subject: Jaw crusher good practice [print this page] Jaw crusher good practice Jaw crusher good practice
Jaw crushers should be fed a consistent rate of feed that will result in the crushing chamber being kept full at all times. This will result in more stone-on-stone crushing, reducing the wear on the (jaw die) manganese wear plates, creating a more cubical product, and result in more even wear over the length of the jaw die
Generally all material smaller than the discharge gap should be removed (scalped) of prior to being fed into the jaw crusher. This will increase the tons per hour of total production by the plant, and reduce wear on the jaw dies. It will also reduce fines production and increase cubical product.
A jaw crusher should not be sized to the maximum size rock that might be fed to the plant, but a size that will handle 95-98% of the material that might be fed to the jaw. Buying to the maximum size of rock that might be fed the jaw will result in buying a jaw crusher that will be under-utilized, difficult to keep choke-fed, cost more than necessary, and have a much higher operating cost. It will cost less to install grizzly bars over the feed hopper to remove the oversize rocks than to buy an over-sized jaw crusher. They can then be manually broken, sold as rip-rap or erosion control or landscaping boulders.
Jaw crushers are typically used as primary crushers, or the first step in the process of reducing rock. They are considered a compression type of crusher. The rock is dropped between two rigid pieces of metal, one of which then moves inwards towards the rock, and the rock is crushed because it has a lower breaking point than the opposing metal piece. The actual metal that contacts the rock is made of a manganese alloy. Manganese has the characteristic of "work-hardening", meaning it becomes stronger and more resistant to wear the more stress it is subjected to. Not all manganese jaw plates are the same, with some having different percentages of manganese and different levels of quality-control in the manufacturing process. They are also referred to as jaw dies, jaw plates, wear surface, and just manganese.
