Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per...

54
Crushing - Principles of Mechanical Crushing

Transcript of Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per...

Page 1: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crushing - Principles of Mechanical Crushing

Page 2: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Per Svedensten

Manager Crushing Chamber and Materials Development Product Development Center

Crushing (R&D) Master of Science in Mechanics,

specialized in mechatronics Ph.D 2007, Chalmers University

Partly funded by Sandvik Modeling, simulation and

optimization of crushing plants Technical-Economic

Optimization Sandvik employee since 2004

Page 3: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Objective

Explain the interaction between

rock material and

crusher

Page 4: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Take home messages

Page 5: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Agenda

Cone Crusher Operating Principal Crusher Operation Rock Breakage Behavior Crushing Forces Optimization and Crusher Performance Map Conclusions

NCC, Borås, Sweden

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Implem

entations

Scientific Approach

Hypothesis / System behavior

Prediction of performance

Utilize results for improvement

Choice of method and/or modeling Study and/or prediction of system behavior

Verification

Problem / Research Question

Customer Values

Page 7: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Cone Crusher

Why Cone Crusher? The cone crusher design

concept is an effective and smart way of realizing compressive crushing

Aggregate Production Mechanical Liberation of

Valuable Minerals

Page 8: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Product

Feed

Power

Operating Principle

Heat

Noise

Lube Oil

Hydraulic Oil

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Operating Principle

Page 10: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principle

Page 11: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principle

Page 12: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principal

Opening Phase = = Transport

Closing Phase = = Crushing

Page 13: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Transport

Crushing

Mantle Concave

Operating Principal

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Operating Principal

10 Indentations

Page 15: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crushing

Mantle Concave

Operating Principal

Transport

Page 16: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Mantle Concave

Crushing

s b

b: Bed Height s: Compression s/b: Compression Ratio

Operating Principal

Crushing Zone

Page 17: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Mantle Concave

Single Particle Breakage SPB

Inter Particle Breakage IPB

Operating Principal

Page 18: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principal

In a cone crusher the stones are crushed with both SPB and IPB as the material moves down through the chamber.

The relative amounts of IPB and SPB depends on factors like chamber design, crusher geometry, speed, css, eccentric throw, and others.

SPB IPB

Fines Less More Shape Flaky Cubic Force Low High

Page 19: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principal Capacity

Cross section area

0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.2 0.21 0.22-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

Yco

ordina

te [m

]

Area [m2]

Area function

Choke level

Page 20: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principals

0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.2 0.21 0.2-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2Nominal Cross-Sectional Area

Y-c

oord

inate

[m

]

Area [m2]

Choke level

Choke zone

Capacity

Page 21: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Operating Principals

Standard

Page 22: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher operation

As the market demand shifts can the crusher operation be modified? The crusher is likely to be installed for maximum production. Can it be

changed to maximum efficiency?

Understanding how breakage and capacity is effected by Eccentric Throw Speed Closed Side Setting

Page 23: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher operation

Running the crusher at different eccentric throws ECC 0.6” (16 mm) 51 tph

ECC 1.0” (25 mm) 75 tph

ECC 1.4” (34 mm) 97 tph

-0.08”: 16% 0.08”-0.5”: 80% +0,5”: 4% Fines/Product: 0.20

-0.08”: 19% 0.08”-0.5”: 74% +0,5”: 7% Fines/Product: 0.25

-0.08”: 20% 0.08”-0.5”: 73% +0,5”: 7% Fines/Product: 0.27

Page 24: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher operation

Running the crusher at different eccentric throws, CSS optimized

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

16 36

Prod

uctio

n [%

]

ECC [mm]

Product

Fines

Re-circulation

Page 25: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher operation

Running the crusher at different speeds

280 rpm 106 tph

360 rpm 104 tph

440 rpm 96 tph

-0.08”: 13% 0.08”-0.5”: 69% +0,5”: 18% Fines/Product: 0.19

-0.08”: 17% 0.08”-0.5”: 71% +0,5”: 12% Fines/Product: 0.24

-0.08”: 21% 0.08”-0.5”: 71% +0,5”: 8% Fines/Product: 0.30

Changing speed can have mechanical effects on the crusher and motor

Page 26: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Chamber Design Design drawings

Fine Coarse

Page 27: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher operation

Page 28: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher operation

Chamber selection

Fine Medium Coarse Extra Coarse

Page 29: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher Operation

Relation between CSS and Shape The size were the best shape

can be found is at CSS It is very difficult for cubical

stones larger then CSS to pass the chamber

Breakage of stones creates flaky particles. Smaller flaky stones will more easily find its way through the chamber

Flak

ines

s ind

ex [%

]

Particle size [mm]

Increasing CSS

Page 30: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher Operation

Relation between Feed size and Shape The greater reduction ratio the

worse particle shape. Inter particle breakage improves

shape. When crushing a bed of material weaker particles will break first. Flaky or elongated particles are weaker then round.

Breaking round particles gives flaky material.

Flak

ines

s ind

ex [%

]

Particle size [mm]

Increasing average feed size x

Page 31: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimum CSS

Reduction

Crusher Operation

Page 32: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Process Capacity

Design capacity: 200 tph Crusher Capacity: 300 tph Choke fed Crusher operation(300 tph): Material in surge bin runs out at even intervals Consequence: Crusher is operated choke fed 66% of total operating time feeding the screen with 300 tph Screen overload Solution: Adjust throw in order to reach 200 tph capacity

32

200

200

200

66% Capacity utilization

300

300

Page 33: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Rock Breakage Behavior

33

SPB IPB

Compression ratio Compression ratio Distribution width

Laboratory investigation of breakage modes Compressive crushing with hydraulic press.

Page 34: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Rock Breakage Behavior

Short fraction

Long fraction

Compression ratio

Packing limit

Sel

ectio

n

Page 35: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Rock Breakage Behavior

Dolerite Gneiss

Page 36: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crushing Force

s

b

b: Bed height s: compression s/b: compression ratio F: Force F = f(s/b, σ ) σ: Fraction length

F

F

Page 37: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crushing Force

( ) 2 2 2 2 21 2 3 4 5 6,p s a s a s a s a s a s a s

size distribution width

σ σ σ σ σ

σℵ ℵ ℵ ℵ ℵ ℵ ℵ ℵ ℵ ℵ ℵ ℵ

= + + + + +

=

Multi (inter) particle -pressure response

Packing!

Page 38: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crushing Force

( ) ( )321 2, kF s d d k s k s

s compression ratiod particle size

ℵ ℵ ℵ

= +

==

0 0.05 0.1 0.15 0.2 0.25 0.3 0.350

500

1000

1500

2000

2500

3000

3500

4000

quartzite 16-19 o tests - simulations

Single particle -force response

Forc

e [N

]

Compression ratio

Page 39: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Who is control of your process performance?

What tools have been provided to make the production efficient?

Page 40: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

The crushers are the last size reduction stage in the value chain.

Over crushing is common. The connection between crusher

setting and yield is often unknown

The rock cannot be repaired. We need to control the crusher

carefully.

Page 41: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Optimization of one parameter (CSS) can be done by sampling and analysis

The invested time and lost production will quickly be repaid by increased productivity

Combine product yield and economic aspects

This can be done by taking samples and making the analysis in MS Excel

Planning Sampling Analysis Optimization

Page 42: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Material from crusher is sampled Measure the capacity at each

crusher settings. CSS will effect the final product capacity, especially in a closed circuit.

Production of 4 valuable products 0.08-0.16’’ (2-4 mm) 0.16-0.32’’ (4-8 mm) 0.32-0.64’’ (8-16 mm) 0.64-0.87’’ (16-22 mm)

By-product with no value 0-0.08’’ (0-2 mm)

Planning Sampling Analysis Optimization

Page 43: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Run the crusher at different settings Take at least one sample at each

setting. (Multiple samples are often useful)

Special Attention to Safety when taking samples!!

Position of point were samples are taking.

Ensure that the conveyor will not start by accident.

Planning Sampling Analysis Optimization

Page 44: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Particle Size Distribution Plots If taking single samples on each

CSS the risk of getting inconsistent results might make the graph look strange.

Impossible to determine optimum setting by only using particle size distribution graphs

Planning Sampling Analysis Optimization

Page 45: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

If taking single samples on each CSS the risk of getting inconsistent results might make the graph look strange.

Impossible to determine optimum setting by only using particle size distribution graphs

Planning Sampling Analysis Optimization

Page 46: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

0

10

20

30

40

50

60

70

80

90

100

0.001 0.01 0.1 1 10

perc

ent p

assi

ng

sieve size ['']

Particle Size Distribution at CSS 0.79''

0,79

Optimization of a Final Crushing Stage

0

50

100

150

200

250

0.50 0.60 0.70 0.80 0.90 1.00

Capa

city

[tph

]

CSS ['']

Capacity and CSS

Planning Sampling Analysis Optimization

Combine the particle size distribution and capacity. Percentage of final product times the capacity gives the production capacity of

each product.

Example 0.08’’-0.16’’ mm at CSS 0.79’’: Percentage of crusher

production 20% - 11% = 9% Crusher capacity 193 tph

Total Production: 193 tph x 9% = 17 tph

Page 47: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Entering all the values into MS Excel makes this easy to get production capacities.

Still difficult to determine the optimal setting

Planning Sampling Analysis Optimization

Page 48: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

Use the price* per ton for all products: 0-0.08’’: $ 0 (by-product) 0.08-0.16’’: $ 12.30 0.16-0.32’’: $ 13.85 0.32-0.64’’: $ 16.90 0.64-0.87’’: $ 10.80

Make an income graph by

combining prices with capacity

Planning Sampling Analysis Optimization

*All prices are estimates based on publicly available data

Page 49: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Optimization of a Final Crushing Stage

What difference does it make?

Running the crusher 0.08’’ off: Decrease the profit by 58.5 $/h Running the crusher at 1600

hours per year: 58.5*1600=$93600

Planning Sampling Analysis Optimization

Page 50: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher Performance Map

Planning Sampling Analysis Optimization

Page 51: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

Crusher Performance Map

Page 52: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development
Page 53: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development
Page 54: Crushing - Principles of Mechanical Crushing · Crushing - Principles of Mechanical Crushing . Per Svedensten Manager Crushing Chamber and Materials Development Product Development

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