A ball mill is a type of grinder that is efficient for grinding materials into fine powder. It works by using impact and attrition between rapidly moving balls and powder materials inside a hollow cylinder. At low speeds, attrition is the dominant mechanism of size reduction, while at higher speeds impact becomes more important. Ball mills consist of a hollow cylinder lined with resistant material and partially filled with balls to grind materials through impact and attrition. They are useful for both wet and dry grinding processes.

1. PREPARED BY: AMARESH MANNA
BALL MILL

2.  It is efficient tool for grinding many materials into fine powder.
 There are two types of grinding, the dry process and wet process.
 A ball mill is a type of grinder used to grind and blend materials for use in
mineral dressing processes, paints, pyrotechnics, ceramics and selective laser
sintering.
 The ball mill works on the impact and attrition between rapidly
moving ball and powder materials which are enclosed in hollow
cylinder.
 In ball mill, at low-speed ball role over each other causing attrition.
Thus, in ball mill both impact and attrition is responsible for size
reduction.
PRINCIPLE:
INTRODUCTION:

3.  Ball mill consist of a hollow cylinder,
which is made up of metal.
 The inner surface of hollow cylinder
is lined with a resistant material such
as rubber.
 It is partially filled with balls. Balls
occupy 30-50% of the mill volume.
 These balls are made up of chrome
steel, stainless steel or rubber.
 The weight of balls is kept constant.
 The ball size depends on the size of
the feed and the diameter of the mill.
BALL MILL
CONSTRUCTIONS:

4. The feed material is placed into the cylinder up to 60% of the volume.
A fixed number of balls is introduced and the cylinder is closed.
At low speeds, the balls roll over each other and attrition will be the
predominate mode of action.
At still higher speeds, the balls will be thrown out to the wall by centrifugal
force and no grinding will occur.
At optimum for correct speeds, the centrifugal force just occurs, as a result the
balls are picked up by the mill wall and carried nearly to the top, where they
break contact with the wall and fall to the bottom.
Low Speed Higher Speed Correct Speed
WORKING:

5. 1. It can produce very fine powder.
2. Ball mill is used both wet and dry grinding processes.
3. The costs of installation, operation and labour are low.
4. Contamination is not possible.
5. Suitable for both batch and continuous operations.
6. Completely enclosed from which is suitable for toxic materials.
1. It consumes more power and expensive.
2. It is very noisy machine.
3. Ball mill is a slow process.
4. Soft and sticky material cannot be milled by ball mill
5. At low speed, the balls will slide or roll over each other and
only negligible amount of size reduction will occur.
6. At high speed the balls will be thrown out to the wall by
centrifugal force and no grinding will occur.
ADVANTAGES:
DISADVANTAGES:

6.  It produces very fine powder.
 Used for grinding of wetting and drying powder.
 It is used for production of ophthalmic parenteral products.
 Ball mill at low speeds is used for milling dyes, pigments and
insecticides
Pharmaceutical Engineering (principles & practices) by C.V. S
Subrahmanyam, J. ThimmaSetty, Sarasija Suresh and V. Kusum Devi
APPLICATION:
REFERENCES: