Mechanical Operations - Study Mode

[#206] Which of the following crushers can be considered as a combination of a jaw crusher and a roller crusher?
Correct Answer

(C) Gyratory crusher

[#207] Length/diameter ratio of a ball mill is
Correct Answer

(C) < 1

Explanation

Solution: A ball mill is a type of grinder used in mechanical operations to grind and blend materials for use in mineral dressing, paints, pyrotechnics, ceramics, and selective laser sintering. The design of a ball mill is typically cylindrical with a horizontal axis, partially filled with the material to be ground plus the grinding medium (like steel balls). The length to diameter (L/D) ratio of a ball mill is an important design factor as it affects the grinding efficiency and operational stability. For ball mills, the L/D ratio is usually less than 1 , meaning the diameter of the mill is greater than its length. This configuration helps in achieving a better cascading action of the grinding media and efficient grinding performance. Therefore, the correct answer is: < 1 (Option C).

[#208] The optimum moisture content in solids to be crushed/ground ranges from __________ percent.
Correct Answer

(A) 3 to 4

[#209] Apron conveyors are used for
Correct Answer

(A) Heavy loads & short runs

[#210] Carbon black is pulverised in a
Correct Answer

(B) Ball mill