Mechanical Operations - Study Mode

Show All Answers

[#356] The most common filter aid is

(A) Diatomaceous earth

(B) Calcium silicate

(C) Sodium carbonate

(D) Silica gel

Correct Answer

(A) Diatomaceous earth

[#357] Froth floatation is the most suitable for treating

(A) Iron ores

(B) Sulphide ores

(C) Quartzite

(D) None of these

Correct Answer

(B) Sulphide ores

[#358] Trommels are revolving screens which normally operate in the range of __________ rpm.

(A) 1 - 2

(B) 15 - 20

(C) 40 - 50

(D) 60 - 75

Correct Answer

(B) 15 - 20

[#359] Separation of a suspension or slurry into a supernatant clear liquid (free from particles) and a thick sludge containing a high concentration of solid is called

(A) Classification

(B) Sedimentation

(C) Clarification

(D) Decantation

Correct Answer

(B) Sedimentation

[#360] At low Reynold's number, the power (P) required for agitating a fluid in a stirred tank becomes independent of inertial forces. In this limit, indicate which of the following relations is satisfied: P o = ρ/ρN 3 D 5 : Power number Re = ρ ND 2 /μ: Reynold's number N is the impeller rotational speed and D is the impeller diameter.

(A) P o ∝ Re -1.0

(B) P o ∝ Re 0.0

(C) P o ∝ Re 0.5

(D) P o ∝ Re 1.0

Correct Answer

(B) P o ∝ Re 0.0