Lecture 1
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Lecture 1






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Lecture 1 Lecture 1 Presentation Transcript

  • Prof.Dr.Salah Elmofty Ph.D.professor Material Technology DepartmentofMiningPetroleum&Metallurgical, Faculty Of Engineering E-mail:s_elmofty@hotmail.com
  • Lecture:1 Comminution
  • Comminution
    • -Ore minerals are usually finely disseminated and intimately associated with gangue minerals.
    • -These minerals should be liberated before concentration.
    • -This liberation accomplished by comminution.
  • - Communiation is one of the primary operations in mineral dressing Comminution Crushing Grinding
  • Crushing
    • Feed size ranging from 3” to 30” can easily be handLed
    The feedsize in all this cases varies from 1.5” to 6” Primary Secondary crushing crushing Jaw crushers & Gyratory crushers Cone crusher & Roll crusher
    • Blake crushers
    • These crushers built in many sizes
    -The largest boluldr is 4 feet in diameter -Smallest Takes feed around 3 to 4 inches
  • Primary crushers Jaw crushers Gyartory crusher
  • Blake crushers
    • Constraction:
  • Liners:
    • -The material used for lining the
    • jaw plates and check plates.
  • Jaw crushers:
  • Characteristics of jaw crushers:
    • 1 -They are working little than half the time.
    • 2 -Because of heavy flywheel and high speed of rotation they are favourable to more efficient action of jaw crushers .
    • 3 - Rate of oscillation of the moving crushing surface determines the machine capacity
    • ordinary taper 4.5 per foot
    • 4 -Have less capacity than gyratory crushers
    • 5 -Work in open circuit with double deck screen
  • Gyratory crushers
  • Characteristics of gyratory :
    • 1 -Capacity is greater than jaw crushers.
    • 2 -Required power less than jaw. crushers.
    • 3 -There is less vibration in operating.
  • Wich of the two following crushers we should choose for small capacity? & why?
    • Gyartory crusher
    Jaw crusher or
  • Jaw crusher is the better choice because of:
    • 1- Jaw crusher can take larger size than gyratory & is better adopted to handle clayey & spongy rocks.
    2- Gyartory crusher consume more power for the same feed as produces more new surfaces than jaw crusher . 3- Installation and housing costs will be more compared to jaw crushers.
  • Secondary crushers Cone crusher Roll crusher
  • Cone crushers
    • 1 -Cone crusher is secondary crusher.
    • 2 -Product of cone crusher is the feed of grinding mill.
    • 3 -It work in closed circuit with double deck screen.
    • 4 -Product is more uniform in size .
  • Cone crushers
  • Merits of cone crusher over gyratory
    • 1 -Cone crusher moves faster than gyratory.
    • 2 -Rapid discharge of crushed material due to increase space from top to bottom.
    • 3 -Hier capacity and reduction ratio than gyartory crushers.
    • 4 -Work in closed circuit.
  • Roll crusher
  • Roll crusher
    • 1 -Used for crushing relatively soft materials like coal & salt.
    • 2 -Capacity is high and reduction ratio is large.
    • 3 -Can not produce fine product owing to the spacing between adjacent teeth.
  • Angie of nip
    • .
    N E a a C D C,D Rolls E sphere of rocks N angle of nip
  • Comparison between roll & cone crushers:
    • 1 -Roll crusher production smaller of fines than cone crushers and smaller reduction ratio.
    • 2 -Rolls,because of theirinability to yield ahigh reduction ratio,have not been installed in recent years.
    • 3 -Reduction ratio for rolls should not exceed
    • 4:1 similar to cone crushers .
    • 4 -Rolls remain to be the best device for intermediate crushing.
  • THANK YOU Thank you Prepared by : Prof. Dr . SALAH ELMOFTY