Monolithic lining for large steel-casting ladles

Drying of steel-teeming ladle monolithic linings

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The use of moist unformed refractories for the production of steel-teeming ladle monolithic linings increases the role of drying as a production operation regulating the preparation of linings and influencing the life of the lining in service of the ladle.Until now the process of drying of linings with the use of the energy liberated in combustion of gas in the ladle has remained unstudied.In the few publications devoted to this operation, its disadvantages have been noted.Nonuniform heating of the surface with the flame of the burning gas leads to significant moistening of the reinforcing layer and formation of undried zones [i, 2], the occurrence of cracks on the whole surface, spalling, and screes in the lower portion of the ladle, and in some cases to collapse of the lining [3,4]. To eliminate the defects occurring attempts have been made to do the drying in two or more stages with different rates of gas consumption [5,6].

However, the ladle drying programs developed in some plants have not been soundly based and opinions on the maximum temperature at the boundary of the lining working and reinforcing layers at the moment of completion of drying have been contradictory.

We should also turn our attention to the long drying time, which involves significant losses of heat in combustion of gas in the ladle.

The efficiency of existing drying equipment based on gas burners has been determined as not more than 5% [i].

The basic reasons for the low effectiveness of drying of linings by the products of gas combustion are the result of the drying method itself.

The input of heat to the moist surface from the high-temperature flame of the burning gas creates high gradients of temperature, capillary or chemical potential, and pressure of the stream-air mixture in the pores of the lining surface layer.

Under the action of temperature and pressure gradients, filtration transfer of moisture in the form of water and steam into the depth of the lining predominates over diffusion mass transfer to the open surface of the lining under the action of the capillary or chemical potential gradient.

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A study of the slag-induced wear of the refarctories made from magnesia-spinellid bodies with an argillaceous binder

“…requires basic refractory materials for lining the molten steel-containing ladles [i]. In view of the fact that mechanized ramming is the most promising among the refractory lining operations involving mechanization and automation, it is necessary to introduce a plasticizer into the body compositions [2][3][4] so as to ensure satisfactory formability of the body and mechanical strength of the lining after ramming and drying. Refractory clays and bentonite are the most frequently used inorganic plasticizers.…”

A high-alumina mass for gunniting the lining of steel-casting buckets

“…1 oxygen converter shop of the Novolipetsk Metallurgical Plant (NLMP), steel of several grades is cast from buckets with a tamped silica--alumina lining while the pipe grades of steel are smelted using synthetic slag and are cast from buckets with a highalumina tamped lining [4][5][6].The composition of the masses for gunniting the tamped high-alumina lining were selected from high-alumina chamottes, with an A1203 concentration of ~58, 72, and 85%. * Chamottes with an A1203 concentration of e 58 or 72% were obtained by firing the natural raw material; chamotte with ~85% of alumina, by firing a mixture of industrial alumina with LTI clay.…”