- Time:Feb 13, 2023
In iron and steel smelting, the ladle is an important thermal equipment for steelmaking, which undertakes the dual tasks of molten steel transportation and refining. Therefore, the selection of ladle working lining material is very important. The quality of its performance not only affects the consumption of refractory materials per ton of steel and the cost of steel smelting, but also has a great impact on the output and quality of steel.
The development of iron and steel smelting technology has promoted the continuous improvement of refractory materials. The development of refractory materials for ladles has roughly gone through the following four stages:
1. Before the 1970s
The lining materials of ladles in my country are mainly clay bricks and high alumina bricks. Because of their abundant clay resources, European and American countries have developed clay bricks and clay-bonded semi-siliceous bricks. The application of continuous casting technology has changed the working conditions of the ladle, and developed andalusite bricks, high alumina bricks and so on. In order to improve the ability to resist alkaline slag erosion, carbon-containing refractory materials have emerged, and low-grade alumina-magnesia-carbon bricks have been used in the former Soviet Union and the United States. But this period is still dominated by high alumina bricks.
2. The 1970s
my country has researched and developed high-alumina ramming materials combined with phosphoric acid and high-alumina castables, which have greatly improved the life of small ladles, but most manufacturers still use high-alumina bricks for lining. In the 1980s, my country successively developed water-glass-bonded aluminum-magnesium castables and alumina-spinel castables. In the 1970s and 1980s, European and American countries mainly used medium and low-grade alumina-magnesia-carbon bricks. After adopting the secondary refining technology, it is difficult for high alumina bricks or high alumina castables to meet the requirements of ladles. European and American countries have begun to use alkaline materials such as magnesia bricks and dolomite bricks. At the same time, Japan has developed high siliceous bricks, which mainly use zircon to improve the corrosion resistance of pyrophyllite bricks. Zircon bricks are used in some ladle slag lines, and the effect is very good.
3. Early 1990s
my country's refractory researchers have successively carried out the research and application of alumina-spinel castables and alumina corundum-spinel castables, and achieved good results. In the late 1990s, Wuhan University of Science and Technology developed high-performance Al2O3-MgO castables, which have the characteristics of carbon-free, labor-saving construction, corrosion resistance, and high-temperature volume stability.
4. Today
The research and application of refractory materials for ladle lining are still mainly concentrated on aluminum-magnesium series, including aluminum-magnesium castables, corundum-spinel castables, aluminum-magnesium spinel castables and their prefabricated blocks. The performance of high-performance aluminum-magnesium castables made by adding ultra-fine powder or using high-purity raw materials has been greatly improved, and the service life of the refining ladle outside the furnace has been greatly improved.
In recent years, with the continuous increase in the demand for high-quality steel in construction, machinery manufacturing and other industries, as well as the improvement of molten steel refining and continuous casting processes, the working conditions of the ladle lining are getting worse, and the requirements for the performance of the refractory materials used are also increasing. come higher.
At present, aluminum-magnesium castables and magnesia-carbon bricks are mostly used as ladle refractory materials. Because different parts of the ladle are subject to different erosion and erosion conditions of molten steel, they are often used together, and should be used for the refractory materials used for the bottom, wall and slag line of the ladle. Comprehensive balance, and strive to achieve optimal design on the basis of considering economic factors and refining technology.
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