How To Select Crusher Wear Materials Properly
The credit crunch is now is the house, the law of nature have taken over, 'only might Joe will survive'. That is 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.
Tips for prolonging jaw crusher wear-part life.
(1) Keep crusher jaws tight and centred
(2) Reverse jaws more than once to even out wear.
(3) Reposition the toggle to a lower setting to minimise abrasion of jaw liners.
Tips for prolonging the dynapactor and impactors wear-part life.
(1) Hardsurface frequently to minimize distortion or metallurgical problems.
(2) Maintain sleeves in dynapactors to allow distribution of wear.
(3) 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.
(1) Install and back mantles and concaves properly and completely to ensure good support and maximum life.
(2) Hardsurface the concaves to prolong wear.
(3) Install metal detectors to minimize introduction of tramp metal.