Dolomite is an important non-metallic mineral with broad application value across various industries, including metallurgy, building materials, chemicals, and environmental protection. The purity of dolomite determines its commercial value. Through beneficiation and processing, the grade of dolomite can be improved and impurities effectively removed to meet the requirements of downstream applications. This article introduces the dolomite beneficiation process, key equipment, and the current state of the industry.
Commonly used methods for dolomite beneficiation include flotation, magnetic separation, gravity separation, and chemical treatment.
Flotation is mainly employed to remove silicate gangue minerals such as quartz.
Gravity separation is suitable for coarse-grained dolomite ores.
Magnetic separation is applied to eliminate iron-bearing impurities such as siderite and hematite.
Detailed Dolomite Processing Process Flow：
1. Ore Pretreatment
The purpose of ore pretreatment is to produce a suitable particle size for subsequent separation and to preliminarily remove easily separable impurities.
Crushing: The dolomite ore is first coarsely crushed by a jaw crusher to ≤100 mm, then finely crushed by a hammer crusher to an output size of 10–30 mm.
Screening: A multi-deck vibrating screen is used to classify the crushed material, remove excessively fine particles, and ensure uniform feeding.
Washing: If the ore contains clay, mud, or is heavily weathered, a washing stage can be added. Surface clay can be removed by water rinsing, and a log washer or attrition scrubber can be used to dislodge clay through mechanical scrubbing. This step can remove approximately 5%–15% of clay and slime impurities.
Grinding: If dolomite and impurities are closely associated and the embedded grain size is fine, a grinding step is required to reduce the particle size to around 0.074 mm. If dolomite and gangue are already dissociated after crushing due to significant differences in physical properties, the ore can be directly sent to the separation stage.
2. Separation (Beneficiation)
Depending on the occurrence and distribution of impurities, gravity separation, magnetic separation, flotation, or a combination of methods may be selected.
Gravity Separation: Suitable for coarse-grained ores with a significant density difference between dolomite and impurities.
Jigging: Utilizes pulsed water flow to stratify and separate heavier minerals.
Shaking Table: Separates particles through differential movement and transverse water flow on a sloped table.
Magnetic Separation: Used to remove iron-bearing impurities.
Low-intensity magnetic separation with a drum magnetic separator is used for preliminary removal of magnetic tailings.
High-gradient magnetic separation is used for fine-grained magnetic minerals such as hematite and siderite.
Flotation: Suitable for finely disseminated ores (<0.1 mm) or complexly associated ores.
Direct flotation: Collectors such as sodium oleate and sulfonates are used to float dolomite, while gangue minerals are suppressed using water glass and starch.
Reverse flotation: Silicates are used to suppress dolomite, while quartz is floated using amine-based collectors.
Sensor-Based Sorting (Emerging Technology): Utilizes differences in optical properties (color or reflectivity) between dolomite and impurities (e.g., biotite, pyrite). AI-assisted image recognition and air-jet ejection are used to separate materials. Sorting accuracy can exceed 90%.
3. Deep Purification
For high-purity applications such as chemical-grade dolomite (MgO ≥ 98%), further purification is required. This is typically achieved through acid leaching and calcination, which help remove residual impurities and improve the final product grade.
4. Typical Process Flow
Ore → Jaw Crusher → Cone Crusher → Screening (+10 mm returns) → Ore Washing → Jig (gravity separation and tailing) → Wet High-Gradient Magnetic Separation (iron removal) → Reverse Flotation (quartz removal) → Thickening and Filtration → Concentrate (MgO ≥ 20%)
1. Crushing and Screening Equipment
Jaw Crusher: Used for primary crushing of large dolomite ore with a crushing ratio of 3–5.
Cone Crusher: Suitable for secondary and tertiary crushing, especially for hard rock.
Impact Crusher: Ideal for intermediate crushing of medium-hard ores, producing better particle shape.
Vibrating Screen: Used to classify crushed material by particle size and ensure consistent feed to downstream processes.
2. Gravity Separation Equipment
Gravity separation equipment for dolomite includes jigs and shaking tables, which are commonly used to pre-concentrate and separate dolomite from quartz and other gangue minerals.
3. Flotation Equipment
Fine-grained separation can be performed using either direct flotation or reverse flotation.
Mechanical agitation flotation cells such as XCF and KYF flotation cells are widely used.
Flotation columns are effective for fine particle separation, offering higher recovery rates and improved selectivity.
4. Dewatering Equipment
A efficiency thickener is used for primary dewatering of flotation slurry.
A filter press is then used for further moisture reduction, lowering the filter cake’s moisture content to below 15%, facilitating transportation and dry stacking.
5. Key Considerations for Equipment Selection
First, select equipment based on ore characteristics. For dolomite with high iron content, magnetic separation is prioritized. For dolomite with high silicate content, flotation is recommended.
Second, match equipment models to processing capacity. Small concentrators may use the combination of ball mill + flotation cell, while large concentrators may prefer vertical mills + flotation columns.
Finally, consider energy efficiency. Use energy-saving ball mills instead of conventional ones, and consider high-pressure grinding rolls (HPGR) to replace traditional crushers, reducing energy consumption and improving output.
Currently, the metallurgical industry represents the largest demand segment for dolomite, where it is primarily used for slag conditioning in blast furnaces and converters. Demand in the building materials sector is also growing steadily, with dolomite being used in glass manufacturing, ceramics, and refractory materials. The chemical and environmental protection industries have become emerging areas of growth, with an annual increase of 8%–10%.
In terms of processing technology, traditional beneficiation processes still dominate the industry. However, emerging technologies such as photoelectric sorting and bioflotation are gradually gaining traction. For deep processing, the acid leaching–calcination method remains the mainstream approach, though it involves high wastewater treatment costs. Microwave calcination and carbonization are new technologies that are gradually being introduced.
Modern dolomite concentrators are becoming increasingly intelligent and automated. Technologies such as online elemental analysis and AI-assisted ore sorting are being implemented. The use of unmanned control systems for crushing, grinding, and flotation not only reduces labor costs but also enhances operational precision and improves concentrate grade.
Conclusion
This article has introduced the dolomite processing flow, key equipment, and industry development trends. Xinhai Mining provides customers with EPCM+O services for dolomite projects—offering full-process solutions from mineral processing tests to concentrator operation.
If you have any needs related to dolomite beneficiation, feel free to contact us!
To find out more about our products and solutions, please fill out the form below and one of our experts will get back to you shortly.
CHAT
MESSAGE
