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Beating The Credit Crunch - Selection of Crusher Wear Materials.The credit crunch is now is the house, the law of nature have taken
over, "˜only might Joe will survive'. That's a fact disputed by some
including me. More mining companies will survive only if they can learn
from the "˜chameleon'. Mines need to adapt to the prevailing world
economic conditions, only then can they out-fox the thief (credit
crunch) at its game. At the back drop of the credit crunch and mining
of more complex ores, a new look at the selection of wearing parts used
in the mineral processing industry becomes a matter of life and death
for some mining companies.There are a number of factors which
play a hand in wear material usage including but not limited to
Cost/Wear ratio, downtime and material availability. It is only logical
to say the greatest wear comes from moving parts of the primary and
secondary crushing and milling equipment. Parts of particular concern
are the mantle, bowl liners, segmental concaves, and the movable and
stationary jaw plates of the jaw crushers.Wear properties of
paramount importance include abrasion resistance (influenced strongly
by carbon content in ferrous materials) and toughness (a measure of
resistance to impact). However during selection care needs to be taken
due to complications arising from the inversely proportional
relationship between abrasion resistance and toughness. It is crucial
that reliability engineers optimise between the two properties
(abrasion resistance and toughness) for each service. In
situations where ore characteristics dictates server-crushing use of
high alloy (10-15%) austenitic manganese steels continue to
predominate. In most circumstances where there is repeated and severe
crushing impact the properties of austenitic Mn steel (including a high
degree of fracture toughness, harden-ability, adequate abrasion
resistance, gouging resistance and moderate cost) comes in to save the
day. When it comes to harden-ability other elements as C, Mo, Cr, Si
and Ni also plays a lesser hand than Mn.Turn around time play a
big role in material selection. Turn around time of wear parts orders
are not always what the engineers expect, a lot of crushing plants have
had to be stopped due to wear parts shortage. It is advisable to plan
for longer lead times in consultation with the suppliers. As usual
failure to plan is planning to fail. Below I have detailed
(practical and easy to implement) tips from my experience in the mine
industry which will help prolong crusher wear-part life.Tips for prolonging jaw crusher wear-part life.(a) Keep crusher jaws tight and centred(b) Reverse jaws more than once to even out wear.(c) Reposition the toggle to a lower setting to minimise abrasion of jaw liners.Tips for prolonging the dynapactor and impactors wear-part life.(a) Hardsurface frequently to minimize distortion or metallurgical problems.(b) Maintain sleeves in dynapactors to allow distribution of wear.(c) Consult the manufacturer on the lowest speed consistent with obtaining desired product and minimum wear for impactors.Tips for prolonging the gyratory crushers wear-part life.(a) Install and back mantles and concaves properly and completely to ensure good support and maximum life.(b) Hardsurface the concaves to prolong wear.(c) Install metal detectors to minimize introduction of tramp metal.
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