The role of blast furnace clay
- The tap hole can be opened and filled many times.
- The gun mud can keep the hole diameter of the iron hole stable, and the iron can be drawn uniformly, and finally the molten iron slag in the furnace can be cleaned.
- The hearth can be protected.
The performance of gun clay
(1) The gun mud must have a certain degree of plasticity to ensure that it does not break when being shot from the mud gun, and is easy to squeeze into and fill the iron hole channel;
(2) The taphole is often in a high temperature state, and the fire resistance of the gun mud is required to be high (generally, the fire resistance of the gun mud is above 1400 ℃);
(3) Good sinterability, high strength, erosion resistance and erosion resistance. Under normal circumstances, the faster the sintering speed, the safer the blasting mud can be used;
(4) It is easy to open the opening, easy to drill the opening machine, which is convenient for on-site operation;
(5) It is required that the gun mud should have high resistance to slag, not easy to be corroded by slag iron, strong resistance to high temperature slag and molten iron corrosion, slow reaming speed of iron hole diameter, stable iron flow, and strong resistance Scour wear
(6) It is required that the gun mud has good volume stability when in use, does not shrink at high temperature, and avoids cracks;
(7) Proper porosity, so that the gun mud has sufficient air permeability, which is conducive to the escape of volatiles in the gun mud;
(8) Environmental pollution is small.
The development status of gun clay
- Traditional Cannon Clay: This cannon clay is made of coke powder, clay, bauxite clinker and tar pitch as the main raw materials, mixed with water, and is commonly known as water cannon clay. Features: This gun mud generally has a small volume density and poor resistance to slag and iron corrosion. When the taphole is blocked on a large and medium-sized blast furnace, the taphole depth is likely to be insufficient. During the tapping period, it often runs out of coke, vents the iron, and produces unclean slag. Melt, etc., affect the normal production of the blast furnace. However, due to its low cost, it is still used in the vast majority of small and medium-sized blast furnaces in my country after being improved by various ironworks, and its unit consumption is above 1.2kg/t.
- Anhydrous artillery mud: Anhydrous artillery mud is generally made of corundum, silicon carbide and coke powder as the main raw materials, and different additives are added at the same time, with tar as the binding agent. Features: Because of the use of high-quality and high-purity raw materials and the use of C-quality raw materials as binders, this gun mud has a much higher resistance to iron slag erosion than water gun mud, which can extend the tapping time and reduce the number of taps. . Each tapping time of Baosteel TA-4 gun mud can reach more than 120 minutes, and the number of tapping times per day is 10-11 times. The disadvantage is that it is difficult to open the taphole. Baosteel uses the plunger method to open the taphole. The unit consumption of gun mud has been reduced from 0.8kg/t iron to 0.35kg/t iron.
The development trend of blast furnace clay
Improve the purity of raw materials, select high-quality binders and add different additives to improve and enhance the quality of blasting mud and meet the needs of blast furnace safety.
Binder: As countries in the world pay more attention to energy saving and environmental protection, tar or anthracene oil, which is a general waterless gun mud binder, will gradually be replaced by environmentally friendly modified resin binders; in order to improve the high temperature strength of the gun mud, The raw materials of gun mud are developing in the direction of high purity, low impurity content, carbon quality and alkalinity;
At the same time, with the emergence of ultra-fine powder and its wide application in materials, in order to improve the density and sintering performance of gun clay, its ingredients are developing in the direction of increasing fine powder. Add high-quality materials such as silicon nitride, silicon carbide combined with silicon nitride, kyanite, ferrosilicon nitride, aluminum powder, etc. to improve volume stability and also increase volume density.