A. At a speed less than the critical speed
B. At a speed more than the critical speed
C. At a speed equal to the critical speed
D. With minimum possible small balls
Related Mcqs:
- Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of__________________?
A. Bronze
B. Stainless steel
C. Flint or porcelain
D. Concrete - Which of the following grinding mills has the horizontally arranged rods as the grinding elements thereby delivering more uniform granular products with minimum fines ?
A. Compartment mill
B. Rod mill
C. Pebble mill
D. Tube mill - Ball mills and tube mills with flint or porcelain balls are used for size reduction of_______________?
A. Asbestos
B. Rubber
C. Non-metallic ores
D. Limestone - Size reduction of the ______________ can be suitably done by ball mills, crushing rolls and rod mills?
A. Metalliferous ores
B. Non-metallic ores
C. Basic slags
D. Asbestos & mica - ____________ mills fall in the category of tumbling mills ?
A. Ball and pebble
B. Rod and tube
C. Compartment
D. All A., B. & C. - Colloidal mills are used for ______________ grinding?
A. Coarse
B. Intermediate
C. Fine
D. Ultrafine - Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should be multiplied with ______________ to get the same for dry grinding?
A. 1.0
B. 0.5
C. 1.34
D. 4.34 - Wet grinding in a revolving mill ______________ as compared to dry grinding ?
A. Gives less wear on chamber walls
B. Requires more energy
C. Increases capacity
D. Complicates handling of the product - A _____________ mill is a revolving mill divided into two or more sections by perforated partitions in which preliminary grinding takes place at one end and the finishing grinding at the discharge end?
A. Compartment
B. Tube
C. Rod
D. Pebble - In closed circuit grinding as compared to open circuit grinding, the_________________?
A. Specific surface of product is more
B. Product has lesser size uniformity
C. Production rate at a given limiting size is lower
D. Operation is economical
