Taphole Clay is an amorphous functional refractory material, used in the process of plugging the taphole of the ironmaking blast furnace. The composition of taphole clay can be divided into two parts: refractory aggregate and binder. Refractory aggregate refers to refractory raw materials such as corundum, mullite, coke gemstone and modified materials such as coke and mica, which are used to improve the refractoriness, high temperature performance and slag resistance of taphole clay; the binder is water, tar pitch or phenolic Organic materials such as resins can also be mixed with SiC, Si?N?, expanding agents and additives to improve the physical properties and product quality of taphole clay.
According to the different binders, taphole clay can be divided into two categories: water taphole clay and waterless taphole clay. Domestically, medium and small blast furnaces (<2000m3) with low top pressure and low level of intensified smelting use water blasting taphole clay; while large and medium blast furnaces (>2000m3) with high top pressure and high level of intensive smelting are generally used Anhydrous cannon taphole clay. Many foreign blast furnaces represented by Japanese blast furnaces generally use high-quality anhydrous taphole clay, and are equipped with special opening methods and opening machines.
The water cannon taphole clay is usually made of clay, coke powder, bauxite clinker and tar pitch as the main materials, and then mixed and stirred with water as a binder. Anhydrous taphole clay is a kind of taphole clay that was used in large quantities in the early days, but because of its relatively small bulk density, its ability to resist scouring of iron slag solution is weak, it is easy to cause insufficient hole depth when used on large and medium blast furnaces and runaway during tapping. Phenomena such as coke, iron tapping and venting and unclean iron slag will affect the normal production of the blast furnace. So far, due to the low cost of water taphole clay, many medium and small blast furnaces (<2000m3) are still improving their composition and working hard to adapt to the smelting environment, and their unit consumption is above 1.2kg·t?1.
Anhydrous taphole clay generally uses corundum, high alumina bauxite, clay, sericite, pitch, silicon carbide, coke powder, etc. as raw materials, and uses tar, resin, etc. as binders. The bulk density of corundum and high alumina bauxite is relatively large, and they play a role in supporting the skeleton in the taphole clay. It is the basis of the taphole clay strength, which greatly improves the ability of the taphole clay to resist the scouring of the iron slag solution; the coke powder has good reduction It can protect other carbon components, maintain the reducing atmosphere of the blast furnace taphole, and has good thermal conductivity, which can be quickly sintered and has a certain sintering strength; silicon carbide has a small thermal expansion coefficient, good thermal conductivity, and excellent thermal shock resistance, which can be improved The refractoriness, volume stability, high temperature strength and erosion resistance of taphole clay; clay and asphalt improve the plasticity of taphole clay; sericite improves the sintering strength and plasticity of taphole clay. Anhydrous taphole clay has the advantages of no dampness, high strength, stable taphole depth, small taphole changes during the tapping process, etc., and it will not cause large flow.
The main factors affecting the performance and quality of blast furnace taphole clay are raw materials, binders, additives and production processes.
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