The document describes the development of a new high-speed pin mill slurry-pot tester that enables testing materials at speeds up to 20 m/s using large abrasive particles up to 10 mm in size. Previous testers had lower speeds under 10 m/s and used smaller particles under 1 mm. The new pin mill configuration allows for testing of different materials, profiles, and abrasives. Initial tests showed large variability that was addressed through a sample rotation method, reducing standard deviation to under 1%. Tests on wear-resistant rubbers correlated with real-world applications.

1. New versatile pin mill slurry-pot
‘High speed slurry-pot type erosion wear tester’
Niko Ojala1*, Veli-Tapani Kuokkala1 and Kati Valtonen1, Päivi Kivikytö-
Reponen2 and Petri Vuorinen2
1Tampere University of Technology, Department of Materials Science,
Tampere Wear Center, P.O.Box 589, FI-33101 Tampere, Finland
2Metso Minerals Inc., Materials Technology Solutions, Tampere, Finland
*email: niko.ojala@tut.fi
Presented at
NORDTRIB 2012
Trondheim, Norway
12th – 15th June 2012

2. Motivation
Wear of components
Component lifetime
Service breakdowns
Major failures
Slurry-erosion wear
in slurry pumps
High velocities
Large particle sizes
[figure] R.J. Llewellyn, S.K. Yick, K.F. Dolman. Scouring erosion resistance of metallic
materials used in slurry pump service. Wear 256 (2004) 592–599.

3. Motivation
In industrial slurry pumping [1]:
• The speeds of the particles
can be up to 30 m/s
• The size of the particles can
vary from micrometers to
several centimeters
In the previous slurry-pot testers
• The speeds are often under
10 m/s
• The particle size under 1 mm
Inlet
Outlet
[1] Basics in Minerals Processing, 6th ed., Metso Minerals, 2008
[upper figure] http://www.mining-technology.com
[lower figure] http://www.metso.com/miningandconstruction

4. Development of the
testing method
Development of the high
speed slurry-pot tester
Overview to topics
The pin mill configuration

5. The pin mill configuration
• Slurry-pot testers are quite simple machines
• There are two distinct types of configurations
• Whirling disc/arm - vertical sample positions
• Pin mill – horizontal sample positions
Whirling disc slurry-pot [2]
[2] A.A. Gadhikar, A. Sharma, D.B. Goel, C.P. Sharma, Fabrication and Testing of Slurry Pot Erosion Tester.
Pin mill slurry-pot

6. Structure of pin mill slurry-pot
With the new pin mill
slurry-pot:
• Max 2000 rpm
(20 m/s sample tip
speed)
• Max 8/10 mm
abrasives

7. Characteristic features of high speed pin mill
configuration
• Velocity distribution over sample length
• Crushability of the abrasives
0
2
4
6
8
10
12
14
16
18
20
22
0 1 2 3 4 5 6
Peripheralspeed[m/s]
Sample length from the sample holder to the sample
tip [cm]
rpm: 2000 1750
0
20
40
60
80
100
0.1 1 10
%
Fraction [mm]
20 min 10 min 5 min
2 min 1 min original 8/10 mm
Velocity distribution over sample length
Abrasive crushability: size fractions after
several test runs

8. Development of the high speed slurry-pot tester...

9. Motor
Lid with
bearing
Slurry-pot
Cooling
coil
Sieves and
drainage
container
...and the current equipment

10. Versatile pin mill equipment
...high velocities...slurry-erosion wear
...many samples...erosiveness of different abrasives
Enables studies of... Enables use of...
...behavior of different materials ...large particle sizes
...different sample profiles

11. Development of the testing method
• Test materials
• AISI 316, round sample profile
• Two wear resistant rubbers, square sample profile
• Test parameters
• 2000 rpm for AISI 316
• 1750 rpm for rubbers
• Slurry:
• 1 kg, 8/10 mm granite gravel
• 10 l of water
• Concentration 9 wt. %
• Change of the slurry with
sample weighing
Figure. Sample levels (L1...L4).

12. 0
1
2
3
4
5
6
7
8
0 10 20 30 40 50 60
Cumulativemassloss[g]
Test time [min]
(L4) AISI 316-4
(L3) AISI 316-3
(L2) AISI 316-2
(L1) AISI 316-1
Longer run times
Fixed sample position test with AISI 316 samples
Fixed sample position tests have large
deviation of results...
The slurry is changed
after each
measurement!

13. time [min] AISI316-8 AISI316-7 AISI316-6 AISI316-5
0-5 L4 L3 L2 L1
5-10 L3 L2 L1 L4
10-15 L2 L1 L4 L3
15-20 L1 L4 L3 L2
Sample levels
Sample rotation scheme for AISI samples
...improving the testing method: ’Sample rotation’

14. 0
1
2
3
0 5 10 15 20
Cumulativemassloss[g]
Test time [min]
AISI316-8
AISI316-7
AISI316-6
AISI316-5
Sample rotation test with AISI 316 samples
Standard deviation with
•fixed sample positions up to ±40 %
•sample rotation under ±1 %
With sample rotation deviation in final results
shows lot smaller deviation
The slurry is changed
after each
measurement!

15. Sample rotation tests with wear resistant rubbers:
Results correlate with the real life applications
• Rubber A is ’normal’ wear resistant styrene-butadiene
rubber with shore A hardness of 60
• Rubber B is slurry-erosion resistant natural rubber with
shore A hardness of 50
• Tested at 1750 rpm for 4x20 minutes with 8/10 mm granite

16. Conclusions
• New high speed slurry-pot tester enables testing
• With high speeds, up to 20 m/s
• With large particle sizes, up to 10 mm
• Of different materials with various sample profiles
• Of erosiveness of different abrasives
10 mm

17. 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