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Structure of blast furnace bottom and configuration of refractory materials
Dec 26, 2018

The blast furnace is an important thermal kiln equipment in the metallurgical production of iron and steel. Its main function is iron making. The blast furnace is composed of a furnace shell and a furnace lining. The furnace shell is a steel plate and the furnace lining is a refractory material. The lining can be divided into six parts: furnace throat, furnace body, furnace waist, furnace belly, hearth and furnace bottom. The following is an example of the hearth of the hearth, and the structure of the bottom of the furnace and the configuration of the refractory material are briefly explained.

The bottom of the blast furnace is mainly divided into two types: corrosion-inhibiting type and relatively permanent type. At present, it is mainly made up of relatively permanent type, and relatively permanent type is divided into two types, namely, a full carbon furnace bottom (also called a black furnace bottom) and a comprehensive furnace bottom. The permanent structure is made of high-conductivity carbon material at the bottom of the furnace, which is nearly two-thirds thinner than the corrosion-resistant furnace bottom. It pays attention to the cooling of the bottom of the furnace, enhances the cooling effect, and forms a protective iron as early as possible at the bottom of the furnace. As long as the heat balance is not destroyed, the slag shell will remain relatively "permanently".

The permanent furnace bottom forms two general schools of integrated furnace bottom and full carbon furnace bottom. From the perspective of heat transfer, the integrated furnace bottom is a combination of heat insulation and heat conduction, and the full carbon furnace bottom is a complete heat conduction mechanism. From the perspective of design concept, the integrated furnace bottom and the full carbon bottom are the outstanding representatives of the "modern refractory method" and "thermal conduction method". From the perspective of economic and blast furnace operation processes, the integrated furnace bottom will be the future development trend.

Although the carbon bottom of the whole carbon furnace adopts the high heat-conducting and high-quality carbon brick to meet the requirements of high heat conduction and strong cooling, the slag iron shell is protected by the heat conduction method to protect the refractory material from the corrosion inside the furnace. However, in the initial stage of the furnace, the cooling effect cannot be fully exerted, the cooling is not normal, and the operation is unstable. The slag iron shell cannot be formed relatively quickly, which inevitably causes strong erosion and erosion of the carbon brick lining. The carbon bricks are severely damaged, which is not conducive to longevity in the steady state period.

In contrast, the integrated furnace bottom is covered with a layer of high-aluminum ceramic material with wear resistance, low thermal conductivity, alkali resistance and resistance to molten iron permeation on the full-filled carbon brick. First, in the dynamic period of the initial stage of the furnace, this layer of high-aluminum ceramics The material directly faces the slag iron, strongly resists the impact of the charge, the scouring of the slag iron, and various chemical erosions at high temperatures in the furnace to protect the underlying carbon bricks; in addition, some of the high-aluminum ceramic materials with heat and micro-expansion are heated. The micro-expansion can squeeze the brick joint and reduce the penetration of the slag iron through the brick joint, effectively extending the dynamic period. After the high-aluminum ceramic material is abraded, it can protect the lower carbon brick from forming the slag as early as possible. Iron shell, this structure is safer and more conducive to the longevity of the furnace bottom.


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