Types of refractory materials

This can be discussed in several ways, for example chemical composition of refractory or use of refractory or method of manufacture or in terms of physical shape. Below is given type of refractory depending on its chemical composition and physical shape.

A) Chemical composition

Refractories are composed of either single or multi-component in organic compounds with non metallic elements.

Acid refractory

The main raw materials used are  and alumino- silicate. They are used where slag and atmosphere are acidic. They cannot be used under basic conditions. Typical refractories are fireclay, quartz and silica.

Basic refractory 
   
Raw materials used are  dolomite and chrome-magnesite. Basic refractories are produced from a composition of dead burnt magnesite, dolomite, chrome ore.

   a)   Magnesite: Chrome combinations have good resistance to chemical action of basic slag and               mechanical strength and volume stability at high temperatures.

   b)  Magnesite: Carbon refractory with varying amount of carbon has excellent resistance to chemical             attack by steelmaking slags.

   c)  Chromite- Magnesite refractory: used in inner lining of BOF and side walls of soaking pits.( basic             refractory)

   d)  Magnesite: Basic refractory in nature. Magnesite bricks cannot resist thermal stock, loose strength         at high temperature and are not resistant to abrasion.

Neutral refractory

Neutral refractory is chemically stable to both acids and bases. They are manufactured from  and carbon.

For details readers may see the references given at the end of lecture 10.