Effect of expansion / contraction rate of cold ramming paste on life of submerged arc furnace lining
Cold ramming paste is a material used at high temperature for a long time, and it is in a thermodynamic non-equilibrium state. With the increase of temperature, some physical and chemical reactions will occur in the coking of binder in Cold ramming paste, which will bring certain volume changes, which may endanger the stability and service life of submerged arc furnace lining, If there is a large shrinkage during use, the furnace lining may crack and lead to furnace penetration accident; on the contrary, if there is a large expansion, it may cause a large stress in the furnace lining and lead to the damage of furnace lining refractory. Therefore, it is necessary to evaluate the expansion / contraction rate of the volume change of the cold ramming paste caused by roasting coking in the use process. The research on the expansion / contraction process of the cold ramming paste is of great significance to the life of the submerged arc furnace lining.
It can be seen from the comparative analysis that the thermal stress of the wide joint masonry of the carbon block of the electric furnace is small and the actual expansion is small. Both are not easy to damage the carbon block at the bottom of the furnace. Therefore, the prevention of the bottom penetration accident of this furnace construction method should be paid attention to the tamping of the cold tamping paste of the brick joint.
The actual expansion of seamless masonry of electric furnace carbon block is large, the thermal stress is large, and the carbon block at the bottom of the furnace is easy to be damaged. In the design of submerged arc furnace, the expansion of all materials at the bottom of the furnace shall be comprehensively calculated, and sufficient expansion space shall be reserved. The furnace bottom cannot be simply changed from the original size of seam to seamless. The higher the quality of furnace construction in this scheme, the greater the probability of bottom penetration.
The expansion rate of the cold rammed whole lining from the beginning of sintering and solidification to the steady-state expansion rate of the cold rammed paste shrinks greatly. If the elasticity of the outer refractory brick and furnace shell of the furnace cannot be restored, this irreversible shrinkage will produce cracks. The larger the furnace diameter, the greater the risk. Therefore, the use of the cold rammed whole lining in large submerged arc furnace needs to be further observed.