Mechanical Operations Questions

• Which of the following gives the crushing energy required to create new surface?
• In bag filters, filter fabrics are never made of
• Separation of isotopes is generally done using a/an __________ centrifuge.
• Which of the following is the most suitable filter for separation of abrasive solids suspended in a corrosive liquid?
• Which of the following size reduction equipments employs mainly attrition for ultrafine grinding?
• Which of the following grinding mills has the horizontally arranged rods as the grinding elements thereby delivering more uniform granular products with minimum fines?
• Pick out the material having minimum Rittinger's number.
• Mechanical conveyors which push the material along an endless trough or tube are called scrappers. Which of the following conveying equipments comes under the category of 'scrappers'?
• Rittinger's crushing law states that
• In case of a revolving mill, wet grinding compared to dry grinding
• Gizzlies are used for separating __________ solids.
• There is practically no alternative/competitor to __________ in the beneficiation treatment of sulphide ores.
• Which of the following is the hardest material?
• Use of 'grinding aids' is done in __________ grinding.
• Critical Speed (Nc) of a ball mill is given by(where R1 and R2 are radii of ball mill and the ball respectively).
• 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: Po = ρ/ρN3 D5 : Power number Re = ρ N D2/μ: Reynold's number N is the impeller rotational speed, and D is the impeller diameter.
• The important dimensional group involved in the power requirement calculation in mixing operation is the __________ number.
• Sphericity of pulverised coal is
• For a sphere falling in the constant drag co-efficient regime, its terminal velocity depends on its diameter (d) as
• For a cyclone of diameter 0.2 m with a tangential velocity of 15 m/s at the wall, the separation factor is