Question

The basic refractory material among the following is:
A. $A{l_2}{O_3}$
B. $Si{O_2}$
C. $F{e_2}{O_3}$
D. $CaO$

Answer 1

Refractory material is a material that is resistant to decomposition of heat, pressure or chemical attack and retains strength and form temperatures.

Complete answer:
A refractory material or refractory is a material that is resistant to decomposition by heat, pressure or chemical attack and retains strength and form at high temperatures. They are inorganic, non-metallic, porous and heterogeneous. They are composed of oxides of materials like silicon, aluminium, magnesium, calcium and zirconium.
These materials are used in furnaces, kilns, incinerators and reactors. They are also used to make crucibles and moulds for casting glass and metals and for surfacing flame deflector systems for rocket launch structures. In today’s date, the iron and steel industry and metal casting sectors use approximately 70% of all refractories produced.
These materials must be chemically and physically stable at high temperatures. Depending on the operating environment they must be resistant to thermal shock, be chemically inert and have specific ranges of thermal conductivity and coefficient of thermal expansion. The oxides of aluminium (alumina or $A{l_2}{O_3}$ ), silicon (silica or $Si{O_2}$ ) and magnesium (magnesia or $MgO$ ) are the most important materials used in the manufacturing of refractories. Other oxide found is of calcium (lime or $CaO$ ). Fire clays are also widely used in the manufacture of refractories.
Refractory materials are useful in many ways as given below:
1. Serving as a thermal barrier between hot medium and the wall of a containing vessel
2. Withstanding physical stress and preventing erosion of vessel walls due to hot medium
3. Protecting against corrosion
4. Protecting thermal insulation
Other uses include one in the metallurgy industry where they are used for lining furnaces, kilns, reactors and other vessels which hold and transport hot mediums such as metal and slag. Other high temperature applications include fired heaters, hydrogen reformers, ammonia reformers, etc.

**Therefore, from the above information we get the answer as option A, B and D.

Note: **
Refractory material is a material that is resistant to decomposition of heat, pressure or chemical attack and retains strength and form temperatures. The basic refractory materials include alumina, silica, magnesia and lime.