Highest melting (m.p = 3070°C) oxide refractory is

Highest melting (m.p = 3070°C) oxide refractory is

A. Alumina

B. Thoria

C. Zirconia

D. Magnesia

Fusion point of an acidic refractory material is

A. Increased by the addition of basic oxides

B. Reduced by the addition of basic oxides

C. Not affected by the addition of basic oxides

D. Not affected by the addition of basic oxides

Which of the following is not a high alumina refractory material?

A. Kyanite

B. Sillimanite

C. Diaspore

D. Periclase

Magnesite refractories are generally not used in the

A. Electric furnace walls

B. Steel melting furnace

C. Open hearth furnace

D. Burning zone of cement kilns