‘Spinel’, a refractory mineral is chemically represented as____________________?

A. MgAl2O4
B. MgAl2O3
C. MgSO4
D. MgAl2O3.2H2O

With increase in the density of silica refractories, its_______________?

A. Resistance to slag attack increases
B. Spalling resistance reduces
C. Both A. and B.
D. Neither A. nor B.

Mixing of ground refractory material and water is done in a ______________ mill?

A. Pug
B. Ball
C. Tube
D. Rod

Silicon carbide refractories are used in the _____________?

A. Muffle furnace
B. Zinc smelting furnace
C. Ceramic recuperators
D. All A., B. and C.

Firing temperature of magnesite bricks is about _____________ °C?

A. 800-1000
B. 1000-1200
C. 1600-1800
D. 2400-2600

Which of the following is not an acidic refractory?

A. Silica bricks
B. Fireclay bricks
C. Bauxite bricks
D. Magnesia bricks

Grog__________________?

A. Contains both alumina and silica
B. Is crushed firebrick
C. Is a non-plastic material
D. All A., B. and C.

Except _____________, all other refractories are bad conductors of electricity (i.e, have low electrical conductivity)?

A. Fireclay
B. Carborundum
C. Graphite
D. Chromite

Refractoriness of a typical silica brick corresponds to Segar cone number, ’32’, which is equivalent to a temperature of _____________ °C?

A. 1380
B. 1520
C. 1710
D. 1915

With increase in the alumina content in firebricks, its fusion point (refractoriness) ?

A. Decreases linearly
B. Remains unchanged
C. Increases
D. Decreases