aggregate grinding
DESCRIPTION
Aggregate Grinding EquipmentTRANSCRIPT
EQUIPMENT FOR
PRODUCTION OF
AGGREGATE
AGGREGATE
Crusher Feeder Screening Handling
CRUSHED-STONE AGGREGATEAND
STONE CRUSHERS
A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, or rock dust.
CLASSIFICATION
Primary Crusher Secondary Crusher Tertiary Crusher
TYPER OF CRUSHER
Jaw Gyratory Hammer Mill Cone Impact
JAW CRUSHER
It consist of set of vertical jaw• Fixed jaw• Movable jaw
Movable jaw which moves back and forth relatively
Manganese steel
Single and double toggle jaw crushers are constructed of heavy duty.
high strength design to accept high power draw
Double Toggle jaw crushers, hydraulic toggle adjusting mechanisms.
JAW CRUSHER
GYRATORY CRUSHER
consisting of a concave surface and a conical head; both surfaces are typically lined with manganese steel.
the movement is generated by an eccentric arrangement
used for primary or secondary
It is designed in size either by the gape and mantle diameter or by the size of the receiving opening.
ILLUSTRATION
short-shaft suspended spindle typemain shaft is suspended at the top
and that the eccentric is mounted above the gear
long-shaft suspended spindle typemain shaft is suspended at the top
and that the eccentric is mounted below the gear
HAMMER MILL
It is other wise called GRINDING MILL
Earlier functionHandAnimalWaterwind
PURPOSES IN ENGINEERING
Following:increase of the surface area of a solidmanufacturing of a solid with a desired
grain sizepulping of resources
GRINDING LAWS
KICK for d > 50 mm
BOND for 50 mm > d > 0.05 mm
RITTINGER for d < 0.05 mm
To calculate the grinding work against the grain size
W = grinding work in kJ/kg, c = grinding coefficient, dA = grain size of the source material dE = grain size of the ground material. A reliable value for the grain sizes dA and dE is d80. Value signifies that 80% (mass) of the solid matter has
a smaller grain size.
With the limits of Bond's range: upper dBU = 50 mm and lower dBL = 0.05 mm
To calculate the KICK's and RITTINGER's coefficients
GRIDING DEGREE Grinding degree referring to grain size d80
Instead of the value of d80 also d50 or other grain
diameter can be used. Grinding degree referring to specific surface
The specific surface area referring to volume Sv and
the specific surface area referring to mass Sm can be found out through experiments.
Pretended grinding degree The discharge die gap a of the grinding machine is
used for the ground solid matter in this formula.
TYPES OF GRINDING MILL
Ball Mill Rod Mill SAG Mill Autogenous Mill Pebble Mill Buhrstone Mill
CONE CRUSHER
similar in operation to a gyratory crusher
with less steepness in the crushing chamber
more of a parallel zone between crushing zones
suitable for crushing varies of mid-hard and above mid-hard ores and rocks
ADVANTAGES
Most reliable construction High productivity Easy adjustment Less cost in operation
IMPACT CRUSHER
Involve the use of impact rather than pressure to crush material
usually used with soft and non-abrasive material such as coal, seeds, limestone, gypsum or soft metallic ores
TYPES OF IMPACT CRUSHER
Horizontal shaft impactor
Vertical shaft impactor
HORIZONTAL SHAFT IMPACTOR
It is fixed upon the outer edge of a spinning rotor.
use of HSI crushers is limited to soft materials and non abrasive materials, such as limestone, phosphate, gypsum, weathered shale's
to crush a mile (or 1.6 km) windrow of material in a single day.
VERTICAL SHAFT IMPACTOR
VSI crushers use a different approach involving a high speed rotor with wear resistant tips and a crushing chamber designed to 'throw' the rock against
CONTROLLED
the velocity at which the rock is thrown against the anvil.
the distance between the end of the rotor and the impact point on the anvil.
FEEDER
It help mainly in handling the input material for the plant
They are two typeApron feederMechanical or reciprocating plate
feeder
APRON FEEDER
It is an heavy-duty construction to take shock from racks dumped directly on them
It consist of a series of overlapping pans.
Widths of feeder range from 01-15ft & lenghts vary from 01-0f times of width.
FORMULA
hourtonsDW
q /4800
Where,q = capacity of the feeder, W = tray width, inD = material depth, in = density of the material, lb/cu ft = material flow velocity, ft/min
The flow velocity depends on the method for loading the feeder – is it fed through a hopper
The velocity is also dependent on the material characteristics, size distribution and moisture content, as well as the slope of the feeder.
The only way to determine the value for is by actual observation and then the feeding rate may vary considerably.
An even flow of material to the primary crusher. The size of the feeder and its speed should
provide a capacity 25-35% greater than the capacity to regulate the feeder in the case of irregular dumping of the raw material.
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