HPGR testwork

8/18/2019 HPGR testwork

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Council for Mineral Technology

An overview of HPGR testwork

program at Mintek5th June 2009

Johnny T. Kalala

Head of Comminution, Minerals Processing Division, Mintek


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• Introduction• HPGR’s on site at Mintek

• Key questions on HPGR

• HPGR testwork program – Development/ Improvement of test procedures

– HPGR operation

– Flowsheets development

– Modelling and simulations

– Downstream benefits

– HPGR control• Conclusion

Presentation overview


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HPGR is maturing to become a

competitive technology in designing

comminution circuits

Introduction

Motivation to implement a HPGRØ Improve Energy efficiency

Ø Cost reduction by not using grinding media

Ø Debottlenecking

Ø Metallurgical performance

Ø Differential comminution


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HPGR’s on site at Mintek

1. Polysius HPGRStudded rolls

Diameter=0.250 m

Width=0.100 mTop size: 12 mm


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Crushing in a HPGR

Feed

Product


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Ø Amenability of different ore type to HPGR?

Key questions

Throughput (t/h)

Ore competency

cost Morley (2006)

Ø Testing

ØQuantification of HPGR benefits

Does an open circuit HPGR do a better job than a modern closed circuit

cone crusher for tertiary crushing duties?

Does HPGR technology provide lower energy and steel consumption?

Does HPGR technology lead to better concentrate circuit grades and recoveries?

Ø Limitations of the technology

Does HPGR technology lead to better kinetic of flotation or leaching?


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1. Improved method for testing

ü Amount of sample to be used

ü Data recording

ü Sampling

2. Development of a flake competency index to

characterise the competency of HPGR flakes

3. Piston die compression test to predict HPGR

performance

4. Wear tests

HPGR testwork program

1. Testing: ore amenability


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1. Influence of operating variables

0

20

40

60

80

100

120

140

160

180

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00

Time[Seconds]

POWERFixedRoller [kW] POWERFloat. Roller [kW] PressureDE[bar] PressureNDE[bar] GapDE[mm] GapNDE[mm]

Typical HPGR test output

Hydraulic pressure

Power

Operating gap

I. Ore amenability


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2. Piston die compression test263g UG2 -12mm, compression at different forces

0

200

400

600

800

1000

1200

1400

1600

1800

0 1 2 3 4 5 6 7

Displacement, mm

A p p l i e d F

o r c e ,

k N

Max. Force 100kN2 500kN2 1700kN3

Input Energy, Nm 85.28 574.15 2519.16

Energy returned, % 7.2 23.7 48.4

RR50 1.4 2.8 5.3

Solid fraction 0.72 - 0.88

I. Ore amenability


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1

10

100

0.01 0.1 1 10 100

Particle mesh size [mm]

M a s s p e r c e n t a g e l e s s

t h a n s i z e

Feed

0.18 kW/t

0.33 kWh/t

0.69kW/t

0.89 kWh/t

1.26 kWh/t

1.54 kWh/t

1.98 kWh/t

Feed fit

0.18 kW/t fit

0.33 kWh/t fit

0.69kW/t fit

0.89 kWh/t fit

1.26 kWh/t fit

1.54 kWh/t fit

1.98 kWh/t fit

2. Piston die compression test

Merensky ore: top size 12 mm

I. Ore amenability


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3. Development of a “ Mintek” flake competency testHPGR flake deagglomeration using a scrubber: Kimberlite oreMerensky ore flake

Kimberlite flake after deagglomeration in a scrubber

Circuit used at Jwaneng

I. Ore amenability


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3. Development of a “ Mintek” flake competency test

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 2.0 4.0 6.0 8.0 10.0

Screening time (min)

% P a s s i n g

m e s h s i z

Merensky

Gold ore

Kimberlite

Influence of ore type on screening kinetic

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 2.0 4.0 6.0 8.0 10.0

Screening time (min)

% P a s i n g

m e s h s i z

HP90 %-3.35 mm

HP120 %-3.35 mm

HP60 %-3.35 mm

Influence of hydraulic pressure on

screening kinetic for a Merensky ore

I. Ore amenability


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0

5

10

15

20

25

30

35

40

45

50

0 1 2 3 4 5 6

Moisture (%)

W

e a r r a t e ( g / t )

UG2 (4 N/m m2) Merensky (4 N/m m2) UG2 (2 N/m m2) UG2 (6N/m m2)


I. Ore amenability

4. Wear test

UG2 and Merensky results on Polysius studded rolls


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II. Influence of operating conditions

Merensky, 1.85% Moisture, product size distribution

10

20

30

40

50

60

70

1 2 3 4 5 6 7 8

Specific press force, N/mm2

% l

e s s t h a n s i z e

% passing 75 microns % passing 300 microns % passing 600 microns


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III. Flowsheet development

Comminution circuit without using steel as grinding media

1 - HPGR feed

2 - HPGR discharge

3 - Repulper dilution

4 - Flash float feed

5 - Flash f loat concentrate

6 - Flash f loat tails

7 - Primary mill discharge8 - Primary float dilution

9 - Primary float feed

10 - Primary float concentrate

11 - Primary float tails

HPGR

0.6 mm

mesh

(-70+25) mm

pebbles

AG mill

Pebble mill

Primary

float

ROM

feed

Water

Secondary

float

Dewatering

hydrocyclone

(-70+0.6) mm

Pebbles + sand


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Ø Assessing HPGR benefits as a tertiary crusher in comparison to modern

cone crusher choke fed


Action in a cone crusher Action in a HPGR


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Ø Assessing HPGR benefits as a tertiary crusher in comparison to modern

cone crusher choke fed

HPGR

Repulper Flash float Primary ball mill

1

2

3

4

10

5

6 7

8

9

1 - HPGR feed

2 - HPGR discharge

3 - Repulper dilution

4 - Flash float feed

5 - Flash float concentrate

6 - Flash f loat tails

7 - Primary mill discharge

8 - Primary float dilution9 - Primary float feed

10 - Primary float concentrate

11 - Primary float tails

11

Basic Northam circuit


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IV. Modelling, simulation and scale up

Objectives:

- Development of steady state and dynamic model for HPGR

- Scale-up from HPGR laboratory test and compression tests

- Plant surveys


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V. Downstream benefits

Objectives: Quantification of HPGR downstream benefits

Ø Milling

- Reduction of spec. energy consumption

- Reduction of BBWI

Ø Flotation and leaching- Faster kinetic

- Better recovery

Ø Mineralogy

- Liberation

- Quantification of microcracks


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Objectives: Improve HPGR performance by providing better control

Ø Maintain throughput by changing roll speed

Ø Maintain or avoid cake formation

Ø Control the quality of HPGR product by changing on line the split between

edge and centre productØ Maintain an autogenous layer on HPGR to minimize wear

VI. HPGR control


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The future of the HPGR depends on

progress made to improve the current

understanding of the technology and on

our ability to exploit all benefits provided.

Conclusion

Current limitations of the technology:Ø Feed top size ( ~ 80 mm)

Ø Feed moisture

Ø Product size distribution

Ø Classification of HPGR product

ØCapacity

ØWear rate


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• Mintek

• Polysius

• IMS

• Comminution group, Minerals ProcessingDivision

Acknowledgements


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www.mintek.co.za

Thank you

Documents

HPGR testwork