HW_No_2-S2015
2
HW No 2 Q1. Trap rock is crushed in gyratory crusher. The feed is nearly uniform 2-in spheres. The differential screen analysis of the product is given in the table below in column 1. The power required to crush this material is 400 kW. Of this 10 kW is needed to operate empty mill. By reducing the clearance between crushing head and the cone, the deferential screen analysis of the product becomes that given in column 2 of the table below. Using the bond method, estimate the work necessary per ton of rock in both first and second grind mesh Product First grind Second grind 4/6 3.1 6/8 10.3 3.3 8/10 20 8.2 10/14 18.6 11.2 14/20 15.2 12.3 20/28 12 13 28/35 9.5 19.5 35/48 6.5 13.5 48/65 4.3 8.5 -65 0.5 65/100 6.2 100/150 4 -150 0.3 Q2. A material consisting originally of 25 mm particles is crushed to an average size of 7 mm and requires 20 kJ/kg for this size reduction. Determine the energy required to crush the material from 25 mm to 3.5 mm assuming a) Rittingers law, b) Kick's law c) Bond's law
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Transcript of HW_No_2-S2015
HW No 2
Q1. Trap rock is crushed in gyratory crusher. The feed is nearly uniform 2-in spheres. The differential screen analysis of the product is given in the table below in column 1. The power required to crush this material is 400 kW. Of this 10 kW is needed to operate empty mill. By reducing the clearance between crushing head and the cone, the deferential screen analysis of the product becomes that given in column 2 of the table below. Using the bond method, estimate the work necessary per ton of rock in both first and second grind
mesh ProductFirst grind Second grind
4/6 3.16/8 10.3 3.38/10 20 8.210/14 18.6 11.214/20 15.2 12.320/28 12 1328/35 9.5 19.535/48 6.5 13.548/65 4.3 8.5-65 0.565/100 6.2100/150 4-150 0.3
Q2. A material consisting originally of 25 mm particles is crushed to an average size of 7 mm and requires 20 kJ/kg for this size reduction. Determine the energy required to crush the material from 25 mm to 3.5 mm assuming
a) Rittingers law,
b) Kick's law
c) Bond's law
Deadline 8/03/2015
