Future development direction of blast furnace shotcrete

The iron outlet is a very important part in the blast furnace, which is the channel for discharging molten iron and slag. Due to the large scale of blast furnace and the application of smelting technology, the iron output times increase, so the technological conditions become more severe. In order to prevent the gas from gushing out, after the molten iron and slag are discharged, the mouth of the blast furnace will be blocked by the mud immediately. Because the mud is forced into the blast furnace by the mud gun, this kind of mud is called the gun mud, which is one of the amorphous refractory materials. In the process of blast furnace operation, the high temperature slag and molten iron and high pressure gas jet erosion scour hole frequently, and the wall of iron, the impact of the high pressure gun mud and mud gun of the impact and vibration, use iron mouth nearby brick lining is easily damaged, so the taphole to sealing, and reduce the destruction of taphole stemming and is particularly important, also can say stemming control the life span of the blast furnace.

From the mixing design to the production process to the preservation before use, each process has an influence on the quality of the gunite. First of all, before production to determine a reasonable proportion of the scheme; Secondly, we should strictly follow the technical operation rules in production, and pay attention to the feeding sequence of all kinds of raw materials during grinding. Wet rolling time should be strictly controlled, the time should not be too short; The preservation of the gun mud after milling also has a great influence on the performance of the gun. Summer temperature is high, to have water cannon mud to take measures such as covering, in order to avoid water evaporation when trapped materials; In winter, when the temperature is low, the cannon mud without water should be heated and preserved to avoid the cannon mud condensing into blocks.

The binder for gunning mud underwent four stages: water-based gunning mud, tar gunning mud, high-performance tar gunning mud and resin gunning mud. At the same time, with the increase of blast furnace size and volume, the material of blasting clay has changed from silicon to high aluminum. At the same time, according to the requirement of environment, the traditional coal tar composition was improved to improve the working environment before furnace; In order to prolong the iron production time, researchers added SiC, Si3N4 and ettringite and electrofused aluminum oxide materials containing special carbon into the mortar, which greatly improved the performance of the mortar. The iron outlet condition is stable, the diameter of the iron outlet is not widened, and the molten iron and slag flow out steadily. However, due to the high strength, special drilling machine is needed to open the iron hole.

With the progress of ironmaking technology with the need of the strengthening smelting of blast furnace, people gradually realized the importance of stemming quality for normal production of blast furnace, stemming manufacturers at home and abroad by improving the purity of raw materials, quality selection of binder and adding different additive, and improves the quality of stemming and meet the requirements of blast furnace AnQuanShun line.

With the attention paid to energy conservation and environmental protection in various countries, the tar or anthracene oil, as the general anhydrous cannon clay binder, will be gradually replaced by the environment-friendly modified resin binder. In order to improve the high temperature strength of the blasting clay, the raw materials of the blasting clay are developing towards high purity, low impurity, carbon and alkalinity. At the same time, with the appearance of micro-powder, especially ultra-fine powder, and its wide application in Europe, the density and sintering properties of blasting mud are greatly improved, and its ingredients are developing towards the direction of increasing fine powder. High quality materials such as silicon carbide, silicon nitrided, blue SPAR, ferrosilicon nitrided and aluminum powder are added to improve the volume stability and density of shotcrete.