The behaviour of basic refractories in atmospheres rich in alkaline vapours 

GT V01 1960 162-173

The quality of refractory  materials comprising the chequers in regenerators of a  tank furnace has an important  influence on  the efficiency and  the  length of life of the furnace. The principal factors which have an effect on the  brick  are  the  action  of condensed alkaline salts, the   cyclical   atmosphere   variations,   and  finally the periodical  temperature  changes.  Generally, basic bricks resist the effect of alkaline salts but  they have a tendency to disintegrate  under the influence of changes in the gas composition if they contain an appreciable  amount of iron oxide or iron silicate. This fact  has also been established by using forsterite or magnesite bricks. It is also equally important to avoid the contact of these brick-s or dust  with  siliceous material, contact  with  which  pro- motes corrosion in the  high  temperature  zones of the chequer-work by the formation of eutectics. Attention vas then  directed to materials  with lower iron  contents  but  richer in magnesia. Long trials are described  which show the good  durability  of  magnesia bricks. The difficulty of assessing the value of  chequer bricks is due to the length of furnace  campaigns. A  quick and  representative trial is necessary. The authors  developed a special type of furnace which permits trials at different temperatures  and  controlled  atmosphere. The trial furnace is  a channel in which the  temperature decreases. The test pieces are put in horizontally and the fIame from the burner  is charged with alkaline  vapours, the flame being alternatively  reducing and oxidizing. An attempt has been made to reproduce in this apparatus the conditions  which exist in  the  regenerators, und it has thus been possible to study  the destruction  process of chequer bricks and also to select  materials. 

P. Eloy, M. Jaupain & E. Plumat