Latest study about effects of testing parameters with high speed slurry-pot wear tester. Parameters as speed, particle size and slurry concentration were tested. Study was presented at ITS 2013 symposium. More information about the tester at Tampere Wear Center: http://www.tut.fi/en/about-tut/departments/materials-science/research/research-equipment/wear-research/high-speed-slurry-pot/index.htm

1. The effect of test parameters
on large particle slurry
erosion testing
Niko Ojala1*, Kati Valtonen1, Pekka Siitonen2 and Veli-Tapani Kuokkala1
1 Tampere University of Technology, Department of Materials Science,
Tampere Wear Center, P.O.Box 589, FI-33101 Tampere, Finland
2 Metso Minerals, Inc., Tampere, Finland
*email: niko.ojala@tut.fi
ITS 2013
Luleå, Sweden
19th – 21st March 2013

2. Motivation
• In mining slurry handling
operations particle sizes
can be up to several
centimeters [1]
[1] Basics in Minerals Processing, 6th ed., Metso Minerals, 2008
[upper figure] http://www.mining-technology.com
[lower figure] http://www.metso.com/miningandconstruction
• But the slurry wear
research have been
often done with under 1
mm particles

3. Overview to topics
1) The equipment
2) The testing program
3) The results

4. High speed slurry-pot tester [2]
• Samples in the pin mill configuration
– Four sample levels
– Both half- and full-length
samples were used
– Sample rotation
[2] Ojala, N et al., High Speed Slurry-Pot Type
Erosion Wear Tester, The 15th Nordic Symposium on
Tribology - NordTrib 2012.
time [min]
0-5 L1 L2 L3 L4
5-10 L4 L1 L2 L3
10-15 L3 L4 L1 L2
15-20 L2 L3 L4 L1
One or two samples on one level
Sample levels

5. Three main parameters were
tested separately
• Sample speed
• Particle size
• Slurry concentration (total weight of the 8/10 mm abrasives)
main shaft sample tip size weight
Speed1 1000 rpm 10 m/s 8/10 mm 1 kg 9 wt% half
Speed2 1500 rpm 15 m/s 8/10 mm 1 kg 9 wt% half
Speed3 2000 rpm 20 m/s 8/10 mm 1 kg 9 wt% half
Size1 2000 rpm 20 m/s 4/6.3 mm 1 kg 9 wt% full
Size2 2000 rpm 20 m/s 6.3/8 mm 1 kg 9 wt% full
Size3 2000 rpm 20 m/s 8/10 mm 1 kg 9 wt% full
Weight1 2000 rpm 20 m/s 8/10 mm 1 kg 9 wt% half
Weight2 2000 rpm 20 m/s 8/10 mm 2 kg 16 wt% half
Weight3 1950 rpm 20 m/s 8/10 mm 3 kg 23 wt% half
Speed of Abrasive Slurry
concentration
Sample
lengthTest ID

6. 0
10
20
30
40
50
60
0 10 20 30 40
Massloss/numberofrotations
[µg]
Sample tip speed [m/s]
Mass loss per number of rotations
1 kg 8/10 mm granite, 10 l water, same
samples
Sample speed
• Higher speed means
higher mass loss, in
general
• With the large
natural abrasives,
the kinetic energy
competes with the
comminution of the
abrasives

7. 0
500
1000
1500
2000
2500
3000
3500
4000
0 2 4 6 8 10
Massloss/initialparticlecount
[µg]
Average original particle size [mm]
Mass loss per particle amount
2000 rpm, 1 kg granite, 10 l water,
same samples
Particle size
• Larger particles induce
more mass loss due to
– Higher kinetic
energy
– Durability of
comminution
2.90 2.94
3.13
0
0.5
1
1.5
2
2.5
3
3.5
4/6.3 mm 6.3/8 mm 8/10 mm
Averagemassloss[g]

8. 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
0.00 % 10.00 % 20.00 % 30.00 %
Massloss[g]
Slurry concentration [wt%]
Effect of slurry concentration
2000 rpm, 8/10 mm granite, 10 l
water, same samples
Slurry concentration
• Higher concentration induce more total mass loss due to
larger amount of particles
• But with high concentrations, particle to particle
collisions and embedding of the particles increase and
start to decrease the mass loss
0
500
1000
1500
2000
2500
0.00 % 10.00 % 20.00 % 30.00 %
Massloss/initialparticlecount
[µg]
Slurry concentration [wt%]

9. Wear surface
Sample tips after the tests with
23 wt% (left) and 16 wt% (right).
Wear surface after the test with the
23 wt% concentration

10. Wear surface
Short wear scars after 23wt% test
Embedded granite particle after 23wt% test

11. Concluding remarks
• With large abrasives, the particles kinetic
energy competes with the comminution of
the particles.
• Larger particles have more kinetic energy
and they endure comminution longer, causing
more mass loss by impact-abrasion.
• With higher slurry concentration protective
mechanisms as particle-particle interaction
and increasing particle embedding reduce
the mass loss.

12. Thank you for your attention!
Questions?
Niko Ojala
Research Scientist
Tampere University of Technology
Department of Materials Science, Tampere Wear Center
P.O.Box 589, FI-33101 Tampere, Finland
phone: +358 50 317 4516
email: niko.ojala@tut.fi
Acknowledgements