Today, as the metallurgical industry continues to pursue high efficiency, environmental protection and high-quality production, bentonite has become an indispensable key material in metallurgical processes due to its unique physical and chemical properties. This natural clay mineral plays an important role in many links in the metallurgical field and greatly improves the efficiency and quality of metallurgical production.
Bentonite is a clay rock with montmorillonite as the main component. The crystal structure of montmorillonite gives bentonite many special properties. It has extremely strong water absorption, and its volume can expand several times or even dozens of times after contacting water to form a high-viscosity gel; it also has excellent adhesion, adsorption and cation exchange properties. These characteristics enable bentonite to play a unique role in the metallurgical process and meet the needs of different process links.
The core role of bentonite in metallurgical pellet production
In the metallurgical pellet production process, bentonite is an extremely important additive. In the pelletizing process of pelletizing raw materials, the bonding properties of bentonite play a key role. It can tightly bond fine iron ore concentrate particles together, enhancing the strength and stability of green balls. Relevant data show that after adding an appropriate amount of bentonite, the drop strength of green balls can be increased from the original 1-2 times/0.5m to 4-6 times/0.5m, and the compressive strength can also be increased by 30%-50%. Stable green balls can reduce the breakage rate of pellets in the subsequent drying, preheating and roasting processes, ensuring the quality and output of pellets.
In addition, the water absorption and expansion characteristics of bentonite help to improve the size distribution of pellets. During the ball making process, it can make the moisture distribution between particles more uniform, promote the formation of regular spherical shapes of pellets, and improve the air permeability of pellets. Good air permeability is crucial for the redox reaction of pellets during roasting, which can accelerate the reaction speed, improve the metallurgical properties of pellets, and provide high-quality raw materials for subsequent blast furnace ironmaking.
Application of bentonite in hot metal pretreatment
Bentonite also has important applications in hot metal pretreatment. Hot metal desulfurization is one of the key processes in hot metal pretreatment, and bentonite can be used as an auxiliary material for desulfurizers. It can be mixed with other desulfurizers (such as calcium oxide, magnesium, etc.) to improve the physical properties of the desulfurizer. The adhesiveness of bentonite can make the desulfurizer better adhere to the surface of the hot metal, increase the contact area between the desulfurizer and the sulfur in the hot metal, and thus improve the desulfurization efficiency. At the same time, its adsorption properties help to adsorb impurities and inclusions generated during the desulfurization process, purify the hot metal, and improve the quality of the hot metal.
For example, in the actual production of a steel company, after the bentonite was mixed with a calcium oxide-based desulfurizer, the desulfurization efficiency of the hot metal increased by 15% - 20%, and the sulfur content in the hot metal was significantly reduced, providing high-quality hot metal raw materials for the subsequent steelmaking process, reducing the desulfurization burden in the steelmaking process, and improving the production efficiency of the entire metallurgical process.
Application of bentonite in other metallurgical fields
In addition to pellet production and molten iron pretreatment, bentonite is also used in the production of protective slag in the steelmaking process and in non-ferrous metal smelting. In protective slag, bentonite can adjust the melting speed, viscosity and spreading performance of the protective slag. It can make the protective slag form a uniform slag layer on the surface of the molten steel, which plays the role of heat preservation, air isolation, and adsorption of inclusions, thereby improving the surface quality of the ingot.
In non-ferrous metal smelting, such as lead and zinc smelting, bentonite can be used as a suspending agent and flocculant for slurry. It can make the solid particles in the slurry evenly suspended and prevent precipitation, which is beneficial to subsequent mineral processing and smelting operations; at the same time, the flocculation effect of bentonite can make fine mineral particles gather together, facilitate solid-liquid separation, and improve the recovery rate of metals.
In the future, the application of bentonite in the metallurgical industry will develop in the direction of refinement, efficiency and greenness. Researchers will be committed to screening and optimizing bentonite resources, and improving the performance and stability of bentonite through technical means such as modification. At the same time, they will explore more environmentally friendly bentonite mining and processing technologies to reduce its impact on the environment. In addition, with the continuous innovation of metallurgical processes, bentonite may play a role in more new fields and processes, providing strong support for the sustainable development of the metallurgical industry.
