The different phases are present at different intervals of time during processing. The combination of different phases  is shown in the figure given below:   

The refractory facing these phases needs careful selection.

Temperature
High temperatures are involved in industrial furnace. The reaction chamber temperatures may vary from 1200-1600°C in liquid stale processing and 700-1200°C in various solid state processing operations.

Abrasion due to movement
Molten metal and slag are turbulent in nature.  Gases are flowing at high speeds inside the reactors. The refractory chamber should be able to withstand the erosion and corrosion caused by the movement of the phases

Lining life
Lining life, i.e. time for complete relining of the furnace is an important consideration and depends on several factors like, maintenance and repair technologies, condition of the phases, temperature, quality of the refractory etc.

References:
       O.P. Gupta: Elements of Fuels. Furnaces and Refractories.

       P.Mullinger and B. Jenkins: Industrial and Process Furnaces

       W. Trinks: Industrial furnaces

       W. Trinks and M.M. Mawhinney: Industrial furnaces