Refractory ceramics are characterized by an outstanding ability to withstand long exposition at high temperatures without significant properties losses. Thus, they are applied as lining materials in a range of industrial fields, in which the steelmaking is the most important one. Besides protecting the steelmaking vessels, the refractory materials play a role of utmost importance, as the increase in the refractory working life leads to the maintenance costs reduction and higher productivity of the plant. In this context, the development of high-performance well blocks is of great concern, as unexpected failures in this component may lead to costs increase, associated to the loss of tons of steel, maintenance stops and re-scheduling of all steelmaking process. Those failures are usually generated by corrosive wearing or by undesirable residual expansion associated to the refractory microstructure development, as the well blocks main thermal treatment takes place during operation. Considering these aspects, the major objective of the present work is to review all the concepts related to the corrosion mechanism which rules the interaction between the well block spinel-containing castable and the molten slag from the steel ladle. The influence of the raw-materials usually used in these castables in the development of phases at high temperatures and how these phases interact with the molten slag along the steel treatment, are discussed in the present review. Therefore, the mastering of the corrosion mechanisms could lead to the production of refractory castables with superior corrosion resistance, reducing the number of unexpected failures and helping to increase the plant productivity.
spinel-containing castables; corrosion; well block
