How to choose refractories for blast furnace, ladle and heating furnace

When choosing the application area of refractory materials, the application needs of refractory materials are clearly defined, including the application needs of blast furnace operation, ladle application needs and heating furnace application needs, etc., which can further refine the application measures of refractory materials and improve the overall application quality of refractory materials in the metallurgical process.

1. Analysis of the application properties of refractory materials

The structural properties of refractory materials compared to ordinary materials, can be manifested as more obvious water absorption, and due to the structural hierarchy of such refractory materials is not closely linked, prompting the refractory material inside the gap is relatively more, and the actual bulk density of the material and the ordinary material there is a more obvious difference between. In the application of such refractory materials, if the material itself has a large water absorption rate, then in the actual application of the process may produce a relatively obvious heat concentration phenomenon, resulting in the internal temperature of the material is too high, affecting the metallurgical work efficiency.

If the analysis from the perspective of the refractory material pore volume ratio, the more accurate the density of the refractory material itself, it also indicates that the refractory material itself has a relatively high true density value, and this relatively high true density refractory material in the actual metallurgical process can show a relatively good structural organization, which can provide a more effective refractory environment for the support of metallurgical work.

Refractory materials with higher bending strength will have higher stress strength limit values in the actual application process, and will show better working stability in the metallurgical process. Refractory materials also show different physical properties at different temperatures. Generally speaking, at room temperature or medium-high temperature conditions, the refractory material will show better ductility, which will promote the overall structural strength of the refractory material decreased. However, at high temperatures, the ductility of the refractory material itself will be limited, and the structural brittleness will be relatively increased, which will also affect the structural stability of some refractory materials.

2.Refractory materials in metallurgy

（1）Refractory materials for blast furnace applications

In the traditional blast furnace steelmaking process, often use shaped refractory materials, including phosphoric acid high-alumina refractory materials, such materials are often mixed with high-alumina content cement, and in order to adapt to the actual needs of the blast furnace steelmaking, but also to adjust the mixing ratio of such materials. However, the application of stereotyped refractories is not very flexible, if you can not strictly control the proportion of the corresponding aggregate, may be in the actual application process of the temperature adaptability of the problem, resulting in refractory materials of high temperature resistance can not meet the actual blast furnace steelmaking application requirements.

Unshaped refractories application better solve these problems, based on multi-level aggregate configuration, can be flexibly adjusted according to the actual production demand with the proportion of unshaped refractories, high temperature adaptability is very good, and has a relatively obvious refractoriness.

Blast Furnace

（2）Refractory materials for ladle applications

The application of refractory materials in ladle is mainly related to the quality of steel production. Generally speaking, in the process of steel out of the steel needs to maintain a better temperature, the actual performance of this temperature is related to the physical properties of the refractory material itself. In order to improve the actual quality of the steel out of the steel, should try to choose the refractory material with higher temperature resistance, Al203-spinel castables as the main component of the refractory material has relatively good corrosion resistance, and also in the high-temperature environment will show good continuity. In addition, the lining of this refractory material has a relatively low probability of spalling of the internal structure during the formation and operation of the ladle, and the actual service life has been extended to a certain extent.

Ladle Furnace

（3）Refractory materials for heating furnaces

The application effect of refractory materials in heating furnace is mainly related to the high temperature characteristics of such refractory materials. In the operation of the heating furnace, often need to adapt to a better heating temperature, in this heating temperature requirements, the general type of refractory shaped often can not withstand higher heating temperatures, under the influence of this heating temperature, the structure of the refractory material itself will undergo a certain amount of change, this change will often be better ductility imbalance state, which leads to a certain amount of stereotypes of refractory materials themselves appear Structural voids, resulting in a sharp decrease in the structural strength of the refractory material itself.

Indeterminate type refractories have relatively good high temperature properties, and in the high temperature environment, the ductility of indeterminate refractories will not be seriously affected, although its own structural brittleness has been shown, but the actual structural strength can still meet the operating requirements of the furnace, but also for the safe operation of the furnace to provide more effective protection.