uses high-quality wear-resistant engineering plastics on the working surface, which are acid- and alkali-resistant, flame retardant, cold-resistant to -30℃, UV-resistant, and anti-aging. Compared with fiberglass (FRP), it has a longer service life. Two sections of three-dimensional spiral lines are arranged on the working surface, effectively improving the "sand dune high wall" phenomenon.
Xinhai's XCF-KYF flotation unit combines the XCF type as the suction cell and the KYF type as the direct-flow cell, allowing for a horizontal layout of the flotation tank without the need for a foam pump. It can be used for roughing, scavenging, and cleaning flotation operations. It features a high degree of automation, convenient management, large processing capacity, low power consumption, and simple structure.
Thickeners are widely used for concentrate and tailings dewatering. Their working principle is based on the sedimentation of solid particles. Xinhai’s efficient transformation thickener includes a degassing tank to eliminate the problem of solid particles attaching to air bubbles, which improves sedimentation performance. The addition of an internal overflow weir guides material flow, prevents short-circuiting, and increases the sedimentation zone area.
Conclusion
Xinhai Mining has been deeply engaged in the mineral processing industry since its establishment in 1997, with nearly 30 years of experience. We have consistently invested significant manpower, materials, and financial resources into optimizing mineral processing flows and developing advanced beneficiation equipment. Our goal is to design more comprehensive mineral processing solutions for our customers and to provide automated, intelligent, and cutting-edge equipment.
If you have any mineral processing needs, please feel free to contact us!
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