Refractory Technology - Practice Test

[#166] Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except

(A) Cost

(B) Electrical conductivity

(C) Thermal conductivity

(D) Fusion point

Correct Answer

(A) Cost

[#167] SiO 2 percentage in firebrick is about

(A) 35 - 40

(B) 55 - 60

(C) 80 - 85

(D) > 94

Correct Answer

(B) 55 - 60

[#168] Refractories are dried in the

(A) Rotary kilns

(B) Tunnel kilns

(C) Sun

(D) None of these

Correct Answer

(B) Tunnel kilns

[#169] Refractoriness/fusion points of 'superduty' refractories is __________ °C.

(A) 1520-1630

(B) 1630-1670

(C) > 1730

(D) > 2000

(E) 1520-1630

(F) 1630-1670

(G) > 1730

(H) > 2000

Correct Answer

(C) > 1730
(G) > 1730

[#170] An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?

(A) Cork

(B) Saw dust

(C) Sand

(D) Chemically prepared foam

Correct Answer

(C) Sand

Refractory Technology - Study Mode

[#166] Beryllia (which is used in making crucibles for melting uranium & thorium) is superior to alumina in all respects for high temperature (> 1900°C ) use, except

Correct Answer

[#167] SiO 2 percentage in firebrick is about

Correct Answer

[#168] Refractories are dried in the

Correct Answer

[#169] Refractoriness/fusion points of 'superduty' refractories is __________ °C.

Correct Answer

[#170] An insulating refractory brick should have high porosity and low thermal conductivity. Which of the following is not used for inducing porosity in the insulating refractory bricks during its manufacture?

Correct Answer