Integral Casting Technology for Permanent Safety Layer of Iron Ditch
The blast furnace tapping ditch is a channel to guide the high temperature molten iron and slag and make it fully separated, and the life of the refractory material used directly affects the normal production of the blast furnace. Due to the effect of periodic high temperature molten iron and molten slag, the life of the iron trench is mainly affected by the following destructive factors:1. Violent scouring of flowing molten iron and molten slag (especially 5 meters before the iron outlet).2. Chemical erosion and infiltration of hot metal and molten slag.3. The temperature change caused by intermittent tapping and the temperature rise of the initial tapping are easy to cause the material to burst.For this purpose, refractory materials for blast furnace tapping trenches shall have the following characteristics:1, sufficient strength to resist the erosion of molten iron and slag.2, the furnace before the operation cycle is short, the time to build the ditch or repair should be as much as possible to the minimum, so the castable to add less water, good fluidity, and can be quickly baked.3. The temperature of the trench lining changes greatly. When tapping, the temperature of the molten iron is about 1500 ℃. After the tapping is stopped, the temperature of the trench lining drops sharply. At present, most of the domestic blast furnaces are sprayed with water to cool the stemming and part of the trench lining after tapping in order to remove the slag. In this way, the castable is frequently in a state of rapid cooling and rapid heating. Therefore, the castable must have good thermal shock resistance and oxidation resistance.4. The iron ditch built with castable is a whole. No matter in baking or use can not appear more than a certain limit of the crack, otherwise there will be drilling iron or leakage of iron accident. Therefore, the castable should have a high packing density and volume stability.