Refractory lining of blast furnace Aug15

Refractory lining of blast furnace...

Refractory lining of blast furnace  A modern blast furnace (BF) is refractory lined to protect the furnace shell from the high temperatures and abrasive materials inside the furnace. The refractory lining is cooled to further enhance the protection against the dispatch of excess heat that can destroy the refractory lining. BF has a complex refractory system to provide a long, safe life that is necessary for the blast furnace availability and for permitting nearly continuous furnace operation and casting. Conditions within the blast furnace vary widely by region and the refractories are subjected to a variety of wear mechanisms. Details are given in Tab 1. The application condition of different regions of a blast furnace is not the same due to the very nature of its geometry and also due to the pyrometallurgical process occurring at different stages. There are diverse physical and chemical wear mechanisms in the different regions of the blast furnace and they are complex in nature. For example mechanical wear or abrasion occurs mainly in the upper stack region and is caused by the decent of the charge materials and by the dust laden gases. High thermal loads are a major factor in the lower stack and the belly regions. In the hearth region, horizontal and vertical flow of hot metal combined with thermal stresses often form undesirable elephant foot shaped cavitation. The refractory materials in these regions are to take care of these wear mechanisms to avoid damage due to them. Therefore, the BF stack (upper middle and lower), belly, bosh, raceway and tuyere region, hearth, and taphole all require different quality of refractories depending on the respective application conditions. Tab 1 Attack mechanisms in different regions of blast furnace       Region Attack mechanism Resulting damage       Upper stack Abrasion...