wear
DESCRIPTION
WEARTRANSCRIPT
Product Handbook 9:1
Wear in operation
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BASICS IN MINERAL PROCESSING
IntroductionMineral processing activities unavoidably result in wear. And wear costs money.Often lots of money. This is related to the structure of rock, ore or minerals, beingcrystals normally both hard and abrasive.
Why wear at all?
Wear is caused by the normal rock stress forces
• Compression (1)
• Impaction (2)
• Shearing (3)
• Attrition (4)
in combination with mineral hardness and energy!
Wear in operation
COMPRESSION
protected by
METALS
ManganeseSteel
SLIDINGIMPACTIONLOW VELOCITY <7m/s
IMPACTIONHIGH VELOCITY >7m/s
Ni hardNi-Cr white iron
High CromeCr white iron
Polymers
Rubber
Polyurethane
CERAMICS
1 2
3 4
caused by
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COMPRESSION
Metals
ManganeseSteel
SLIDINGIMPACTIONLOW VELOCITY <7m/s
IMPACTIONHIGH VELOCITY >7m/s
Ni hardNi-Cr white iron
High CromeCr white iron
Wear by Compression
Applications:
CrushersGyratory
Cone
Jaw
Metals and compression
Manganese steel: The first option for compressionwear is manganese steel. This alloy has a very specialproperty, being self hardening and self healing whenexposed to large amounts of compression and impactenergy.Normal standard is a 14% Mn alloy which is firstoption in most crushing applications.18 % Mn alloy is a harder but also a more brittle alloyused in applications where the rock is softer (limitedself hardening) but very abrasive.Restrictions:When installed in applications without work hardeningservice life will be poor!
The alloys of cast ”white iron” type (High-chrome andNi- hard) shall be avoided in crushers submitted toheavy compression.
}COMPRESSION
Metals
ManganeseSteel
SLIDINGIMPACTIONLOW VELOCITY <7m/s
IMPACTIONHIGH VELOCITY >7m/s
Ni hardNi-Cr white iron
High CromeCr white iron
Applications:
Impactors
Grinding Mills
Slurry Pumps
HSI
VSI
Metals and impaction
The metals can be classified as:
Manganese: Needs high impaction for selfhardening. If impaction is getting lower andsliding is increasing Manganese is not suitable.High Chrome: Opposite to manganese, cantake heavy sliding but is more fragile andtherefore limited against impaction.Ni-hard: Somewhere between the two materialsabove.Cr-Mo: Used in grinding when High Crome is toobrittle
Note! The use of chrome steel (less brittle thanchrome iron) is increasing for liners, curtainsand hammers.
}
Wear by Impaction (high)
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COMPRESSION
Metals
Rubber
SLIDINGIMPACTIONLOW VELOCITY <7m/s
IMPACTIONHIGH VELOCITY >7m/s
Polyurethane
CERAMICS
Wear by Impaction (low)
Applications:Dump Trucks, Feeder hoppers,Transfer points, Grinding MillsSlurry pumps
Rubber and impactionFor low velocity impaction (material speedless than 7 m/s) SBR, styrene butadienerubber (60 ShA) is always the first choiceand will give the best cost effectiveness.The material is also very tolerant tomaterial size and is excellent for use ingrinding mills, dump trucks and primaryhoppers.
Restrictions:Look out for aromatic and fuel oils.Impact angles have to be considered, see9:4.
COMPRESSION
Polymers
Rubber
SLIDINGIMPACTIONLOW VELOCITY <7m/s
IMPACTIONHIGH VELOCITY >7m/s
Polyurethane
CERAMICS
Wear by Sliding
Applications:Chutes, Spouts
Rubber and slidingNatural rubber is an outstanding option for thesliding abrasion of small, hard and sharpparticles. Also for wet conditions.
Restrictions:If sliding speed is exceeding 7 m/s (dry appli-cations) temperature can start to rise andcause damage. Besides temperature oil isalways a threat.
Polyurethane and slidingBest option for tough sliding applications whenparticle size is lower than 50 mm. Excellent inwet applications. Tolerant to chemicals and oil.
Restrictions:Large sizes and high velocity might cause problems.
Ceramics and slidingThe natural choice when mission is too hard for the options above. Hardness,resistance to temperature and corrosion plus low weight gives a masterpiece forsliding.Al203 (Aluminium oxide) is the most cost-effective material.
Restrictions:Impaction is dangerous for ceramics (cracking) and must be avoided. Combinationceramics + rubber is an option. Composition and quality can vary from supplier tosupplier.
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Wear Protection – Wear Products
Modules
Rubber modulePolyurethanemodule
Ceramicmodule
Sheets, elements and profiles
Customized lining systems
>1000 >500 >100 >80 64 32 22 16 11 8 4 0 Size mm
100 micron
HEAVY IMPACT
IMPACT & SLIDING
SLIDING & IMPACT
SLIDING/ BUILD UP
Elements – Rubber
Square Modules– Rubber– Polyurethane– Ceramic
Sheeting– Rubber– Polyurethane
Low Friction
Wear products – applications
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100 micron
Heavy Impact – Selection
NGLD UP
Truck Box
Primary FeederHopper
Thickness
Rubber 60 Sh
Steel Backing
Size / Weight
Drop Height
=
&
Impact and Sliding – Selection (modules)
>1000 >500 >100 >80 64 32 22 16 11 8 4 0 Size mm
100 micron
>1000 >500 >100 >80 64 32 22 16 11 8 4 0 Size mm
Impact angle
Capacity
Size / Weight
Drop Height&
&
&
Ru
Pu
Ceram
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Impact and sliding – Selection (sheeting)
>1000 >500 >100 >80 64 32 22 16 11 8 4 0 Size mm
100 micron
Impact angle
Capacity
Size / Weight
Drop Height&
&
&
=
Sliding and build up – selection
>1000 >500 >100 >80 64 32 22 16 11 8 4 0 Size mm
100 micron
Thickness
MATERIAL THICKNESS
mm mm
<20 3 - 10
<35 10 - 25
<70 25 - 40
Low Friction Elements – UHMWPE**Ultra high Molecule Weight Poly Ethylene
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Wear Protection – Wear Parts
Wear parts – Screening
Self supportingrubber panels
Rubber & polyurethanetension mats
Rubber & polyurethanebolt down panels
Antiblindingrubber mats
Rubber / polyurethanemodular systems
Rubber linings Poly-MetTM linings OrebedTM linings
Steel linings Discharge systems Trommel screens
Wear parts – Grinding
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Tumbling mill – lining components
Lining life time – Standard Linings“ball park figures”
Type of mill Months
AG 12 – 24
SAG 3 – 12
Rod 6 – 24
Ball 6 – 36
Pebble 12 – 48
1. 2. 3. 4. 5.
6. 7. 8. 9. 10.
Lifter bars – rubber and compound
Auto
geno
us a
nd S
emi-a
utog
enou
s M
ills
Prim
ary
Bal
l M
ills
Rod
Mill
s
Seco
ndar
y B
all M
ills
Reg
rind
and
Peb
ble
Mill
s
Rubber Poly-MetHiCr HB 700
Poly-MetHiCr HB 700
Ow
erflo
w B
all a
nd R
od M
ills
Auto
geno
us M
ills
Poly-MetMartensitic steelHB 500
Sem
i Au
toge
nous
Mill
s
higherspeeds
lowerspeeds
higherspeeds
lowerspeeds
= mill rotation
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AG and SAG mills Rod mills
Dry: Metal (white iron700 Br)
Wet: Metal (white iron700 Br)or Poly Met (700 Br)
Dry: Metal (Cr-Mo350 Br)
Wet: Metal (Cr-Mo350 Br)or Poly Met(500 Br)
Dry: Metal (white iron 700 Br)Wet: Metal (white iron 700 Br)
Rubber and Poly Met,(Poly Met at mill ends)
Dry: Metal (or rubber if temperaturenot critical)
Wet: Rubber (Secondary and re-grind) Poly Met (700 Br)
Dry-rod: Metal
Dry-ball: Metal (or rubber iftemperature not critical)
Wet-rod: Metal
Wet-ball:Rubber
Tumbling mill liners– material
Ball and Pebble mills SRR mills
VERTIMILL® – Liners
Screw – metal with Nihard linersChamber – Orebed magnetic liner
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Wear parts – Slurry PumpsAlthough the size of solids in a slurry is smaller than the feed size to a crusher ora grinding mill, wear represents a high operation cost for slurry pumping. This isnaturally related to the high dynamic energy input in the form of high tip speed ofthe pump impeller causing both sliding and impaction wear.
Wear material vs size
Wear parts pumps –metal
High chrome iron (600Br) can be used at Ph down to 2.5. Standard wear materialfor most pump ranges.
Ni –hard with hardness exceeding 600 Bn used mainly as casing material forpumps in grinding circuits or dredging.
High density frozen Ni-hard with hardness up to 900 Bn used as casing materialin primary grinding circuits.
Manganese steel with hardness up to 350 Bn used for dredging applications.
Size 1m 1 dm 1 cm 1 mm 100 micron 10 micron 1 micron
LIM
IT F
OR
HYD
RAU
LIC
TR
ANSP
OR
T HIGH CHROME
LIM
IT F
OR
HAR
D IR
ON
S
LIM
IT F
OR
RUB
BER
LIN
ERS
LIM
IT F
OR
RUB
BER
IMPE
LLER
S
MANGANESESTEEL
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Material Physical Chemical Thermalproperties properties properties
Max. Wear Hot water, Strong and Oils, Highest serviceImpeller Tip resistance diluted acids oxidising hydro temp.(oC)
Speed acids carbons Contin. Occasion.(m/s)
Elasta family 27 Very good Excellent Fair Bad (-50) to 65 100
(Natural rubber)
MeroPrene 452 27 Good Excellent Fair Good 90 120
(Chloroprene type)
MeroLen 016 30 Good Excellent Good Bad 100 130
(EPDM type)
MeroTyle 30 Fair Excellent Good Bad 100 130
(Butyl type)
MeroThane 30 Very good Fair Bad Good 45-50 65
Polyurethane
Wear parts pumps – elastomers
Something About Ceramic LinersAlthough ceramics have high resistance against wear, temperature and mostchemicals, they have never really been accepted as day-to-day standards inSlurry Pumping.
Being both brittle and expensive to manufacture.
Development work on ceramics continue in an attempt to improve the possibleacceptance.
micron
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Wear in Slurry PipelinesIt is not easy to compare wear rates for different materials in a slurry pipelinedepending on variations in duty. As a guide the figures below can be used (BritishSteel Corporation test report).
Average wear rates given as loss of material in mm³ per hour at a given speedand slurry composition.
Material Average Relative wear ratewear rate (months)
Polyurethane 0,024 19,0
Rubber 0,033 13,8
Stainless steel 0,056 8,1
Alumina (97.5%Al2O3) 0,070 6,5
Cast iron(2.8% C, 2.0%Cr, 3.8%Ni) 0,287 1,6
Polyethylene 0,353 1,3
API steel 0,396 1,2
Mild steel 0,456 1,0
PVC 0,880 0,5
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