technical NOTES

If high Limestone crusher capacity required to full fill the plant requirement, where
single Limestone crusher capacity is not sufficient, only in that case secondary
crushing with screening arrangement shall be considered.

If desired output size is considered as 0-25mm for an input size of 2000mm,
for the same type of limestone as above, then requirement of secondary crushing
with impact crusher or Hammer crusher arises.

2.3 Type of Raw Grinding Equipment
Various raw grinding equipment require different sizes of input material varying
from <50mm to 90 mm max. Accordingly crusher is selected to achieve the
desired output size of the product.
The vertical roller mills will accept the input size as 90 %< 70mm and up to a
maximum of 90mm. For this type of grinding, impact crusher or Hammer crusher
with screen are the suited options.

The requirement of Wobbler feeder or suitable screen shall be considered based
on raw material properties (i.e. fragmentation during blasting) to segregate
fine and clay components. For new mines wobbler should be considered as material
properties are unknow.

The roller press will accept the input size less than 65mm. For this type of
grinding, impact crusher with screen or hammer crusher are good options.

2.4 Feed Size and Output Size
Various crushers are designed for various reduction ratios and accordingly the
feed size and the output size of material is governed by their design. The basic
requirement of feed and output sizes for different type of crusher is listed in
comparative table.

2.5 Achievable Operating Capacity of Crusher
The operating capacity of different type of crushers varies from <1000 TPH to
<2500 TPH. For example, the Jaw crusher the achievable capacity is less than
1000 TPH, so above 1000 TPH Jaw crusher is not suitable selection.

2.6 Basic Selection Criteria for Different types of Crushers:

Parameters Hammer Crusher Impact Crusher Jaw Crusher Roll Sizer

Physical

Properties

Suitable for Soft

material like

wet and sticky

combined with

clay.

Suitable for

comparatively

hard, mildly

abrasive and

non-sticky

material.

Suitable for

extremely hard,

mild abrasive,

not sticky and

highly siliceous

material.

Suitable for

hard, Wet and

highly sticky

material

combined with

clay.