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__________________?

Related Mcqs:

1. 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

2. ____________ mills fall in the category of tumbling mills ?

   A. Ball and pebble
   B. Rod and tube
   C. Compartment
   D. All A., B. & C.

3. 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

4. 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

5. In a ball mill, the volume occupied by the balls (when the mill is stopped) is about _______________ percent of the volume of the mill?

   A. 35
   B. 50
   C. 70
   D. 85

6. Which of the following is not a revolving/tumbling mill used for size reduction ?

   A. Compartment mill
   B. Pebble mill
   C. Cage mill
   D. Rod mill

7. 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

8. For grinding of cereals, grains, spices, pigments, saw dust, cork etc., the most extensively used size reduction equipment is a__________________?

   A. Buhrstone mill
   B. Ball mill
   C. Crushing rolls
   D. Hammer mill

9. 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

10. 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