Production of aggregates

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Production of aggregates
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Where does gravel come from

• Mines rivers, banks, quarries
• Rivers use dragline to mine gravel from river
• Banks veins of gravel run thru a sand pit.
  Gravel mined by front end loader
• Quarries rock blasted from walls of quarry,
  loaded on trucks and crushed
• Most gravel needs to be crushed

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Rock Crusher

• Reduce gravel to a smaller size
• T 7-1
• F 7-1, 7-2
• Limemill makes lime
• Crusher output depends on crusher size and type,
  crusher settings, feed size, crusher speed,
  other operating conditions F 7-3
• T 7-2 T 7-3 specs
• Primary crusher first crusher in series
• Secondary tertiary crushers

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Feeders and Screens

• Feeders supply gravel to crusher
• Apron hopper box over plate feeder F 7-4
• Reciprocating plate
• Vibratory
• Belt uses hopper to feed belt
• Grizzly used over hoppers to remove oversize
  material series of bars

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Feeders and Screens

• Screens
• Separate aggregate by size for storage, blending,
  recrushing
• Rotating, vibrating (horizontal, inclined)
• Usually in a deck of 2 or more screens F7-5
• Scalping screen removes oversized materials
• Capacity based on
• Screen size, screen opening size, slope of
  screen, position in deck, amount of oversize and
  half size material, material conditions, shape,
  weight.
• F 7-6, Ex 7-1

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Crushing Cycle

• F 7-7
• Ex 7-2

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Washing Belt conveyor

• Need to wash aggregate before and after crushing
• Scrubber drums inclined revolving drum with
  fins and spray nozzles
• Wet screens screens with spray nozzles overhead
• Log washers revolving auger paddles in a tub of
  water
• Sand Dehydrators rotating augers in an inclined
  trough
• Clarifying tank takes water fines and
  clarifies water
• Belt conveyor major piece of equip in quarry
  carries aggregate from place to place
• Radial stacker conveyor on a pivot to rotate