Every furnace lining should be treated as an experiment.

Every furnace reline should be an attempt to achieve a better performance the last lining.

Every aspect of every lining should be meticulously recorded.

Selection of materials:

When a lining needs replacement, you need to spend hours examining it. You need to be fairly certain of the cause of failure. If you misinterpret the cause of failure you are unlikely to choose a better material for the next lining . your selection of material should be one that you expect to be better resist the cause of failure of the last lining.

In your notes, be specific about why you decided to reline the furnace.

Examples of reasons can be:

• A change in the process is expected to cause different stresses.

• Patching of the lining is causing downtime.

• Patching of the lining is costing too much.

• You are approaching a dangerous situation; leak/explosion.

• Heat loss is causing damage to the shell.

• Heat loss is causing a high fuel cost.

• Heat loss is causing extended cycle time.

• Heat loss is causing the process to not achieve ideal process temperature.

• Your research has yielded a material with better potential.

Having made your choice, get data sheets and prices from suppliers, and then get samples. Read the data sheets, see 9.

Use your training and experience to check the samples against the data sheets. Check the maximum particle size. Identify the aggregate. If the data sheet does not specify the aggregate, be very wary of it, they could be using grog. They could use bauxite sometimes and andalusite other times; bauxite shrinks, andalusite expands, this can lead to catastrophic failure. For a castable, make a test cube following the data sheets instructions and test it. The quickest and easiest test is cutting at an angle. The material cuttable to the sharpest point is generally the best in all its properties.