4. Reconditioning and doping cowpers

4.1 Reconditioning

After ten or fifteen years of operation, we often notice a drop in efficiency, especially when the gas cleaning is not perfect.

This is due to the slagging of the hives on the surface as a result of the reaction of the refractory with dust, mainly iron oxide and carbon. The initial state can be restored by changing some of the hives at the top of the stack. The difficulty lies in the fact that the slagged hives are often welded together, and it is difficult to remove them without breaking them or breaking off slag fragments that may obstruct channels. What's more, in such an operation you never know in advance how far you'll have to change the hives.

We often take advantage of the shutdown to redo part of the inner...