Release Time：2018-03-23
Cannon mud is a key refractory material that affects the smooth operation of the blast furnace during the smelting process. The main function is to fill the iron hole. In the iron tapping operation in front of the blast furnace, the function of the gun mud is like a valve. When iron needs to be tapped, the tapping hole should be opened. After the iron is tapped, the tapping hole should be promptly blocked and sufficient tapping time should be ensured.
With the rapid development of China’s steel industry, blast furnaces are constantly moving towards large-scale, longevity, and strengthened smelting, and the requirements for the performance of anhydrous blast furnace mud at the tapping hole are becoming higher and higher. Nowadays, it is required to have good workability (filling and opening properties), breathability, sintering properties, the combination of new and old gun mud, corrosion resistance, and erosion resistance, especially for the short splashing time and slow hole expansion speed in the iron making process.
Cannon clay is divided into three types based on its binder:
1. Water used as a binder is called water cannon mud
2. Organic materials such as tar, anthracene oil, and resin used as binders are called anhydrous gunpowder.
3. Special gun mud using special organic materials as binders, such as environmentally friendly gun mud.
In addition to binders, the composition of gunpowder also includes aggregates, powders, and additives. The commonly used anhydrous gunpowder raw materials are generally corundum, high alumina bauxite, pyroxene, silicon carbide, sticky mica, soil, and coke powder, etc., which are composed of a matrix according to a certain particle size and weight. The addition of various micro powders and ultrafine powder raw materials further improves their density and sintering performance. With the blending of binders, they have a certain degree of plasticity, so that the molten iron can be blocked by the iron mouth through the gunpowder.
The following is a brief analysis of the functions of several raw materials used in the manufacturing of gun mud:
1. Silicon carbide is added to the mud to fill the gaps between the main aggregate particles, forming a refractory matrix. By utilizing its high melting point (2200 ℃), corrosion resistance, high thermal conductivity, high wear resistance (hardness value of 2500kg/mm2), high high-temperature strength, low coefficient of thermal expansion, and good thermal shock stability, the mud has better slag resistance, high-temperature structural strength, and thermal shock stability, It can improve its resistance to slag erosion and erosion. However, silicon carbide is prone to oxidation in high-temperature oxidation atmospheres, so it should be taken into consideration when mixed with mud. Adding an excessive amount of silicon carbide can lead to poor sintering performance of gun mud.
2. Coke powder is mainly used to improve the breathability and opening performance of gun mud. At the same time, at the production temperature, carbon elements combine with the residual carbon volatilized from tar to form a carbon binding image, ensuring the final strength of gun mud. Different types of coke will result in different chemical reactions and other characteristics. The characteristics of coke are high porosity, good thermal and electrical conductivity, good slag resistance and thermal shock stability, maintaining a reducing atmosphere in the iron mouth, and providing protection for SiC, carbonization network, and carbon materials.
3. Corundum aggregate and powder. Corundum belongs to refractory materials with high density, high melting point, and high hardness. It forms a-Al2O3 at high temperatures, which improves the resistance of blast furnace slag to iron erosion and chemical erosion, as well as the high-temperature structural strength of blast furnace slag. It has good resistance to high-temperature iron erosion and erosion wear. Coarse particles serve as a skeleton, while powder can improve the strength and high-temperature performance of gunpowder, improve breathability and volume stability, increase flexural strength, and prevent gunpowder from being damaged