If you want to know more information (such as product/process price, etc.), please contact us 24-hour telephone
Hematite is an important mineral resource, and flotation is a common method for selecting hematite. The key to improving the value of hematite and the efficiency of the beneficiation plant lies in efficient recovery. However, hematite often has the characteristics of fine disseminated particle size, easy sliming, and high silicon and aluminum impurities. Using traditional flotation technology for treatment will face problems such as low recovery rate, unstable concentrate grade, and high reagent cost.
With 28 years of experience in the mineral processing industry, Xinhai Mining has broken through technical bottlenecks and laid a solid foundation for improving the efficiency of the beneficiation plant and the value of mineral resources. This article explains the technical difficulties of hematite flotation and Xinhai's solutions, and shares successful cases.
The difficulties in hematite flotation mainly exist in four aspects: mineral characteristics, reagent system, process control, and equipment adaptability.
Because hematite has weak magnetism, the effect of pretreatment before flotation is limited, and flotation must be relied upon as the main process. However, a high proportion of hematite particles are fine (-30 μm), and it is prone to over-grinding and the generation of slimes during the grinding process, which affects the flotation index.
In addition, hematite has strong surface hydrophilicity, and the difference in floatability from gangue minerals such as quartz and silicates is small, which also poses great challenges to flotation.
A more complex reagent system needs to be formulated in the flotation process of hematite.
First, it is necessary to use high-efficiency collectors to activate the surface of hematite and selectively depress silicon and aluminum impurities.
Secondly, traditional fatty acid collectors have poor activity at low temperatures and are easily affected by elements such as Ca²⁺ and Mg²⁺.
Finally, if the amount of depressant is too large, it will lead to high costs and increased environmental pressure. How to suppress the activity of impurities and improve the recovery rate of hematite while controlling the dosage of depressants has become a major challenge.
The control of the flotation process is also a major difficulty. During flotation, an alkaline environment should always be maintained, and the pH value should be strictly controlled between 8 and 11. In addition, the fluctuation range of pulp concentration should be kept small; otherwise, the efficiency of bubble–mineral interaction will decrease. Fine-grained minerals are prone to foam entrainment in the flotation cell, reducing selectivity.
Conventional flotation machines have low recovery efficiency for fine-grained minerals. At the same time, because the ore is prone to sliming, the pulp with high slime content easily aggravates the wear of the flotation machine impeller during operation, thereby shortening the service life of the flotation machine.
How to overcome the above difficulties has become the key to breakthroughs in hematite flotation technology. Xinhai Mining has rich experience in hematite flotation. Over the years, it has continuously optimized the process flow and developed adaptive equipment, and has achieved certain success.
(1) Scientific and reasonable reagent system
Collector: In order to improve the problem of low adsorption activity in low-temperature environments, Xinhai abandoned the traditional fatty acid and sulfonate combination collectors and adopted a modified hydroxamic acid + fatty acid composite collector, which greatly improved adsorption activity and laid the foundation for improving the recovery rate.
Depressant: A starch–sodium silicate synergistic depressant is used, and the inhibition rate of silicon and aluminum impurities reaches more than 90%, achieving efficient removal.
Reagent concentration detection system: Through the online reagent concentration detection system, reagent concentration can be monitored in real time, and the dosage can be dynamically adjusted, reducing reagent costs by more than 15%.
(2) Process flow
Stage grinding and stage flotation: Since fine-grained hematite accounts for a large proportion, it is prone to over-grinding during the grinding process. To avoid this issue, stage grinding and stage flotation are adopted to control the proportion of -20 μm particles to less than 15%.
Reverse flotation desiliconization process: Since the natural floatability of quartz is 3–5 times higher than that of hematite, the reverse flotation desiliconization process is adopted, which performs better than direct flotation. The Fe concentrate grade reaches over 65%, and the recovery rate is between 82% and 88%.
Magnetic separation–flotation combined process: Magnetic separation is used as a pretreatment before flotation to discard tailings in advance. This effectively reduces the flotation processing volume and increases the overall recovery rate by 8–12%.
For hematite flotation equipment, it is recommended to use the XCF-KYF flotation machine combined unit produced by Xinhai.
This equipment uses XCF as the suction cell and KYF as the direct-flow cell, which compensates for the lack of slurry suction capacity of the KYF-type flotation machine. The self-suction function of the XCF flotation machine eliminates the need for a foam pump and enables horizontal configuration.
The XCF-KYF flotation machine combined unit adopts a U-shaped tank, hollow-shaft air inflation, and a suspended stator. The impeller is a conical impeller with backward-inclined blades, featuring high slurry handling capacity, low pressure head, low power consumption, and a simple structure. At the same time, air is well dispersed, and the impeller functions as a centrifugal pump to keep solids suspended in the tank, making operation and management convenient.
The XCF-KYF flotation machine combined unit is suitable for processing fine-grained disseminated hematite, with large processing capacity and high flotation efficiency. The mineralization efficiency is more than 30% higher than that of conventional flotation machines.
Project Background: A large hematite concentrator had a concentrate grade of 58% Fe and a recovery rate of only 62%, resulting in an annual loss of more than 20 million yuan. The owner approached Xinhai in hopes of carrying out a technical transformation.
Xinhai Solution: After repeated tests and comparisons, Xinhai Mine Design Institute determined that the beneficiation process should be a "one roughing, two cleaning, and three scavenging" reverse flotation process. Six XCF-50 flotation machines and two flotation columns were configured in the process. The reagent system used collector DS-301 and depressant IN-45.
Transformation Results: After the transformation of this project, the concentrate grade increased to 65.2% Fe, the recovery rate rose to 78.5%, and the annual economic benefits increased by more than 40 million yuan.
Xinhai provides customers with EPC+M+O full-process services. From beneficiation tests, equipment manufacturing, installation and commissioning, and worker training to plant operation, we offer one-stop delivery services.
Test: Xinhai can provide customers with small and medium-scale tests. We have our own pilot plant, which can carry out pilot tests (semi-industrial tests) and adjust the beneficiation scheme based on issues identified during testing. This ensures that customers can move into production with confidence—what you see is what you get—guaranteeing the final beneficiation recovery rate and concentrate grade.
Design: In terms of scheme design, Xinhai has its own mining design institute, which can design a reasonable mineral processing solution based on test results and a comprehensive analysis of the economic benefits of the beneficiation plant.
Equipment: Xinhai has a professional R&D team that integrates advanced technologies from both domestic and international sources, continuously improving mineral processing equipment to ensure advanced automation and intelligent control systems.
Operation: In terms of plant operation, Xinhai has a pool of professional talent who lead the beneficiation team to become familiar with operations, ensuring the smooth running of the plant and securing the economic benefits of the beneficiation project.
Conclusion
The above is an introduction to the challenges, technological breakthroughs, and project cases of hematite flotation technology. If you have related projects requiring technical consultation or are looking for EPC+M+O service providers, please feel free to contact us.
+86 13811510145