# multiple choice

• The operation of the cyclone causes particles that have a greater mass to move __________ towards the high-velocity rotating wall.
 outward inward across slowly

4 points

Question 2

1. All of the following are used to move refuse EXCEPT:
 rubber-belted conveyors. live-bottom hoppers. screw conveyors. leachate.

4 points

Question 3

1. Determine the capacity of a roll crusher. The separation is 7 mm, speed of the rollers is 50 rpm, roller diameter is 23 cm, roller length is 0.4 m, and material density is 2.9 g/cm3.
 5.6 tonne/hr 560 tonne/hr 5600 tonne/hr 560,000 tonne/hr

4 points

Question 4

1. A(n) __________ is a device that achieves the separation of less dense from more dense particles by using the differences in their abilities to penetrate a shaking bed.
 jig air purifier sink separator air classifier

4 points

Question 5

1. Consider a binary separator used to separate aluminum cans from glass. A total mass of 0.8 tonne/hr enters. It is desired to have all aluminum go to output 1 and all glass to output 2, but the separator isn’t perfect. If 0.4 tonne/hr of aluminum goes to output 1 and 0.1 tonne/hr of aluminum goes to output 2, what is the recovery of aluminum?
 50% 63% 80% 100%

4 points

Question 6

1. All of the following are forms of size reduction in solid waste management EXCEPT:
 shearing. shredding. grinding. picking.

4 points

Question 7

1. A 2 ft diameter trommel screen is used to separate municipal refuse. Estimate its critical speed.
 0.90 rpm 38 rpm 49 rpm 54 rpm

4 points

Question 8

1. An experiment is conducted to determine the drag coefficient for an air flow/sink separator used to suspend metal particles. The particles have a density of 3.1 g/cm3. The air has a density of 0.0012 g/cm3. The measured velocity is 1600 cm/s. The particles are 2.5 cm diameter spheres. What is the drag coefficient?
 0.033 0.82 3.29 5270

4 points

Question 9

1. Shredding municipal solid waste prior to landfilling is preferable to leaving it unshredded for all of the following reasons EXCEPT:
 shredded particle sizes are more uniform. shredded material decomposes more quickly. shredded material is fairly homogeneous. shredded material does not require an earth cover.

4 points

Question 10

1. Two methods that are presently used to reduce the damage when explosions occur in refuse shredders are:
 dynamite and gunpowder. gasoline and gunpowder. venting and flame suppression. dynamite and venting.

4 points

Question 11

1. Identify and define the two types of separators used in separating various pure materials from a mixture. How is each one effective?

Your response should be at least 200 words in length.

Path: p

Words:0

30 points

Question 12

1. Explain how magnets are used as electromechanical separators. Describe their usage in detail, and explain some potential problems with their usage. What are some advantages?

Your response should be at least 200 words in length.

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