Lecture 1


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Lecture 1

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