Energy-efficient sol combined mullite castable used for blast furnace air supply branch pipe inner liner

Abstract

The invention discloses an energy-efficient sol combined mullite castable used for a blast furnace air supply branch pipe inner liner, which belongs to the refractory material technical field. The energy-efficient sol combined mullite castable used for the blast furnace air supply branch pipe inner liner comprises the following raw materials by weight: 50-55% of calcining kaolin granules, 4-6% of quartz sand, 14-20% of mullite powder, 6-10% of brown lapis amiridis, 5-10% of alpha-active alumina micro powder, 0.9-1.3% of magnesium oxide powder, 1-2% of dispersible alumina and 8-12% of silica sol. The energy-efficient sol combined mullite castable has the advantages of excellent physical and chemical performances, low cost, good application property and short making period, and is the high-quality inner liner material adapted to operation and making condition of the blast furnace air supply branch pipe.

Description

technical field [0001] The invention belongs to the technical field of refractory materials, and in particular relates to a sol-bonded mould, which has good volume stability, good thermal shock stability, fast curing, fast baking, high strength and low cost, and is used for the lining of blast furnace air supply branch pipes. Come stone castable. Background technique [0002] In the prior art, the blast furnace air supply branch pipe is a device for supplying air to the ironmaking blast furnace. It blows the hot air sent by the hot blast surrounding pipe into the furnace hearth through the tuyere equipment, and is also a device for injecting pulverized coal fuel to the blast furnace. The most important part of the front equipment is the weakest link in the air supply system. Blast furnace air supply branch pipe is generally composed of variable diameter pipe, metal bellows pipe, bent pipe and straight blow pipe, etc., most of which are lined with unshaped refractory castabl...

AI Technical Summary

Problems solved by technology

[0003] 1) Poor volume stability performance - low cement castables at the working temperature (1300°C), coupled with the effect of low-melting materials, the castable linings all show Because of volume shrinkage, it is very easy to crack at this time, which is one of the important factors to shorten the service life of the air supply branch pipe

[0004] 2) Low thermal shock stability - low cement castables expand and shrink greatly with temperature changes, and the internal stress generated by excessive temperature difference changes causes damage to the lining structure, which is reflected in cracking and peeling of the lining

From the physical index of the material, the thermal stability of the low-cement castable (1100°C water cooling) used for the blast furnace air supply branch pipe is only about 20 times, which leads to the temperature rise and redness of the air supply branch pipe surface, and the heat dissipation of the shell is serious. The temperature of the hot air entering the blast furnace drops, which wastes a lot of energy and seriously endangers the normal production of the blast furnace

On the other hand, frequent maintenance and replacement of air supply branch pipes also bring considerable economic losses to iron and steel enterprises due to blast furnace shutdown and air supply branch pipe materials and production.

[0005] 3) The structural strength of the lining body is low at the service temperature - due to the addition of low-melt cement in the castable, its high-temperature physical properties are lost, resulting in a decrease in the wear resistance of the lining body structure, and at the same time, the structural strength is not enough to resist excessive temperature difference stress and damaged

[0006] 4) Long construction period - use low-cement castables as the lining material of the air supply branch pipe. According to the characteristics of the cement binder, during the prefabrication process, maintenance and oven are crucial links. Generally, the air supply branch pipe The production cycle of the inner lining is at least 120 hours, and the maximum temperature of the oven is only raised to 300°C. If the temperature rise rate is too fast in the later stage, the lining body will still crack. It can be seen how to shorten the production cycle of the pouring lining body and improve the drying The furnace system is the key to reducing the cost of equipment manufacturing, and it is our top priority

[0007] Therefore, the long-standing problems of the blast furnace air supply device have been the long production cycle, air leakage during use, redness, high surface temperature, and short service life. These problems can only be solved fundamentally through the improvement of the performance of the lining material.

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